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Author SHA1 Message Date
06678a5888 #1617 update license headers 2021-01-24 20:07:40 +02:00
11d0912c6e #1617 merge dto pattern examples 2021-01-24 19:57:21 +02:00
3adc3cda05 update gitignore (#1632)
.checkstyle files are being tracked which should not be
2021-01-24 11:17:05 +02:00
18a1a725ee #1469 Add lambda expressions implementation for Strategy Pattern (#1631)
* #1469 Add Strategy Pattern lambda implementation

After Java 8.
Also take advantage of enum

* #1469 Update class diagrams

* #1469 Update README.md

Add lambda programmatic example

* #1469 Remove unused imports

Co-authored-by: Subhrodip Mohanta <subhrodipmohanta@gmail.com>
2021-01-19 12:06:26 +05:30
25ed2540f4 docs: add demirhalil as a contributor (#1630)
* docs: update README.md [skip ci]

* docs: update .all-contributorsrc [skip ci]

Co-authored-by: allcontributors[bot] <46447321+allcontributors[bot]@users.noreply.github.com>
2021-01-16 21:00:23 +02:00
aa46e119d6 Fix flag image size 2021-01-16 20:55:20 +02:00
7e56491e92 #1625 Turkish translation - initialization part (#1629)
* #1625 init Turkish translation and add the flag

* #1625 update the Main README.md for Turkish translation

* #1625 add Turkish translation for README.md

Co-authored-by: Halil Demir <halil.demir@zalando.de>
2021-01-16 20:49:35 +02:00
6918a4bac2 docs: add ignite1771 as a contributor (#1626)
* docs: update README.md [skip ci]

* docs: update .all-contributorsrc [skip ci]

Co-authored-by: allcontributors[bot] <46447321+allcontributors[bot]@users.noreply.github.com>
Co-authored-by: Subhrodip Mohanta <subhrodipmohanta@gmail.com>
2021-01-13 13:31:11 +05:30
dea7ecfb7a #1317 Special Case Pattern (#1624)
* #1317 Add Special Case Pattern

To focus on pattern itself, I implement DB and
maintenance lock by the singleton instance.

* #1317 Add special cases unit tests

Assert the logger output
(ref: https://stackoverflow.com/a/52229629)

* #1317 Add README.md

Add Special Case Pattern README

* #1317 Format: add a new line to end of file

Co-authored-by: Subhrodip Mohanta <subhrodipmohanta@gmail.com>
2021-01-13 13:06:21 +05:30
bbc4fdfc24 docs: add tkhadir as a contributor (#1623)
* docs: update README.md [skip ci]

* docs: update .all-contributorsrc [skip ci]

Co-authored-by: allcontributors[bot] <46447321+allcontributors[bot]@users.noreply.github.com>
Co-authored-by: Subhrodip Mohanta <subhrodipmohanta@gmail.com>
2021-01-04 19:42:58 +05:30
829cd41455 #1620 french translation - initialization part (#1622)
* 🚀 init fr translation

* #1620 evo add french translation - main part

* #1620 evo add french translation - main part

* #1620 evo french translation - add french flag

* Update README.md

* Update README.md

* #1620 add cn and kr flags

* Update README.md

* Update README.md

* Update README.md

* Update README.md
2021-01-04 19:27:32 +05:30
85a05dd718 docs: add warp125 as a contributor (#1619)
* docs: update README.md [skip ci]

* docs: update .all-contributorsrc [skip ci]

Co-authored-by: allcontributors[bot] <46447321+allcontributors[bot]@users.noreply.github.com>
2020-12-20 20:20:51 +02:00
0c66e48d81 README.md translated into Korean (#1582)
* Translate README.md via GitLocalize

* Translate README.md via GitLocalize

* Update README.md

* Translate README.md via GitLocalize

* Update README.md

* Update README.md

* Update README.md

* Update README.md

* Update README.md

* Update README.md

* Translate README.md via GitLocalize

* Update README.md

* Update README.md

* Update README.md

* Update README.md

* Update README.md

* Translate README.md via GitLocalize

* Update README.md

* Update README.md

* Update README.md

* Update README.md

* Update README.md

* Update README.md

* Update README.md

* Translate README.md via GitLocalize

* Update README.md

Co-authored-by: mt-gitlocalize <mt@gitlocalize.com>
2020-12-20 20:18:23 +02:00
801006337a docs: add ruchpeanuts as a contributor (#1618)
* docs: update README.md [skip ci]

* docs: update .all-contributorsrc [skip ci]

Co-authored-by: allcontributors[bot] <46447321+allcontributors[bot]@users.noreply.github.com>
2020-12-13 17:35:37 +02:00
2aa4c963eb Update README.md (#1598)
Factory method is updated with real world examples
2020-12-13 17:33:43 +02:00
8632962362 docs: add siavashsoleymani as a contributor (#1616)
* docs: update README.md [skip ci]

* docs: update .all-contributorsrc [skip ci]

Co-authored-by: allcontributors[bot] <46447321+allcontributors[bot]@users.noreply.github.com>
Co-authored-by: Subhrodip Mohanta <subhrodipmohanta@gmail.com>
2020-12-09 13:11:15 +05:30
5bc61c8c28 #1569 DTO pattern implementation using Enums (#1570)
* #1569 DTO pattern implemented using Enums

* #1569 DTO pattern implemented using Enums

* #1569 adding some java docs

* #1569 some changes in java doc and code style

* #1569 some changes in java doc and code style

* #1569 some changes in java doc and code style

* #1569 some changes in java doc and code style

* #1569 adding suggested extra line

* #1569 license added to pom.xml

* #1569 more checkstyle problems resolved

* #1569 more checkstyle problems resolved

* #1569 more checkstyle problems resolved

Co-authored-by: siavashsoleymani <siavash.soleimani@snapp.cab>
Co-authored-by: Subhrodip Mohanta <subhrodipmohanta@gmail.com>
2020-12-09 12:51:24 +05:30
a94615ac54 docs: add viveksb007 as a contributor (#1613)
* docs: update README.md [skip ci]

* docs: update .all-contributorsrc [skip ci]

Co-authored-by: allcontributors[bot] <46447321+allcontributors[bot]@users.noreply.github.com>
2020-12-08 10:58:39 +05:30
14c4710435 Implemented Registry pattern (#1543)
* #1310 Implemented registry pattern

* fixed parent pom version

* added empty line in registry.urm.puml

Co-authored-by: Subhrodip Mohanta <subhrodipmohanta@gmail.com>
2020-12-08 10:34:42 +05:30
428cbc1027 docs: add jeff303 as a contributor (#1612)
* docs: update README.md [skip ci]

* docs: update .all-contributorsrc [skip ci]

Co-authored-by: allcontributors[bot] <46447321+allcontributors[bot]@users.noreply.github.com>
2020-12-07 20:25:59 +02:00
a118a995ec docs: add omk13 as a contributor (#1611)
* docs: update README.md [skip ci]

* docs: update .all-contributorsrc [skip ci]

Co-authored-by: allcontributors[bot] <46447321+allcontributors[bot]@users.noreply.github.com>
2020-12-07 19:58:05 +02:00
759c99d078 JUnit4 to JUnit5 (#1589)
* Getting @Test from JUnit5 instead of JUnit4

* Changed FixedStepGameLoopTest.java imports and tests to JUnit5

* JUnit4 to JUnit5

* JUnit4 to JUnit5

* JUnit4 to JUnit5

* JUnit4 to JUnit5
2020-12-07 19:55:13 +02:00
e9f73bcf0b Translation zh (#1610)
* add state and callback pattern

* add command and template-method pattern

* add iterator pattern

* add bridege and DI pattern

* fix issue #1600

Co-authored-by: Mike <admin@xiaod.info>
Co-authored-by: Ilkka Seppälä <iluwatar@users.noreply.github.com>
2020-12-06 16:13:48 +02:00
29ceac2fb0 Update README.md (#1592) 2020-12-05 10:56:00 +02:00
7255c2c5e7 docs: add Anurag870 as a contributor (#1609)
* docs: update README.md [skip ci]

* docs: update .all-contributorsrc [skip ci]

* docs: update README.md [skip ci]

* docs: update .all-contributorsrc [skip ci]

* Update README.md

Co-authored-by: allcontributors[bot] <46447321+allcontributors[bot]@users.noreply.github.com>
Co-authored-by: Ilkka Seppälä <ilkka.seppala@gofore.com>
Co-authored-by: Ilkka Seppälä <iluwatar@users.noreply.github.com>
2020-12-05 10:50:09 +02:00
68308dc550 Update README.md (#1590) 2020-12-05 10:34:49 +02:00
1e10951c23 Translation zh (#1597)
* add state and callback pattern

* add command and template-method pattern

* add iterator pattern

Co-authored-by: Mike <admin@xiaod.info>
2020-12-04 20:03:14 +02:00
f3c876ed2e Merge pull request #1607 from iluwatar/all-contributors/add-gkulkarni2020
docs: add gkulkarni2020 as a contributor
2020-12-04 15:48:40 +02:00
ecd1a5d07f docs: update .all-contributorsrc [skip ci] 2020-12-04 13:47:58 +00:00
8b15c24753 docs: update README.md [skip ci] 2020-12-04 13:47:57 +00:00
f5a6161044 Merge pull request #1604 from gkulkarni2020/master
Word mistake in factory/README.md #1601
closes #1601
2020-12-04 14:17:32 +05:30
76eefa80b5 Merge branch 'master' into master 2020-12-04 13:30:11 +05:30
c282ab80fd Merge pull request #1606 from iluwatar/all-contributors/add-ibrahimAlii
docs: add ibrahimAlii as a contributor
2020-12-01 22:48:24 +02:00
1edfb44642 docs: update .all-contributorsrc [skip ci] 2020-12-01 20:47:33 +00:00
e185c497ac docs: update README.md [skip ci] 2020-12-01 20:47:32 +00:00
d5a054c1f8 Merge pull request #1605 from iluwatar/all-contributors/add-OrangePants-R
docs: add OrangePants-R as a contributor
2020-11-30 16:57:52 +02:00
7931471b99 Word mistake in factory/README.md #1601 2020-11-30 15:26:01 +05:30
71 changed files with 4930 additions and 208 deletions

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@ -315,7 +315,8 @@
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8
.gitignore vendored
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@ -4,7 +4,8 @@ target
.classpath
.project
*.class
# Package Files #
### Package Files ###
*.jar
*.war
*.ear
@ -13,7 +14,8 @@ target
*.swp
datanucleus.log
/bin/
/bin/
/bin/
*.log
event-sourcing/Journal.json
### Checkstyle ###
.checkstyle

308
README.md
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@ -10,9 +10,15 @@
[![Coverage](https://sonarcloud.io/api/project_badges/measure?project=iluwatar_java-design-patterns&metric=coverage)](https://sonarcloud.io/dashboard?id=iluwatar_java-design-patterns)
[![Join the chat at https://gitter.im/iluwatar/java-design-patterns](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/iluwatar/java-design-patterns?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
<!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
[![All Contributors](https://img.shields.io/badge/all_contributors-140-orange.svg?style=flat-square)](#contributors-)
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<br/>
Read in different language : [![CN](/assets/flags/CN.png)**CN**](/zh/README.md),[![KR](/assets/flags/KR.png)**KR**](/ko/README.md),[![FR](/assets/flags/FR.png)**FR**](/fr/README.md),[![TR](/assets/flags/TR.png)**TR**](/tr/README.md),
<br/>
# Introduction
Design patterns are the best formalized practices a programmer can use to
@ -70,217 +76,235 @@ This project is licensed under the terms of the MIT license.
<!-- markdownlint-disable -->
<table>
<tr>
<td align="center"><a href="https://github.com/iluwatar"><img src="https://avatars1.githubusercontent.com/u/582346?v=4" width="100px;" alt=""/><br /><sub><b>Ilkka Seppälä</b></sub></a><br /><a href="#projectManagement-iluwatar" title="Project Management">📆</a> <a href="#maintenance-iluwatar" title="Maintenance">🚧</a> <a href="#content-iluwatar" title="Content">🖋</a></td>
<td align="center"><a href="https://github.com/amit1307"><img src="https://avatars0.githubusercontent.com/u/23420222?v=4" width="100px;" alt=""/><br /><sub><b>amit1307</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=amit1307" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/npathai"><img src="https://avatars2.githubusercontent.com/u/1792515?v=4" width="100px;" alt=""/><br /><sub><b>Narendra Pathai</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=npathai" title="Code">💻</a> <a href="#ideas-npathai" title="Ideas, Planning, & Feedback">🤔</a> <a href="https://github.com/iluwatar/java-design-patterns/pulls?q=is%3Apr+reviewed-by%3Anpathai" title="Reviewed Pull Requests">👀</a></td>
<td align="center"><a href="https://github.com/fluxw42"><img src="https://avatars1.githubusercontent.com/u/1545460?v=4" width="100px;" alt=""/><br /><sub><b>Jeroen Meulemeester</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=fluxw42" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/iluwatar"><img src="https://avatars1.githubusercontent.com/u/582346?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ilkka Seppälä</b></sub></a><br /><a href="#projectManagement-iluwatar" title="Project Management">📆</a> <a href="#maintenance-iluwatar" title="Maintenance">🚧</a> <a href="#content-iluwatar" title="Content">🖋</a></td>
<td align="center"><a href="https://github.com/amit1307"><img src="https://avatars0.githubusercontent.com/u/23420222?v=4?s=100" width="100px;" alt=""/><br /><sub><b>amit1307</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=amit1307" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/npathai"><img src="https://avatars2.githubusercontent.com/u/1792515?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Narendra Pathai</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=npathai" title="Code">💻</a> <a href="#ideas-npathai" title="Ideas, Planning, & Feedback">🤔</a> <a href="https://github.com/iluwatar/java-design-patterns/pulls?q=is%3Apr+reviewed-by%3Anpathai" title="Reviewed Pull Requests">👀</a></td>
<td align="center"><a href="https://github.com/fluxw42"><img src="https://avatars1.githubusercontent.com/u/1545460?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Jeroen Meulemeester</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=fluxw42" title="Code">💻</a></td>
</tr>
<tr>
<td align="center"><a href="http://www.joemccarthy.co.uk"><img src="https://avatars0.githubusercontent.com/u/4526195?v=4" width="100px;" alt=""/><br /><sub><b>Joseph McCarthy</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=mikulucky" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/thomasoss"><img src="https://avatars1.githubusercontent.com/u/22516154?v=4" width="100px;" alt=""/><br /><sub><b>Thomas</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=thomasoss" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/anuragagarwal561994"><img src="https://avatars1.githubusercontent.com/u/6075379?v=4" width="100px;" alt=""/><br /><sub><b>Anurag Agarwal</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=anuragagarwal561994" title="Code">💻</a></td>
<td align="center"><a href="https://markusmo3.github.io"><img src="https://avatars1.githubusercontent.com/u/3317416?v=4" width="100px;" alt=""/><br /><sub><b>Markus Moser</b></sub></a><br /><a href="#design-markusmo3" title="Design">🎨</a> <a href="https://github.com/iluwatar/java-design-patterns/commits?author=markusmo3" title="Code">💻</a> <a href="#ideas-markusmo3" title="Ideas, Planning, & Feedback">🤔</a></td>
<td align="center"><a href="http://www.joemccarthy.co.uk"><img src="https://avatars0.githubusercontent.com/u/4526195?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Joseph McCarthy</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=mikulucky" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/thomasoss"><img src="https://avatars1.githubusercontent.com/u/22516154?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Thomas</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=thomasoss" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/anuragagarwal561994"><img src="https://avatars1.githubusercontent.com/u/6075379?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Anurag Agarwal</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=anuragagarwal561994" title="Code">💻</a></td>
<td align="center"><a href="https://markusmo3.github.io"><img src="https://avatars1.githubusercontent.com/u/3317416?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Markus Moser</b></sub></a><br /><a href="#design-markusmo3" title="Design">🎨</a> <a href="https://github.com/iluwatar/java-design-patterns/commits?author=markusmo3" title="Code">💻</a> <a href="#ideas-markusmo3" title="Ideas, Planning, & Feedback">🤔</a></td>
</tr>
<tr>
<td align="center"><a href="https://twitter.com/i_sabiq"><img src="https://avatars1.githubusercontent.com/u/19510920?v=4" width="100px;" alt=""/><br /><sub><b>Sabiq Ihab</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=isabiq" title="Code">💻</a></td>
<td align="center"><a href="http://inbravo.github.io"><img src="https://avatars3.githubusercontent.com/u/5253764?v=4" width="100px;" alt=""/><br /><sub><b>Amit Dixit</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=inbravo" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/piyushchaudhari04"><img src="https://avatars3.githubusercontent.com/u/10268029?v=4" width="100px;" alt=""/><br /><sub><b>Piyush Kailash Chaudhari</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=piyushchaudhari04" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/joshzambales"><img src="https://avatars1.githubusercontent.com/u/8704552?v=4" width="100px;" alt=""/><br /><sub><b>joshzambales</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=joshzambales" title="Code">💻</a></td>
<td align="center"><a href="https://twitter.com/i_sabiq"><img src="https://avatars1.githubusercontent.com/u/19510920?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Sabiq Ihab</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=isabiq" title="Code">💻</a></td>
<td align="center"><a href="http://inbravo.github.io"><img src="https://avatars3.githubusercontent.com/u/5253764?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Amit Dixit</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=inbravo" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/piyushchaudhari04"><img src="https://avatars3.githubusercontent.com/u/10268029?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Piyush Kailash Chaudhari</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=piyushchaudhari04" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/joshzambales"><img src="https://avatars1.githubusercontent.com/u/8704552?v=4?s=100" width="100px;" alt=""/><br /><sub><b>joshzambales</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=joshzambales" title="Code">💻</a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/Crossy147"><img src="https://avatars2.githubusercontent.com/u/7272996?v=4" width="100px;" alt=""/><br /><sub><b>Kamil Pietruszka</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=Crossy147" title="Code">💻</a></td>
<td align="center"><a href="http://cs.joensuu.fi/~zkhayda"><img src="https://avatars2.githubusercontent.com/u/660742?v=4" width="100px;" alt=""/><br /><sub><b>Zafar Khaydarov</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=zafarella" title="Code">💻</a> <a href="https://github.com/iluwatar/java-design-patterns/commits?author=zafarella" title="Documentation">📖</a></td>
<td align="center"><a href="https://kemitix.github.io/"><img src="https://avatars1.githubusercontent.com/u/1147749?v=4" width="100px;" alt=""/><br /><sub><b>Paul Campbell</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=kemitix" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/Argyro-Sioziou"><img src="https://avatars0.githubusercontent.com/u/22822639?v=4" width="100px;" alt=""/><br /><sub><b>Argyro Sioziou</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=Argyro-Sioziou" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/Crossy147"><img src="https://avatars2.githubusercontent.com/u/7272996?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Kamil Pietruszka</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=Crossy147" title="Code">💻</a></td>
<td align="center"><a href="http://cs.joensuu.fi/~zkhayda"><img src="https://avatars2.githubusercontent.com/u/660742?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Zafar Khaydarov</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=zafarella" title="Code">💻</a> <a href="https://github.com/iluwatar/java-design-patterns/commits?author=zafarella" title="Documentation">📖</a></td>
<td align="center"><a href="https://kemitix.github.io/"><img src="https://avatars1.githubusercontent.com/u/1147749?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Paul Campbell</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=kemitix" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/Argyro-Sioziou"><img src="https://avatars0.githubusercontent.com/u/22822639?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Argyro Sioziou</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=Argyro-Sioziou" title="Code">💻</a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/TylerMcConville"><img src="https://avatars0.githubusercontent.com/u/4946449?v=4" width="100px;" alt=""/><br /><sub><b>TylerMcConville</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=TylerMcConville" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/saksham93"><img src="https://avatars1.githubusercontent.com/u/37399540?v=4" width="100px;" alt=""/><br /><sub><b>saksham93</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=saksham93" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/nikhilbarar"><img src="https://avatars2.githubusercontent.com/u/37332144?v=4" width="100px;" alt=""/><br /><sub><b>nikhilbarar</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=nikhilbarar" title="Code">💻</a></td>
<td align="center"><a href="http://colinbut.com"><img src="https://avatars2.githubusercontent.com/u/10725674?v=4" width="100px;" alt=""/><br /><sub><b>Colin But</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=colinbut" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/TylerMcConville"><img src="https://avatars0.githubusercontent.com/u/4946449?v=4?s=100" width="100px;" alt=""/><br /><sub><b>TylerMcConville</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=TylerMcConville" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/saksham93"><img src="https://avatars1.githubusercontent.com/u/37399540?v=4?s=100" width="100px;" alt=""/><br /><sub><b>saksham93</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=saksham93" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/nikhilbarar"><img src="https://avatars2.githubusercontent.com/u/37332144?v=4?s=100" width="100px;" alt=""/><br /><sub><b>nikhilbarar</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=nikhilbarar" title="Code">💻</a></td>
<td align="center"><a href="http://colinbut.com"><img src="https://avatars2.githubusercontent.com/u/10725674?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Colin But</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=colinbut" title="Code">💻</a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/ruslanpa"><img src="https://avatars2.githubusercontent.com/u/1503411?v=4" width="100px;" alt=""/><br /><sub><b>Ruslan</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=ruslanpa" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/JuhoKang"><img src="https://avatars1.githubusercontent.com/u/4745294?v=4" width="100px;" alt=""/><br /><sub><b>Juho Kang</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=JuhoKang" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/dheeraj-mummareddy"><img src="https://avatars2.githubusercontent.com/u/7002230?v=4" width="100px;" alt=""/><br /><sub><b>Dheeraj Mummareddy</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=dheeraj-mummareddy" title="Code">💻</a></td>
<td align="center"><a href="https://www.bernardosulzbach.com"><img src="https://avatars0.githubusercontent.com/u/8271090?v=4" width="100px;" alt=""/><br /><sub><b>Bernardo Sulzbach</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=bernardosulzbach" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/ruslanpa"><img src="https://avatars2.githubusercontent.com/u/1503411?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ruslan</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=ruslanpa" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/JuhoKang"><img src="https://avatars1.githubusercontent.com/u/4745294?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Juho Kang</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=JuhoKang" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/dheeraj-mummareddy"><img src="https://avatars2.githubusercontent.com/u/7002230?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Dheeraj Mummareddy</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=dheeraj-mummareddy" title="Code">💻</a></td>
<td align="center"><a href="https://www.bernardosulzbach.com"><img src="https://avatars0.githubusercontent.com/u/8271090?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Bernardo Sulzbach</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=bernardosulzbach" title="Code">💻</a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/4lexis"><img src="https://avatars0.githubusercontent.com/u/19871727?v=4" width="100px;" alt=""/><br /><sub><b>Aleksandar Dudukovic</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=4lexis" title="Code">💻</a></td>
<td align="center"><a href="https://www.yusufaytas.com"><img src="https://avatars2.githubusercontent.com/u/1049483?v=4" width="100px;" alt=""/><br /><sub><b>Yusuf Aytaş</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=yusufaytas" title="Code">💻</a></td>
<td align="center"><a href="http://futurehomes.hu"><img src="https://avatars2.githubusercontent.com/u/1001491?v=4" width="100px;" alt=""/><br /><sub><b>Mihály Kuprivecz</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=qpi" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/kapinuss"><img src="https://avatars0.githubusercontent.com/u/17639945?v=4" width="100px;" alt=""/><br /><sub><b>Stanislav Kapinus</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=kapinuss" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/4lexis"><img src="https://avatars0.githubusercontent.com/u/19871727?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Aleksandar Dudukovic</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=4lexis" title="Code">💻</a></td>
<td align="center"><a href="https://www.yusufaytas.com"><img src="https://avatars2.githubusercontent.com/u/1049483?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Yusuf Aytaş</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=yusufaytas" title="Code">💻</a></td>
<td align="center"><a href="http://futurehomes.hu"><img src="https://avatars2.githubusercontent.com/u/1001491?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Mihály Kuprivecz</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=qpi" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/kapinuss"><img src="https://avatars0.githubusercontent.com/u/17639945?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Stanislav Kapinus</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=kapinuss" title="Code">💻</a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/gvsharma"><img src="https://avatars1.githubusercontent.com/u/6648152?v=4" width="100px;" alt=""/><br /><sub><b>GVSharma</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=gvsharma" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/SrdjanPaunovic"><img src="https://avatars1.githubusercontent.com/u/22815104?v=4" width="100px;" alt=""/><br /><sub><b>Srđan Paunović</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=SrdjanPaunovic" title="Code">💻</a></td>
<td align="center"><a href="https://sideris.xyz/"><img src="https://avatars3.githubusercontent.com/u/5484694?v=4" width="100px;" alt=""/><br /><sub><b>Petros G. Sideris</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=sideris" title="Code">💻</a></td>
<td align="center"><a href="https://www.linkedin.com/in/pramodgupta3/"><img src="https://avatars1.githubusercontent.com/u/2184241?v=4" width="100px;" alt=""/><br /><sub><b>Pramod Gupta</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/pulls?q=is%3Apr+reviewed-by%3AIAmPramod" title="Reviewed Pull Requests">👀</a></td>
<td align="center"><a href="https://github.com/gvsharma"><img src="https://avatars1.githubusercontent.com/u/6648152?v=4?s=100" width="100px;" alt=""/><br /><sub><b>GVSharma</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=gvsharma" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/SrdjanPaunovic"><img src="https://avatars1.githubusercontent.com/u/22815104?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Srđan Paunović</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=SrdjanPaunovic" title="Code">💻</a></td>
<td align="center"><a href="https://sideris.xyz/"><img src="https://avatars3.githubusercontent.com/u/5484694?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Petros G. Sideris</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=sideris" title="Code">💻</a></td>
<td align="center"><a href="https://www.linkedin.com/in/pramodgupta3/"><img src="https://avatars1.githubusercontent.com/u/2184241?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Pramod Gupta</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/pulls?q=is%3Apr+reviewed-by%3AIAmPramod" title="Reviewed Pull Requests">👀</a></td>
</tr>
<tr>
<td align="center"><a href="https://amarnath510.github.io/portfolio"><img src="https://avatars0.githubusercontent.com/u/4599623?v=4" width="100px;" alt=""/><br /><sub><b>Amarnath Chandana</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=Amarnath510" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/Anurag870"><img src="https://avatars1.githubusercontent.com/u/6295975?v=4" width="100px;" alt=""/><br /><sub><b>Anurag870</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=Anurag870" title="Code">💻</a></td>
<td align="center"><a href="http://theerroris.me"><img src="https://avatars0.githubusercontent.com/u/1685953?v=4" width="100px;" alt=""/><br /><sub><b>Wes Gilleland</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=Deathnerd" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/Harshrajsinh"><img src="https://avatars2.githubusercontent.com/u/22811531?v=4" width="100px;" alt=""/><br /><sub><b>Harshraj Thakor</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=Harshrajsinh" title="Code">💻</a></td>
<td align="center"><a href="https://amarnath510.github.io/portfolio"><img src="https://avatars0.githubusercontent.com/u/4599623?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Amarnath Chandana</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=Amarnath510" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/Anurag870"><img src="https://avatars1.githubusercontent.com/u/6295975?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Anurag870</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=Anurag870" title="Code">💻</a> <a href="https://github.com/iluwatar/java-design-patterns/commits?author=Anurag870" title="Documentation">📖</a></td>
<td align="center"><a href="http://theerroris.me"><img src="https://avatars0.githubusercontent.com/u/1685953?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Wes Gilleland</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=Deathnerd" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/Harshrajsinh"><img src="https://avatars2.githubusercontent.com/u/22811531?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Harshraj Thakor</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=Harshrajsinh" title="Code">💻</a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/MaVdbussche"><img src="https://avatars1.githubusercontent.com/u/26136934?v=4" width="100px;" alt=""/><br /><sub><b>Martin Vandenbussche</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=MaVdbussche" title="Code">💻</a></td>
<td align="center"><a href="https://alexsomai.com"><img src="https://avatars1.githubusercontent.com/u/5720977?v=4" width="100px;" alt=""/><br /><sub><b>Alexandru Somai</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=alexsomai" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/amogozov"><img src="https://avatars3.githubusercontent.com/u/7372215?v=4" width="100px;" alt=""/><br /><sub><b>Artur Mogozov</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=amogozov" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/anthonycampbell"><img src="https://avatars3.githubusercontent.com/u/10249255?v=4" width="100px;" alt=""/><br /><sub><b>anthony</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=anthonycampbell" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/MaVdbussche"><img src="https://avatars1.githubusercontent.com/u/26136934?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Martin Vandenbussche</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=MaVdbussche" title="Code">💻</a></td>
<td align="center"><a href="https://alexsomai.com"><img src="https://avatars1.githubusercontent.com/u/5720977?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Alexandru Somai</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=alexsomai" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/amogozov"><img src="https://avatars3.githubusercontent.com/u/7372215?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Artur Mogozov</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=amogozov" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/anthonycampbell"><img src="https://avatars3.githubusercontent.com/u/10249255?v=4?s=100" width="100px;" alt=""/><br /><sub><b>anthony</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=anthonycampbell" title="Code">💻</a></td>
</tr>
<tr>
<td align="center"><a href="http://ccygnus.com/"><img src="https://avatars1.githubusercontent.com/u/9342724?v=4" width="100px;" alt=""/><br /><sub><b>Christian Cygnus</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=christophercolumbusdog" title="Code">💻</a></td>
<td align="center"><a href="https://about.me/dzmitryh"><img src="https://avatars2.githubusercontent.com/u/5390492?v=4" width="100px;" alt=""/><br /><sub><b>Dima Gubin</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=dzmitryh" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/jjjimenez100"><img src="https://avatars3.githubusercontent.com/u/22243493?v=4" width="100px;" alt=""/><br /><sub><b>Joshua Jimenez</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=jjjimenez100" title="Code">💻</a></td>
<td align="center"><a href="http://about.me/kaiwinter"><img src="https://avatars0.githubusercontent.com/u/110982?v=4" width="100px;" alt=""/><br /><sub><b>Kai Winter</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=kaiwinter" title="Code">💻</a></td>
<td align="center"><a href="http://ccygnus.com/"><img src="https://avatars1.githubusercontent.com/u/9342724?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Christian Cygnus</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=christophercolumbusdog" title="Code">💻</a></td>
<td align="center"><a href="https://about.me/dzmitryh"><img src="https://avatars2.githubusercontent.com/u/5390492?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Dima Gubin</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=dzmitryh" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/jjjimenez100"><img src="https://avatars3.githubusercontent.com/u/22243493?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Joshua Jimenez</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=jjjimenez100" title="Code">💻</a></td>
<td align="center"><a href="http://about.me/kaiwinter"><img src="https://avatars0.githubusercontent.com/u/110982?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Kai Winter</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=kaiwinter" title="Code">💻</a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/lbroman"><img src="https://avatars1.githubusercontent.com/u/86007?v=4" width="100px;" alt=""/><br /><sub><b>lbroman</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=lbroman" title="Code">💻</a></td>
<td align="center"><a href="https://przemeknowak.com"><img src="https://avatars1.githubusercontent.com/u/3254609?v=4" width="100px;" alt=""/><br /><sub><b>Przemek</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=pnowy" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/prafful1"><img src="https://avatars0.githubusercontent.com/u/14350274?v=4" width="100px;" alt=""/><br /><sub><b>Prafful Agarwal</b></sub></a><br /><a href="#content-prafful1" title="Content">🖋</a></td>
<td align="center"><a href="https://github.com/sankypanhale"><img src="https://avatars1.githubusercontent.com/u/6478783?v=4" width="100px;" alt=""/><br /><sub><b>Sanket Panhale</b></sub></a><br /><a href="#content-sankypanhale" title="Content">🖋</a></td>
<td align="center"><a href="https://github.com/lbroman"><img src="https://avatars1.githubusercontent.com/u/86007?v=4?s=100" width="100px;" alt=""/><br /><sub><b>lbroman</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=lbroman" title="Code">💻</a></td>
<td align="center"><a href="https://przemeknowak.com"><img src="https://avatars1.githubusercontent.com/u/3254609?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Przemek</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=pnowy" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/prafful1"><img src="https://avatars0.githubusercontent.com/u/14350274?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Prafful Agarwal</b></sub></a><br /><a href="#content-prafful1" title="Content">🖋</a></td>
<td align="center"><a href="https://github.com/sankypanhale"><img src="https://avatars1.githubusercontent.com/u/6478783?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Sanket Panhale</b></sub></a><br /><a href="#content-sankypanhale" title="Content">🖋</a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/staillebois"><img src="https://avatars0.githubusercontent.com/u/23701200?v=4" width="100px;" alt=""/><br /><sub><b>staillebois</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=staillebois" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/valdar-hu"><img src="https://avatars3.githubusercontent.com/u/17962817?v=4" width="100px;" alt=""/><br /><sub><b>Krisztián Nagy</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=valdar-hu" title="Code">💻</a></td>
<td align="center"><a href="https://www.vanogrid.com"><img src="https://avatars0.githubusercontent.com/u/4307918?v=4" width="100px;" alt=""/><br /><sub><b>Alexander Ivanov</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=vanogrid" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/yosfik"><img src="https://avatars3.githubusercontent.com/u/4850270?v=4" width="100px;" alt=""/><br /><sub><b>Yosfik Alqadri</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=yosfik" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/staillebois"><img src="https://avatars0.githubusercontent.com/u/23701200?v=4?s=100" width="100px;" alt=""/><br /><sub><b>staillebois</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=staillebois" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/valdar-hu"><img src="https://avatars3.githubusercontent.com/u/17962817?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Krisztián Nagy</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=valdar-hu" title="Code">💻</a></td>
<td align="center"><a href="https://www.vanogrid.com"><img src="https://avatars0.githubusercontent.com/u/4307918?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Alexander Ivanov</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=vanogrid" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/yosfik"><img src="https://avatars3.githubusercontent.com/u/4850270?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Yosfik Alqadri</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=yosfik" title="Code">💻</a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/7agustibm"><img src="https://avatars0.githubusercontent.com/u/8149332?v=4" width="100px;" alt=""/><br /><sub><b>Agustí Becerra Milà</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=7agustibm" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/Juaanma"><img src="https://avatars3.githubusercontent.com/u/7390500?v=4" width="100px;" alt=""/><br /><sub><b>Juan Manuel Suárez</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=Juaanma" title="Code">💻</a></td>
<td align="center"><a href="http://www.devsedge.net/"><img src="https://avatars0.githubusercontent.com/u/9956006?v=4" width="100px;" alt=""/><br /><sub><b>Luigi Cortese</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=LuigiCortese" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/Rzeposlaw"><img src="https://avatars2.githubusercontent.com/u/18425745?v=4" width="100px;" alt=""/><br /><sub><b>Katarzyna Rzepecka</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=Rzeposlaw" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/7agustibm"><img src="https://avatars0.githubusercontent.com/u/8149332?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Agustí Becerra Milà</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=7agustibm" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/Juaanma"><img src="https://avatars3.githubusercontent.com/u/7390500?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Juan Manuel Suárez</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=Juaanma" title="Code">💻</a></td>
<td align="center"><a href="http://www.devsedge.net/"><img src="https://avatars0.githubusercontent.com/u/9956006?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Luigi Cortese</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=LuigiCortese" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/Rzeposlaw"><img src="https://avatars2.githubusercontent.com/u/18425745?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Katarzyna Rzepecka</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=Rzeposlaw" title="Code">💻</a></td>
</tr>
<tr>
<td align="center"><a href="http://adamski.pro"><img src="https://avatars1.githubusercontent.com/u/6537430?v=4" width="100px;" alt=""/><br /><sub><b>adamski.pro</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=akrystian" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/baislsl"><img src="https://avatars0.githubusercontent.com/u/17060584?v=4" width="100px;" alt=""/><br /><sub><b>Shengli Bai</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=baislsl" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/besok"><img src="https://avatars2.githubusercontent.com/u/29834592?v=4" width="100px;" alt=""/><br /><sub><b>Boris</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=besok" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/dmitraver"><img src="https://avatars3.githubusercontent.com/u/1798156?v=4" width="100px;" alt=""/><br /><sub><b>Dmitry Avershin</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=dmitraver" title="Code">💻</a></td>
<td align="center"><a href="http://adamski.pro"><img src="https://avatars1.githubusercontent.com/u/6537430?v=4?s=100" width="100px;" alt=""/><br /><sub><b>adamski.pro</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=akrystian" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/baislsl"><img src="https://avatars0.githubusercontent.com/u/17060584?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Shengli Bai</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=baislsl" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/besok"><img src="https://avatars2.githubusercontent.com/u/29834592?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Boris</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=besok" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/dmitraver"><img src="https://avatars3.githubusercontent.com/u/1798156?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Dmitry Avershin</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=dmitraver" title="Code">💻</a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/fanofxiaofeng"><img src="https://avatars0.githubusercontent.com/u/3983683?v=4" width="100px;" alt=""/><br /><sub><b>靳阳</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=fanofxiaofeng" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/hoangnam2261"><img src="https://avatars2.githubusercontent.com/u/31692990?v=4" width="100px;" alt=""/><br /><sub><b>hoangnam2261</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=hoangnam2261" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/jarpit96"><img src="https://avatars2.githubusercontent.com/u/10098713?v=4" width="100px;" alt=""/><br /><sub><b>Arpit Jain</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=jarpit96" title="Code">💻</a></td>
<td align="center"><a href="http://joningi.net"><img src="https://avatars2.githubusercontent.com/u/6115148?v=4" width="100px;" alt=""/><br /><sub><b>Jón Ingi Sveinbjörnsson</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=joningiwork" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/fanofxiaofeng"><img src="https://avatars0.githubusercontent.com/u/3983683?v=4?s=100" width="100px;" alt=""/><br /><sub><b>靳阳</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=fanofxiaofeng" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/hoangnam2261"><img src="https://avatars2.githubusercontent.com/u/31692990?v=4?s=100" width="100px;" alt=""/><br /><sub><b>hoangnam2261</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=hoangnam2261" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/jarpit96"><img src="https://avatars2.githubusercontent.com/u/10098713?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Arpit Jain</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=jarpit96" title="Code">💻</a></td>
<td align="center"><a href="http://joningi.net"><img src="https://avatars2.githubusercontent.com/u/6115148?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Jón Ingi Sveinbjörnsson</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=joningiwork" title="Code">💻</a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/kirill-vlasov"><img src="https://avatars3.githubusercontent.com/u/16112495?v=4" width="100px;" alt=""/><br /><sub><b>Kirill Vlasov</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=kirill-vlasov" title="Code">💻</a></td>
<td align="center"><a href="http://mitchell-irvin.com"><img src="https://avatars0.githubusercontent.com/u/16233245?v=4" width="100px;" alt=""/><br /><sub><b>Mitchell Irvin</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=mitchellirvin" title="Code">💻</a></td>
<td align="center"><a href="https://ranjeet-floyd.github.io"><img src="https://avatars0.githubusercontent.com/u/1992972?v=4" width="100px;" alt=""/><br /><sub><b>Ranjeet</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=ranjeet-floyd" title="Code">💻</a></td>
<td align="center"><a href="https://alwayswithme.github.io"><img src="https://avatars3.githubusercontent.com/u/3234786?v=4" width="100px;" alt=""/><br /><sub><b>PhoenixYip</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=Alwayswithme" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/kirill-vlasov"><img src="https://avatars3.githubusercontent.com/u/16112495?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Kirill Vlasov</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=kirill-vlasov" title="Code">💻</a></td>
<td align="center"><a href="http://mitchell-irvin.com"><img src="https://avatars0.githubusercontent.com/u/16233245?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Mitchell Irvin</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=mitchellirvin" title="Code">💻</a></td>
<td align="center"><a href="https://ranjeet-floyd.github.io"><img src="https://avatars0.githubusercontent.com/u/1992972?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ranjeet</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=ranjeet-floyd" title="Code">💻</a></td>
<td align="center"><a href="https://alwayswithme.github.io"><img src="https://avatars3.githubusercontent.com/u/3234786?v=4?s=100" width="100px;" alt=""/><br /><sub><b>PhoenixYip</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=Alwayswithme" title="Code">💻</a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/MSaifAsif"><img src="https://avatars1.githubusercontent.com/u/6280554?v=4" width="100px;" alt=""/><br /><sub><b>M Saif Asif</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=MSaifAsif" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/kanwarpreet25"><img src="https://avatars0.githubusercontent.com/u/39183641?v=4" width="100px;" alt=""/><br /><sub><b>kanwarpreet25</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=kanwarpreet25" title="Code">💻</a></td>
<td align="center"><a href="http://leonmak.me"><img src="https://avatars3.githubusercontent.com/u/13071508?v=4" width="100px;" alt=""/><br /><sub><b>Leon Mak</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=leonmak" title="Code">💻</a></td>
<td align="center"><a href="http://www.wramdemark.se"><img src="https://avatars2.githubusercontent.com/u/7052193?v=4" width="100px;" alt=""/><br /><sub><b>Per Wramdemark</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=perwramdemark" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/MSaifAsif"><img src="https://avatars1.githubusercontent.com/u/6280554?v=4?s=100" width="100px;" alt=""/><br /><sub><b>M Saif Asif</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=MSaifAsif" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/kanwarpreet25"><img src="https://avatars0.githubusercontent.com/u/39183641?v=4?s=100" width="100px;" alt=""/><br /><sub><b>kanwarpreet25</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=kanwarpreet25" title="Code">💻</a></td>
<td align="center"><a href="http://leonmak.me"><img src="https://avatars3.githubusercontent.com/u/13071508?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Leon Mak</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=leonmak" title="Code">💻</a></td>
<td align="center"><a href="http://www.wramdemark.se"><img src="https://avatars2.githubusercontent.com/u/7052193?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Per Wramdemark</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=perwramdemark" title="Code">💻</a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/waisuan"><img src="https://avatars2.githubusercontent.com/u/10975700?v=4" width="100px;" alt=""/><br /><sub><b>Evan Sia Wai Suan</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=waisuan" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/AnaghaSasikumar"><img src="https://avatars2.githubusercontent.com/u/42939261?v=4" width="100px;" alt=""/><br /><sub><b>AnaghaSasikumar</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=AnaghaSasikumar" title="Code">💻</a></td>
<td align="center"><a href="https://christofferh.com"><img src="https://avatars1.githubusercontent.com/u/767643?v=4" width="100px;" alt=""/><br /><sub><b>Christoffer Hamberg</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=christofferh" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/dgruntz"><img src="https://avatars0.githubusercontent.com/u/1516800?v=4" width="100px;" alt=""/><br /><sub><b>Dominik Gruntz</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=dgruntz" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/waisuan"><img src="https://avatars2.githubusercontent.com/u/10975700?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Evan Sia Wai Suan</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=waisuan" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/AnaghaSasikumar"><img src="https://avatars2.githubusercontent.com/u/42939261?v=4?s=100" width="100px;" alt=""/><br /><sub><b>AnaghaSasikumar</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=AnaghaSasikumar" title="Code">💻</a></td>
<td align="center"><a href="https://christofferh.com"><img src="https://avatars1.githubusercontent.com/u/767643?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Christoffer Hamberg</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=christofferh" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/dgruntz"><img src="https://avatars0.githubusercontent.com/u/1516800?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Dominik Gruntz</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=dgruntz" title="Code">💻</a></td>
</tr>
<tr>
<td align="center"><a href="https://bitbucket.org/hannespernpeintner/"><img src="https://avatars3.githubusercontent.com/u/1679437?v=4" width="100px;" alt=""/><br /><sub><b>Hannes</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=hannespernpeintner" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/leogtzr"><img src="https://avatars0.githubusercontent.com/u/1211969?v=4" width="100px;" alt=""/><br /><sub><b>Leo Gutiérrez Ramírez</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=leogtzr" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/npczwh"><img src="https://avatars0.githubusercontent.com/u/14066422?v=4" width="100px;" alt=""/><br /><sub><b>Zhang WH</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=npczwh" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/oconnelc"><img src="https://avatars0.githubusercontent.com/u/1112973?v=4" width="100px;" alt=""/><br /><sub><b>Christopher O'Connell</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=oconnelc" title="Code">💻</a></td>
<td align="center"><a href="https://bitbucket.org/hannespernpeintner/"><img src="https://avatars3.githubusercontent.com/u/1679437?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Hannes</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=hannespernpeintner" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/leogtzr"><img src="https://avatars0.githubusercontent.com/u/1211969?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Leo Gutiérrez Ramírez</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=leogtzr" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/npczwh"><img src="https://avatars0.githubusercontent.com/u/14066422?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Zhang WH</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=npczwh" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/oconnelc"><img src="https://avatars0.githubusercontent.com/u/1112973?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Christopher O'Connell</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=oconnelc" title="Code">💻</a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/giorgosmav21"><img src="https://avatars2.githubusercontent.com/u/22855493?v=4" width="100px;" alt=""/><br /><sub><b>George Mavroeidis</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=giorgosmav21" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/hbothra15"><img src="https://avatars1.githubusercontent.com/u/7418012?v=4" width="100px;" alt=""/><br /><sub><b>Hemant Bothra</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=hbothra15" title="Code">💻</a> <a href="#design-hbothra15" title="Design">🎨</a></td>
<td align="center"><a href="https://www.kevinpeters.net/about/"><img src="https://avatars1.githubusercontent.com/u/12736734?v=4" width="100px;" alt=""/><br /><sub><b>Kevin Peters</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=igeligel" title="Code">💻</a></td>
<td align="center"><a href="https://llorllale.github.io/"><img src="https://avatars1.githubusercontent.com/u/2019896?v=4" width="100px;" alt=""/><br /><sub><b>George Aristy</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=llorllale" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/giorgosmav21"><img src="https://avatars2.githubusercontent.com/u/22855493?v=4?s=100" width="100px;" alt=""/><br /><sub><b>George Mavroeidis</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=giorgosmav21" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/hbothra15"><img src="https://avatars1.githubusercontent.com/u/7418012?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Hemant Bothra</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=hbothra15" title="Code">💻</a> <a href="#design-hbothra15" title="Design">🎨</a></td>
<td align="center"><a href="https://www.kevinpeters.net/about/"><img src="https://avatars1.githubusercontent.com/u/12736734?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Kevin Peters</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=igeligel" title="Code">💻</a></td>
<td align="center"><a href="https://llorllale.github.io/"><img src="https://avatars1.githubusercontent.com/u/2019896?v=4?s=100" width="100px;" alt=""/><br /><sub><b>George Aristy</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=llorllale" title="Code">💻</a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/mookkiah"><img src="https://avatars1.githubusercontent.com/u/8975264?v=4" width="100px;" alt=""/><br /><sub><b>Mahendran Mookkiah</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=mookkiah" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/Azureyjt"><img src="https://avatars2.githubusercontent.com/u/18476317?v=4" width="100px;" alt=""/><br /><sub><b>Azureyjt</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=Azureyjt" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/vehpsr"><img src="https://avatars2.githubusercontent.com/u/3133265?v=4" width="100px;" alt=""/><br /><sub><b>gans</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=vehpsr" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/ThatGuyWithTheHat"><img src="https://avatars0.githubusercontent.com/u/24470582?v=4" width="100px;" alt=""/><br /><sub><b>Matt</b></sub></a><br /><a href="#content-ThatGuyWithTheHat" title="Content">🖋</a></td>
<td align="center"><a href="https://github.com/mookkiah"><img src="https://avatars1.githubusercontent.com/u/8975264?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Mahendran Mookkiah</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=mookkiah" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/Azureyjt"><img src="https://avatars2.githubusercontent.com/u/18476317?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Azureyjt</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=Azureyjt" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/vehpsr"><img src="https://avatars2.githubusercontent.com/u/3133265?v=4?s=100" width="100px;" alt=""/><br /><sub><b>gans</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=vehpsr" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/ThatGuyWithTheHat"><img src="https://avatars0.githubusercontent.com/u/24470582?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Matt</b></sub></a><br /><a href="#content-ThatGuyWithTheHat" title="Content">🖋</a></td>
</tr>
<tr>
<td align="center"><a href="https://www.linkedin.com/in/gopinathlangote/"><img src="https://avatars2.githubusercontent.com/u/10210778?v=4" width="100px;" alt=""/><br /><sub><b>Gopinath Langote</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=gopinath-langote" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/hoswey"><img src="https://avatars3.githubusercontent.com/u/3689445?v=4" width="100px;" alt=""/><br /><sub><b>Hoswey</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=hoswey" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/amit2103"><img src="https://avatars3.githubusercontent.com/u/7566692?v=4" width="100px;" alt=""/><br /><sub><b>Amit Pandey</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=amit2103" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/gwildor28"><img src="https://avatars0.githubusercontent.com/u/16000365?v=4" width="100px;" alt=""/><br /><sub><b>gwildor28</b></sub></a><br /><a href="#content-gwildor28" title="Content">🖋</a></td>
<td align="center"><a href="https://www.linkedin.com/in/gopinathlangote/"><img src="https://avatars2.githubusercontent.com/u/10210778?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Gopinath Langote</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=gopinath-langote" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/hoswey"><img src="https://avatars3.githubusercontent.com/u/3689445?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Hoswey</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=hoswey" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/amit2103"><img src="https://avatars3.githubusercontent.com/u/7566692?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Amit Pandey</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=amit2103" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/gwildor28"><img src="https://avatars0.githubusercontent.com/u/16000365?v=4?s=100" width="100px;" alt=""/><br /><sub><b>gwildor28</b></sub></a><br /><a href="#content-gwildor28" title="Content">🖋</a></td>
</tr>
<tr>
<td align="center"><a href="https://t.me/paul_docker"><img src="https://avatars1.githubusercontent.com/u/2404785?v=4" width="100px;" alt=""/><br /><sub><b>田浩</b></sub></a><br /><a href="#content-llitfkitfk" title="Content">🖋</a></td>
<td align="center"><a href="https://twitter.com/StPitsios"><img src="https://avatars1.githubusercontent.com/u/6773603?v=4" width="100px;" alt=""/><br /><sub><b>Stamatis Pitsios</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=pitsios-s" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/qza"><img src="https://avatars3.githubusercontent.com/u/233149?v=4" width="100px;" alt=""/><br /><sub><b>qza</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=qza" title="Code">💻</a></td>
<td align="center"><a href="http://tschis.github.io"><img src="https://avatars1.githubusercontent.com/u/20662669?v=4" width="100px;" alt=""/><br /><sub><b>Rodolfo Forte</b></sub></a><br /><a href="#content-Tschis" title="Content">🖋</a></td>
<td align="center"><a href="https://t.me/paul_docker"><img src="https://avatars1.githubusercontent.com/u/2404785?v=4?s=100" width="100px;" alt=""/><br /><sub><b>田浩</b></sub></a><br /><a href="#content-llitfkitfk" title="Content">🖋</a></td>
<td align="center"><a href="https://twitter.com/StPitsios"><img src="https://avatars1.githubusercontent.com/u/6773603?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Stamatis Pitsios</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=pitsios-s" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/qza"><img src="https://avatars3.githubusercontent.com/u/233149?v=4?s=100" width="100px;" alt=""/><br /><sub><b>qza</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=qza" title="Code">💻</a></td>
<td align="center"><a href="http://tschis.github.io"><img src="https://avatars1.githubusercontent.com/u/20662669?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Rodolfo Forte</b></sub></a><br /><a href="#content-Tschis" title="Content">🖋</a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/ankurkaushal"><img src="https://avatars2.githubusercontent.com/u/2236616?v=4" width="100px;" alt=""/><br /><sub><b>Ankur Kaushal</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=ankurkaushal" title="Code">💻</a></td>
<td align="center"><a href="https://www.linkedin.com/in/ovidijus-okinskas/"><img src="https://avatars0.githubusercontent.com/u/20372387?v=4" width="100px;" alt=""/><br /><sub><b>Ovidijus Okinskas</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=okinskas" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/robertt240"><img src="https://avatars1.githubusercontent.com/u/9137432?v=4" width="100px;" alt=""/><br /><sub><b>Robert Kasperczyk</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=robertt240" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/trautonen"><img src="https://avatars3.githubusercontent.com/u/1641063?v=4" width="100px;" alt=""/><br /><sub><b>Tapio Rautonen</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=trautonen" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/ankurkaushal"><img src="https://avatars2.githubusercontent.com/u/2236616?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ankur Kaushal</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=ankurkaushal" title="Code">💻</a></td>
<td align="center"><a href="https://www.linkedin.com/in/ovidijus-okinskas/"><img src="https://avatars0.githubusercontent.com/u/20372387?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ovidijus Okinskas</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=okinskas" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/robertt240"><img src="https://avatars1.githubusercontent.com/u/9137432?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Robert Kasperczyk</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=robertt240" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/trautonen"><img src="https://avatars3.githubusercontent.com/u/1641063?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Tapio Rautonen</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=trautonen" title="Code">💻</a></td>
</tr>
<tr>
<td align="center"><a href="http://vk.com/yuri.orlov"><img src="https://avatars0.githubusercontent.com/u/1595733?v=4" width="100px;" alt=""/><br /><sub><b>Yuri Orlov</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=yorlov" title="Code">💻</a></td>
<td align="center"><a href="https://www.linkedin.com/in/varunu28/"><img src="https://avatars0.githubusercontent.com/u/7676016?v=4" width="100px;" alt=""/><br /><sub><b>Varun Upadhyay</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=varunu28" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/PalAditya"><img src="https://avatars2.githubusercontent.com/u/25523604?v=4" width="100px;" alt=""/><br /><sub><b>Aditya Pal</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=PalAditya" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/grzesiekkedzior"><img src="https://avatars3.githubusercontent.com/u/23739158?v=4" width="100px;" alt=""/><br /><sub><b>grzesiekkedzior</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=grzesiekkedzior" title="Code">💻</a> <a href="https://github.com/iluwatar/java-design-patterns/pulls?q=is%3Apr+reviewed-by%3Agrzesiekkedzior" title="Reviewed Pull Requests">👀</a></td>
<td align="center"><a href="http://vk.com/yuri.orlov"><img src="https://avatars0.githubusercontent.com/u/1595733?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Yuri Orlov</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=yorlov" title="Code">💻</a></td>
<td align="center"><a href="https://www.linkedin.com/in/varunu28/"><img src="https://avatars0.githubusercontent.com/u/7676016?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Varun Upadhyay</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=varunu28" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/PalAditya"><img src="https://avatars2.githubusercontent.com/u/25523604?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Aditya Pal</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=PalAditya" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/grzesiekkedzior"><img src="https://avatars3.githubusercontent.com/u/23739158?v=4?s=100" width="100px;" alt=""/><br /><sub><b>grzesiekkedzior</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=grzesiekkedzior" title="Code">💻</a> <a href="https://github.com/iluwatar/java-design-patterns/pulls?q=is%3Apr+reviewed-by%3Agrzesiekkedzior" title="Reviewed Pull Requests">👀</a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/sivasubramanim"><img src="https://avatars2.githubusercontent.com/u/51107434?v=4" width="100px;" alt=""/><br /><sub><b>Sivasubramani M</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=sivasubramanim" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/d4gg4d"><img src="https://avatars2.githubusercontent.com/u/99457?v=4" width="100px;" alt=""/><br /><sub><b>Sami Airaksinen</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=d4gg4d" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/vertti"><img src="https://avatars0.githubusercontent.com/u/557751?v=4" width="100px;" alt=""/><br /><sub><b>Janne Sinivirta</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=vertti" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/Bobo1239"><img src="https://avatars1.githubusercontent.com/u/2302947?v=4" width="100px;" alt=""/><br /><sub><b>Boris-Chengbiao Zhou</b></sub></a><br /><a href="#content-Bobo1239" title="Content">🖋</a></td>
<td align="center"><a href="https://github.com/sivasubramanim"><img src="https://avatars2.githubusercontent.com/u/51107434?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Sivasubramani M</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=sivasubramanim" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/d4gg4d"><img src="https://avatars2.githubusercontent.com/u/99457?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Sami Airaksinen</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=d4gg4d" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/vertti"><img src="https://avatars0.githubusercontent.com/u/557751?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Janne Sinivirta</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=vertti" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/Bobo1239"><img src="https://avatars1.githubusercontent.com/u/2302947?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Boris-Chengbiao Zhou</b></sub></a><br /><a href="#content-Bobo1239" title="Content">🖋</a></td>
</tr>
<tr>
<td align="center"><a href="https://jahhein.github.io"><img src="https://avatars2.githubusercontent.com/u/10779515?v=4" width="100px;" alt=""/><br /><sub><b>Jacob Hein</b></sub></a><br /><a href="#content-Jahhein" title="Content">🖋</a></td>
<td align="center"><a href="https://github.com/iamrichardjones"><img src="https://avatars3.githubusercontent.com/u/14842151?v=4" width="100px;" alt=""/><br /><sub><b>Richard Jones</b></sub></a><br /><a href="#content-iamrichardjones" title="Content">🖋</a></td>
<td align="center"><a href="https://rachelcarmena.github.io"><img src="https://avatars0.githubusercontent.com/u/22792183?v=4" width="100px;" alt=""/><br /><sub><b>Rachel M. Carmena</b></sub></a><br /><a href="#content-rachelcarmena" title="Content">🖋</a></td>
<td align="center"><a href="https://zd-zero.github.io"><img src="https://avatars0.githubusercontent.com/u/21978370?v=4" width="100px;" alt=""/><br /><sub><b>Zaerald Denze Lungos</b></sub></a><br /><a href="#content-zd-zero" title="Content">🖋</a></td>
<td align="center"><a href="https://jahhein.github.io"><img src="https://avatars2.githubusercontent.com/u/10779515?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Jacob Hein</b></sub></a><br /><a href="#content-Jahhein" title="Content">🖋</a></td>
<td align="center"><a href="https://github.com/iamrichardjones"><img src="https://avatars3.githubusercontent.com/u/14842151?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Richard Jones</b></sub></a><br /><a href="#content-iamrichardjones" title="Content">🖋</a></td>
<td align="center"><a href="https://rachelcarmena.github.io"><img src="https://avatars0.githubusercontent.com/u/22792183?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Rachel M. Carmena</b></sub></a><br /><a href="#content-rachelcarmena" title="Content">🖋</a></td>
<td align="center"><a href="https://zd-zero.github.io"><img src="https://avatars0.githubusercontent.com/u/21978370?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Zaerald Denze Lungos</b></sub></a><br /><a href="#content-zd-zero" title="Content">🖋</a></td>
</tr>
<tr>
<td align="center"><a href="https://webpro.nl"><img src="https://avatars1.githubusercontent.com/u/456426?v=4" width="100px;" alt=""/><br /><sub><b>Lars Kappert</b></sub></a><br /><a href="#content-webpro" title="Content">🖋</a></td>
<td align="center"><a href="https://xiaod.info"><img src="https://avatars2.githubusercontent.com/u/21277644?v=4" width="100px;" alt=""/><br /><sub><b>Mike Liu</b></sub></a><br /><a href="#translation-xiaod-dev" title="Translation">🌍</a></td>
<td align="center"><a href="https://github.com/charlesfinley"><img src="https://avatars1.githubusercontent.com/u/6307904?v=4" width="100px;" alt=""/><br /><sub><b>Matt Dolan</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=charlesfinley" title="Code">💻</a> <a href="https://github.com/iluwatar/java-design-patterns/pulls?q=is%3Apr+reviewed-by%3Acharlesfinley" title="Reviewed Pull Requests">👀</a></td>
<td align="center"><a href="https://github.com/MananS77"><img src="https://avatars3.githubusercontent.com/u/21033516?v=4" width="100px;" alt=""/><br /><sub><b>Manan</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/pulls?q=is%3Apr+reviewed-by%3AMananS77" title="Reviewed Pull Requests">👀</a></td>
<td align="center"><a href="https://webpro.nl"><img src="https://avatars1.githubusercontent.com/u/456426?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Lars Kappert</b></sub></a><br /><a href="#content-webpro" title="Content">🖋</a></td>
<td align="center"><a href="https://xiaod.info"><img src="https://avatars2.githubusercontent.com/u/21277644?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Mike Liu</b></sub></a><br /><a href="#translation-xiaod-dev" title="Translation">🌍</a></td>
<td align="center"><a href="https://github.com/charlesfinley"><img src="https://avatars1.githubusercontent.com/u/6307904?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Matt Dolan</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=charlesfinley" title="Code">💻</a> <a href="https://github.com/iluwatar/java-design-patterns/pulls?q=is%3Apr+reviewed-by%3Acharlesfinley" title="Reviewed Pull Requests">👀</a></td>
<td align="center"><a href="https://github.com/MananS77"><img src="https://avatars3.githubusercontent.com/u/21033516?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Manan</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/pulls?q=is%3Apr+reviewed-by%3AMananS77" title="Reviewed Pull Requests">👀</a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/nishant"><img src="https://avatars2.githubusercontent.com/u/15331971?v=4" width="100px;" alt=""/><br /><sub><b>Nishant Arora</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=nishant" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/raja-peeyush-kumar-singh"><img src="https://avatars0.githubusercontent.com/u/5496024?v=4" width="100px;" alt=""/><br /><sub><b>Peeyush</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=raja-peeyush-kumar-singh" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/ravening"><img src="https://avatars1.githubusercontent.com/u/10645273?v=4" width="100px;" alt=""/><br /><sub><b>Rakesh</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=ravening" title="Code">💻</a> <a href="https://github.com/iluwatar/java-design-patterns/pulls?q=is%3Apr+reviewed-by%3Aravening" title="Reviewed Pull Requests">👀</a></td>
<td align="center"><a href="https://github.com/vINCENT8888801"><img src="https://avatars0.githubusercontent.com/u/8037883?v=4" width="100px;" alt=""/><br /><sub><b>Wei Seng</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=vINCENT8888801" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/nishant"><img src="https://avatars2.githubusercontent.com/u/15331971?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Nishant Arora</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=nishant" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/raja-peeyush-kumar-singh"><img src="https://avatars0.githubusercontent.com/u/5496024?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Peeyush</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=raja-peeyush-kumar-singh" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/ravening"><img src="https://avatars1.githubusercontent.com/u/10645273?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Rakesh</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=ravening" title="Code">💻</a> <a href="https://github.com/iluwatar/java-design-patterns/pulls?q=is%3Apr+reviewed-by%3Aravening" title="Reviewed Pull Requests">👀</a></td>
<td align="center"><a href="https://github.com/vINCENT8888801"><img src="https://avatars0.githubusercontent.com/u/8037883?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Wei Seng</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=vINCENT8888801" title="Code">💻</a></td>
</tr>
<tr>
<td align="center"><a href="https://www.linkedin.com/in/ashish-trivedi-218379135/"><img src="https://avatars3.githubusercontent.com/u/23194128?v=4" width="100px;" alt=""/><br /><sub><b>Ashish Trivedi</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=ashishtrivedi16" title="Code">💻</a></td>
<td align="center"><a href="https://rayyounghong.com"><img src="https://avatars1.githubusercontent.com/u/41055099?v=4" width="100px;" alt=""/><br /><sub><b>洪月阳</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=RayYH" title="Code">💻</a></td>
<td align="center"><a href="https://xdvrx1.github.io/"><img src="https://avatars0.githubusercontent.com/u/47092464?v=4" width="100px;" alt=""/><br /><sub><b>xdvrx1</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/pulls?q=is%3Apr+reviewed-by%3Axdvrx1" title="Reviewed Pull Requests">👀</a> <a href="#ideas-xdvrx1" title="Ideas, Planning, & Feedback">🤔</a></td>
<td align="center"><a href="http://subho.xyz"><img src="https://avatars0.githubusercontent.com/u/13291222?v=4" width="100px;" alt=""/><br /><sub><b>Subhrodip Mohanta</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=ohbus" title="Code">💻</a> <a href="https://github.com/iluwatar/java-design-patterns/pulls?q=is%3Apr+reviewed-by%3Aohbus" title="Reviewed Pull Requests">👀</a></td>
<td align="center"><a href="https://www.linkedin.com/in/ashish-trivedi-218379135/"><img src="https://avatars3.githubusercontent.com/u/23194128?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ashish Trivedi</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=ashishtrivedi16" title="Code">💻</a></td>
<td align="center"><a href="https://rayyounghong.com"><img src="https://avatars1.githubusercontent.com/u/41055099?v=4?s=100" width="100px;" alt=""/><br /><sub><b>洪月阳</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=RayYH" title="Code">💻</a></td>
<td align="center"><a href="https://xdvrx1.github.io/"><img src="https://avatars0.githubusercontent.com/u/47092464?v=4?s=100" width="100px;" alt=""/><br /><sub><b>xdvrx1</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/pulls?q=is%3Apr+reviewed-by%3Axdvrx1" title="Reviewed Pull Requests">👀</a> <a href="#ideas-xdvrx1" title="Ideas, Planning, & Feedback">🤔</a></td>
<td align="center"><a href="http://subho.xyz"><img src="https://avatars0.githubusercontent.com/u/13291222?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Subhrodip Mohanta</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=ohbus" title="Code">💻</a> <a href="https://github.com/iluwatar/java-design-patterns/pulls?q=is%3Apr+reviewed-by%3Aohbus" title="Reviewed Pull Requests">👀</a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/nahteb"><img src="https://avatars3.githubusercontent.com/u/13121570?v=4" width="100px;" alt=""/><br /><sub><b>Bethan Palmer</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=nahteb" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/ToxicDreamz"><img src="https://avatars0.githubusercontent.com/u/45225562?v=4" width="100px;" alt=""/><br /><sub><b>Toxic Dreamz</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=ToxicDreamz" title="Code">💻</a></td>
<td align="center"><a href="http://www.edycutjong.com"><img src="https://avatars1.githubusercontent.com/u/1098102?v=4" width="100px;" alt=""/><br /><sub><b>Edy Cu Tjong</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=edycutjong" title="Documentation">📖</a></td>
<td align="center"><a href="https://github.com/mkrzywanski"><img src="https://avatars0.githubusercontent.com/u/15279585?v=4" width="100px;" alt=""/><br /><sub><b>Michał Krzywański</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=mkrzywanski" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/nahteb"><img src="https://avatars3.githubusercontent.com/u/13121570?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Bethan Palmer</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=nahteb" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/ToxicDreamz"><img src="https://avatars0.githubusercontent.com/u/45225562?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Toxic Dreamz</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=ToxicDreamz" title="Code">💻</a></td>
<td align="center"><a href="http://www.edycutjong.com"><img src="https://avatars1.githubusercontent.com/u/1098102?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Edy Cu Tjong</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=edycutjong" title="Documentation">📖</a></td>
<td align="center"><a href="https://github.com/mkrzywanski"><img src="https://avatars0.githubusercontent.com/u/15279585?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Michał Krzywański</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=mkrzywanski" title="Code">💻</a></td>
</tr>
<tr>
<td align="center"><a href="https://www.stefan-birkner.de"><img src="https://avatars1.githubusercontent.com/u/711349?v=4" width="100px;" alt=""/><br /><sub><b>Stefan Birkner</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=stefanbirkner" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/fedorskvorcov"><img src="https://avatars3.githubusercontent.com/u/43882212?v=4" width="100px;" alt=""/><br /><sub><b>Fedor Skvorcov</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=fedorskvorcov" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/samilAyoub"><img src="https://avatars0.githubusercontent.com/u/61546990?v=4" width="100px;" alt=""/><br /><sub><b>samilAyoub</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=samilAyoub" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/vdlald"><img src="https://avatars0.githubusercontent.com/u/29997701?v=4" width="100px;" alt=""/><br /><sub><b>Vladislav Golubinov</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=vdlald" title="Code">💻</a></td>
<td align="center"><a href="https://www.stefan-birkner.de"><img src="https://avatars1.githubusercontent.com/u/711349?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Stefan Birkner</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=stefanbirkner" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/fedorskvorcov"><img src="https://avatars3.githubusercontent.com/u/43882212?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Fedor Skvorcov</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=fedorskvorcov" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/samilAyoub"><img src="https://avatars0.githubusercontent.com/u/61546990?v=4?s=100" width="100px;" alt=""/><br /><sub><b>samilAyoub</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=samilAyoub" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/vdlald"><img src="https://avatars0.githubusercontent.com/u/29997701?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Vladislav Golubinov</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=vdlald" title="Code">💻</a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/swarajsaaj"><img src="https://avatars2.githubusercontent.com/u/6285049?v=4" width="100px;" alt=""/><br /><sub><b>Swaraj</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=swarajsaaj" title="Code">💻</a></td>
<td align="center"><a href="http://christophflick.de"><img src="https://avatars0.githubusercontent.com/u/4465376?v=4" width="100px;" alt=""/><br /><sub><b>Christoph Flick</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=ChFlick" title="Documentation">📖</a></td>
<td align="center"><a href="https://github.com/Ascenio"><img src="https://avatars1.githubusercontent.com/u/7662016?v=4" width="100px;" alt=""/><br /><sub><b>Ascênio</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/pulls?q=is%3Apr+reviewed-by%3AAscenio" title="Reviewed Pull Requests">👀</a></td>
<td align="center"><a href="https://www.linkedin.com/in/domenico-sibilio/"><img src="https://avatars2.githubusercontent.com/u/24280982?v=4" width="100px;" alt=""/><br /><sub><b>Domenico Sibilio</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=dsibilio" title="Documentation">📖</a></td>
<td align="center"><a href="https://github.com/swarajsaaj"><img src="https://avatars2.githubusercontent.com/u/6285049?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Swaraj</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=swarajsaaj" title="Code">💻</a></td>
<td align="center"><a href="http://christophflick.de"><img src="https://avatars0.githubusercontent.com/u/4465376?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Christoph Flick</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=ChFlick" title="Documentation">📖</a></td>
<td align="center"><a href="https://github.com/Ascenio"><img src="https://avatars1.githubusercontent.com/u/7662016?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ascênio</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/pulls?q=is%3Apr+reviewed-by%3AAscenio" title="Reviewed Pull Requests">👀</a></td>
<td align="center"><a href="https://www.linkedin.com/in/domenico-sibilio/"><img src="https://avatars2.githubusercontent.com/u/24280982?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Domenico Sibilio</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=dsibilio" title="Documentation">📖</a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/akashchandwani"><img src="https://avatars2.githubusercontent.com/u/3483277?v=4" width="100px;" alt=""/><br /><sub><b>Akash Chandwani</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/pulls?q=is%3Apr+reviewed-by%3Aakashchandwani" title="Reviewed Pull Requests">👀</a></td>
<td align="center"><a href="http://www.linkedin.com/in/manannikov"><img src="https://avatars2.githubusercontent.com/u/7019769?v=4" width="100px;" alt=""/><br /><sub><b>Pavlo Manannikov</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=manannikov" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/eimanip"><img src="https://avatars0.githubusercontent.com/u/20307301?v=4" width="100px;" alt=""/><br /><sub><b>Eiman</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=eimanip" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/OrangePants-R"><img src="https://avatars0.githubusercontent.com/u/42976136?v=4" width="100px;" alt=""/><br /><sub><b>Rocky</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=OrangePants-R" title="Documentation">📖</a></td>
<td align="center"><a href="https://github.com/akashchandwani"><img src="https://avatars2.githubusercontent.com/u/3483277?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Akash Chandwani</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/pulls?q=is%3Apr+reviewed-by%3Aakashchandwani" title="Reviewed Pull Requests">👀</a></td>
<td align="center"><a href="http://www.linkedin.com/in/manannikov"><img src="https://avatars2.githubusercontent.com/u/7019769?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Pavlo Manannikov</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=manannikov" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/eimanip"><img src="https://avatars0.githubusercontent.com/u/20307301?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Eiman</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=eimanip" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/OrangePants-R"><img src="https://avatars0.githubusercontent.com/u/42976136?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Rocky</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=OrangePants-R" title="Documentation">📖</a></td>
</tr>
<tr>
<td align="center"><a href="https://ibrahimalii.github.io/"><img src="https://avatars2.githubusercontent.com/u/21141301?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Ibrahim ali abdelghany</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/pulls?q=is%3Apr+reviewed-by%3AibrahimAlii" title="Reviewed Pull Requests">👀</a></td>
<td align="center"><a href="https://github.com/gkulkarni2020"><img src="https://avatars3.githubusercontent.com/u/5161548?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Girish Kulkarni</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=gkulkarni2020" title="Documentation">📖</a></td>
<td align="center"><a href="https://github.com/omk13"><img src="https://avatars0.githubusercontent.com/u/59054172?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Omar Karazoun</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=omk13" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/jeff303"><img src="https://avatars0.githubusercontent.com/u/3521562?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Jeff Evans</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=jeff303" title="Code">💻</a></td>
</tr>
<tr>
<td align="center"><a href="https://viveksb007.github.io"><img src="https://avatars1.githubusercontent.com/u/12713808?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Vivek Singh</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=viveksb007" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/siavashsoleymani"><img src="https://avatars2.githubusercontent.com/u/18074419?v=4?s=100" width="100px;" alt=""/><br /><sub><b>siavash</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=siavashsoleymani" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/ruchpeanuts"><img src="https://avatars0.githubusercontent.com/u/29301900?v=4?s=100" width="100px;" alt=""/><br /><sub><b>ruchpeanuts</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=ruchpeanuts" title="Documentation">📖</a></td>
<td align="center"><a href="https://github.com/warp125"><img src="https://avatars1.githubusercontent.com/u/48073115?v=4?s=100" width="100px;" alt=""/><br /><sub><b>warp125</b></sub></a><br /><a href="#translation-warp125" title="Translation">🌍</a></td>
</tr>
<tr>
<td align="center"><a href="http://libkhadir.fr"><img src="https://avatars1.githubusercontent.com/u/45130488?v=4?s=100" width="100px;" alt=""/><br /><sub><b>KHADIR Tayeb</b></sub></a><br /><a href="#translation-tkhadir" title="Translation">🌍</a></td>
<td align="center"><a href="https://github.com/ignite1771"><img src="https://avatars2.githubusercontent.com/u/59446563?v=4?s=100" width="100px;" alt=""/><br /><sub><b>ignite1771</b></sub></a><br /><a href="https://github.com/iluwatar/java-design-patterns/commits?author=ignite1771" title="Code">💻</a></td>
<td align="center"><a href="https://github.com/demirhalil"><img src="https://avatars1.githubusercontent.com/u/22895118?v=4?s=100" width="100px;" alt=""/><br /><sub><b>Halil Demir</b></sub></a><br /><a href="#translation-demirhalil" title="Translation">🌍</a></td>
</tr>
</table>
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@ -23,7 +23,13 @@
package com.iluwatar.datatransfer;
import com.iluwatar.datatransfer.customer.CustomerDto;
import com.iluwatar.datatransfer.customer.CustomerResource;
import com.iluwatar.datatransfer.product.Product;
import com.iluwatar.datatransfer.product.ProductDto;
import com.iluwatar.datatransfer.product.ProductResource;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
@ -32,11 +38,17 @@ import org.slf4j.LoggerFactory;
* The Data Transfer Object pattern is a design pattern in which an data transfer object is used to
* serve related information together to avoid multiple call for each piece of information.
*
* <p>In this example, ({@link App}) as as customer details consumer i.e. client to
* request for customer details to server.
* <p>In the first example, {@link App} is a customer details consumer i.e. client to
* request for customer details to server. {@link CustomerResource} act as server to serve customer
* information. {@link CustomerDto} is data transfer object to share customer information.
*
* <p>In the second example, {@link App} is a product details consumer i.e. client to
* request for product details to server. {@link ProductResource} acts as server to serve
* product information. {@link ProductDto} is data transfer object to share product information.
*
* <p>The pattern implementation is a bit different in each of the examples. The first can be
* thought as a traditional example and the second is an enum based implementation.
*
* <p>CustomerResource ({@link CustomerResource}) act as server to serve customer information. And
* The CustomerDto ({@link CustomerDto} is data transfer object to share customer information.
*/
public class App {
@ -48,6 +60,8 @@ public class App {
* @param args program argument.
*/
public static void main(String[] args) {
// Example 1: Customer DTO
var customerOne = new CustomerDto("1", "Kelly", "Brown");
var customerTwo = new CustomerDto("2", "Alfonso", "Bass");
var customers = new ArrayList<>(List.of(customerOne, customerTwo));
@ -72,6 +86,53 @@ public class App {
customerResource.save(customerThree);
allCustomers = customerResource.getAllCustomers();
printCustomerDetails(allCustomers);
// Example 2: Product DTO
Product tv =
new Product().setId(1L).setName("TV").setSupplier("Sony").setPrice(1000D).setCost(1090D);
Product microwave =
new Product()
.setId(2L)
.setName("microwave")
.setSupplier("Delonghi")
.setPrice(1000D)
.setCost(1090D);
Product refrigerator =
new Product()
.setId(3L)
.setName("refrigerator")
.setSupplier("Botsch")
.setPrice(1000D)
.setCost(1090D);
Product airConditioner =
new Product()
.setId(4L)
.setName("airConditioner")
.setSupplier("LG")
.setPrice(1000D)
.setCost(1090D);
List<Product> products =
new ArrayList<>(Arrays.asList(tv, microwave, refrigerator, airConditioner));
ProductResource productResource = new ProductResource(products);
LOGGER.info(
"####### List of products including sensitive data just for admins: \n {}",
Arrays.toString(productResource.getAllProductsForAdmin().toArray()));
LOGGER.info(
"####### List of products for customers: \n {}",
Arrays.toString(productResource.getAllProductsForCustomer().toArray()));
LOGGER.info("####### Going to save Sony PS5 ...");
ProductDto.Request.Create createProductRequestDto =
new ProductDto.Request.Create()
.setName("PS5")
.setCost(1000D)
.setPrice(1220D)
.setSupplier("Sony");
productResource.save(createProductRequestDto);
LOGGER.info(
"####### List of products after adding PS5: {}",
Arrays.toString(productResource.getProducts().toArray()));
}
private static void printCustomerDetails(List<CustomerDto> allCustomers) {

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@ -21,7 +21,7 @@
* THE SOFTWARE.
*/
package com.iluwatar.datatransfer;
package com.iluwatar.datatransfer.customer;
/**
* {@link CustomerDto} is a data transfer object POJO. Instead of sending individual information to

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@ -21,7 +21,7 @@
* THE SOFTWARE.
*/
package com.iluwatar.datatransfer;
package com.iluwatar.datatransfer.customer;
import java.util.List;

View File

@ -0,0 +1,114 @@
/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.datatransfer.product;
/**
* {@link Product} is a entity class for product entity. This class act as entity in the demo.
*/
public final class Product {
private Long id;
private String name;
private Double price;
private Double cost;
private String supplier;
/**
* Constructor.
*
* @param id product id
* @param name product name
* @param price product price
* @param cost product cost
* @param supplier product supplier
*/
public Product(Long id, String name, Double price, Double cost, String supplier) {
this.id = id;
this.name = name;
this.price = price;
this.cost = cost;
this.supplier = supplier;
}
/**
* Constructor.
*/
public Product() {
}
public Long getId() {
return id;
}
public Product setId(Long id) {
this.id = id;
return this;
}
public String getName() {
return name;
}
public Product setName(String name) {
this.name = name;
return this;
}
public Double getPrice() {
return price;
}
public Product setPrice(Double price) {
this.price = price;
return this;
}
public Double getCost() {
return cost;
}
public Product setCost(Double cost) {
this.cost = cost;
return this;
}
public String getSupplier() {
return supplier;
}
public Product setSupplier(String supplier) {
this.supplier = supplier;
return this;
}
@Override
public String toString() {
return "Product{"
+ "id=" + id
+ ", name='" + name + '\''
+ ", price=" + price
+ ", cost=" + cost
+ ", supplier='" + supplier + '\''
+ '}';
}
}

View File

@ -0,0 +1,287 @@
/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.datatransfer.product;
/**
* {@link ProductDto} is a data transfer object POJO.
* Instead of sending individual information to
* client We can send related information together in POJO.
*
* <p>Dto will not have any business logic in it.
*/
public enum ProductDto {
;
/**
* This is Request class which consist of Create or any other request DTO's
* you might want to use in your API.
*/
public enum Request {
;
/**
* This is Create dto class for requesting create new product.
*/
public static final class Create implements Name, Price, Cost, Supplier {
private String name;
private Double price;
private Double cost;
private String supplier;
@Override
public String getName() {
return name;
}
public Create setName(String name) {
this.name = name;
return this;
}
@Override
public Double getPrice() {
return price;
}
public Create setPrice(Double price) {
this.price = price;
return this;
}
@Override
public Double getCost() {
return cost;
}
public Create setCost(Double cost) {
this.cost = cost;
return this;
}
@Override
public String getSupplier() {
return supplier;
}
public Create setSupplier(String supplier) {
this.supplier = supplier;
return this;
}
}
}
/**
* This is Response class which consist of any response DTO's
* you might want to provide to your clients.
*/
public enum Response {
;
/**
* This is Public dto class for API response with the lowest data security.
*/
public static final class Public implements Id, Name, Price {
private Long id;
private String name;
private Double price;
@Override
public Long getId() {
return id;
}
public Public setId(Long id) {
this.id = id;
return this;
}
@Override
public String getName() {
return name;
}
public Public setName(String name) {
this.name = name;
return this;
}
@Override
public Double getPrice() {
return price;
}
public Public setPrice(Double price) {
this.price = price;
return this;
}
@Override
public String toString() {
return "Public{"
+ "id="
+ id
+ ", name='"
+ name
+ '\''
+ ", price="
+ price
+ '}';
}
}
/**
* This is Private dto class for API response with the highest data security.
*/
public static final class Private implements Id, Name, Price, Cost {
private Long id;
private String name;
private Double price;
private Double cost;
@Override
public Long getId() {
return id;
}
public Private setId(Long id) {
this.id = id;
return this;
}
@Override
public String getName() {
return name;
}
public Private setName(String name) {
this.name = name;
return this;
}
@Override
public Double getPrice() {
return price;
}
public Private setPrice(Double price) {
this.price = price;
return this;
}
@Override
public Double getCost() {
return cost;
}
public Private setCost(Double cost) {
this.cost = cost;
return this;
}
@Override
public String toString() {
return "Private{"
+
"id="
+ id
+
", name='"
+ name
+ '\''
+
", price="
+ price
+
", cost="
+ cost
+
'}';
}
}
}
/**
* Use this interface whenever you want to provide the product Id in your DTO.
*/
private interface Id {
/**
* Unique identifier of the product.
*
* @return : id of the product.
*/
Long getId();
}
/**
* Use this interface whenever you want to provide the product Name in your DTO.
*/
private interface Name {
/**
* The name of the product.
*
* @return : name of the product.
*/
String getName();
}
/**
* Use this interface whenever you want to provide the product Price in your DTO.
*/
private interface Price {
/**
* The amount we sell a product for.
* <b>This data is not confidential</b>
*
* @return : price of the product.
*/
Double getPrice();
}
/**
* Use this interface whenever you want to provide the product Cost in your DTO.
*/
private interface Cost {
/**
* The amount that it costs us to purchase this product
* For the amount we sell a product for, see the {@link Price Price} parameter.
* <b>This data is confidential</b>
*
* @return : cost of the product.
*/
Double getCost();
}
/**
* Use this interface whenever you want to provide the product Supplier in your DTO.
*/
private interface Supplier {
/**
* The name of supplier of the product or its manufacturer.
* <b>This data is highly confidential</b>
*
* @return : supplier of the product.
*/
String getSupplier();
}
}

View File

@ -0,0 +1,94 @@
/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.datatransfer.product;
import java.util.List;
import java.util.stream.Collectors;
/**
* The resource class which serves product information. This class act as server in the demo. Which
* has all product details.
*/
public class ProductResource {
private final List<Product> products;
/**
* Initialise resource with existing products.
*
* @param products initialize resource with existing products. Act as database.
*/
public ProductResource(final List<Product> products) {
this.products = products;
}
/**
* Get all products.
*
* @return : all products in list but in the scheme of private dto.
*/
public List<ProductDto.Response.Private> getAllProductsForAdmin() {
return products
.stream()
.map(p -> new ProductDto.Response.Private().setId(p.getId()).setName(p.getName())
.setCost(p.getCost())
.setPrice(p.getPrice()))
.collect(Collectors.toList());
}
/**
* Get all products.
*
* @return : all products in list but in the scheme of public dto.
*/
public List<ProductDto.Response.Public> getAllProductsForCustomer() {
return products
.stream()
.map(p -> new ProductDto.Response.Public().setId(p.getId()).setName(p.getName())
.setPrice(p.getPrice()))
.collect(Collectors.toList());
}
/**
* Save new product.
*
* @param createProductDto save new product to list.
*/
public void save(ProductDto.Request.Create createProductDto) {
products.add(new Product()
.setId((long) (products.size() + 1))
.setName(createProductDto.getName())
.setSupplier(createProductDto.getSupplier())
.setPrice(createProductDto.getPrice())
.setCost(createProductDto.getCost()));
}
/**
* List of all products in an entity representation.
*
* @return : all the products entity that stored in the products list
*/
public List<Product> getProducts() {
return products;
}
}

View File

@ -21,13 +21,16 @@
* THE SOFTWARE.
*/
package com.iluwatar.datatransfer;
package com.iluwatar.datatransfer.customer;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertTrue;
import java.util.ArrayList;
import java.util.List;
import com.iluwatar.datatransfer.customer.CustomerDto;
import com.iluwatar.datatransfer.customer.CustomerResource;
import org.junit.jupiter.api.Test;
/**

View File

@ -81,7 +81,7 @@ public enum CarType {
}
```
Then we have the static method `getCar` to create car objects encapsulated in the factory class
`CarSimpleFactory`.
`CarsFactory`.
```java
public class CarsFactory {
@ -98,7 +98,7 @@ Now on the client code we can create different types of cars using the factory c
var car1 = CarsFactory.getCar(CarType.FORD);
var car2 = CarsFactory.getCar(CarType.FERRARI);
LOGGER.info(car1.getDescription());
LOGGER.info(car2.getDescription());;
LOGGER.info(car2.getDescription());
```
Program output:
@ -119,13 +119,23 @@ and manage it.
Pros
* Allows keeping all objects creation in one place and avoid of spreading 'new' key value across codebase.
* Allows to writs loosely coupled code. Some of its main advantages include better testability, easy-to-understand code, swappable components, scalability and isolated features.
* Allows keeping all objects creation in one place and avoid of spreading 'new' keyword across codebase.
* Allows to write loosely coupled code. Some of its main advantages include better testability, easy-to-understand code, swappable components, scalability and isolated features.
Cons
* The code becomes more complicated than it should be.
## Real world examples
* [java.util.Calendar#getInstance()](https://docs.oracle.com/javase/8/docs/api/java/util/Calendar.html#getInstance--)
* [java.util.ResourceBundle#getBundle()](https://docs.oracle.com/javase/8/docs/api/java/util/ResourceBundle.html#getBundle-java.lang.String-)
* [java.text.NumberFormat#getInstance()](https://docs.oracle.com/javase/8/docs/api/java/text/NumberFormat.html#getInstance--)
* [java.nio.charset.Charset#forName()](https://docs.oracle.com/javase/8/docs/api/java/nio/charset/Charset.html#forName-java.lang.String-)
* [java.net.URLStreamHandlerFactory#createURLStreamHandler(String)](https://docs.oracle.com/javase/8/docs/api/java/net/URLStreamHandlerFactory.html) (Returns different singleton objects, depending on a protocol)
* [java.util.EnumSet#of()](https://docs.oracle.com/javase/8/docs/api/java/util/EnumSet.html#of(E))
* [javax.xml.bind.JAXBContext#createMarshaller()](https://docs.oracle.com/javase/8/docs/api/javax/xml/bind/JAXBContext.html#createMarshaller--) and other similar methods.
## Related patterns
* [Factory Method](https://java-design-patterns.com/patterns/factory-method/)

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@ -0,0 +1,60 @@
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afin qu'on puisse avoir un affichage agréable comme sur un
site web par exemple -->
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# Introduction
Le patron de conception est la meilleure formatalisation qu'un programmeur
peut utiliser pour résoudre un problème lors d'une conception d'une application/system.
Le patron de conception (design pattern) est là pour accélérer le processus de
développement en fournissant des paradigmes éprouvés.
La réutilisation de patron de conception aide à prévenir des problèmes subtiles mais
qui sont à l'origine de problèmes majeures, comme cette pratique augmente la lisibilitée
du code par les développeurs/architectes familiers avec l'utilisation de ces concepts.
# Commencer
Ce site présente des modèles de conception Java. Les solutions ont été développées par des
développeurs et architectes expérimentés de la communauté open source. Les modèles peuvent être parcourus par leurs descriptions de haut niveau ou en regardant leur code source. Les exemples de code source sont bien commentés et peuvent être considérés comme tutoriels de programmation sur la façon d'implémenter un modèle spécifique. Nous utilisons le plus technologies Java open source éprouvées au combat.
Avant de plonger dans le matériau, vous devez vous familiariser avec divers
[Principes de conception de logiciels](https://java-design-patterns.com/principles/).
Toutes les conceptions doivent être aussi simples que possible. Vous devriez commencer par KISS, YAGNI,
et faire la chose la plus simple qui pourrait éventuellement fonctionner principes. Complexité et
les modèles ne devraient être introduits que lorsqu'ils sont nécessaires pour
extensibilité.
Une fois que vous êtes familiarisé avec ces concepts, vous pouvez commencer à explorer
[modèles de conception disponibles](https://java-design-patterns.com/patterns/) par tout
des approches suivantes
- Recherchez un modèle spécifique par son nom. Vous n'en trouvez pas? Veuillez signaler un nouveau modèle [ici](https://github.com/iluwatar/java-design-patterns/issues).
- Utilisation de balises telles que `Performance`, `Gang of Four` ou `Data access`.
- Utilisation des catégories de modèles, `Créatif`, `Comportemental` et autres.
J'espère que les solutions orientées objet présentées sur ce site vous seront utiles
dans vos architectures et ayez autant de plaisir à les apprendre que nous en avons eu à les développer.
# Comment contribuer
Si vous souhaitez contribuer au projet, vous trouverez les informations pertinentes dans
notre [wiki développeur](https://github.com/iluwatar/java-design-patterns/wiki). Nous aiderons
vous et répondez à vos questions dans le [Gitter chatroom](https://gitter.im/iluwatar/java-design-patterns).
# Licence
Ce projet est concédé sous les termes de la licence MIT.

View File

@ -23,7 +23,7 @@
package com.iluwatar.gameloop;
import org.junit.Test;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;

View File

@ -23,10 +23,11 @@
package com.iluwatar.gameloop;
import org.junit.After;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import static org.junit.jupiter.api.Assertions.assertEquals;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
/**
* FixedStepGameLoop unit test class.
@ -35,12 +36,12 @@ public class FixedStepGameLoopTest {
private FixedStepGameLoop gameLoop;
@Before
@BeforeEach
public void setup() {
gameLoop = new FixedStepGameLoop();
}
@After
@AfterEach
public void tearDown() {
gameLoop = null;
}
@ -48,7 +49,7 @@ public class FixedStepGameLoopTest {
@Test
public void testUpdate() {
gameLoop.update();
Assert.assertEquals(0.01f, gameLoop.controller.getBulletPosition(), 0);
assertEquals(0.01f, gameLoop.controller.getBulletPosition(), 0);
}
}

View File

@ -23,10 +23,10 @@
package com.iluwatar.gameloop;
import org.junit.After;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import static org.junit.jupiter.api.Assertions.assertEquals;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
/**
* FrameBasedGameLoop unit test class.
@ -35,19 +35,19 @@ public class FrameBasedGameLoopTest {
private FrameBasedGameLoop gameLoop;
@Before
@BeforeEach
public void setup() {
gameLoop = new FrameBasedGameLoop();
}
@After
@AfterEach
public void tearDown() {
gameLoop = null;
}
@Test
@org.junit.jupiter.api.Test
public void testUpdate() {
gameLoop.update();
Assert.assertEquals(0.5f, gameLoop.controller.getBulletPosition(), 0);
assertEquals(0.5f, gameLoop.controller.getBulletPosition(), 0);
}
}

View File

@ -23,34 +23,33 @@
package com.iluwatar.gameloop;
import org.junit.After;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
public class GameControllerTest {
private GameController controller;
@Before
@BeforeEach
public void setup() {
controller = new GameController();
}
@After
@AfterEach
public void tearDown() {
controller = null;
}
@Test
@org.junit.jupiter.api.Test
public void testMoveBullet() {
controller.moveBullet(1.5f);
Assert.assertEquals(1.5f, controller.bullet.getPosition(), 0);
Assertions.assertEquals(1.5f, controller.bullet.getPosition(), 0);
}
@Test
@org.junit.jupiter.api.Test
public void testGetBulletPosition() {
Assert.assertEquals(controller.bullet.getPosition(), controller.getBulletPosition(), 0);
Assertions.assertEquals(controller.bullet.getPosition(), controller.getBulletPosition(), 0);
}
}

View File

@ -23,10 +23,9 @@
package com.iluwatar.gameloop;
import org.junit.After;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.BeforeEach;
/**
* GameLoop unit test class.
@ -38,7 +37,7 @@ public class GameLoopTest {
/**
* Create mock implementation of GameLoop.
*/
@Before
@BeforeEach
public void setup() {
gameLoop = new GameLoop() {
@Override
@ -46,26 +45,26 @@ public class GameLoopTest {
};
}
@After
@AfterEach
public void tearDown() {
gameLoop = null;
}
@Test
@org.junit.jupiter.api.Test
public void testRun() {
gameLoop.run();
Assert.assertEquals(GameStatus.RUNNING, gameLoop.status);
Assertions.assertEquals(GameStatus.RUNNING, gameLoop.status);
}
@Test
@org.junit.jupiter.api.Test
public void testStop() {
gameLoop.stop();
Assert.assertEquals(GameStatus.STOPPED, gameLoop.status);
Assertions.assertEquals(GameStatus.STOPPED, gameLoop.status);
}
@Test
@org.junit.jupiter.api.Test
public void testIsGameRunning() {
Assert.assertFalse(gameLoop.isGameRunning());
Assertions.assertFalse(gameLoop.isGameRunning());
}
}

View File

@ -23,11 +23,9 @@
package com.iluwatar.gameloop;
import java.lang.reflect.InvocationTargetException;
import org.junit.After;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeEach;
/**
* VariableStepGameLoop unit test class.
@ -36,19 +34,19 @@ public class VariableStepGameLoopTest {
private VariableStepGameLoop gameLoop;
@Before
@BeforeEach
public void setup() {
gameLoop = new VariableStepGameLoop();
}
@After
@AfterEach
public void tearDown() {
gameLoop = null;
}
@Test
@org.junit.jupiter.api.Test
public void testUpdate() {
gameLoop.update(20L);
Assert.assertEquals(0.01f, gameLoop.controller.getBulletPosition(), 0);
Assertions.assertEquals(0.01f, gameLoop.controller.getBulletPosition(), 0);
}
}

263
ko/README.md Normal file
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@ -0,0 +1,263 @@
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that smart and dearly wants an empty line before a heading to be able to
display it as such, e.g. website) -->
# 자바로 구현된 디자인 패턴
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<!-- ALL-CONTRIBUTORS-BADGE:END -->
# 소개
디자인 패턴은 프로그래머가 응용 프로그램이나 시스템을 디자인 할 때 일반적인 문제를 해결하는 데 사용할 수있는 가장 공식화 된 방법입니다.
디자인 패턴은 테스트되고 입증 된 개발 패러다임을 제공하여 개발 프로세스 속도를 높일 수 있습니다.
디자인 패턴을 재사용하면 주요 문제를 유발하는 미묘한 이슈들을 방지하는데 도움이 되며 또한 패턴에 익숙한 코더와 아키텍트의 코드 가독성도 향상됩니다.
# 시작하기
이 사이트는 Java 디자인 패턴을 보여줍니다. 이 솔루션은 오픈 소스 커뮤니티의 경험이 많은 프로그래머와 설계자가 개발했습니다. 패턴은 높은 수준의 설명이나 소스 코드를 통해 찾아 볼 수 있습니다. 소스 코드 예제는 잘 설명되어 있으며 특정 패턴을 구현하는 방법을 알려주는 프로그래밍 튜토리얼로 생각할 수 있습니다. 우리는 가장 널리 알려지고 실무에서 입증된 오픈 소스 Java 기술을 사용합니다.
자료를 살펴보기 전에 다양한 [소프트웨어 설계 원칙](https://java-design-patterns.com/principles/)을 숙지해야합니다.
모든 디자인은 가능한 한 단순해야합니다. 당신은 KISS, YAGNI로 시작해야하며, 원칙을 작동 할 수 있는 가장 단순한 일을 해야합니다. 복잡성과 패턴은 실용적인 확장성을 위해 필요할 때만 도입되어야합니다.
이러한 개념에 익숙해지면 다음 접근 방식 중 하나를 이용하여 [사용 가능한 디자인 패턴](https://java-design-patterns.com/patterns/)으로 드릴다운 할 수 있습니다.
- 이름으로 특정 패턴을 검색합니다. 찾을 수 없습니까? [여기](https://github.com/iluwatar/java-design-patterns/issues)에서 새 패턴을 보고하십시오.
- `Performance`, `Gang of Four` 또는 `Data access` 태그 사용.
- 패턴 카테고리, `Creational`, `Behavioral` 및 기타 사용
이 사이트에 제시된 객체 지향 솔루션이 여러분의 아키텍처에서 유용하고 우리가 개발 한 것만큼 재미있게 배우기를 바랍니다.
# 기여하는 방법
프로젝트에 기여할 의향이 있다면 [developer wiki](https://github.com/iluwatar/java-design-patterns/wiki)에서 관련 정보를 찾을 수 있습니다. [Gitter chatroom](https://gitter.im/iluwatar/java-design-patterns)에서 귀하를 돕고 질문에 답변 해 드리겠습니다.
# 특허
이 프로젝트는 MIT 라이센스 조건에 따라 라이센스가 부여됩니다.
# 기여자
<!-- ALL-CONTRIBUTORS-LIST:START - Do not remove or modify this section -->
<!-- prettier-ignore-start -->
<!-- markdownlint-disable -->
<table>
<tr>
<td align="center"><a href="https://github.com/iluwatar"><img src="https://avatars1.githubusercontent.com/u/582346?v=4" width="100px;" alt=""><br><sub><b>Ilkka Seppälä</b></sub></a></td>
<td align="center"><a href="https://github.com/amit1307"><img src="https://avatars0.githubusercontent.com/u/23420222?v=4" width="100px;" alt=""><br><sub><b>amit1307</b></sub></a></td>
<td align="center"><a href="https://github.com/npathai"><img src="https://avatars2.githubusercontent.com/u/1792515?v=4" width="100px;" alt=""><br><sub><b>Narendra Pathai</b></sub></a></td>
<td align="center"><a href="https://github.com/fluxw42"><img src="https://avatars1.githubusercontent.com/u/1545460?v=4" width="100px;" alt=""><br><sub><b>Jeroen Meulemeester</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="http://www.joemccarthy.co.uk"><img src="https://avatars0.githubusercontent.com/u/4526195?v=4" width="100px;" alt=""><br><sub><b>Joseph McCarthy</b></sub></a></td>
<td align="center"><a href="https://github.com/thomasoss"><img src="https://avatars1.githubusercontent.com/u/22516154?v=4" width="100px;" alt=""><br><sub><b>Thomas</b></sub></a></td>
<td align="center"><a href="https://github.com/anuragagarwal561994"><img src="https://avatars1.githubusercontent.com/u/6075379?v=4" width="100px;" alt=""><br><sub><b>Anurag Agarwal</b></sub></a></td>
<td align="center"><a href="https://markusmo3.github.io"><img src="https://avatars1.githubusercontent.com/u/3317416?v=4" width="100px;" alt=""><br><sub><b>Markus Moser</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://twitter.com/i_sabiq"><img src="https://avatars1.githubusercontent.com/u/19510920?v=4" width="100px;" alt=""><br><sub><b>Sabiq Ihab</b></sub></a></td>
<td align="center"><a href="http://inbravo.github.io"><img src="https://avatars3.githubusercontent.com/u/5253764?v=4" width="100px;" alt=""><br><sub><b>Amit Dixit</b></sub></a></td>
<td align="center"><a href="https://github.com/piyushchaudhari04"><img src="https://avatars3.githubusercontent.com/u/10268029?v=4" width="100px;" alt=""><br><sub><b>Piyush Kailash Chaudhari</b></sub></a></td>
<td align="center"><a href="https://github.com/joshzambales"><img src="https://avatars1.githubusercontent.com/u/8704552?v=4" width="100px;" alt=""><br><sub><b>joshzambales</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/Crossy147"><img src="https://avatars2.githubusercontent.com/u/7272996?v=4" width="100px;" alt=""><br><sub><b>Kamil Pietruszka</b></sub></a></td>
<td align="center"><a href="http://cs.joensuu.fi/~zkhayda"><img src="https://avatars2.githubusercontent.com/u/660742?v=4" width="100px;" alt=""><br><sub><b>Zafar Khaydarov</b></sub></a></td>
<td align="center"><a href="https://kemitix.github.io/"><img src="https://avatars1.githubusercontent.com/u/1147749?v=4" width="100px;" alt=""><br><sub><b>Paul Campbell</b></sub></a></td>
<td align="center"><a href="https://github.com/Argyro-Sioziou"><img src="https://avatars0.githubusercontent.com/u/22822639?v=4" width="100px;" alt=""><br><sub><b>Argyro Sioziou</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/TylerMcConville"><img src="https://avatars0.githubusercontent.com/u/4946449?v=4" width="100px;" alt=""><br><sub><b>TylerMcConville</b></sub></a></td>
<td align="center"><a href="https://github.com/saksham93"><img src="https://avatars1.githubusercontent.com/u/37399540?v=4" width="100px;" alt=""><br><sub><b>saksham93</b></sub></a></td>
<td align="center"><a href="https://github.com/nikhilbarar"><img src="https://avatars2.githubusercontent.com/u/37332144?v=4" width="100px;" alt=""><br><sub><b>nikhilbarar</b></sub></a></td>
<td align="center"><a href="http://colinbut.com"><img src="https://avatars2.githubusercontent.com/u/10725674?v=4" width="100px;" alt=""><br><sub><b>Colin But</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/ruslanpa"><img src="https://avatars2.githubusercontent.com/u/1503411?v=4" width="100px;" alt=""><br><sub><b>Ruslan</b></sub></a></td>
<td align="center"><a href="https://github.com/JuhoKang"><img src="https://avatars1.githubusercontent.com/u/4745294?v=4" width="100px;" alt=""><br><sub><b>Juho Kang</b></sub></a></td>
<td align="center"><a href="https://github.com/dheeraj-mummareddy"><img src="https://avatars2.githubusercontent.com/u/7002230?v=4" width="100px;" alt=""><br><sub><b>Dheeraj Mummareddy</b></sub></a></td>
<td align="center"><a href="https://www.bernardosulzbach.com"><img src="https://avatars0.githubusercontent.com/u/8271090?v=4" width="100px;" alt=""><br><sub><b>Bernardo Sulzbach</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/4lexis"><img src="https://avatars0.githubusercontent.com/u/19871727?v=4" width="100px;" alt=""><br><sub><b>Aleksandar Dudukovic</b></sub></a></td>
<td align="center"><a href="https://www.yusufaytas.com"><img src="https://avatars2.githubusercontent.com/u/1049483?v=4" width="100px;" alt=""><br><sub><b>Yusuf Aytaş</b></sub></a></td>
<td align="center"><a href="http://futurehomes.hu"><img src="https://avatars2.githubusercontent.com/u/1001491?v=4" width="100px;" alt=""><br><sub><b>Mihály Kuprivecz</b></sub></a></td>
<td align="center"><a href="https://github.com/kapinuss"><img src="https://avatars0.githubusercontent.com/u/17639945?v=4" width="100px;" alt=""><br><sub><b>Stanislav Kapinus</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/gvsharma"><img src="https://avatars1.githubusercontent.com/u/6648152?v=4" width="100px;" alt=""><br><sub><b>GVSharma</b></sub></a></td>
<td align="center"><a href="https://github.com/SrdjanPaunovic"><img src="https://avatars1.githubusercontent.com/u/22815104?v=4" width="100px;" alt=""><br><sub><b>Srđan Paunović</b></sub></a></td>
<td align="center"><a href="https://sideris.xyz/"><img src="https://avatars3.githubusercontent.com/u/5484694?v=4" width="100px;" alt=""><br><sub><b>Petros G. Sideris</b></sub></a></td>
<td align="center"><a href="https://www.linkedin.com/in/pramodgupta3/"><img src="https://avatars1.githubusercontent.com/u/2184241?v=4" width="100px;" alt=""><br><sub><b>Pramod Gupta</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://amarnath510.github.io/portfolio"><img src="https://avatars0.githubusercontent.com/u/4599623?v=4" width="100px;" alt=""><br><sub><b>Amarnath Chandana</b></sub></a></td>
<td align="center"><a href="https://github.com/Anurag870"><img src="https://avatars1.githubusercontent.com/u/6295975?v=4" width="100px;" alt=""><br><sub><b>Anurag870</b></sub></a></td>
<td align="center"><a href="http://theerroris.me"><img src="https://avatars0.githubusercontent.com/u/1685953?v=4" width="100px;" alt=""><br><sub><b>Wes Gilleland</b></sub></a></td>
<td align="center"><a href="https://github.com/Harshrajsinh"><img src="https://avatars2.githubusercontent.com/u/22811531?v=4" width="100px;" alt=""><br><sub><b>Harshraj Thakor</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/MaVdbussche"><img src="https://avatars1.githubusercontent.com/u/26136934?v=4" width="100px;" alt=""><br><sub><b>Martin Vandenbussche</b></sub></a></td>
<td align="center"><a href="https://alexsomai.com"><img src="https://avatars1.githubusercontent.com/u/5720977?v=4" width="100px;" alt=""><br><sub><b>Alexandru Somai</b></sub></a></td>
<td align="center"><a href="https://github.com/amogozov"><img src="https://avatars3.githubusercontent.com/u/7372215?v=4" width="100px;" alt=""><br><sub><b>Artur Mogozov</b></sub></a></td>
<td align="center"><a href="https://github.com/anthonycampbell"><img src="https://avatars3.githubusercontent.com/u/10249255?v=4" width="100px;" alt=""><br><sub><b>anthony</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="http://ccygnus.com/"><img src="https://avatars1.githubusercontent.com/u/9342724?v=4" width="100px;" alt=""><br><sub><b>Christian Cygnus</b></sub></a></td>
<td align="center"><a href="https://about.me/dzmitryh"><img src="https://avatars2.githubusercontent.com/u/5390492?v=4" width="100px;" alt=""><br><sub><b>Dima Gubin</b></sub></a></td>
<td align="center"><a href="https://github.com/jjjimenez100"><img src="https://avatars3.githubusercontent.com/u/22243493?v=4" width="100px;" alt=""><br><sub><b>Joshua Jimenez</b></sub></a></td>
<td align="center"><a href="http://about.me/kaiwinter"><img src="https://avatars0.githubusercontent.com/u/110982?v=4" width="100px;" alt=""><br><sub><b>Kai Winter</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/lbroman"><img src="https://avatars1.githubusercontent.com/u/86007?v=4" width="100px;" alt=""><br><sub><b>lbroman</b></sub></a></td>
<td align="center"><a href="https://przemeknowak.com"><img src="https://avatars1.githubusercontent.com/u/3254609?v=4" width="100px;" alt=""><br><sub><b>Przemek</b></sub></a></td>
<td align="center"><a href="https://github.com/prafful1"><img src="https://avatars0.githubusercontent.com/u/14350274?v=4" width="100px;" alt=""><br><sub><b>Prafful Agarwal</b></sub></a></td>
<td align="center"><a href="https://github.com/sankypanhale"><img src="https://avatars1.githubusercontent.com/u/6478783?v=4" width="100px;" alt=""><br><sub><b>Sanket Panhale</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/staillebois"><img src="https://avatars0.githubusercontent.com/u/23701200?v=4" width="100px;" alt=""><br><sub><b>staillebois</b></sub></a></td>
<td align="center"><a href="https://github.com/valdar-hu"><img src="https://avatars3.githubusercontent.com/u/17962817?v=4" width="100px;" alt=""><br><sub><b>Krisztián Nagy</b></sub></a></td>
<td align="center"><a href="https://www.vanogrid.com"><img src="https://avatars0.githubusercontent.com/u/4307918?v=4" width="100px;" alt=""><br><sub><b>Alexander Ivanov</b></sub></a></td>
<td align="center"><a href="https://github.com/yosfik"><img src="https://avatars3.githubusercontent.com/u/4850270?v=4" width="100px;" alt=""><br><sub><b>Yosfik Alqadri</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/7agustibm"><img src="https://avatars0.githubusercontent.com/u/8149332?v=4" width="100px;" alt=""><br><sub><b>Agustí Becerra Milà</b></sub></a></td>
<td align="center"><a href="https://github.com/Juaanma"><img src="https://avatars3.githubusercontent.com/u/7390500?v=4" width="100px;" alt=""><br><sub><b>Juan Manuel Suárez</b></sub></a></td>
<td align="center"><a href="http://www.devsedge.net/"><img src="https://avatars0.githubusercontent.com/u/9956006?v=4" width="100px;" alt=""><br><sub><b>Luigi Cortese</b></sub></a></td>
<td align="center"><a href="https://github.com/Rzeposlaw"><img src="https://avatars2.githubusercontent.com/u/18425745?v=4" width="100px;" alt=""><br><sub><b>Katarzyna Rzepecka</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="http://adamski.pro"><img src="https://avatars1.githubusercontent.com/u/6537430?v=4" width="100px;" alt=""><br><sub><b>adamski.pro</b></sub></a></td>
<td align="center"><a href="https://github.com/baislsl"><img src="https://avatars0.githubusercontent.com/u/17060584?v=4" width="100px;" alt=""><br><sub><b>Shengli Bai</b></sub></a></td>
<td align="center"><a href="https://github.com/besok"><img src="https://avatars2.githubusercontent.com/u/29834592?v=4" width="100px;" alt=""><br><sub><b>Boris</b></sub></a></td>
<td align="center"><a href="https://github.com/dmitraver"><img src="https://avatars3.githubusercontent.com/u/1798156?v=4" width="100px;" alt=""><br><sub><b>Dmitry Avershin</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/fanofxiaofeng"><img src="https://avatars0.githubusercontent.com/u/3983683?v=4" width="100px;" alt=""><br><sub><b>靳阳</b></sub></a></td>
<td align="center"><a href="https://github.com/hoangnam2261"><img src="https://avatars2.githubusercontent.com/u/31692990?v=4" width="100px;" alt=""><br><sub><b>hoangnam2261</b></sub></a></td>
<td align="center"><a href="https://github.com/jarpit96"><img src="https://avatars2.githubusercontent.com/u/10098713?v=4" width="100px;" alt=""><br><sub><b>Arpit Jain</b></sub></a></td>
<td align="center"><a href="http://joningi.net"><img src="https://avatars2.githubusercontent.com/u/6115148?v=4" width="100px;" alt=""><br><sub><b>Jón Ingi Sveinbjörnsson</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/kirill-vlasov"><img src="https://avatars3.githubusercontent.com/u/16112495?v=4" width="100px;" alt=""><br><sub><b>Kirill Vlasov</b></sub></a></td>
<td align="center"><a href="http://mitchell-irvin.com"><img src="https://avatars0.githubusercontent.com/u/16233245?v=4" width="100px;" alt=""><br><sub><b>Mitchell Irvin</b></sub></a></td>
<td align="center"><a href="https://ranjeet-floyd.github.io"><img src="https://avatars0.githubusercontent.com/u/1992972?v=4" width="100px;" alt=""><br><sub><b>Ranjeet</b></sub></a></td>
<td align="center"><a href="https://alwayswithme.github.io"><img src="https://avatars3.githubusercontent.com/u/3234786?v=4" width="100px;" alt=""><br><sub><b>PhoenixYip</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/MSaifAsif"><img src="https://avatars1.githubusercontent.com/u/6280554?v=4" width="100px;" alt=""><br><sub><b>M Saif Asif</b></sub></a></td>
<td align="center"><a href="https://github.com/kanwarpreet25"><img src="https://avatars0.githubusercontent.com/u/39183641?v=4" width="100px;" alt=""><br><sub><b>kanwarpreet25</b></sub></a></td>
<td align="center"><a href="http://leonmak.me"><img src="https://avatars3.githubusercontent.com/u/13071508?v=4" width="100px;" alt=""><br><sub><b>Leon Mak</b></sub></a></td>
<td align="center"><a href="http://www.wramdemark.se"><img src="https://avatars2.githubusercontent.com/u/7052193?v=4" width="100px;" alt=""><br><sub><b>Per Wramdemark</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/waisuan"><img src="https://avatars2.githubusercontent.com/u/10975700?v=4" width="100px;" alt=""><br><sub><b>Evan Sia Wai Suan</b></sub></a></td>
<td align="center"><a href="https://github.com/AnaghaSasikumar"><img src="https://avatars2.githubusercontent.com/u/42939261?v=4" width="100px;" alt=""><br><sub><b>AnaghaSasikumar</b></sub></a></td>
<td align="center"><a href="https://christofferh.com"><img src="https://avatars1.githubusercontent.com/u/767643?v=4" width="100px;" alt=""><br><sub><b>Christoffer Hamberg</b></sub></a></td>
<td align="center"><a href="https://github.com/dgruntz"><img src="https://avatars0.githubusercontent.com/u/1516800?v=4" width="100px;" alt=""><br><sub><b>Dominik Gruntz</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://bitbucket.org/hannespernpeintner/"><img src="https://avatars3.githubusercontent.com/u/1679437?v=4" width="100px;" alt=""><br><sub><b>Hannes</b></sub></a></td>
<td align="center"><a href="https://github.com/leogtzr"><img src="https://avatars0.githubusercontent.com/u/1211969?v=4" width="100px;" alt=""><br><sub><b>Leo Gutiérrez Ramírez</b></sub></a></td>
<td align="center"><a href="https://github.com/npczwh"><img src="https://avatars0.githubusercontent.com/u/14066422?v=4" width="100px;" alt=""><br><sub><b>Zhang WH</b></sub></a></td>
<td align="center"><a href="https://github.com/oconnelc"><img src="https://avatars0.githubusercontent.com/u/1112973?v=4" width="100px;" alt=""><br><sub><b>Christopher O'Connell</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/giorgosmav21"><img src="https://avatars2.githubusercontent.com/u/22855493?v=4" width="100px;" alt=""><br><sub><b>George Mavroeidis</b></sub></a></td>
<td align="center"><a href="https://github.com/hbothra15"><img src="https://avatars1.githubusercontent.com/u/7418012?v=4" width="100px;" alt=""><br><sub><b>Hemant Bothra</b></sub></a></td>
<td align="center"><a href="https://www.kevinpeters.net/about/"><img src="https://avatars1.githubusercontent.com/u/12736734?v=4" width="100px;" alt=""><br><sub><b>Kevin Peters</b></sub></a></td>
<td align="center"><a href="https://llorllale.github.io/"><img src="https://avatars1.githubusercontent.com/u/2019896?v=4" width="100px;" alt=""><br><sub><b>George Aristy</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/mookkiah"><img src="https://avatars1.githubusercontent.com/u/8975264?v=4" width="100px;" alt=""><br><sub><b>Mahendran Mookkiah</b></sub></a></td>
<td align="center"><a href="https://github.com/Azureyjt"><img src="https://avatars2.githubusercontent.com/u/18476317?v=4" width="100px;" alt=""><br><sub><b>Azureyjt</b></sub></a></td>
<td align="center"><a href="https://github.com/vehpsr"><img src="https://avatars2.githubusercontent.com/u/3133265?v=4" width="100px;" alt=""><br><sub><b>gans</b></sub></a></td>
<td align="center"><a href="https://github.com/ThatGuyWithTheHat"><img src="https://avatars0.githubusercontent.com/u/24470582?v=4" width="100px;" alt=""><br><sub><b>Matt</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://www.linkedin.com/in/gopinathlangote/"><img src="https://avatars2.githubusercontent.com/u/10210778?v=4" width="100px;" alt=""><br><sub><b>Gopinath Langote</b></sub></a></td>
<td align="center"><a href="https://github.com/hoswey"><img src="https://avatars3.githubusercontent.com/u/3689445?v=4" width="100px;" alt=""><br><sub><b>Hoswey</b></sub></a></td>
<td align="center"><a href="https://github.com/amit2103"><img src="https://avatars3.githubusercontent.com/u/7566692?v=4" width="100px;" alt=""><br><sub><b>Amit Pandey</b></sub></a></td>
<td align="center"><a href="https://github.com/gwildor28"><img src="https://avatars0.githubusercontent.com/u/16000365?v=4" width="100px;" alt=""><br><sub><b>gwildor28</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://t.me/paul_docker"><img src="https://avatars1.githubusercontent.com/u/2404785?v=4" width="100px;" alt=""><br><sub><b>田浩</b></sub></a></td>
<td align="center"><a href="https://twitter.com/StPitsios"><img src="https://avatars1.githubusercontent.com/u/6773603?v=4" width="100px;" alt=""><br><sub><b>Stamatis Pitsios</b></sub></a></td>
<td align="center"><a href="https://github.com/qza"><img src="https://avatars3.githubusercontent.com/u/233149?v=4" width="100px;" alt=""><br><sub><b>qza</b></sub></a></td>
<td align="center"><a href="http://tschis.github.io"><img src="https://avatars1.githubusercontent.com/u/20662669?v=4" width="100px;" alt=""><br><sub><b>Rodolfo Forte</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/ankurkaushal"><img src="https://avatars2.githubusercontent.com/u/2236616?v=4" width="100px;" alt=""><br><sub><b>Ankur Kaushal</b></sub></a></td>
<td align="center"><a href="https://www.linkedin.com/in/ovidijus-okinskas/"><img src="https://avatars0.githubusercontent.com/u/20372387?v=4" width="100px;" alt=""><br><sub><b>Ovidijus Okinskas</b></sub></a></td>
<td align="center"><a href="https://github.com/robertt240"><img src="https://avatars1.githubusercontent.com/u/9137432?v=4" width="100px;" alt=""><br><sub><b>Robert Kasperczyk</b></sub></a></td>
<td align="center"><a href="https://github.com/trautonen"><img src="https://avatars3.githubusercontent.com/u/1641063?v=4" width="100px;" alt=""><br><sub><b>Tapio Rautonen</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="http://vk.com/yuri.orlov"><img src="https://avatars0.githubusercontent.com/u/1595733?v=4" width="100px;" alt=""><br><sub><b>Yuri Orlov</b></sub></a></td>
<td align="center"><a href="https://www.linkedin.com/in/varunu28/"><img src="https://avatars0.githubusercontent.com/u/7676016?v=4" width="100px;" alt=""><br><sub><b>Varun Upadhyay</b></sub></a></td>
<td align="center"><a href="https://github.com/PalAditya"><img src="https://avatars2.githubusercontent.com/u/25523604?v=4" width="100px;" alt=""><br><sub><b>Aditya Pal</b></sub></a></td>
<td align="center"><a href="https://github.com/grzesiekkedzior"><img src="https://avatars3.githubusercontent.com/u/23739158?v=4" width="100px;" alt=""><br><sub><b>grzesiekkedzior</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/sivasubramanim"><img src="https://avatars2.githubusercontent.com/u/51107434?v=4" width="100px;" alt=""><br><sub><b>Sivasubramani M</b></sub></a></td>
<td align="center"><a href="https://github.com/d4gg4d"><img src="https://avatars2.githubusercontent.com/u/99457?v=4" width="100px;" alt=""><br><sub><b>Sami Airaksinen</b></sub></a></td>
<td align="center"><a href="https://github.com/vertti"><img src="https://avatars0.githubusercontent.com/u/557751?v=4" width="100px;" alt=""><br><sub><b>Janne Sinivirta</b></sub></a></td>
<td align="center"><a href="https://github.com/Bobo1239"><img src="https://avatars1.githubusercontent.com/u/2302947?v=4" width="100px;" alt=""><br><sub><b>Boris-Chengbiao Zhou</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://jahhein.github.io"><img src="https://avatars2.githubusercontent.com/u/10779515?v=4" width="100px;" alt=""><br><sub><b>Jacob Hein</b></sub></a></td>
<td align="center"><a href="https://github.com/iamrichardjones"><img src="https://avatars3.githubusercontent.com/u/14842151?v=4" width="100px;" alt=""><br><sub><b>Richard Jones</b></sub></a></td>
<td align="center"><a href="https://rachelcarmena.github.io"><img src="https://avatars0.githubusercontent.com/u/22792183?v=4" width="100px;" alt=""><br><sub><b>Rachel M. Carmena</b></sub></a></td>
<td align="center"><a href="https://zd-zero.github.io"><img src="https://avatars0.githubusercontent.com/u/21978370?v=4" width="100px;" alt=""><br><sub><b>Zaerald Denze Lungos</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://webpro.nl"><img src="https://avatars1.githubusercontent.com/u/456426?v=4" width="100px;" alt=""><br><sub><b>Lars Kappert</b></sub></a></td>
<td align="center"><a href="https://xiaod.info"><img src="https://avatars2.githubusercontent.com/u/21277644?v=4" width="100px;" alt=""><br><sub><b>Mike Liu</b></sub></a></td>
<td align="center"><a href="https://github.com/charlesfinley"><img src="https://avatars1.githubusercontent.com/u/6307904?v=4" width="100px;" alt=""><br><sub><b>Matt Dolan</b></sub></a></td>
<td align="center"><a href="https://github.com/MananS77"><img src="https://avatars3.githubusercontent.com/u/21033516?v=4" width="100px;" alt=""><br><sub><b>Manan</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/nishant"><img src="https://avatars2.githubusercontent.com/u/15331971?v=4" width="100px;" alt=""><br><sub><b>Nishant Arora</b></sub></a></td>
<td align="center"><a href="https://github.com/raja-peeyush-kumar-singh"><img src="https://avatars0.githubusercontent.com/u/5496024?v=4" width="100px;" alt=""><br><sub><b>Peeyush</b></sub></a></td>
<td align="center"><a href="https://github.com/ravening"><img src="https://avatars1.githubusercontent.com/u/10645273?v=4" width="100px;" alt=""><br><sub><b>Rakesh</b></sub></a></td>
<td align="center"><a href="https://github.com/vINCENT8888801"><img src="https://avatars0.githubusercontent.com/u/8037883?v=4" width="100px;" alt=""><br><sub><b>Wei Seng</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://www.linkedin.com/in/ashish-trivedi-218379135/"><img src="https://avatars3.githubusercontent.com/u/23194128?v=4" width="100px;" alt=""><br><sub><b>Ashish Trivedi</b></sub></a></td>
<td align="center"><a href="https://rayyounghong.com"><img src="https://avatars1.githubusercontent.com/u/41055099?v=4" width="100px;" alt=""><br><sub><b>洪月阳</b></sub></a></td>
<td align="center"><a href="https://xdvrx1.github.io/"><img src="https://avatars0.githubusercontent.com/u/47092464?v=4" width="100px;" alt=""><br><sub><b>xdvrx1</b></sub></a></td>
<td align="center"><a href="http://subho.xyz"><img src="https://avatars0.githubusercontent.com/u/13291222?v=4" width="100px;" alt=""><br><sub><b>Subhrodip Mohanta</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/nahteb"><img src="https://avatars3.githubusercontent.com/u/13121570?v=4" width="100px;" alt=""><br><sub><b>Bethan Palmer</b></sub></a></td>
<td align="center"><a href="https://github.com/ToxicDreamz"><img src="https://avatars0.githubusercontent.com/u/45225562?v=4" width="100px;" alt=""><br><sub><b>Toxic Dreamz</b></sub></a></td>
<td align="center"><a href="http://www.edycutjong.com"><img src="https://avatars1.githubusercontent.com/u/1098102?v=4" width="100px;" alt=""><br><sub><b>Edy Cu Tjong</b></sub></a></td>
<td align="center"><a href="https://github.com/mkrzywanski"><img src="https://avatars0.githubusercontent.com/u/15279585?v=4" width="100px;" alt=""><br><sub><b>Michał Krzywański</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://www.stefan-birkner.de"><img src="https://avatars1.githubusercontent.com/u/711349?v=4" width="100px;" alt=""><br><sub><b>Stefan Birkner</b></sub></a></td>
<td align="center"><a href="https://github.com/fedorskvorcov"><img src="https://avatars3.githubusercontent.com/u/43882212?v=4" width="100px;" alt=""><br><sub><b>Fedor Skvorcov</b></sub></a></td>
<td align="center"><a href="https://github.com/samilAyoub"><img src="https://avatars0.githubusercontent.com/u/61546990?v=4" width="100px;" alt=""><br><sub><b>samilAyoub</b></sub></a></td>
<td align="center"><a href="https://github.com/vdlald"><img src="https://avatars0.githubusercontent.com/u/29997701?v=4" width="100px;" alt=""><br><sub><b>Vladislav Golubinov</b></sub></a></td>
</tr>
<tr>
<td align="center"><a href="https://github.com/swarajsaaj"><img src="https://avatars2.githubusercontent.com/u/6285049?v=4" width="100px;" alt=""><br><sub><b>Swaraj</b></sub></a></td>
</tr>
</table>
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---
layout: pattern
title: Adapter
folder: adapter
permalink: "/patterns/adapter/"
categories: Structural
tags:
- Gang of Four
---
## 또한 ~으로 알려진
Wrapper
## 의도
클래스의 인터페이스를 클라이언트가 기대하는 다른 인터페이스로 변환합니다. adapter를 사용하면 호환되지 않는 인터페이스로 인해 같이 쓸 수 없는 클래스를 함께 작동 할 수 있습니다.
## 설명
예시
> 메모리 카드에 몇 장의 사진이 있고 컴퓨터로 전송해야한다고 생각하십시오. 이들을 전송하려면 컴퓨터에 메모리 카드를 연결할 수 있도록 컴퓨터 포트와 호환되는 어댑터가 필요합니다. 이 경우 카드 리더는 어댑터입니다. 또 다른 예는 유명한 전원 어댑터입니다. 세 갈래 플러그는 두 갈래 콘센트에 연결할 수 없습니다. 두 갈래 콘센트와 호환되는 전원 어댑터를 사용해야합니다. 또 다른 예는 한 사람이 말한 단어를 다른 사람에게 번역하는 번역가입니다.
평범하게 말하자면
> adapter 패턴을 사용하면 호환되지 않는 개체를 adapter에 연결하여 다른 클래스와 호환되도록 할 수 있습니다.
Wikipedia 말에 의하면
> 소프트웨어 엔지니어링에서 adapter 패턴은 기존 클래스의 인터페이스를 다른 인터페이스로 사용할 수 있도록 하는 소프트웨어 디자인 패턴입니다. 소스 코드를 수정하지 않고 기존 클래스가 다른 클래스와 함께 작동하도록 만드는 데 자주 사용됩니다.
**프로그램 코드 예제**
조정 보트만 사용할 수 있고 전혀 항해할 수 없는 선장을 생각해보십시오.
먼저 `RowingBoat``FishingBoat` 인터페이스가 있습니다.
```java
public interface RowingBoat {
void row();
}
public class FishingBoat {
private static final Logger LOGGER = LoggerFactory.getLogger(FishingBoat.class);
public void sail() {
LOGGER.info("The fishing boat is sailing");
}
}
```
그리고 선장은 `RowingBoat` 인터페이스를 이동할 수 있게 구현했습니다.
```java
public class Captain {
private final RowingBoat rowingBoat;
// default constructor and setter for rowingBoat
public Captain(RowingBoat rowingBoat) {
this.rowingBoat = rowingBoat;
}
public void row() {
rowingBoat.row();
}
}
```
이제 해적이오고 있고 우리 선장이 탈출해야하는데 어선만 있습니다. 선장이 조정 보트 기술로 어선을 조작 할 수있는 adapter를 만들어야합니다.
```java
public class FishingBoatAdapter implements RowingBoat {
private static final Logger LOGGER = LoggerFactory.getLogger(FishingBoatAdapter.class);
private final FishingBoat boat;
public FishingBoatAdapter() {
boat = new FishingBoat();
}
@Override
public void row() {
boat.sail();
}
}
```
이제 `Captain``FishingBoat` 를 사용하여 해적을 탈출 할 수 있습니다.
```java
var captain = new Captain(new FishingBoatAdapter());
captain.row();
```
## 클레스 다이어그램
![alt text](https://github.com/warp125/java-design-patterns/blob/master/adapter/etc/adapter.urm.png?raw=true)
## 적용 가능성
다음과 같은 경우 adapter 패턴을 사용합니다.
- 기존 클래스를 사용 하려는데 해당 인터페이스가 필요한 클래스와 일치하지 않습니다.
- 관련이 없거나 예상치 못한 클래스, 즉 호환되는 인터페이스가 반드시 필요하지 않은 클래스와 협력하는 재사용 가능한 클래스를 만들고 싶습니다.
- 기존의 여러 하위 클래스를 사용해야하지만 모든 하위 클래스를 하위 클래스로 지정하여 인터페이스를 조정하는 것은 비현실적입니다. 개체 adapter는 부모 클래스의 인터페이스를 조정할 수 있습니다.
- 타사 라이브러리를 사용하는 대부분의 응용 프로그램은 adapter를 응용 프로그램과 타사 라이브러리 사이의 중간 계층으로 사용하여 라이브러리에서 응용 프로그램을 분리합니다. 다른 라이브러리를 사용해야하는 경우 애플리케이션 코드를 변경할 필요없이 새 라이브러리 용 adapter만 필요합니다.
## 결과 :
클래스 및 개체 adapter에는 서로 다른 장단점이 있습니다. <br>클래스 adapter
- 구체적인 Adaptee 클래스를 커밋하여 Adaptee를 Target에 적용합니다. 결과적으로 클래스와 모든 하위 클래스를 조정하려는 경우 클래스 adapter가 작동하지 않습니다.
- adapter는 Adaptee의 하위 클래스이기 때문에 Adaptee의 일부 동작을 오버라이드합니다.
- 하나의 객체만 생성하고 adaptee를 얻기위해 위해 추가 포인터 간접 지정이 필요하지 않습니다.
개체 adapter
- 하나의 adapter가 많은 Adaptees, 즉 Adaptee 자체와 모든 하위 클래스 (있는 경우)와 함께 작동하도록합시다. adapter는 한 번에 모든 어댑터에 기능을 추가 할 수도 있습니다.
- Adaptee 동작을 오버라이드하기가 더 어렵습니다. Adaptee를 서브 클래싱하고 어댑터가 Adaptee 자체가 아닌 서브 클래스를 참조하도록 해야합니다.
## 실제 사례
- [java.util.Arrays#asList()](http://docs.oracle.com/javase/8/docs/api/java/util/Arrays.html#asList%28T...%29)
- [java.util.Collections#list()](https://docs.oracle.com/javase/8/docs/api/java/util/Collections.html#list-java.util.Enumeration-)
- [java.util.Collections#enumeration()](https://docs.oracle.com/javase/8/docs/api/java/util/Collections.html#enumeration-java.util.Collection-)
- [javax.xml.bind.annotation.adapters.XMLAdapter](http://docs.oracle.com/javase/8/docs/api/javax/xml/bind/annotation/adapters/XmlAdapter.html#marshal-BoundType-)
## 크레딧
- [Design Patterns: Elements of Reusable Object-Oriented Software](https://www.amazon.com/gp/product/0201633612/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0201633612&linkCode=as2&tag=javadesignpat-20&linkId=675d49790ce11db99d90bde47f1aeb59)
- [J2EE Design Patterns](https://www.amazon.com/gp/product/0596004273/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0596004273&linkCode=as2&tag=javadesignpat-20&linkId=48d37c67fb3d845b802fa9b619ad8f31)
- [Head First Design Patterns: A Brain-Friendly Guide](https://www.amazon.com/gp/product/0596007124/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0596007124&linkCode=as2&tag=javadesignpat-20&linkId=6b8b6eea86021af6c8e3cd3fc382cb5b)
- [Refactoring to Patterns](https://www.amazon.com/gp/product/0321213351/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0321213351&linkCode=as2&tag=javadesignpat-20&linkId=2a76fcb387234bc71b1c61150b3cc3a7)

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---
layout: pattern
title: Factory
folder: factory
permalink: "/patterns/factory/"
categories: Creational
tags:
- Gang of Four
---
## 또한 ~으로 알려진
- Simple Factory
- Static Factory Method
## 의도
구현 논리를 숨기고 클라이언트 코드가 새 객체를 초기화하는 대신 사용에 집중하도록하기 위해 factory라는 클래스에 캡슐화 된 정적 메서드를 제공합니다.
## 설명
예시
> SQLServer에 연결된 웹 응용 프로그램이 있지만 이제 Oracle로 전환하려고 합니다. 기존 소스 코드를 수정하지 않고 이를 수행하려면 주어진 데이터베이스에 대한 연결을 생성하기 위해 정적 메서드를 호출 할 수 있는 Simple Factory 패턴을 구현해야합니다.
Wikipedia 말에 의하면
> factory는 다른 객체를 생성하기위한 객체입니다. 공식적으로 factory는 다양한 프로토 타입 또는 클래스의 객체를 반환하는 함수 또는 메서드입니다.
**프로그램 코드 예제**
우리는 인터페이스 `Car` 와 두 가지 구현 `Ford``Ferrari`을 가지고 있습니다.
```java
public interface Car {
String getDescription();
}
public class Ford implements Car {
static final String DESCRIPTION = "This is Ford.";
@Override
public String getDescription() {
return DESCRIPTION;
}
}
public class Ferrari implements Car {
static final String DESCRIPTION = "This is Ferrari.";
@Override
public String getDescription() {
return DESCRIPTION;
}
}
```
열거형은 우리가 지원하는 자동차 유형을 나타냅니다 ( `Ford``Ferrari` ).
```java
public enum CarType {
FORD(Ford::new),
FERRARI(Ferrari::new);
private final Supplier<Car> constructor;
CarType(Supplier<Car> constructor) {
this.constructor = constructor;
}
public Supplier<Car> getConstructor() {
return this.constructor;
}
}
```
그런 다음 factory 클래스 `CarsFactory` 캡슐화 된 자동차 객체를 만드는 정적 메서드 `getCar` 가 있습니다.
```java
public class CarsFactory {
public static Car getCar(CarType type) {
return type.getConstructor().get();
}
}
```
이제 클라이언트 코드에서 factory 클래스를 사용하여 다양한 유형의 자동차를 만들 수 있습니다.
```java
var car1 = CarsFactory.getCar(CarType.FORD);
var car2 = CarsFactory.getCar(CarType.FERRARI);
LOGGER.info(car1.getDescription());
LOGGER.info(car2.getDescription());;
```
프로그램 출력 :
```java
This is Ford.
This Ferrari.
```
## 클래스 다이어그램
![alt text](https://github.com/iluwatar/java-design-patterns/blob/master/factory/etc/factory.urm.png)
## 적용 가능성
객체 생성 및 관리 방법이 아닌 객체 생성에만 관심이있을 때 Simple Factory 패턴을 사용합니다.
장점
- 모든 객체 생성을 한곳에 유지하고 코드베이스에 '새'키 값이 확산되는 것을 방지합니다.
- 느슨하게 결합 된 코드를 작성할 수 있습니다. 주요 장점 중 일부는 더 나은 테스트 가능성, 이해하기 쉬운 코드, 교체 가능한 구성 요소, 확장성 및 격리된 기능을 포함합니다.
단점
- 코드는 생각보다 복잡해집니다.
## 관련 패턴
- [Factory Method](https://java-design-patterns.com/patterns/factory-method/)
- [Factory Kit](https://java-design-patterns.com/patterns/factory-kit/)
- [Abstract Factory](https://java-design-patterns.com/patterns/abstract-factory/)

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---
layout: pattern
title: Observer
folder: observer
permalink: "/patterns/observer/"
categories: Behavioral
tags:
- Gang Of Four
- Reactive
---
## 또한 ~으로 알려진
Dependents, Publish-Subscribe
## 의도
하나의 개체가 상태를 변경하면 모든 종속 항목에 알림이 전송되고 자동으로 업데이트 되도록 개체간의 일대 다 종속성을 정의합니다.
## 설명
예시
> 멀리 떨어진 땅에는 호빗과 오크 종족이 살고 있습니다. 둘 다 대부분 야외에 있으므로 날씨 변화를 면밀히 따릅니다. 끊임없이 날씨를 관찰하고 있다고 말할 수 있습니다.
평범하게 말하자면
> observer로 등록하여 개체의 상태 변경을 수신합니다.
Wikipedia 말에 의하면
> observer 패턴은 주제라고하는 객체가 observer라고 하는 종속 항목 목록을 유지하고 일반적으로 메서드 중 하나를 호출하여 상태 변경을 자동으로 알리는 소프트웨어 디자인 패턴입니다.
**프로그램 코드 예제**
먼저 `WeatherObserver` 인터페이스와 우리의 종족 `Orcs``Hobbits` 소개하겠습니다.
```java
public interface WeatherObserver {
void update(WeatherType currentWeather);
}
public class Orcs implements WeatherObserver {
private static final Logger LOGGER = LoggerFactory.getLogger(Orcs.class);
@Override
public void update(WeatherType currentWeather) {
LOGGER.info("The orcs are facing " + currentWeather.getDescription() + " weather now");
}
}
public class Hobbits implements WeatherObserver {
private static final Logger LOGGER = LoggerFactory.getLogger(Hobbits.class);
@Override
public void update(WeatherType currentWeather) {
switch (currentWeather) {
LOGGER.info("The hobbits are facing " + currentWeather.getDescription() + " weather now");
}
}
}
```
그리고 끊임없이 변화하는 `Weather` 가 있습니다.
```java
public class Weather {
private static final Logger LOGGER = LoggerFactory.getLogger(Weather.class);
private WeatherType currentWeather;
private final List<WeatherObserver> observers;
public Weather() {
observers = new ArrayList<>();
currentWeather = WeatherType.SUNNY;
}
public void addObserver(WeatherObserver obs) {
observers.add(obs);
}
public void removeObserver(WeatherObserver obs) {
observers.remove(obs);
}
/**
* Makes time pass for weather.
*/
public void timePasses() {
var enumValues = WeatherType.values();
currentWeather = enumValues[(currentWeather.ordinal() + 1) % enumValues.length];
LOGGER.info("The weather changed to {}.", currentWeather);
notifyObservers();
}
private void notifyObservers() {
for (var obs : observers) {
obs.update(currentWeather);
}
}
}
```
여기에 전체 예제가 있습니다.
```java
var weather = new Weather();
weather.addObserver(new Orcs());
weather.addObserver(new Hobbits());
weather.timePasses();
weather.timePasses();
weather.timePasses();
weather.timePasses();
```
프로그램 출력 :
```
The weather changed to rainy.
The orcs are facing rainy weather now
The hobbits are facing rainy weather now
The weather changed to windy.
The orcs are facing windy weather now
The hobbits are facing windy weather now
The weather changed to cold.
The orcs are facing cold weather now
The hobbits are facing cold weather now
The weather changed to sunny.
The orcs are facing sunny weather now
The hobbits are facing sunny weather now
```
## 클래스 다이어그램
![alt text](https://github.com/iluwatar/java-design-patterns/blob/master/observer/etc/observer.png)
## 적용 가능성
다음 상황에서 관찰자 패턴을 사용하십시오.
- 추상화에 두 가지 측면이 있을 때 하나는 다른 하나에 종속됩니다. 이러한 측면을 별도의 개체에 캡슐화하면 독립적으로 변경하고 재사용 할 수 있습니다.
- 한 개체를 변경하려면 얼마나 다른 개체를 변경해야 하는지 알 수 없는 경우입니다.
- 개체가 다른 개체가 누구인지 가정하지 않고 알릴 수 있어야하는 경우. 즉, 개체가 단단히 결합되는 것을 원하지 않습니다.
## 일반적인 사용 사례
- 한 개체를 변경하면 다른 개체도 변경됩니다.
## 실제 사례
- [java.util.Observer](http://docs.oracle.com/javase/8/docs/api/java/util/Observer.html)
- [java.util.EventListener](http://docs.oracle.com/javase/8/docs/api/java/util/EventListener.html)
- [javax.servlet.http.HttpSessionBindingListener](http://docs.oracle.com/javaee/7/api/javax/servlet/http/HttpSessionBindingListener.html)
- [RxJava](https://github.com/ReactiveX/RxJava)
## 크레딧
- [Design Patterns: Elements of Reusable Object-Oriented Software](https://www.amazon.com/gp/product/0201633612/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0201633612&linkCode=as2&tag=javadesignpat-20&linkId=675d49790ce11db99d90bde47f1aeb59)
- [Java Generics and Collections](https://www.amazon.com/gp/product/0596527756/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0596527756&linkCode=as2&tag=javadesignpat-20&linkId=246e5e2c26fe1c3ada6a70b15afcb195)
- [Head First Design Patterns: A Brain-Friendly Guide](https://www.amazon.com/gp/product/0596007124/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0596007124&linkCode=as2&tag=javadesignpat-20&linkId=6b8b6eea86021af6c8e3cd3fc382cb5b)
- [Refactoring to Patterns](https://www.amazon.com/gp/product/0321213351/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0321213351&linkCode=as2&tag=javadesignpat-20&linkId=2a76fcb387234bc71b1c61150b3cc3a7)

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---
layout: pattern
title: Prototype
folder: prototype
permalink: "/patterns/prototype/"
categories: Creational
tags:
- Gang Of Four
- Instantiation
---
## 의도
prototype 인스턴스를 사용하여 만들 개체의 종류를 지정하고 prototype을 복사하여 새 개체를 만듭니다.
## 설명
먼저 성능 이점을 얻기 위해 prototype 패턴이 사용되지 않는다는 점에 유의해야합니다. 오직 prototype 인스턴스에서 새 개체를 만드는 데만 사용됩니다.
예시
> 복제된 양인 돌리에 대해 기억나십니까? 자세한 내용은 다루지 않겠습니다만 여기서 핵심은 복제에 관한 것입니다.
평범한 말하자면
> 복제를 통해 기존 개체를 기반으로 개체를 만듭니다.
Wikipedia 말에 의하면
> prototype 패턴은 소프트웨어 개발에서 생성 디자인 패턴입니다. 생성 할 개체의 유형이 새 개체를 생성하기 위해 복제되는 prototype 인스턴스에 의해 결정될 때 사용됩니다.
간단히 말해, 객체를 처음부터 만들고 설정하는 문제를 겪는 대신 기존 객체의 복사본을 만들어 필요에 맞게 수정할 수 있습니다.
**프로그램 코드 예제**
Java에서는 `Cloneable` 을 구현하고 `Object` 에서 `clone` 을 오버라이딩하여 쉽게 수행 할 수 있습니다.
```java
class Sheep implements Cloneable {
private String name;
public Sheep(String name) { this.name = name; }
public void setName(String name) { this.name = name; }
public String getName() { return name; }
@Override
public Sheep clone() {
try {
return (Sheep)super.clone();
} catch(CloneNotSuportedException) {
throw new InternalError();
}
}
}
```
그런 다음 아래와 같이 복제할 수 있습니다.
```java
var original = new Sheep("Jolly");
System.out.println(original.getName()); // Jolly
// Clone and modify what is required
var cloned = original.clone();
cloned.setName("Dolly");
System.out.println(cloned.getName()); // Dolly
```
## 클래스 다이어그램
![alt text](https://github.com/iluwatar/java-design-patterns/blob/master/prototype/etc/prototype.urm.png)
## 적용 가능성
시스템이 제품의 생성, 구성, 표현 및 표현 방식에 독립적이어야 할 때 prototype 패턴을 사용
- 인스턴스화할 클래스가 런타임에 지정되는 경우 (예 : 동적 로딩)
- 제품의 클래스 계층 구조와 유사한 팩토리의 클래스 계층 구조 구축을 방지해야할 경우
- 클래스의 인스턴스가 몇 가지 다른 상태 조합 중 하나만 가질 수 있는 경우. 적절한 상태로 매번 클래스를 수동으로 인스턴스화하는 것보다 해당하는 수의 prototype을 설치하고 복제하는 것이 더 편리 할 수 있습니다.
- 복제에 비해 개체 생성 비용이 많이 드는 경우.
## 실제 사례
- [java.lang.Object#clone()](https://docs.oracle.com/javase/8/docs/api/java/lang/Object.html#clone%28%29)
## 크레딧
- [Design Patterns: Elements of Reusable Object-Oriented Software](https://www.amazon.com/gp/product/0201633612/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0201633612&linkCode=as2&tag=javadesignpat-20&linkId=675d49790ce11db99d90bde47f1aeb59)
- [Head First Design Patterns: A Brain-Friendly Guide](https://www.amazon.com/gp/product/0596007124/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0596007124&linkCode=as2&tag=javadesignpat-20&linkId=6b8b6eea86021af6c8e3cd3fc382cb5b)

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---
layout: pattern
title: Singleton
folder: singleton
permalink: "/patterns/singleton/"
categories: Creational
tags:
- Gang of Four
---
## 의도
클래스에 인스턴스가 하나만 있는지 확인하고 이에 대한 전역 access point을 제공합니다.
## 설명
예시
> 마법사들이 마법을 연구하는 상아탑은 단 하나뿐입니다. 마법사는 항상 동일한 마법의 상아탑을 사용합니다. 여기서 상아탑은 singleton입니다.
평범하게 말하자면
> 특정 클래스의 개체가 하나만 생성되도록합니다.
Wikipedia 말에 의하면
> 소프트웨어 엔지니어링에서 singleton 패턴은 클래스의 인스턴스화를 하나의 객체로 제한하는 소프트웨어 디자인 패턴입니다. 이는 시스템 전체에서 작업을 조정하는 데 정확히 하나의 개체가 필요할 때 유용합니다.
**프로그램 코드 예제**
Joshua Bloch, Effective Java 2nd Edition p.18
> 단일 요소 열거형은 singleton을 구현하는 가장 좋은 방법입니다.
```java
public enum EnumIvoryTower {
INSTANCE
}
```
그런 다음 사용하려면 :
```java
var enumIvoryTower1 = EnumIvoryTower.INSTANCE;
var enumIvoryTower2 = EnumIvoryTower.INSTANCE;
assertEquals(enumIvoryTower1, enumIvoryTower2); // true
```
## 클래스 다이어그램
![alt text](https://github.com/iluwatar/java-design-patterns/blob/master/singleton/etc/singleton.urm.png)
## 적용 가능성
다음과 같은 경우 Singleton 패턴을 사용합니다.
- 정확히 하나의 클래스 인스턴스가 있어야하며 잘 알려진 access point에서 클라이언트에 접근할 수 있어야합니다.
- 단일 인스턴스가 서브 클래싱으로 확장 가능해야하고 클라이언트가 코드를 수정하지 않고 확장 인스턴스를 사용할 수 있어야 하는 경우
## 일반적인 사용 사례
- 로깅 클래스
- 데이터베이스에 대한 연결 관리
- 파일 관리자
## 실제 사례
- [java.lang.Runtime#getRuntime()](http://docs.oracle.com/javase/8/docs/api/java/lang/Runtime.html#getRuntime%28%29)
- [java.awt.Desktop#getDesktop()](http://docs.oracle.com/javase/8/docs/api/java/awt/Desktop.html#getDesktop--)
- [java.lang.System#getSecurityManager()](http://docs.oracle.com/javase/8/docs/api/java/lang/System.html#getSecurityManager--)
## 결과
- 자체 생성 및 수명주기를 제어하여 SRP (Single Responsibility Principle)를 위반합니다.
- 이 개체가 사용하는 개체와 리소스가 할당 해제되는 것을 방지하는 전역 공유 인스턴스를 사용하도록 권장합니다.
- 밀접하게 연결된 코드를 만듭니다. Singleton의 클라이언트는 테스트하기가 어려워집니다.
- Singleton의 하위 클래스를 만드는 것이 거의 불가능합니다.
## 크레딧
- [Design Patterns: Elements of Reusable Object-Oriented Software](https://www.amazon.com/gp/product/0201633612/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0201633612&linkCode=as2&tag=javadesignpat-20&linkId=675d49790ce11db99d90bde47f1aeb59)
- [Effective Java](https://www.amazon.com/gp/product/0134685997/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0134685997&linkCode=as2&tag=javadesignpat-20&linkId=4e349f4b3ff8c50123f8147c828e53eb)
- [Head First Design Patterns: A Brain-Friendly Guide](https://www.amazon.com/gp/product/0596007124/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0596007124&linkCode=as2&tag=javadesignpat-20&linkId=6b8b6eea86021af6c8e3cd3fc382cb5b)
- [Refactoring to Patterns](https://www.amazon.com/gp/product/0321213351/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0321213351&linkCode=as2&tag=javadesignpat-20&linkId=2a76fcb387234bc71b1c61150b3cc3a7)

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@ -195,9 +195,11 @@
<module>strangler</module>
<module>arrange-act-assert</module>
<module>transaction-script</module>
<module>registry</module>
<module>filterer</module>
<module>factory</module>
<module>separated-interface</module>
<module>special-case</module>
</modules>
<repositories>

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---
layout: pattern
title: Registry
folder: registry
permalink: /patterns/registry/
categories: Creational
tags:
- Instantiation
---
## Intent
Stores the objects of a single class and provide a global point of access to them.
Similar to Multiton pattern, only difference is that in a registry there is no restriction on the number of objects.
## Explanation
In Plain Words
> Registry is a well-known object that other objects can use to find common objects and services.
**Programmatic Example**
Below is a `Customer` Class
```java
public class Customer {
private final String id;
private final String name;
public Customer(String id, String name) {
this.id = id;
this.name = name;
}
public String getId() {
return id;
}
public String getName() {
return name;
}
}
```
This registry of the `Customer` objects is `CustomerRegistry`
```java
public final class CustomerRegistry {
private static final CustomerRegistry instance = new CustomerRegistry();
public static CustomerRegistry getInstance() {
return instance;
}
private final Map<String, Customer> customerMap;
private CustomerRegistry() {
customerMap = new ConcurrentHashMap<>();
}
public Customer addCustomer(Customer customer) {
return customerMap.put(customer.getId(), customer);
}
public Customer getCustomer(String id) {
return customerMap.get(id);
}
}
```
## Class diagram
![Registry](./etc/registry.png)
## Applicability
Use Registry pattern when
* client wants reference of some object, so client can lookup for that object in the object's registry.
## Consequences
Large number of bulky objects added to registry would result in a lot of memory consumption as objects in the registry are not garbage collected.
## Credits
* https://www.martinfowler.com/eaaCatalog/registry.html
* https://wiki.c2.com/?RegistryPattern

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@startuml
package com.iluwatar.registry {
class App {
- LOGGER : Logger {static}
+ App()
+ main(args : String[]) {static}
}
class Customer {
- id : String
- name : String
+ getId() : String
+ getName() : String
+ toString() : String
}
class CustomerRegistry {
+ addCustomer(customer : Customer)
+ getCustomer(id : String)
}
}
Customer --> "-addCustomer" CustomerRegistry
@enduml

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<?xml version="1.0" encoding="UTF-8"?>
<!--
The MIT License
Copyright © 2014-2019 Ilkka Seppälä
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
-->
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>com.iluwatar</groupId>
<artifactId>java-design-patterns</artifactId>
<version>1.24.0-SNAPSHOT</version>
</parent>
<artifactId>registry</artifactId>
<dependencies>
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-engine</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-assembly-plugin</artifactId>
<executions>
<execution>
<configuration>
<archive>
<manifest>
<mainClass>com.iluwatar.registry.App</mainClass>
</manifest>
</archive>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>

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@ -0,0 +1,50 @@
/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.registry;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class App {
private static final Logger LOGGER = LoggerFactory.getLogger(App.class);
/**
* Program entry point.
*
* @param args command line args
*/
public static void main(String[] args) {
CustomerRegistry customerRegistry = CustomerRegistry.getInstance();
var john = new Customer("1", "John");
customerRegistry.addCustomer(john);
var julia = new Customer("2", "Julia");
customerRegistry.addCustomer(julia);
LOGGER.info("John {}", customerRegistry.getCustomer("1"));
LOGGER.info("Julia {}", customerRegistry.getCustomer("2"));
}
}

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@ -0,0 +1,51 @@
/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.registry;
public class Customer {
private final String id;
private final String name;
public Customer(String id, String name) {
this.id = id;
this.name = name;
}
public String getId() {
return id;
}
public String getName() {
return name;
}
@Override
public String toString() {
return "Customer{"
+ "id='" + id + '\''
+ ", name='" + name + '\''
+ '}';
}
}

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@ -0,0 +1,51 @@
/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.registry;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
public final class CustomerRegistry {
private static final CustomerRegistry instance = new CustomerRegistry();
public static CustomerRegistry getInstance() {
return instance;
}
private final Map<String, Customer> customerMap;
private CustomerRegistry() {
customerMap = new ConcurrentHashMap<>();
}
public Customer addCustomer(Customer customer) {
return customerMap.put(customer.getId(), customer);
}
public Customer getCustomer(String id) {
return customerMap.get(id);
}
}

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@ -0,0 +1,67 @@
/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.registry;
import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.Test;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertNull;
public class CustomerRegistryTest {
private static CustomerRegistry customerRegistry;
@BeforeAll
public static void setUp() {
customerRegistry = CustomerRegistry.getInstance();
}
@Test
public void shouldBeAbleToAddAndQueryCustomerObjectFromRegistry() {
Customer john = new Customer("1", "john");
Customer julia = new Customer("2", "julia");
customerRegistry.addCustomer(john);
customerRegistry.addCustomer(julia);
Customer customerWithId1 = customerRegistry.getCustomer("1");
assertNotNull(customerWithId1);
assertEquals("1", customerWithId1.getId());
assertEquals("john", customerWithId1.getName());
Customer customerWithId2 = customerRegistry.getCustomer("2");
assertNotNull(customerWithId2);
assertEquals("2", customerWithId2.getId());
assertEquals("julia", customerWithId2.getName());
}
@Test
public void shouldReturnNullWhenQueriedCustomerIsNotInRegistry() {
Customer customerWithId5 = customerRegistry.getCustomer("5");
assertNull(customerWithId5);
}
}

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---
layout: pattern
title: Special Case
folder: special-case
permalink: /patterns/special-case/
categories: Behavioral
tags:
- Extensibility
---
## Intent
Define some special cases, and encapsulates them into subclasses that provide different special behaviors.
## Explanation
Real world example
> In an e-commerce system, presentation layer expects application layer to produce certain view model.
> We have a successful scenario, in which receipt view model contains actual data from the purchase,
> and a couple of failure scenarios.
In plain words
> Special Case pattern allows returning non-null real objects that perform special behaviors.
In [Patterns of Enterprise Application Architecture](https://martinfowler.com/books/eaa.html) says
the difference from Null Object Pattern
> If youll pardon the unresistable pun, I see Null Object as special case of Special Case.
**Programmatic Example**
To focus on the pattern itself, we implement DB and maintenance lock of the e-commerce system by the singleton instance.
```java
public class Db {
private static Db instance;
private Map<String, User> userName2User;
private Map<User, Account> user2Account;
private Map<String, Product> itemName2Product;
public static Db getInstance() {
if (instance == null) {
synchronized (Db.class) {
if (instance == null) {
instance = new Db();
instance.userName2User = new HashMap<>();
instance.user2Account = new HashMap<>();
instance.itemName2Product = new HashMap<>();
}
}
}
return instance;
}
public void seedUser(String userName, Double amount) {
User user = new User(userName);
instance.userName2User.put(userName, user);
Account account = new Account(amount);
instance.user2Account.put(user, account);
}
public void seedItem(String itemName, Double price) {
Product item = new Product(price);
itemName2Product.put(itemName, item);
}
public User findUserByUserName(String userName) {
if (!userName2User.containsKey(userName)) {
return null;
}
return userName2User.get(userName);
}
public Account findAccountByUser(User user) {
if (!user2Account.containsKey(user)) {
return null;
}
return user2Account.get(user);
}
public Product findProductByItemName(String itemName) {
if (!itemName2Product.containsKey(itemName)) {
return null;
}
return itemName2Product.get(itemName);
}
public class User {
private String userName;
public User(String userName) {
this.userName = userName;
}
public String getUserName() {
return userName;
}
public ReceiptDto purchase(Product item) {
return new ReceiptDto(item.getPrice());
}
}
public class Account {
private Double amount;
public Account(Double amount) {
this.amount = amount;
}
public MoneyTransaction withdraw(Double price) {
if (price > amount) {
return null;
}
return new MoneyTransaction(amount, price);
}
public Double getAmount() {
return amount;
}
}
public class Product {
private Double price;
public Product(Double price) {
this.price = price;
}
public Double getPrice() {
return price;
}
}
}
public class MaintenanceLock {
private static final Logger LOGGER = LoggerFactory.getLogger(MaintenanceLock.class);
private static MaintenanceLock instance;
private boolean lock = true;
public static MaintenanceLock getInstance() {
if (instance == null) {
synchronized (MaintenanceLock.class) {
if (instance == null) {
instance = new MaintenanceLock();
}
}
}
return instance;
}
public boolean isLock() {
return lock;
}
public void setLock(boolean lock) {
this.lock = lock;
LOGGER.info("Maintenance lock is set to: " + lock);
}
}
```
Let's first introduce presentation layer, the receipt view model interface and its implementation of successful scenario.
```java
public interface ReceiptViewModel {
void show();
}
public class ReceiptDto implements ReceiptViewModel {
private static final Logger LOGGER = LoggerFactory.getLogger(ReceiptDto.class);
private Double price;
public ReceiptDto(Double price) {
this.price = price;
}
public Double getPrice() {
return price;
}
@Override
public void show() {
LOGGER.info("Receipt: " + price + " paid");
}
}
```
And here are the implementations of failure scenarios, which are the special cases.
```java
public class DownForMaintenance implements ReceiptViewModel {
private static final Logger LOGGER = LoggerFactory.getLogger(DownForMaintenance.class);
@Override
public void show() {
LOGGER.info("Down for maintenance");
}
}
public class InvalidUser implements ReceiptViewModel {
private static final Logger LOGGER = LoggerFactory.getLogger(InvalidUser.class);
private final String userName;
public InvalidUser(String userName) {
this.userName = userName;
}
@Override
public void show() {
LOGGER.info("Invalid user: " + userName);
}
}
public class OutOfStock implements ReceiptViewModel {
private static final Logger LOGGER = LoggerFactory.getLogger(OutOfStock.class);
private String userName;
private String itemName;
public OutOfStock(String userName, String itemName) {
this.userName = userName;
this.itemName = itemName;
}
@Override
public void show() {
LOGGER.info("Out of stock: " + itemName + " for user = " + userName + " to buy");
}
}
public class InsufficientFunds implements ReceiptViewModel {
private static final Logger LOGGER = LoggerFactory.getLogger(InsufficientFunds.class);
private String userName;
private Double amount;
private String itemName;
public InsufficientFunds(String userName, Double amount, String itemName) {
this.userName = userName;
this.amount = amount;
this.itemName = itemName;
}
@Override
public void show() {
LOGGER.info("Insufficient funds: " + amount + " of user: " + userName
+ " for buying item: " + itemName);
}
}
```
Second, here's the application layer, the application services implementation and the domain services implementation.
```java
public class ApplicationServicesImpl implements ApplicationServices {
private DomainServicesImpl domain = new DomainServicesImpl();
@Override
public ReceiptViewModel loggedInUserPurchase(String userName, String itemName) {
if (isDownForMaintenance()) {
return new DownForMaintenance();
}
return this.domain.purchase(userName, itemName);
}
private boolean isDownForMaintenance() {
return MaintenanceLock.getInstance().isLock();
}
}
public class DomainServicesImpl implements DomainServices {
public ReceiptViewModel purchase(String userName, String itemName) {
Db.User user = Db.getInstance().findUserByUserName(userName);
if (user == null) {
return new InvalidUser(userName);
}
Db.Account account = Db.getInstance().findAccountByUser(user);
return purchase(user, account, itemName);
}
private ReceiptViewModel purchase(Db.User user, Db.Account account, String itemName) {
Db.Product item = Db.getInstance().findProductByItemName(itemName);
if (item == null) {
return new OutOfStock(user.getUserName(), itemName);
}
ReceiptDto receipt = user.purchase(item);
MoneyTransaction transaction = account.withdraw(receipt.getPrice());
if (transaction == null) {
return new InsufficientFunds(user.getUserName(), account.getAmount(), itemName);
}
return receipt;
}
}
```
Finally, the client send requests the application services to get the presentation view.
```java
// DB seeding
LOGGER.info("Db seeding: " + "1 user: {\"ignite1771\", amount = 1000.0}, "
+ "2 products: {\"computer\": price = 800.0, \"car\": price = 20000.0}");
Db.getInstance().seedUser("ignite1771", 1000.0);
Db.getInstance().seedItem("computer", 800.0);
Db.getInstance().seedItem("car", 20000.0);
var applicationServices = new ApplicationServicesImpl();
ReceiptViewModel receipt;
LOGGER.info("[REQUEST] User: " + "abc123" + " buy product: " + "tv");
receipt = applicationServices.loggedInUserPurchase("abc123", "tv");
receipt.show();
MaintenanceLock.getInstance().setLock(false);
LOGGER.info("[REQUEST] User: " + "abc123" + " buy product: " + "tv");
receipt = applicationServices.loggedInUserPurchase("abc123", "tv");
receipt.show();
LOGGER.info("[REQUEST] User: " + "ignite1771" + " buy product: " + "tv");
receipt = applicationServices.loggedInUserPurchase("ignite1771", "tv");
receipt.show();
LOGGER.info("[REQUEST] User: " + "ignite1771" + " buy product: " + "car");
receipt = applicationServices.loggedInUserPurchase("ignite1771", "car");
receipt.show();
LOGGER.info("[REQUEST] User: " + "ignite1771" + " buy product: " + "computer");
receipt = applicationServices.loggedInUserPurchase("ignite1771", "computer");
receipt.show();
```
Program output of every request:
```
Down for maintenance
Invalid user: abc123
Out of stock: tv for user = ignite1771 to buy
Insufficient funds: 1000.0 of user: ignite1771 for buying item: car
Receipt: 800.0 paid
```
## Class diagram
![alt text](./etc/special_case_urm.png "Special Case")
## Applicability
Use the Special Case pattern when
* You have multiple places in the system that have the same behavior after a conditional check
for a particular class instance, or the same behavior after a null check.
* Return a real object that performs the real behavior, instead of a null object that performs nothing.
## Tutorial
* [Special Case Tutorial](https://www.codinghelmet.com/articles/reduce-cyclomatic-complexity-special-case)
## Credits
* [How to Reduce Cyclomatic Complexity Part 2: Special Case Pattern](https://www.codinghelmet.com/articles/reduce-cyclomatic-complexity-special-case)
* [Patterns of Enterprise Application Architecture](https://martinfowler.com/books/eaa.html)
* [Special Case](https://www.martinfowler.com/eaaCatalog/specialCase.html)

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@startuml
left to right direction
package com.iluwatar.specialcase {
class App {
- LOGGER : Logger {static}
+ App()
+ main(args : String[]) {static}
}
interface ApplicationServices {
+ loggedInUserPurchase(String, String) : ReceiptViewModel {abstract}
}
class ApplicationServicesImpl {
- domain : DomainServicesImpl
+ ApplicationServicesImpl()
- isDownForMaintenance() : boolean
+ loggedInUserPurchase(userName : String, itemName : String) : ReceiptViewModel
}
class Db {
- instance : Db {static}
- itemName2Product : Map<String, Product>
- user2Account : Map<User, Account>
- userName2User : Map<String, User>
+ Db()
+ findAccountByUser(user : User) : Account
+ findProductByItemName(itemName : String) : Product
+ findUserByUserName(userName : String) : User
+ getInstance() : Db {static}
+ seedItem(itemName : String, price : Double)
+ seedUser(userName : String, amount : Double)
}
class Account {
- amount : Double
+ Account(this$0 : Double)
+ getAmount() : Double
+ withdraw(price : Double) : MoneyTransaction
}
class Product {
- price : Double
+ Product(this$0 : Double)
+ getPrice() : Double
}
class User {
- userName : String
+ User(this$0 : String)
+ getUserName() : String
+ purchase(item : Product) : ReceiptDto
}
interface DomainServices {
}
class DomainServicesImpl {
+ DomainServicesImpl()
- purchase(user : User, account : Account, itemName : String) : ReceiptViewModel
+ purchase(userName : String, itemName : String) : ReceiptViewModel
}
class DownForMaintenance {
- LOGGER : Logger {static}
+ DownForMaintenance()
+ show()
}
class InsufficientFunds {
- LOGGER : Logger {static}
- amount : Double
- itemName : String
- userName : String
+ InsufficientFunds(userName : String, amount : Double, itemName : String)
+ show()
}
class InvalidUser {
- LOGGER : Logger {static}
- userName : String
+ InvalidUser(userName : String)
+ show()
}
class MaintenanceLock {
- LOGGER : Logger {static}
- instance : MaintenanceLock {static}
- lock : boolean
+ MaintenanceLock()
+ getInstance() : MaintenanceLock {static}
+ isLock() : boolean
+ setLock(lock : boolean)
}
class MoneyTransaction {
- amount : Double
- price : Double
+ MoneyTransaction(amount : Double, price : Double)
}
class OutOfStock {
- LOGGER : Logger {static}
- itemName : String
- userName : String
+ OutOfStock(userName : String, itemName : String)
+ show()
}
class ReceiptDto {
- LOGGER : Logger {static}
- price : Double
+ ReceiptDto(price : Double)
+ getPrice() : Double
+ show()
}
interface ReceiptViewModel {
+ show() {abstract}
}
}
User --+ Db
Product --+ Db
MaintenanceLock --> "-instance" MaintenanceLock
Db --> "-instance" Db
ApplicationServicesImpl --> "-domain" DomainServicesImpl
Account --+ Db
ApplicationServicesImpl ..|> ApplicationServices
DomainServicesImpl ..|> DomainServices
DownForMaintenance ..|> ReceiptViewModel
InsufficientFunds ..|> ReceiptViewModel
InvalidUser ..|> ReceiptViewModel
OutOfStock ..|> ReceiptViewModel
ReceiptDto ..|> ReceiptViewModel
@enduml

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<?xml version="1.0" encoding="UTF-8"?>
<!--
The MIT License
Copyright © 2014-2019 Ilkka Seppälä
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
-->
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<artifactId>java-design-patterns</artifactId>
<groupId>com.iluwatar</groupId>
<version>1.24.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>special-case</artifactId>
<dependencies>
<dependency>
<groupId>org.junit.jupiter</groupId>
<artifactId>junit-jupiter-engine</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
</project>

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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.specialcase;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* <p>The Special Case Pattern is a software design pattern that encapsulates particular cases
* into subclasses that provide special behaviors.</p>
*
* <p>In this example ({@link ReceiptViewModel}) encapsulates all particular cases.</p>
*/
public class App {
private static final Logger LOGGER = LoggerFactory.getLogger(App.class);
/**
* Program entry point.
*/
public static void main(String[] args) {
// DB seeding
LOGGER.info("Db seeding: " + "1 user: {\"ignite1771\", amount = 1000.0}, "
+ "2 products: {\"computer\": price = 800.0, \"car\": price = 20000.0}");
Db.getInstance().seedUser("ignite1771", 1000.0);
Db.getInstance().seedItem("computer", 800.0);
Db.getInstance().seedItem("car", 20000.0);
final var applicationServices = new ApplicationServicesImpl();
ReceiptViewModel receipt;
LOGGER.info("[REQUEST] User: " + "abc123" + " buy product: " + "tv");
receipt = applicationServices.loggedInUserPurchase("abc123", "tv");
receipt.show();
MaintenanceLock.getInstance().setLock(false);
LOGGER.info("[REQUEST] User: " + "abc123" + " buy product: " + "tv");
receipt = applicationServices.loggedInUserPurchase("abc123", "tv");
receipt.show();
LOGGER.info("[REQUEST] User: " + "ignite1771" + " buy product: " + "tv");
receipt = applicationServices.loggedInUserPurchase("ignite1771", "tv");
receipt.show();
LOGGER.info("[REQUEST] User: " + "ignite1771" + " buy product: " + "car");
receipt = applicationServices.loggedInUserPurchase("ignite1771", "car");
receipt.show();
LOGGER.info("[REQUEST] User: " + "ignite1771" + " buy product: " + "computer");
receipt = applicationServices.loggedInUserPurchase("ignite1771", "computer");
receipt.show();
}
}

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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.specialcase;
public interface ApplicationServices {
ReceiptViewModel loggedInUserPurchase(String userName, String itemName);
}

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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.specialcase;
public class ApplicationServicesImpl implements ApplicationServices {
private DomainServicesImpl domain = new DomainServicesImpl();
@Override
public ReceiptViewModel loggedInUserPurchase(String userName, String itemName) {
if (isDownForMaintenance()) {
return new DownForMaintenance();
}
return this.domain.purchase(userName, itemName);
}
private boolean isDownForMaintenance() {
return MaintenanceLock.getInstance().isLock();
}
}

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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.specialcase;
import java.util.HashMap;
import java.util.Map;
public class Db {
private static Db instance;
private Map<String, User> userName2User;
private Map<User, Account> user2Account;
private Map<String, Product> itemName2Product;
/**
* Get the instance of Db.
*
* @return singleton instance of Db class
*/
public static Db getInstance() {
if (instance == null) {
synchronized (Db.class) {
if (instance == null) {
instance = new Db();
instance.userName2User = new HashMap<>();
instance.user2Account = new HashMap<>();
instance.itemName2Product = new HashMap<>();
}
}
}
return instance;
}
/**
* Seed a user into Db.
*
* @param userName of the user
* @param amount of the user's account
*/
public void seedUser(String userName, Double amount) {
User user = new User(userName);
instance.userName2User.put(userName, user);
Account account = new Account(amount);
instance.user2Account.put(user, account);
}
/**
* Seed an item into Db.
*
* @param itemName of the item
* @param price of the item
*/
public void seedItem(String itemName, Double price) {
Product item = new Product(price);
itemName2Product.put(itemName, item);
}
/**
* Find a user with the userName.
*
* @param userName of the user
* @return instance of User
*/
public User findUserByUserName(String userName) {
if (!userName2User.containsKey(userName)) {
return null;
}
return userName2User.get(userName);
}
/**
* Find an account of the user.
*
* @param user in Db
* @return instance of Account of the user
*/
public Account findAccountByUser(User user) {
if (!user2Account.containsKey(user)) {
return null;
}
return user2Account.get(user);
}
/**
* Find a product with the itemName.
*
* @param itemName of the item
* @return instance of Product
*/
public Product findProductByItemName(String itemName) {
if (!itemName2Product.containsKey(itemName)) {
return null;
}
return itemName2Product.get(itemName);
}
public class User {
private String userName;
public User(String userName) {
this.userName = userName;
}
public String getUserName() {
return userName;
}
public ReceiptDto purchase(Product item) {
return new ReceiptDto(item.getPrice());
}
}
public class Account {
private Double amount;
public Account(Double amount) {
this.amount = amount;
}
/**
* Withdraw the price of the item from the account.
*
* @param price of the item
* @return instance of MoneyTransaction
*/
public MoneyTransaction withdraw(Double price) {
if (price > amount) {
return null;
}
return new MoneyTransaction(amount, price);
}
public Double getAmount() {
return amount;
}
}
public class Product {
private Double price;
public Product(Double price) {
this.price = price;
}
public Double getPrice() {
return price;
}
}
}

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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.specialcase;
public interface DomainServices {
}

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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.specialcase;
public class DomainServicesImpl implements DomainServices {
/**
* Domain purchase with userName and itemName, with validation for userName.
*
* @param userName of the user
* @param itemName of the item
* @return instance of ReceiptViewModel
*/
public ReceiptViewModel purchase(String userName, String itemName) {
Db.User user = Db.getInstance().findUserByUserName(userName);
if (user == null) {
return new InvalidUser(userName);
}
Db.Account account = Db.getInstance().findAccountByUser(user);
return purchase(user, account, itemName);
}
/**
* Domain purchase with user, account and itemName,
* with validation for whether product is out of stock
* and whether user has insufficient funds in the account.
*
* @param user in Db
* @param account in Db
* @param itemName of the item
* @return instance of ReceiptViewModel
*/
private ReceiptViewModel purchase(Db.User user, Db.Account account, String itemName) {
Db.Product item = Db.getInstance().findProductByItemName(itemName);
if (item == null) {
return new OutOfStock(user.getUserName(), itemName);
}
ReceiptDto receipt = user.purchase(item);
MoneyTransaction transaction = account.withdraw(receipt.getPrice());
if (transaction == null) {
return new InsufficientFunds(user.getUserName(), account.getAmount(), itemName);
}
return receipt;
}
}

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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.specialcase;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class DownForMaintenance implements ReceiptViewModel {
private static final Logger LOGGER = LoggerFactory.getLogger(DownForMaintenance.class);
@Override
public void show() {
LOGGER.info("Down for maintenance");
}
}

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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.specialcase;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class InsufficientFunds implements ReceiptViewModel {
private static final Logger LOGGER = LoggerFactory.getLogger(InsufficientFunds.class);
private String userName;
private Double amount;
private String itemName;
/**
* Constructor of InsufficientFunds.
*
* @param userName of the user
* @param amount of the user's account
* @param itemName of the item
*/
public InsufficientFunds(String userName, Double amount, String itemName) {
this.userName = userName;
this.amount = amount;
this.itemName = itemName;
}
@Override
public void show() {
LOGGER.info("Insufficient funds: " + amount + " of user: " + userName
+ " for buying item: " + itemName);
}
}

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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.specialcase;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class InvalidUser implements ReceiptViewModel {
private static final Logger LOGGER = LoggerFactory.getLogger(InvalidUser.class);
private final String userName;
public InvalidUser(String userName) {
this.userName = userName;
}
@Override
public void show() {
LOGGER.info("Invalid user: " + userName);
}
}

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/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.specialcase;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class MaintenanceLock {
private static final Logger LOGGER = LoggerFactory.getLogger(MaintenanceLock.class);
private static MaintenanceLock instance;
private boolean lock = true;
/**
* Get the instance of MaintenanceLock.
*
* @return singleton instance of MaintenanceLock
*/
public static MaintenanceLock getInstance() {
if (instance == null) {
synchronized (MaintenanceLock.class) {
if (instance == null) {
instance = new MaintenanceLock();
}
}
}
return instance;
}
public boolean isLock() {
return lock;
}
public void setLock(boolean lock) {
this.lock = lock;
LOGGER.info("Maintenance lock is set to: " + lock);
}
}

View File

@ -0,0 +1,35 @@
/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.specialcase;
public class MoneyTransaction {
private Double amount;
private Double price;
public MoneyTransaction(Double amount, Double price) {
this.amount = amount;
this.price = price;
}
}

View File

@ -0,0 +1,45 @@
/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.specialcase;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class OutOfStock implements ReceiptViewModel {
private static final Logger LOGGER = LoggerFactory.getLogger(OutOfStock.class);
private String userName;
private String itemName;
public OutOfStock(String userName, String itemName) {
this.userName = userName;
this.itemName = itemName;
}
@Override
public void show() {
LOGGER.info("Out of stock: " + itemName + " for user = " + userName + " to buy");
}
}

View File

@ -0,0 +1,47 @@
/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.specialcase;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class ReceiptDto implements ReceiptViewModel {
private static final Logger LOGGER = LoggerFactory.getLogger(ReceiptDto.class);
private Double price;
public ReceiptDto(Double price) {
this.price = price;
}
public Double getPrice() {
return price;
}
@Override
public void show() {
LOGGER.info("Receipt: " + price + " paid");
}
}

View File

@ -0,0 +1,29 @@
/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.specialcase;
public interface ReceiptViewModel {
void show();
}

View File

@ -0,0 +1,39 @@
/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.specialcase;
import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
import org.junit.jupiter.api.Test;
/**
* Application test.
*/
public class AppTest {
@Test
void shouldExecuteWithoutException() {
assertDoesNotThrow(() -> App.main(new String[]{}));
}
}

View File

@ -0,0 +1,143 @@
/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.specialcase;
import static org.junit.jupiter.api.Assertions.assertEquals;
import org.junit.jupiter.api.BeforeAll;
import org.slf4j.LoggerFactory;
import ch.qos.logback.classic.Level;
import ch.qos.logback.classic.Logger;
import ch.qos.logback.classic.spi.ILoggingEvent;
import ch.qos.logback.core.read.ListAppender;
import java.util.List;
import org.junit.jupiter.api.Test;
import org.junit.jupiter.api.BeforeEach;
/**
* Special cases unit tests. (including the successful scenario {@link ReceiptDto})
*/
public class SpecialCasesTest {
private static ApplicationServices applicationServices;
private static ReceiptViewModel receipt;
@BeforeAll
static void beforeAll() {
Db.getInstance().seedUser("ignite1771", 1000.0);
Db.getInstance().seedItem("computer", 800.0);
Db.getInstance().seedItem("car", 20000.0);
applicationServices = new ApplicationServicesImpl();
}
@BeforeEach
public void beforeEach() {
MaintenanceLock.getInstance().setLock(false);
}
@Test
public void testDownForMaintenance() {
final Logger LOGGER = (Logger) LoggerFactory.getLogger(DownForMaintenance.class);
ListAppender<ILoggingEvent> listAppender = new ListAppender<>();
listAppender.start();
LOGGER.addAppender(listAppender);
MaintenanceLock.getInstance().setLock(true);
receipt = applicationServices.loggedInUserPurchase(null, null);
receipt.show();
List<ILoggingEvent> loggingEventList = listAppender.list;
assertEquals("Down for maintenance", loggingEventList.get(0).getMessage());
assertEquals(Level.INFO, loggingEventList.get(0).getLevel());
}
@Test
public void testInvalidUser() {
final Logger LOGGER = (Logger) LoggerFactory.getLogger(InvalidUser.class);
ListAppender<ILoggingEvent> listAppender = new ListAppender<>();
listAppender.start();
LOGGER.addAppender(listAppender);
receipt = applicationServices.loggedInUserPurchase("a", null);
receipt.show();
List<ILoggingEvent> loggingEventList = listAppender.list;
assertEquals("Invalid user: a", loggingEventList.get(0).getMessage());
assertEquals(Level.INFO, loggingEventList.get(0).getLevel());
}
@Test
public void testOutOfStock() {
final Logger LOGGER = (Logger) LoggerFactory.getLogger(OutOfStock.class);
ListAppender<ILoggingEvent> listAppender = new ListAppender<>();
listAppender.start();
LOGGER.addAppender(listAppender);
receipt = applicationServices.loggedInUserPurchase("ignite1771", "tv");
receipt.show();
List<ILoggingEvent> loggingEventList = listAppender.list;
assertEquals("Out of stock: tv for user = ignite1771 to buy"
, loggingEventList.get(0).getMessage());
assertEquals(Level.INFO, loggingEventList.get(0).getLevel());
}
@Test
public void testInsufficientFunds() {
final Logger LOGGER = (Logger) LoggerFactory.getLogger(InsufficientFunds.class);
ListAppender<ILoggingEvent> listAppender = new ListAppender<>();
listAppender.start();
LOGGER.addAppender(listAppender);
receipt = applicationServices.loggedInUserPurchase("ignite1771", "car");
receipt.show();
List<ILoggingEvent> loggingEventList = listAppender.list;
assertEquals("Insufficient funds: 1000.0 of user: ignite1771 for buying item: car"
, loggingEventList.get(0).getMessage());
assertEquals(Level.INFO, loggingEventList.get(0).getLevel());
}
@Test
public void testReceiptDto() {
final Logger LOGGER = (Logger) LoggerFactory.getLogger(ReceiptDto.class);
ListAppender<ILoggingEvent> listAppender = new ListAppender<>();
listAppender.start();
LOGGER.addAppender(listAppender);
receipt = applicationServices.loggedInUserPurchase("ignite1771", "computer");
receipt.show();
List<ILoggingEvent> loggingEventList = listAppender.list;
assertEquals("Receipt: 800.0 paid"
, loggingEventList.get(0).getMessage());
assertEquals(Level.INFO, loggingEventList.get(0).getLevel());
}
}

View File

@ -122,6 +122,51 @@ Program output:
You cast the spell of disintegration and the dragon vaporizes in a pile of dust!
```
What's more, the new feature Lambda Expressions in Java 8 provides another approach for the implementation:
```java
public class LambdaStrategy {
private static final Logger LOGGER = LoggerFactory.getLogger(LambdaStrategy.class);
public enum Strategy implements DragonSlayingStrategy {
MeleeStrategy(() -> LOGGER.info(
"With your Excalibur you severe the dragon's head!")),
ProjectileStrategy(() -> LOGGER.info(
"You shoot the dragon with the magical crossbow and it falls dead on the ground!")),
SpellStrategy(() -> LOGGER.info(
"You cast the spell of disintegration and the dragon vaporizes in a pile of dust!"));
private final DragonSlayingStrategy dragonSlayingStrategy;
Strategy(DragonSlayingStrategy dragonSlayingStrategy) {
this.dragonSlayingStrategy = dragonSlayingStrategy;
}
@Override
public void execute() {
dragonSlayingStrategy.execute();
}
}
}
```
And here's the dragonslayer in action.
```java
LOGGER.info("Green dragon spotted ahead!");
dragonSlayer.changeStrategy(LambdaStrategy.Strategy.MeleeStrategy);
dragonSlayer.goToBattle();
LOGGER.info("Red dragon emerges.");
dragonSlayer.changeStrategy(LambdaStrategy.Strategy.ProjectileStrategy);
dragonSlayer.goToBattle();
LOGGER.info("Black dragon lands before you.");
dragonSlayer.changeStrategy(LambdaStrategy.Strategy.SpellStrategy);
dragonSlayer.goToBattle();
```
Program output is the same as above one.
## Class diagram
![alt text](./etc/strategy_urm.png "Strategy")

View File

@ -14,6 +14,19 @@ package com.iluwatar.strategy {
interface DragonSlayingStrategy {
+ execute() {abstract}
}
class LambdaStrategy {
- LOGGER : Logger {static}
+ LambdaStrategy()
}
enum Strategy {
+ MeleeStrategy {static}
+ ProjectileStrategy {static}
+ SpellStrategy {static}
- dragonSlayingStrategy : DragonSlayingStrategy
+ execute()
+ valueOf(name : String) : Strategy {static}
+ values() : Strategy[] {static}
}
class MeleeStrategy {
- LOGGER : Logger {static}
+ MeleeStrategy()
@ -30,7 +43,10 @@ package com.iluwatar.strategy {
+ execute()
}
}
Strategy ..+ LambdaStrategy
Strategy --> "-dragonSlayingStrategy" DragonSlayingStrategy
DragonSlayer --> "-strategy" DragonSlayingStrategy
Strategy ..|> DragonSlayingStrategy
MeleeStrategy ..|> DragonSlayingStrategy
ProjectileStrategy ..|> DragonSlayingStrategy
SpellStrategy ..|> DragonSlayingStrategy

Binary file not shown.

Before

Width:  |  Height:  |  Size: 29 KiB

After

Width:  |  Height:  |  Size: 140 KiB

View File

@ -45,7 +45,7 @@ public class App {
/**
* Program entry point.
*
*
* @param args command line args
*/
public static void main(String[] args) {
@ -60,7 +60,7 @@ public class App {
dragonSlayer.changeStrategy(new SpellStrategy());
dragonSlayer.goToBattle();
// Java 8 Strategy pattern
// Java 8 functional implementation Strategy pattern
LOGGER.info("Green dragon spotted ahead!");
dragonSlayer = new DragonSlayer(
() -> LOGGER.info("With your Excalibur you severe the dragon's head!"));
@ -73,5 +73,16 @@ public class App {
dragonSlayer.changeStrategy(() -> LOGGER.info(
"You cast the spell of disintegration and the dragon vaporizes in a pile of dust!"));
dragonSlayer.goToBattle();
// Java 8 lambda implementation with enum Strategy pattern
LOGGER.info("Green dragon spotted ahead!");
dragonSlayer.changeStrategy(LambdaStrategy.Strategy.MeleeStrategy);
dragonSlayer.goToBattle();
LOGGER.info("Red dragon emerges.");
dragonSlayer.changeStrategy(LambdaStrategy.Strategy.ProjectileStrategy);
dragonSlayer.goToBattle();
LOGGER.info("Black dragon lands before you.");
dragonSlayer.changeStrategy(LambdaStrategy.Strategy.SpellStrategy);
dragonSlayer.goToBattle();
}
}

View File

@ -0,0 +1,52 @@
/*
* The MIT License
* Copyright © 2014-2019 Ilkka Seppälä
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.iluwatar.strategy;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class LambdaStrategy {
private static final Logger LOGGER = LoggerFactory.getLogger(LambdaStrategy.class);
public enum Strategy implements DragonSlayingStrategy {
MeleeStrategy(() -> LOGGER.info(
"With your Excalibur you severe the dragon's head!")),
ProjectileStrategy(() -> LOGGER.info(
"You shoot the dragon with the magical crossbow and it falls dead on the ground!")),
SpellStrategy(() -> LOGGER.info(
"You cast the spell of disintegration and the dragon vaporizes in a pile of dust!"));
private final DragonSlayingStrategy dragonSlayingStrategy;
Strategy(DragonSlayingStrategy dragonSlayingStrategy) {
this.dragonSlayingStrategy = dragonSlayingStrategy;
}
@Override
public void execute() {
dragonSlayingStrategy.execute();
}
}
}

42
tr/README.md Normal file
View File

@ -0,0 +1,42 @@
<!-- Biçimlendirme nedeniyle bu satır boş bırakılmalıdır böylelikle hoş bir görüntüye sahip olabiliriz. örneğin web sitesi -->
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# Giriş
Tasarım desenleri, bir yazılım mühendisi bir uygulamayı veya sistemi tasarlarken yaygın sorunları çözmek için kullanabileceği en iyi çözüm prensipleridir.
Tasarım desenleri, test edilip kanıtlanmış prensipler olduğu için yazılım geliştirme sürecini hızlandırabilir.
Tasarım desenlerini yeniden kullanmak, büyük sorunlara neden olan ince sorunları önlemeye yardımcı olur ve aynı zamanda tasarım desenlerine alışkın olan yazılım mühendisileri ve yazılım mimarları için kod okunabilirliğini artırır.
# Başlangıç
Bu site Java Tasarım Desenlerini sergiliyor. Çözümler, açık kaynak topluluğundan deneyimli yazılım mühendisileri ve yazılım mimarları tarafından geliştirilmiştir. Bu yazılım desenleri, detaylııklamalarıyla veya kaynak kodlarına bakılarak göz atılabilir. Kaynak kod örneklerinde iyi derecede açıklayıcı yorum satırlarına sahip olup ve belirli bir tasarım deseninin nasıl uygulanacağına dair programlama dersi olarak düşünülebilir. Savaşta en çok kanıtlanmış açık kaynak Java teknolojilerini kullanıyoruz.
Bu projeye başlamadan önce çeşitli [Yazılım Tasarım İlkelerine](https://java-design-patterns.com/principles/) aşina olmalısınız.
Tüm tasarımlar olabildiğince basit olmalıdır. [KISS](https://en.wikipedia.org/wiki/KISS_principle), [YAGNI](https://en.wikipedia.org/wiki/You_aren%27t_gonna_need_it) ve [Do The Simplest Thing That Could Possibly Work](https://learning.oreilly.com/library/view/extreme-programming-pocket/9781449399849/ch17.html) ilkeleri ile başlamalısınız.
Bu kavramlara aşina olduktan sonra, aşağıdaki yaklaşımlardan herhangi birini kullanarak [mevcut tasarım desenlerini](https://java-design-patterns.com/patterns/) derinlemesine incelemeye başlayabilirsiniz.
- İsme göre belirli bir tasarım deseni arayın. Bulamadınız mı? Lütfen yeni bir tasarım deseni için [bizim ile](https://github.com/iluwatar/java-design-patterns/issues) iletişime geçin.
- Performance, Gang of Four ya da Data access gibi etiketleri kullanın.
- Creational(Yaratıcı Tasarım Desenleri), Behavioral(Davranışsal Tasarım Desenleri), ve Structural(Yapısal Tasarım Desenleri) gibi tasarım kategorilerini kullanın.
Umarım bu sitede sunulan nesne yönelimli çözümleri yazılım mimarileriniz için yararlı bulursunuz ve onları geliştirirken bizim kadar eğlenirsiniz.
# Nasıl Katkı Sağlayabilirim
Projeye katkıda bulunmaya istekliysen, ilgili bilgileri [geliştirici wiki'mizde](https://github.com/iluwatar/java-design-patterns/wiki) bulabilirsin. [Gitter](https://gitter.im/iluwatar/java-design-patterns) ile size yardımcı olacağız ve sorularınızı cevaplayacağız.
# Lisans
Bu proje, MIT lisansı koşulları altında lisanslanmıştır.

205
zh/bridge/README.md Normal file
View File

@ -0,0 +1,205 @@
---
layout: pattern
title: Bridge
folder: bridge
permalink: /patterns/bridge/
categories: Structural
tags:
- Gang of Four
---
## 又被称为
手柄/身体模式
## 目的
将抽象与其实现分离,以便二者可以独立变化。
## 解释
真实世界例子
> 考虑一下你拥有一种具有不同附魔的武器,并且应该允许将具有不同附魔的不同武器混合使用。 你会怎么做? 为每个附魔创建每种武器的多个副本,还是只是创建单独的附魔并根据需要为武器设置它? 桥接模式使您可以进行第二次操作。
通俗的说
> 桥接模式是一个更推荐组合而不是继承的模式。将实现细节从一个层次结构推送到具有单独层次结构的另一个对象。
维基百科说
> 桥接模式是软件工程中使用的一种设计模式,旨在“将抽象与其实现分离,从而使两者可以独立变化”
**程序示例**
翻译一下上面的武器示例。下面我们有武器的类层级:
```java
public interface Weapon {
void wield();
void swing();
void unwield();
Enchantment getEnchantment();
}
public class Sword implements Weapon {
private final Enchantment enchantment;
public Sword(Enchantment enchantment) {
this.enchantment = enchantment;
}
@Override
public void wield() {
LOGGER.info("The sword is wielded.");
enchantment.onActivate();
}
@Override
public void swing() {
LOGGER.info("The sword is swinged.");
enchantment.apply();
}
@Override
public void unwield() {
LOGGER.info("The sword is unwielded.");
enchantment.onDeactivate();
}
@Override
public Enchantment getEnchantment() {
return enchantment;
}
}
public class Hammer implements Weapon {
private final Enchantment enchantment;
public Hammer(Enchantment enchantment) {
this.enchantment = enchantment;
}
@Override
public void wield() {
LOGGER.info("The hammer is wielded.");
enchantment.onActivate();
}
@Override
public void swing() {
LOGGER.info("The hammer is swinged.");
enchantment.apply();
}
@Override
public void unwield() {
LOGGER.info("The hammer is unwielded.");
enchantment.onDeactivate();
}
@Override
public Enchantment getEnchantment() {
return enchantment;
}
}
```
这里是单独的附魔类结构:
```java
public interface Enchantment {
void onActivate();
void apply();
void onDeactivate();
}
public class FlyingEnchantment implements Enchantment {
@Override
public void onActivate() {
LOGGER.info("The item begins to glow faintly.");
}
@Override
public void apply() {
LOGGER.info("The item flies and strikes the enemies finally returning to owner's hand.");
}
@Override
public void onDeactivate() {
LOGGER.info("The item's glow fades.");
}
}
public class SoulEatingEnchantment implements Enchantment {
@Override
public void onActivate() {
LOGGER.info("The item spreads bloodlust.");
}
@Override
public void apply() {
LOGGER.info("The item eats the soul of enemies.");
}
@Override
public void onDeactivate() {
LOGGER.info("Bloodlust slowly disappears.");
}
}
```
这里是两种层次结构的实践:
```java
var enchantedSword = new Sword(new SoulEatingEnchantment());
enchantedSword.wield();
enchantedSword.swing();
enchantedSword.unwield();
// The sword is wielded.
// The item spreads bloodlust.
// The sword is swinged.
// The item eats the soul of enemies.
// The sword is unwielded.
// Bloodlust slowly disappears.
var hammer = new Hammer(new FlyingEnchantment());
hammer.wield();
hammer.swing();
hammer.unwield();
// The hammer is wielded.
// The item begins to glow faintly.
// The hammer is swinged.
// The item flies and strikes the enemies finally returning to owner's hand.
// The hammer is unwielded.
// The item's glow fades.
```
## 类图
![alt text](../../bridge/etc/bridge.urm.png "Bridge class diagram")
## 适用性
使用桥接模式当
* 你想永久性的避免抽象和他的实现之间的绑定。有可能是这种情况,当实现需要被选择或者在运行时切换。
* 抽象和他们的实现应该能通过写子类来扩展。这种情况下,桥接模式让你可以组合不同的抽象和实现并独立的扩展他们。
* 对抽象的实现的改动应当不会对客户产生影响;也就是说,他们的代码不必重新编译。
* 你有种类繁多的类。这样的类层次结构表明需要将一个对象分为两部分。Rumbaugh 使用术语“嵌套归纳”来指代这种类层次结构。
* 你想在多个对象间分享一种实现可能使用引用计数这个事实应该对客户隐藏。一个简单的示例是Coplien的String类其中多个对象可以共享同一字符串表示形式
## 教程
* [Bridge Pattern Tutorial](https://www.journaldev.com/1491/bridge-design-pattern-java)
## 鸣谢
* [Design Patterns: Elements of Reusable Object-Oriented Software](https://www.amazon.com/gp/product/0201633612/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0201633612&linkCode=as2&tag=javadesignpat-20&linkId=675d49790ce11db99d90bde47f1aeb59)
* [Head First Design Patterns: A Brain-Friendly Guide](https://www.amazon.com/gp/product/0596007124/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0596007124&linkCode=as2&tag=javadesignpat-20&linkId=6b8b6eea86021af6c8e3cd3fc382cb5b)

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---
layout: pattern
title: Callback
folder: callback
permalink: /patterns/callback/
categories: Idiom
tags:
- Reactive
---
## 目的
回调是一部分被当为参数来传递给其他代码的可执行代码,接收方的代码可以在一些方便的时候来调用它。
## 解释
真实世界例子
> 我们需要被通知当执行的任务结束时。我们为调用者传递一个回调方法然后等它调用通知我们。
通俗的讲
> 回调是一个用来传递给调用者的方法,它将在定义的时刻被调用。
维基百科说
> 在计算机编程中,回调又被称为“稍后调用”函数,可以是任何可执行的代码用来作为参数传递给其他代码;其它代码被期望在给定时间内调用回调方法。
**编程示例**
回调是一个只有一个方法的简单接口。
```java
public interface Callback {
void call();
}
```
下面我们定义一个任务它将在任务执行完成后执行回调。
```java
public abstract class Task {
final void executeWith(Callback callback) {
execute();
Optional.ofNullable(callback).ifPresent(Callback::call);
}
public abstract void execute();
}
public final class SimpleTask extends Task {
private static final Logger LOGGER = getLogger(SimpleTask.class);
@Override
public void execute() {
LOGGER.info("Perform some important activity and after call the callback method.");
}
}
```
最后这里是我们如何执行一个任务然后接收一个回调当它完成时。
```java
var task = new SimpleTask();
task.executeWith(() -> LOGGER.info("I'm done now."));
```
## 类图
![alt text](../../callback/etc/callback.png "Callback")
## 适用性
使用回调模式当
* 当一些同步或异步架构动作必须在一些定义好的活动执行后执行时。
## Java例子
* [CyclicBarrier](http://docs.oracle.com/javase/7/docs/api/java/util/concurrent/CyclicBarrier.html#CyclicBarrier%28int,%20java.lang.Runnable%29) 构造函数可以接受回调,该回调将在每次障碍被触发时触发。

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---
layout: pattern
title: Command
folder: command
permalink: /patterns/command/
categories: Behavioral
tags:
- Gang of Four
---
## 或称
行动, 事务模式
## 目的
将请求封装为对象,从而使你可以将具有不同请求的客户端参数化,队列或记录请求,并且支持可撤销操作。
## 解释
真实世界例子
> 有一个巫师在地精上施放咒语。咒语在地精上一一执行。第一个咒语使地精缩小,第二个使他不可见。然后巫师将咒语一个个的反转。这里的每一个咒语都是一个可撤销的命令对象。
用通俗的话说
> 用命令对象的方式存储请求以在将来时可以执行它或撤销它。
维基百科说
> 在面向对象编程中,命令模式是一种行为型设计模式,它把在稍后执行的一个动作或触发的一个事件所需要的所有信息封装到一个对象中。
**编程示例**
这是巫师和地精的示例代码。让我们从巫师类开始。
```java
public class Wizard {
private static final Logger LOGGER = LoggerFactory.getLogger(Wizard.class);
private final Deque<Command> undoStack = new LinkedList<>();
private final Deque<Command> redoStack = new LinkedList<>();
public Wizard() {}
public void castSpell(Command command, Target target) {
LOGGER.info("{} casts {} at {}", this, command, target);
command.execute(target);
undoStack.offerLast(command);
}
public void undoLastSpell() {
if (!undoStack.isEmpty()) {
var previousSpell = undoStack.pollLast();
redoStack.offerLast(previousSpell);
LOGGER.info("{} undoes {}", this, previousSpell);
previousSpell.undo();
}
}
public void redoLastSpell() {
if (!redoStack.isEmpty()) {
var previousSpell = redoStack.pollLast();
undoStack.offerLast(previousSpell);
LOGGER.info("{} redoes {}", this, previousSpell);
previousSpell.redo();
}
}
@Override
public String toString() {
return "Wizard";
}
}
```
接下来我们介绍咒语层级
```java
public interface Command {
void execute(Target target);
void undo();
void redo();
String toString();
}
public class InvisibilitySpell implements Command {
private Target target;
@Override
public void execute(Target target) {
target.setVisibility(Visibility.INVISIBLE);
this.target = target;
}
@Override
public void undo() {
if (target != null) {
target.setVisibility(Visibility.VISIBLE);
}
}
@Override
public void redo() {
if (target != null) {
target.setVisibility(Visibility.INVISIBLE);
}
}
@Override
public String toString() {
return "Invisibility spell";
}
}
public class ShrinkSpell implements Command {
private Size oldSize;
private Target target;
@Override
public void execute(Target target) {
oldSize = target.getSize();
target.setSize(Size.SMALL);
this.target = target;
}
@Override
public void undo() {
if (oldSize != null && target != null) {
var temp = target.getSize();
target.setSize(oldSize);
oldSize = temp;
}
}
@Override
public void redo() {
undo();
}
@Override
public String toString() {
return "Shrink spell";
}
}
```
最后我们有咒语的目标地精。
```java
public abstract class Target {
private static final Logger LOGGER = LoggerFactory.getLogger(Target.class);
private Size size;
private Visibility visibility;
public Size getSize() {
return size;
}
public void setSize(Size size) {
this.size = size;
}
public Visibility getVisibility() {
return visibility;
}
public void setVisibility(Visibility visibility) {
this.visibility = visibility;
}
@Override
public abstract String toString();
public void printStatus() {
LOGGER.info("{}, [size={}] [visibility={}]", this, getSize(), getVisibility());
}
}
public class Goblin extends Target {
public Goblin() {
setSize(Size.NORMAL);
setVisibility(Visibility.VISIBLE);
}
@Override
public String toString() {
return "Goblin";
}
}
```
最后是整个示例的实践。
```java
var wizard = new Wizard();
var goblin = new Goblin();
goblin.printStatus();
// Goblin, [size=normal] [visibility=visible]
wizard.castSpell(new ShrinkSpell(), goblin);
// Wizard casts Shrink spell at Goblin
goblin.printStatus();
// Goblin, [size=small] [visibility=visible]
wizard.castSpell(new InvisibilitySpell(), goblin);
// Wizard casts Invisibility spell at Goblin
goblin.printStatus();
// Goblin, [size=small] [visibility=invisible]
wizard.undoLastSpell();
// Wizard undoes Invisibility spell
goblin.printStatus();
// Goblin, [size=small] [visibility=visible]
```
## 类图
![alt text](../../command/etc/command.png "Command")
## 适用性
使用命令模式当你想
* 通过操作将对象参数化。您可以使用回调函数(即,已在某处注册以便稍后调用的函数)以过程语言表示这种参数化。命令是回调的一种面向对象替代方案。
* 在不同的时间指定,排队和执行请求。一个命令对象的生存期可以独立于原始请求。如果请求的接收方可以以地址空间无关的方式来表示,那么你可以将请求的命令对象传输到其他进程并在那里执行请求。
* 支持撤销。命令的执行操作可以在命令本身中存储状态以反转其效果。命令接口必须有添加的反执行操作该操作可以逆转上一次执行调用的效果。执行的命令存储在历史列表中。无限撤消和重做通过分别向后和向前遍历此列表来实现分别调用unexecute和execute。
* 支持日志记录更改,以便在系统崩溃时可以重新应用它们。通过使用加载和存储操作扩展命令接口,你可以保留更改的永久日志。从崩溃中恢复涉及从磁盘重新加载记录的命令,并通过执行操作重新执行它们。
* 通过原始的操作来构建一个以高级操作围绕的系统。这种结构在支持事务的信息系统中很常见。事务封装了一组数据更改。命令模式提供了一种对事务进行建模的方法。命令具有公共接口,让你以相同的方式调用所有事务。该模式还可以通过新的事务来轻松扩展系统。
## 典型用例
* 保留请求历史
* 实现回调功能
* 实现撤销功能
## Java世界例子
* [java.lang.Runnable](http://docs.oracle.com/javase/8/docs/api/java/lang/Runnable.html)
* [org.junit.runners.model.Statement](https://github.com/junit-team/junit4/blob/master/src/main/java/org/junit/runners/model/Statement.java)
* [Netflix Hystrix](https://github.com/Netflix/Hystrix/wiki)
* [javax.swing.Action](http://docs.oracle.com/javase/8/docs/api/javax/swing/Action.html)
## 鸣谢
* [Design Patterns: Elements of Reusable Object-Oriented Software](https://www.amazon.com/gp/product/0201633612/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0201633612&linkCode=as2&tag=javadesignpat-20&linkId=675d49790ce11db99d90bde47f1aeb59)
* [Head First Design Patterns: A Brain-Friendly Guide](https://www.amazon.com/gp/product/0596007124/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0596007124&linkCode=as2&tag=javadesignpat-20&linkId=6b8b6eea86021af6c8e3cd3fc382cb5b)
* [Refactoring to Patterns](https://www.amazon.com/gp/product/0321213351/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0321213351&linkCode=as2&tag=javadesignpat-20&linkId=2a76fcb387234bc71b1c61150b3cc3a7)
* [J2EE Design Patterns](https://www.amazon.com/gp/product/0596004273/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0596004273&linkCode=as2&tag=javadesignpat-20&linkId=f27d2644fbe5026ea448791a8ad09c94)

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以巨魔的为例。首先我有有一个简单的巨魔,实现了巨魔接口。
程序mple. First of all we have a simple troll implementing the troll interface
```java
public interface Troll {
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---
layout: pattern
title: Dependency Injection
folder: dependency-injection
permalink: /patterns/dependency-injection/
categories: Creational
tags:
- Decoupling
---
## 目的
依赖注入是一种软件设计模式,其中一个或多个依赖项(或服务)被注入或通过引用传递到一个依赖对象(或客户端)中,并成为客户端状态的一部分。该模式将客户的依赖关系的创建与其自身的行为分开,这使程序设计可以松散耦合,并遵循控制反转和单一职责原则。
## 解释
真实世界例子
> 老巫师喜欢不时地装满烟斗抽烟。 但是,他不想只依赖一个烟草品牌,而是希望能够互换使用它们。
通俗的说
> 依赖注入将客户端依赖的创建与其自身行为分开。
维基百科说
> 在软件工程中,依赖注入是一种对象接收其依赖的其他对象的技术。 这些其他对象称为依赖项。
**程序示例**
先介绍一下烟草接口和具体的品牌。
```java
public abstract class Tobacco {
private static final Logger LOGGER = LoggerFactory.getLogger(Tobacco.class);
public void smoke(Wizard wizard) {
LOGGER.info("{} smoking {}", wizard.getClass().getSimpleName(),
this.getClass().getSimpleName());
}
}
public class SecondBreakfastTobacco extends Tobacco {
}
public class RivendellTobacco extends Tobacco {
}
public class OldTobyTobacco extends Tobacco {
}
```
下面是老巫师的类的层次结构。
```java
public interface Wizard {
void smoke();
}
public class AdvancedWizard implements Wizard {
private final Tobacco tobacco;
public AdvancedWizard(Tobacco tobacco) {
this.tobacco = tobacco;
}
@Override
public void smoke() {
tobacco.smoke(this);
}
}
```
最后我们可以看到给老巫师任意品牌的烟草是多么的简单。
```java
var advancedWizard = new AdvancedWizard(new SecondBreakfastTobacco());
advancedWizard.smoke();
```
## 类图
![alt text](../../dependency-injection/etc/dependency-injection.png "Dependency Injection")
## 适用性
使用依赖注入当:
- 当你需要从对象中移除掉具体的实现内容时
* 使用模拟对象或存根隔离地启用类的单元测试
## 鸣谢
* [Dependency Injection Principles, Practices, and Patterns](https://www.amazon.com/gp/product/161729473X/ref=as_li_qf_asin_il_tl?ie=UTF8&tag=javadesignpat-20&creative=9325&linkCode=as2&creativeASIN=161729473X&linkId=57079257a5c7d33755493802f3b884bd)
* [Clean Code: A Handbook of Agile Software Craftsmanship](https://www.amazon.com/gp/product/0132350882/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0132350882&linkCode=as2&tag=javadesignpat-20&linkId=2c390d89cc9e61c01b9e7005c7842871)
* [Java 9 Dependency Injection: Write loosely coupled code with Spring 5 and Guice](https://www.amazon.com/gp/product/1788296257/ref=as_li_tl?ie=UTF8&tag=javadesignpat-20&camp=1789&creative=9325&linkCode=as2&creativeASIN=1788296257&linkId=4e9137a3bf722a8b5b156cce1eec0fc1)
* [Google Guice Tutorial: Open source Java based dependency injection framework](https://www.amazon.com/gp/product/B083P7DZ8M/ref=as_li_tl?ie=UTF8&tag=javadesignpat-20&camp=1789&creative=9325&linkCode=as2&creativeASIN=B083P7DZ8M&linkId=04f0f902c877921e45215b624a124bfe)

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---
layout: pattern
title: Iterator
folder: iterator
permalink: /patterns/iterator/
categories: Behavioral
tags:
- Gang of Four
---
## 又被称为
游标
## 目的
提供一种在不暴露其基础表示的情况下顺序访问聚合对象的元素的方法。
## 解释
真实世界例子
> 百宝箱包含一组魔法物品。有多种物品,例如戒指,药水和武器。可以使用藏宝箱提供的迭代器按类型浏览商品。
通俗地说
> 容器可以提供与表示形式无关的迭代器接口,以提供对元素的访问。
维基百科说
> 在面向对象的编程中,迭代器模式是一种设计模式,其中迭代器用于遍历容器并访问容器的元素。
**程序示例**
在我们的示例中包含物品的藏宝箱是主要类。
```java
public class TreasureChest {
private final List<Item> items;
public TreasureChest() {
items = List.of(
new Item(ItemType.POTION, "Potion of courage"),
new Item(ItemType.RING, "Ring of shadows"),
new Item(ItemType.POTION, "Potion of wisdom"),
new Item(ItemType.POTION, "Potion of blood"),
new Item(ItemType.WEAPON, "Sword of silver +1"),
new Item(ItemType.POTION, "Potion of rust"),
new Item(ItemType.POTION, "Potion of healing"),
new Item(ItemType.RING, "Ring of armor"),
new Item(ItemType.WEAPON, "Steel halberd"),
new Item(ItemType.WEAPON, "Dagger of poison"));
}
public Iterator<Item> iterator(ItemType itemType) {
return new TreasureChestItemIterator(this, itemType);
}
public List<Item> getItems() {
return new ArrayList<>(items);
}
}
public class Item {
private ItemType type;
private final String name;
public Item(ItemType type, String name) {
this.setType(type);
this.name = name;
}
@Override
public String toString() {
return name;
}
public ItemType getType() {
return type;
}
public final void setType(ItemType type) {
this.type = type;
}
}
public enum ItemType {
ANY, WEAPON, RING, POTION
}
```
迭代器接口极度简单。
```java
public interface Iterator<T> {
boolean hasNext();
T next();
}
```
在以下示例中,我们遍历在宝箱中找到的戒指类型物品。
```java
var itemIterator = TREASURE_CHEST.iterator(ItemType.RING);
while (itemIterator.hasNext()) {
LOGGER.info(itemIterator.next().toString());
}
// Ring of shadows
// Ring of armor
```
## 类图
![alt text](../../iterator/etc/iterator_1.png "Iterator")
## 适用性
以下情况使用迭代器模式
* 在不暴露其内部表示的情况下访问聚合对象的内容
* 为了支持聚合对象的多种遍历方式
* 提供一个遍历不同聚合结构的统一接口
## Java世界例子
* [java.util.Iterator](http://docs.oracle.com/javase/8/docs/api/java/util/Iterator.html)
* [java.util.Enumeration](http://docs.oracle.com/javase/8/docs/api/java/util/Enumeration.html)
## 鸣谢
* [Design Patterns: Elements of Reusable Object-Oriented Software](https://www.amazon.com/gp/product/0201633612/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0201633612&linkCode=as2&tag=javadesignpat-20&linkId=675d49790ce11db99d90bde47f1aeb59)
* [Head First Design Patterns: A Brain-Friendly Guide](https://www.amazon.com/gp/product/0596007124/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0596007124&linkCode=as2&tag=javadesignpat-20&linkId=6b8b6eea86021af6c8e3cd3fc382cb5b)

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---
layout: pattern
title: State
folder: state
permalink: /patterns/state/
categories: Behavioral
tags:
- Gang of Four
---
## 又被称为
对象状态
## 目的
允许对象在内部状态改变时改变它的行为。对象看起来好像修改了它的类。
## 解释
真实世界例子
> 当在长毛象的自然栖息地观察长毛象时,似乎它会根据情况来改变自己的行为。它开始可能很平静但是随着时间推移当它检测到威胁时它会对周围的环境感到愤怒和危险。
通俗的说
> 状态模式允许对象改变它的行为。
维基百科说
> 状态模式是一种允许对象在内部状态改变时改变它的行为的行为型设计模式。这种模式接近于有限状态机的概念。状态模式可以被理解为策略模式,它能够通过调用在模式接口中定义的方法来切换策略。
**编程示例**
这里是模式接口和它具体的实现。
```java
public interface State {
void onEnterState();
void observe();
}
public class PeacefulState implements State {
private static final Logger LOGGER = LoggerFactory.getLogger(PeacefulState.class);
private final Mammoth mammoth;
public PeacefulState(Mammoth mammoth) {
this.mammoth = mammoth;
}
@Override
public void observe() {
LOGGER.info("{} is calm and peaceful.", mammoth);
}
@Override
public void onEnterState() {
LOGGER.info("{} calms down.", mammoth);
}
}
public class AngryState implements State {
private static final Logger LOGGER = LoggerFactory.getLogger(AngryState.class);
private final Mammoth mammoth;
public AngryState(Mammoth mammoth) {
this.mammoth = mammoth;
}
@Override
public void observe() {
LOGGER.info("{} is furious!", mammoth);
}
@Override
public void onEnterState() {
LOGGER.info("{} gets angry!", mammoth);
}
}
```
然后这里是包含状态的长毛象。
```java
public class Mammoth {
private State state;
public Mammoth() {
state = new PeacefulState(this);
}
public void timePasses() {
if (state.getClass().equals(PeacefulState.class)) {
changeStateTo(new AngryState(this));
} else {
changeStateTo(new PeacefulState(this));
}
}
private void changeStateTo(State newState) {
this.state = newState;
this.state.onEnterState();
}
@Override
public String toString() {
return "The mammoth";
}
public void observe() {
this.state.observe();
}
}
```
然后这里是长毛象随着时间的推移后的整个行为示例。
```java
var mammoth = new Mammoth();
mammoth.observe();
mammoth.timePasses();
mammoth.observe();
mammoth.timePasses();
mammoth.observe();
// The mammoth gets angry!
// The mammoth is furious!
// The mammoth calms down.
// The mammoth is calm and peaceful.
```
## 类图
![alt text](../../state/etc/state_1.png "State")
## 适用性
在以下两种情况下请使用State模式
* 对象的行为取决于它的状态,并且它必须在运行时根据状态更改其行为。
* 根据对象状态的不同,操作有大量的条件语句。此状态通常由一个或多个枚举常量表示。通常,几个操作将包含此相同的条件结构。状态模式把条件语句的分支分别放入单独的类中。这样一来,你就可以将对象的状态视为独立的对象,该对象可以独立于其他对象而变化。
## Java中例子
* [javax.faces.lifecycle.Lifecycle#execute()](http://docs.oracle.com/javaee/7/api/javax/faces/lifecycle/Lifecycle.html#execute-javax.faces.context.FacesContext-) controlled by [FacesServlet](http://docs.oracle.com/javaee/7/api/javax/faces/webapp/FacesServlet.html), the behavior is dependent on current phase of lifecycle.
* [JDiameter - Diameter State Machine](https://github.com/npathai/jdiameter/blob/master/core/jdiameter/api/src/main/java/org/jdiameter/api/app/State.java)
## 鸣谢
* [Design Patterns: Elements of Reusable Object-Oriented Software](https://www.amazon.com/gp/product/0201633612/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0201633612&linkCode=as2&tag=javadesignpat-20&linkId=675d49790ce11db99d90bde47f1aeb59)
* [Head First Design Patterns: A Brain-Friendly Guide](https://www.amazon.com/gp/product/0596007124/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0596007124&linkCode=as2&tag=javadesignpat-20&linkId=6b8b6eea86021af6c8e3cd3fc382cb5b)
* [Refactoring to Patterns](https://www.amazon.com/gp/product/0321213351/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0321213351&linkCode=as2&tag=javadesignpat-20&linkId=2a76fcb387234bc71b1c61150b3cc3a7)

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@ -0,0 +1,145 @@
---
layout: pattern
title: Template method
folder: template-method
permalink: /patterns/template-method/
categories: Behavioral
tags:
- Gang of Four
---
## 目的
在一个操作中定义算法的骨架,将某些步骤推迟到子类。模板方法允许子类重新定义算法的某些步骤,而无需更改算法的结构。
## 解释
真实世界例子
> 偷东西的一般步骤是相同的。 首先,选择目标,然后以某种方式使其迷惑,最后,你偷走了该物品。然而这些步骤有很多实现方式。
通俗的说
> 模板方法模式在父类中列出一般的步骤然后让具体的子类定义实现细节。
维基百科说
> 在面向对象的编程中模板方法是Gamma等人确定的行为设计模式之一。在《设计模式》一书中。模板方法是父类中一个方法通常是一个抽象父类根据许多高级步骤定义了操作的骨架。这些步骤本身由与模板方法在同一类中的其他帮助程序方法实现。
**编程示例**
让我们首先介绍模板方法类及其具体实现。
```java
public abstract class StealingMethod {
private static final Logger LOGGER = LoggerFactory.getLogger(StealingMethod.class);
protected abstract String pickTarget();
protected abstract void confuseTarget(String target);
protected abstract void stealTheItem(String target);
public void steal() {
var target = pickTarget();
LOGGER.info("The target has been chosen as {}.", target);
confuseTarget(target);
stealTheItem(target);
}
}
public class SubtleMethod extends StealingMethod {
private static final Logger LOGGER = LoggerFactory.getLogger(SubtleMethod.class);
@Override
protected String pickTarget() {
return "shop keeper";
}
@Override
protected void confuseTarget(String target) {
LOGGER.info("Approach the {} with tears running and hug him!", target);
}
@Override
protected void stealTheItem(String target) {
LOGGER.info("While in close contact grab the {}'s wallet.", target);
}
}
public class HitAndRunMethod extends StealingMethod {
private static final Logger LOGGER = LoggerFactory.getLogger(HitAndRunMethod.class);
@Override
protected String pickTarget() {
return "old goblin woman";
}
@Override
protected void confuseTarget(String target) {
LOGGER.info("Approach the {} from behind.", target);
}
@Override
protected void stealTheItem(String target) {
LOGGER.info("Grab the handbag and run away fast!");
}
}
```
这是包含模板方法的半身贼类。
```java
public class HalflingThief {
private StealingMethod method;
public HalflingThief(StealingMethod method) {
this.method = method;
}
public void steal() {
method.steal();
}
public void changeMethod(StealingMethod method) {
this.method = method;
}
}
```
最后,我们展示半身人贼如何利用不同的偷窃方法。
```java
var thief = new HalflingThief(new HitAndRunMethod());
thief.steal();
thief.changeMethod(new SubtleMethod());
thief.steal();
```
## 类图
![alt text](../../template-method/etc/template-method_1.png "Template Method")
## 适用性
使用模板方法模式可以
* 一次性实现一个算法中不变的部分并将其留给子类来实现可能变化的行为。
* 子类之间的共同行为应分解并集中在一个共同类中以避免代码重复。如Opdyke和Johnson所描述的这是“重构概括”的一个很好的例子。你首先要确定现有代码中的差异然后将差异拆分为新的操作。最后将不同的代码替换为调用这些新操作之一的模板方法。
* 控制子类扩展。您可以定义一个模板方法,该方法在特定点调用“ 钩子”操作,从而仅允许在这些点进行扩展
## 教程
* [Template-method Pattern Tutorial](https://www.journaldev.com/1763/template-method-design-pattern-in-java)
## Java例子
* [javax.servlet.GenericServlet.init](https://jakarta.ee/specifications/servlet/4.0/apidocs/javax/servlet/GenericServlet.html#init--):
Method `GenericServlet.init(ServletConfig config)` calls the parameterless method `GenericServlet.init()` which is intended to be overridden in subclasses.
Method `GenericServlet.init(ServletConfig config)` is the template method in this example.
## 鸣谢
* [Design Patterns: Elements of Reusable Object-Oriented Software](https://www.amazon.com/gp/product/0201633612/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0201633612&linkCode=as2&tag=javadesignpat-20&linkId=675d49790ce11db99d90bde47f1aeb59)
* [Head First Design Patterns: A Brain-Friendly Guide](https://www.amazon.com/gp/product/0596007124/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0596007124&linkCode=as2&tag=javadesignpat-20&linkId=6b8b6eea86021af6c8e3cd3fc382cb5b)
* [Refactoring to Patterns](https://www.amazon.com/gp/product/0321213351/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0321213351&linkCode=as2&tag=javadesignpat-20&linkId=2a76fcb387234bc71b1c61150b3cc3a7)