Merge remote-tracking branch 'origin/master'
This commit is contained in:
Ashish Trivedi
commit
8166a1835d
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.all-contributorsrc
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.all-contributorsrc
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Load Diff
6
.github/workflows/maven.yml
vendored
6
.github/workflows/maven.yml
vendored
@ -46,7 +46,13 @@ jobs:
|
||||
# Some tests need screen access
|
||||
- name: Install xvfb
|
||||
run: sudo apt-get install xvfb
|
||||
# SonarQube scan does not work for forked repositories
|
||||
# See https://jira.sonarsource.com/browse/MMF-1371
|
||||
- name: Build with Maven
|
||||
if: github.ref != 'refs/heads/master'
|
||||
run: xvfb-run mvn clean verify
|
||||
- name: Build with Maven and run SonarQube analysis
|
||||
if: github.ref == 'refs/heads/master'
|
||||
run: xvfb-run mvn clean verify org.sonarsource.scanner.maven:sonar-maven-plugin:sonar
|
||||
env:
|
||||
# These two env variables are needed for sonar analysis
|
||||
|
||||
205
README.md
205
README.md
@ -8,6 +8,9 @@
|
||||
[](https://raw.githubusercontent.com/iluwatar/java-design-patterns/master/LICENSE.md)
|
||||
[](https://gitter.im/iluwatar/java-design-patterns?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
|
||||
[](https://sonarcloud.io/dashboard?id=iluwatar_java-design-patterns)
|
||||
<!-- ALL-CONTRIBUTORS-BADGE:START - Do not remove or modify this section -->
|
||||
[](#contributors-)
|
||||
<!-- ALL-CONTRIBUTORS-BADGE:END -->
|
||||
|
||||
# Introduction
|
||||
|
||||
@ -31,19 +34,20 @@ programming tutorials how to implement a specific pattern. We use the most
|
||||
popular battle-proven open source Java technologies.
|
||||
|
||||
Before you dive into the material, you should be familiar with various
|
||||
software design principles.
|
||||
[Software Design Principles](https://java-design-patterns.com/principles/).
|
||||
|
||||
All designs should be as simple as possible. You should start with KISS, YAGNI,
|
||||
and Do The Simplest Thing That Could Possibly Work principles. Complexity and
|
||||
patterns should only be introduced when they are needed for practical
|
||||
extensibility.
|
||||
|
||||
Once you are familiar with these concepts you can start drilling down into
|
||||
patterns by any of the following approaches
|
||||
Once you are familiar with these concepts you can start drilling down into the
|
||||
[available design patterns](https://java-design-patterns.com/patterns/) by any
|
||||
of the following approaches
|
||||
|
||||
- Using difficulty tags, `Difficulty-Beginner`, `Difficulty-Intermediate` & `Difficulty-Expert`.
|
||||
- Search for a specific pattern by name. Can't find one? Please report a new pattern [here](https://github.com/iluwatar/java-design-patterns/issues).
|
||||
- Using tags such as `Performance`, `Gang of Four` or `Data access`.
|
||||
- Using pattern categories, `Creational`, `Behavioral`, and others.
|
||||
- Search for a specific pattern. Can't find one? Please report a new pattern [here](https://github.com/iluwatar/java-design-patterns/issues).
|
||||
|
||||
Hopefully you find the object oriented solutions presented on this site useful
|
||||
in your architectures and have as much fun learning them as we had developing them.
|
||||
@ -57,3 +61,194 @@ you and answer your questions in the [Gitter chatroom](https://gitter.im/iluwata
|
||||
# License
|
||||
|
||||
This project is licensed under the terms of the MIT license.
|
||||
|
||||
# Contributors
|
||||
|
||||
<!-- 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><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>
|
||||
</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>
|
||||
</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>
|
||||
</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>
|
||||
</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>
|
||||
</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>
|
||||
</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>
|
||||
</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>
|
||||
</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>
|
||||
</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>
|
||||
</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>
|
||||
</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>
|
||||
</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>
|
||||
</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>
|
||||
</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>
|
||||
</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>
|
||||
</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>
|
||||
</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>
|
||||
</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>
|
||||
</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>
|
||||
</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>
|
||||
</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>
|
||||
</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>
|
||||
</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>
|
||||
</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>
|
||||
</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></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>
|
||||
</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>
|
||||
</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>
|
||||
</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></td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<!-- markdownlint-enable -->
|
||||
<!-- prettier-ignore-end -->
|
||||
<!-- ALL-CONTRIBUTORS-LIST:END -->
|
||||
|
||||
@ -9,21 +9,182 @@ tags:
|
||||
---
|
||||
|
||||
## Intent
|
||||
Achieve flexibility of untyped languages and keep the type-safety
|
||||
|
||||
Use dynamic properties and achieve flexibility of untyped languages while keeping type-safety.
|
||||
|
||||
## Explanation
|
||||
|
||||
The Abstract Document pattern enables handling additional, non-static properties. This pattern
|
||||
uses concept of traits to enable type safety and separate properties of different classes into
|
||||
set of interfaces.
|
||||
|
||||
Real world example
|
||||
|
||||
> Consider a car that consists of multiple parts. However we don't know if the specific car really has all the parts, or just some of them. Our cars are dynamic and extremely flexible.
|
||||
|
||||
In plain words
|
||||
|
||||
> Abstract Document pattern allows attaching properties to objects without them knowing about it.
|
||||
|
||||
Wikipedia says
|
||||
|
||||
> An object-oriented structural design pattern for organizing objects in loosely typed key-value stores and exposing
|
||||
the data using typed views. The purpose of the pattern is to achieve a high degree of flexibility between components
|
||||
in a strongly typed language where new properties can be added to the object-tree on the fly, without losing the
|
||||
support of type-safety. The pattern makes use of traits to separate different properties of a class into different
|
||||
interfaces.
|
||||
|
||||
**Programmatic Example**
|
||||
|
||||
Let's first define the base classes `Document` and `AbstractDocument`. They basically make the object hold a property
|
||||
map and any amount of child objects.
|
||||
|
||||
```java
|
||||
public interface Document {
|
||||
|
||||
Void put(String key, Object value);
|
||||
|
||||
Object get(String key);
|
||||
|
||||
<T> Stream<T> children(String key, Function<Map<String, Object>, T> constructor);
|
||||
}
|
||||
|
||||
public abstract class AbstractDocument implements Document {
|
||||
|
||||
private final Map<String, Object> properties;
|
||||
|
||||
protected AbstractDocument(Map<String, Object> properties) {
|
||||
Objects.requireNonNull(properties, "properties map is required");
|
||||
this.properties = properties;
|
||||
}
|
||||
|
||||
@Override
|
||||
public Void put(String key, Object value) {
|
||||
properties.put(key, value);
|
||||
return null;
|
||||
}
|
||||
|
||||
@Override
|
||||
public Object get(String key) {
|
||||
return properties.get(key);
|
||||
}
|
||||
|
||||
@Override
|
||||
public <T> Stream<T> children(String key, Function<Map<String, Object>, T> constructor) {
|
||||
return Stream.ofNullable(get(key))
|
||||
.filter(Objects::nonNull)
|
||||
.map(el -> (List<Map<String, Object>>) el)
|
||||
.findAny()
|
||||
.stream()
|
||||
.flatMap(Collection::stream)
|
||||
.map(constructor);
|
||||
}
|
||||
...
|
||||
}
|
||||
```
|
||||
Next we define an enum `Property` and a set of interfaces for type, price, model and parts. This allows us to create
|
||||
static looking interface to our `Car` class.
|
||||
|
||||
```java
|
||||
public enum Property {
|
||||
|
||||
PARTS, TYPE, PRICE, MODEL
|
||||
}
|
||||
|
||||
public interface HasType extends Document {
|
||||
|
||||
default Optional<String> getType() {
|
||||
return Optional.ofNullable((String) get(Property.TYPE.toString()));
|
||||
}
|
||||
}
|
||||
|
||||
public interface HasPrice extends Document {
|
||||
|
||||
default Optional<Number> getPrice() {
|
||||
return Optional.ofNullable((Number) get(Property.PRICE.toString()));
|
||||
}
|
||||
}
|
||||
public interface HasModel extends Document {
|
||||
|
||||
default Optional<String> getModel() {
|
||||
return Optional.ofNullable((String) get(Property.MODEL.toString()));
|
||||
}
|
||||
}
|
||||
|
||||
public interface HasParts extends Document {
|
||||
|
||||
default Stream<Part> getParts() {
|
||||
return children(Property.PARTS.toString(), Part::new);
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
Now we are ready to introduce the `Car`.
|
||||
|
||||
```java
|
||||
public class Car extends AbstractDocument implements HasModel, HasPrice, HasParts {
|
||||
|
||||
public Car(Map<String, Object> properties) {
|
||||
super(properties);
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
And finally here's how we construct and use the `Car` in a full example.
|
||||
|
||||
```java
|
||||
LOGGER.info("Constructing parts and car");
|
||||
|
||||
var wheelProperties = Map.of(
|
||||
Property.TYPE.toString(), "wheel",
|
||||
Property.MODEL.toString(), "15C",
|
||||
Property.PRICE.toString(), 100L);
|
||||
|
||||
var doorProperties = Map.of(
|
||||
Property.TYPE.toString(), "door",
|
||||
Property.MODEL.toString(), "Lambo",
|
||||
Property.PRICE.toString(), 300L);
|
||||
|
||||
var carProperties = Map.of(
|
||||
Property.MODEL.toString(), "300SL",
|
||||
Property.PRICE.toString(), 10000L,
|
||||
Property.PARTS.toString(), List.of(wheelProperties, doorProperties));
|
||||
|
||||
var car = new Car(carProperties);
|
||||
|
||||
LOGGER.info("Here is our car:");
|
||||
LOGGER.info("-> model: {}", car.getModel().orElseThrow());
|
||||
LOGGER.info("-> price: {}", car.getPrice().orElseThrow());
|
||||
LOGGER.info("-> parts: ");
|
||||
car.getParts().forEach(p -> LOGGER.info("\t{}/{}/{}",
|
||||
p.getType().orElse(null),
|
||||
p.getModel().orElse(null),
|
||||
p.getPrice().orElse(null))
|
||||
);
|
||||
|
||||
// Constructing parts and car
|
||||
// Here is our car:
|
||||
// model: 300SL
|
||||
// price: 10000
|
||||
// parts:
|
||||
// wheel/15C/100
|
||||
// door/Lambo/300
|
||||
```
|
||||
|
||||
## Class diagram
|
||||
|
||||
|
||||
|
||||
|
||||
## Applicability
|
||||
|
||||
Use the Abstract Document Pattern when
|
||||
|
||||
* there is a need to add new properties on the fly
|
||||
* you want a flexible way to organize domain in tree like structure
|
||||
* you want more loosely coupled system
|
||||
|
||||
* There is a need to add new properties on the fly
|
||||
* You want a flexible way to organize domain in tree like structure
|
||||
* You want more loosely coupled system
|
||||
|
||||
## Credits
|
||||
|
||||
* [Wikipedia: Abstract Document Pattern](https://en.wikipedia.org/wiki/Abstract_Document_Pattern)
|
||||
* [Martin Fowler: Dealing with properties](http://martinfowler.com/apsupp/properties.pdf)
|
||||
* [Pattern-Oriented Software Architecture Volume 4: A Pattern Language for Distributed Computing (v. 4)](https://www.amazon.com/gp/product/0470059028/ref=as_li_qf_asin_il_tl?ie=UTF8&tag=javadesignpat-20&creative=9325&linkCode=as2&creativeASIN=0470059028&linkId=e3aacaea7017258acf184f9f3283b492)
|
||||
|
||||
@ -43,9 +43,11 @@ public class App {
|
||||
private static final Logger LOGGER = LoggerFactory.getLogger(App.class);
|
||||
|
||||
/**
|
||||
* Executes the App.
|
||||
* Program entry point.
|
||||
*
|
||||
* @param args command line args
|
||||
*/
|
||||
public App() {
|
||||
public static void main(String[] args) {
|
||||
LOGGER.info("Constructing parts and car");
|
||||
|
||||
var wheelProperties = Map.of(
|
||||
@ -75,14 +77,4 @@ public class App {
|
||||
p.getPrice().orElse(null))
|
||||
);
|
||||
}
|
||||
|
||||
/**
|
||||
* Program entry point.
|
||||
*
|
||||
* @param args command line args
|
||||
*/
|
||||
public static void main(String[] args) {
|
||||
new App();
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
@ -32,7 +32,6 @@ import java.util.stream.Stream;
|
||||
*/
|
||||
public interface HasParts extends Document {
|
||||
|
||||
|
||||
default Stream<Part> getParts() {
|
||||
return children(Property.PARTS.toString(), Part::new);
|
||||
}
|
||||
|
||||
@ -32,7 +32,6 @@ import java.util.Optional;
|
||||
*/
|
||||
public interface HasPrice extends Document {
|
||||
|
||||
|
||||
default Optional<Number> getPrice() {
|
||||
return Optional.ofNullable((Number) get(Property.PRICE.toString()));
|
||||
}
|
||||
|
||||
@ -32,7 +32,6 @@ import java.util.Optional;
|
||||
*/
|
||||
public interface HasType extends Document {
|
||||
|
||||
|
||||
default Optional<String> getType() {
|
||||
return Optional.ofNullable((String) get(Property.TYPE.toString()));
|
||||
}
|
||||
|
||||
@ -1,26 +0,0 @@
|
||||
/*
|
||||
* 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.
|
||||
*/
|
||||
|
||||
module com.iluwatar.abstractdocument {
|
||||
requires org.slf4j;
|
||||
}
|
||||
@ -40,14 +40,14 @@ public class AbstractDocumentTest {
|
||||
private static final String KEY = "key";
|
||||
private static final String VALUE = "value";
|
||||
|
||||
private class DocumentImplementation extends AbstractDocument {
|
||||
private static class DocumentImplementation extends AbstractDocument {
|
||||
|
||||
DocumentImplementation(Map<String, Object> properties) {
|
||||
super(properties);
|
||||
}
|
||||
}
|
||||
|
||||
private DocumentImplementation document = new DocumentImplementation(new HashMap<>());
|
||||
private final DocumentImplementation document = new DocumentImplementation(new HashMap<>());
|
||||
|
||||
@Test
|
||||
public void shouldPutAndGetValue() {
|
||||
|
||||
@ -9,16 +9,19 @@ tags:
|
||||
---
|
||||
|
||||
## Also known as
|
||||
|
||||
Kit
|
||||
|
||||
## Intent
|
||||
|
||||
Provide an interface for creating families of related or dependent
|
||||
objects without specifying their concrete classes.
|
||||
|
||||
## Explanation
|
||||
|
||||
Real world example
|
||||
|
||||
> To create a kingdom we need objects with common theme. Elven kingdom needs an Elven king, Elven castle and Elven army whereas Orcish kingdom needs an Orcish king, Orcish castle and Orcish army. There is a dependency between the objects in the kingdom.
|
||||
> To create a kingdom we need objects with a common theme. Elven kingdom needs an Elven king, Elven castle and Elven army whereas Orcish kingdom needs an Orcish king, Orcish castle and Orcish army. There is a dependency between the objects in the kingdom.
|
||||
|
||||
In plain words
|
||||
|
||||
@ -30,15 +33,18 @@ Wikipedia says
|
||||
|
||||
**Programmatic Example**
|
||||
|
||||
Translating the kingdom example above. First of all we have some interfaces and implementation for the objects in the kingdom
|
||||
Translating the kingdom example above. First of all we have some interfaces and implementation for the objects in the
|
||||
kingdom.
|
||||
|
||||
```java
|
||||
public interface Castle {
|
||||
String getDescription();
|
||||
}
|
||||
|
||||
public interface King {
|
||||
String getDescription();
|
||||
}
|
||||
|
||||
public interface Army {
|
||||
String getDescription();
|
||||
}
|
||||
@ -66,7 +72,7 @@ public class ElfArmy implements Army {
|
||||
}
|
||||
}
|
||||
|
||||
// Orcish implementations similarly...
|
||||
// Orcish implementations similarly -> ...
|
||||
|
||||
```
|
||||
|
||||
@ -112,9 +118,17 @@ var castle = factory.createCastle();
|
||||
var king = factory.createKing();
|
||||
var army = factory.createArmy();
|
||||
|
||||
castle.getDescription(); // Output: This is the Elven castle!
|
||||
king.getDescription(); // Output: This is the Elven king!
|
||||
army.getDescription(); // Output: This is the Elven Army!
|
||||
castle.getDescription();
|
||||
king.getDescription();
|
||||
army.getDescription();
|
||||
```
|
||||
|
||||
Program output:
|
||||
|
||||
```java
|
||||
This is the Elven castle!
|
||||
This is the Elven king!
|
||||
This is the Elven Army!
|
||||
```
|
||||
|
||||
Now, we can design a factory for our different kingdom factories. In this example, we created FactoryMaker, responsible for returning an instance of either ElfKingdomFactory or OrcKingdomFactory.
|
||||
@ -156,46 +170,52 @@ public static void main(String[] args) {
|
||||
```
|
||||
|
||||
## Class diagram
|
||||
|
||||
|
||||
|
||||
|
||||
## Applicability
|
||||
|
||||
Use the Abstract Factory pattern when
|
||||
|
||||
* a system should be independent of how its products are created, composed and represented
|
||||
* a system should be configured with one of multiple families of products
|
||||
* a family of related product objects is designed to be used together, and you need to enforce this constraint
|
||||
* you want to provide a class library of products, and you want to reveal just their interfaces, not their implementations
|
||||
* the lifetime of the dependency is conceptually shorter than the lifetime of the consumer.
|
||||
* you need a run-time value to construct a particular dependency
|
||||
* you want to decide which product to call from a family at runtime.
|
||||
* you need to supply one or more parameters only known at run-time before you can resolve a dependency.
|
||||
* when you need consistency among products
|
||||
* you don’t want to change existing code when adding new products or families of products to the program.
|
||||
* The system should be independent of how its products are created, composed and represented
|
||||
* The system should be configured with one of multiple families of products
|
||||
* The family of related product objects is designed to be used together, and you need to enforce this constraint
|
||||
* You want to provide a class library of products, and you want to reveal just their interfaces, not their implementations
|
||||
* The lifetime of the dependency is conceptually shorter than the lifetime of the consumer.
|
||||
* You need a run-time value to construct a particular dependency
|
||||
* You want to decide which product to call from a family at runtime.
|
||||
* You need to supply one or more parameters only known at run-time before you can resolve a dependency.
|
||||
* When you need consistency among products
|
||||
* You don’t want to change existing code when adding new products or families of products to the program.
|
||||
|
||||
## Use Cases:
|
||||
Example use cases
|
||||
|
||||
* Selecting to call the appropriate implementation of FileSystemAcmeService or DatabaseAcmeService or NetworkAcmeService at runtime.
|
||||
* Unit test case writing becomes much easier
|
||||
* Selecting to call to the appropriate implementation of FileSystemAcmeService or DatabaseAcmeService or NetworkAcmeService at runtime.
|
||||
* Unit test case writing becomes much easier
|
||||
* UI tools for different OS
|
||||
|
||||
## Consequences:
|
||||
|
||||
* Dependency injection in java hides the service class dependencies that can lead to runtime errors that would have been caught at compile time.
|
||||
* Dependency injection in java hides the service class dependencies that can lead to runtime errors that would have been caught at compile time.
|
||||
* While the pattern is great when creating predefined objects, adding the new ones might be challenging.
|
||||
* The code may become more complicated than it should be, since a lot of new interfaces and classes are introduced along with the pattern.
|
||||
|
||||
* The code becomes more complicated than it should be, since a lot of new interfaces and classes are introduced along with the pattern.
|
||||
|
||||
## Tutorial
|
||||
|
||||
* [Abstract Factory Pattern Tutorial](https://www.journaldev.com/1418/abstract-factory-design-pattern-in-java)
|
||||
|
||||
|
||||
## Real world examples
|
||||
## Known uses
|
||||
|
||||
* [javax.xml.parsers.DocumentBuilderFactory](http://docs.oracle.com/javase/8/docs/api/javax/xml/parsers/DocumentBuilderFactory.html)
|
||||
* [javax.xml.transform.TransformerFactory](http://docs.oracle.com/javase/8/docs/api/javax/xml/transform/TransformerFactory.html#newInstance--)
|
||||
* [javax.xml.xpath.XPathFactory](http://docs.oracle.com/javase/8/docs/api/javax/xml/xpath/XPathFactory.html#newInstance--)
|
||||
|
||||
## Related patterns
|
||||
|
||||
[Factory Method](https://java-design-patterns.com/patterns/factory-method/)
|
||||
[Factory Kit](https://java-design-patterns.com/patterns/factory-kit/)
|
||||
|
||||
## Credits
|
||||
|
||||
* [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)
|
||||
|
||||
@ -1,26 +0,0 @@
|
||||
/*
|
||||
* 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.
|
||||
*/
|
||||
|
||||
module com.iluwatar.abstractfactory {
|
||||
requires org.slf4j;
|
||||
}
|
||||
@ -36,7 +36,7 @@ import org.junit.jupiter.api.Test;
|
||||
*/
|
||||
public class AbstractFactoryTest {
|
||||
|
||||
private App app = new App();
|
||||
private final App app = new App();
|
||||
private KingdomFactory elfFactory;
|
||||
private KingdomFactory orcFactory;
|
||||
|
||||
|
||||
@ -9,12 +9,126 @@ tags:
|
||||
---
|
||||
|
||||
## Intent
|
||||
Allow new functions to be added to existing class hierarchies without affecting those hierarchies, and without creating the troublesome dependency cycles that are inherent to the GOF VISITOR Pattern.
|
||||
|
||||
Allow new functions to be added to existing class hierarchies without affecting those hierarchies, and without creating
|
||||
the troublesome dependency cycles that are inherent to the GoF Visitor Pattern.
|
||||
|
||||
## Explanation
|
||||
|
||||
Real world example
|
||||
|
||||
> We have a hierarchy of modem classes. The modems in this hierarchy need to be visited by an external algorithm based
|
||||
> on filtering criteria (is it Unix or DOS compatible modem).
|
||||
|
||||
In plain words
|
||||
|
||||
> Acyclic Visitor allows functions to be added to existing class hierarchies without modifying the hierarchies.
|
||||
|
||||
[WikiWikiWeb](https://wiki.c2.com/?AcyclicVisitor) says
|
||||
|
||||
> The Acyclic Visitor pattern allows new functions to be added to existing class hierarchies without affecting those
|
||||
> hierarchies, and without creating the dependency cycles that are inherent to the GangOfFour VisitorPattern.
|
||||
|
||||
**Programmatic Example**
|
||||
|
||||
Here's the `Modem` hierarchy.
|
||||
|
||||
```java
|
||||
public abstract class Modem {
|
||||
public abstract void accept(ModemVisitor modemVisitor);
|
||||
}
|
||||
|
||||
public class Zoom extends Modem {
|
||||
...
|
||||
@Override
|
||||
public void accept(ModemVisitor modemVisitor) {
|
||||
if (modemVisitor instanceof ZoomVisitor) {
|
||||
((ZoomVisitor) modemVisitor).visit(this);
|
||||
} else {
|
||||
LOGGER.info("Only ZoomVisitor is allowed to visit Zoom modem");
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
public class Hayes extends Modem {
|
||||
...
|
||||
@Override
|
||||
public void accept(ModemVisitor modemVisitor) {
|
||||
if (modemVisitor instanceof HayesVisitor) {
|
||||
((HayesVisitor) modemVisitor).visit(this);
|
||||
} else {
|
||||
LOGGER.info("Only HayesVisitor is allowed to visit Hayes modem");
|
||||
}
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
Next we introduce the `ModemVisitor` hierarchy.
|
||||
|
||||
```java
|
||||
public interface ModemVisitor {
|
||||
}
|
||||
|
||||
public interface HayesVisitor extends ModemVisitor {
|
||||
void visit(Hayes hayes);
|
||||
}
|
||||
|
||||
public interface ZoomVisitor extends ModemVisitor {
|
||||
void visit(Zoom zoom);
|
||||
}
|
||||
|
||||
public interface AllModemVisitor extends ZoomVisitor, HayesVisitor {
|
||||
}
|
||||
|
||||
public class ConfigureForDosVisitor implements AllModemVisitor {
|
||||
...
|
||||
@Override
|
||||
public void visit(Hayes hayes) {
|
||||
LOGGER.info(hayes + " used with Dos configurator.");
|
||||
}
|
||||
@Override
|
||||
public void visit(Zoom zoom) {
|
||||
LOGGER.info(zoom + " used with Dos configurator.");
|
||||
}
|
||||
}
|
||||
|
||||
public class ConfigureForUnixVisitor implements ZoomVisitor {
|
||||
...
|
||||
@Override
|
||||
public void visit(Zoom zoom) {
|
||||
LOGGER.info(zoom + " used with Unix configurator.");
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
Finally, here are the visitors in action.
|
||||
|
||||
```java
|
||||
var conUnix = new ConfigureForUnixVisitor();
|
||||
var conDos = new ConfigureForDosVisitor();
|
||||
var zoom = new Zoom();
|
||||
var hayes = new Hayes();
|
||||
hayes.accept(conDos);
|
||||
zoom.accept(conDos);
|
||||
hayes.accept(conUnix);
|
||||
zoom.accept(conUnix);
|
||||
```
|
||||
|
||||
Program output:
|
||||
|
||||
```
|
||||
// Hayes modem used with Dos configurator.
|
||||
// Zoom modem used with Dos configurator.
|
||||
// Only HayesVisitor is allowed to visit Hayes modem
|
||||
// Zoom modem used with Unix configurator.
|
||||
```
|
||||
|
||||
## Class diagram
|
||||
|
||||
|
||||
|
||||
## Applicability
|
||||
|
||||
This pattern can be used:
|
||||
|
||||
* When you need to add a new function to an existing hierarchy without the need to alter or affect that hierarchy.
|
||||
@ -24,6 +138,7 @@ This pattern can be used:
|
||||
* When the recompilation, relinking, retesting or redistribution of the derivatives of Element is very expensive.
|
||||
|
||||
## Consequences
|
||||
|
||||
The good:
|
||||
|
||||
* No dependency cycles between class hierarchies.
|
||||
@ -32,11 +147,14 @@ The good:
|
||||
|
||||
The bad:
|
||||
|
||||
* Violates the principle of least surprise or Liskov's Substitution principle by showing that it can accept all visitors but actually only being interested in particular visitors.
|
||||
* Violates [Liskov's Substitution Principle](https://java-design-patterns.com/principles/#liskov-substitution-principle) by showing that it can accept all visitors but actually only being interested in particular visitors.
|
||||
* Parallel hierarchy of visitors has to be created for all members in visitable class hierarchy.
|
||||
|
||||
## Related patterns
|
||||
* [Visitor Pattern](../visitor/)
|
||||
|
||||
* [Visitor Pattern](https://java-design-patterns.com/patterns/visitor/)
|
||||
|
||||
## Credits
|
||||
* [Acyclic Visitor](http://condor.depaul.edu/dmumaugh/OOT/Design-Principles/acv.pdf)
|
||||
|
||||
* [Acyclic Visitor by Robert C. Martin](http://condor.depaul.edu/dmumaugh/OOT/Design-Principles/acv.pdf)
|
||||
* [Acyclic Visitor in WikiWikiWeb](https://wiki.c2.com/?AcyclicVisitor)
|
||||
|
||||
@ -1,115 +0,0 @@
|
||||
<?xml version="1.0" encoding="UTF-8"?>
|
||||
<class-diagram version="1.2.2" icons="true" always-add-relationships="false" generalizations="true" realizations="true"
|
||||
associations="true" dependencies="false" nesting-relationships="true" router="FAN">
|
||||
<interface id="1" language="java" name="com.iluwatar.acyclicvisitor.ModemVisitor" project="acyclic-visitor"
|
||||
file="/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ModemVisitor.java" binary="false"
|
||||
corner="BOTTOM_RIGHT">
|
||||
<position height="-1" width="-1" x="860" y="67"/>
|
||||
<display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
|
||||
sort-features="false" accessors="true" visibility="true">
|
||||
<attributes public="true" package="true" protected="true" private="true" static="true"/>
|
||||
<operations public="true" package="true" protected="true" private="true" static="true"/>
|
||||
</display>
|
||||
</interface>
|
||||
<class id="2" language="java" name="com.iluwatar.acyclicvisitor.Modem" project="acyclic-visitor"
|
||||
file="/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Modem.java" binary="false" corner="BOTTOM_RIGHT">
|
||||
<position height="-1" width="-1" x="327" y="77"/>
|
||||
<display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
|
||||
sort-features="false" accessors="true" visibility="true">
|
||||
<attributes public="true" package="true" protected="true" private="true" static="true"/>
|
||||
<operations public="true" package="true" protected="true" private="true" static="true"/>
|
||||
</display>
|
||||
</class>
|
||||
<class id="3" language="java" name="com.iluwatar.acyclicvisitor.ConfigureForUnixVisitor" project="acyclic-visitor"
|
||||
file="/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ConfigureForUnixVisitor.java" binary="false"
|
||||
corner="BOTTOM_RIGHT">
|
||||
<position height="124" width="196" x="647" y="225"/>
|
||||
<display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
|
||||
sort-features="false" accessors="true" visibility="true">
|
||||
<attributes public="true" package="true" protected="true" private="true" static="true"/>
|
||||
<operations public="true" package="true" protected="true" private="true" static="true"/>
|
||||
</display>
|
||||
</class>
|
||||
<class id="4" language="java" name="com.iluwatar.acyclicvisitor.Zoom" project="acyclic-visitor"
|
||||
file="/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Zoom.java" binary="false" corner="BOTTOM_RIGHT">
|
||||
<position height="-1" width="-1" x="203" y="305"/>
|
||||
<display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
|
||||
sort-features="false" accessors="true" visibility="true">
|
||||
<attributes public="true" package="true" protected="true" private="true" static="true"/>
|
||||
<operations public="true" package="true" protected="true" private="true" static="true"/>
|
||||
</display>
|
||||
</class>
|
||||
<interface id="5" language="java" name="com.iluwatar.acyclicvisitor.HayesVisitor" project="acyclic-visitor"
|
||||
file="/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/HayesVisitor.java" binary="false"
|
||||
corner="BOTTOM_RIGHT">
|
||||
<position height="-1" width="-1" x="1019" y="468"/>
|
||||
<display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
|
||||
sort-features="false" accessors="true" visibility="true">
|
||||
<attributes public="true" package="true" protected="true" private="true" static="true"/>
|
||||
<operations public="true" package="true" protected="true" private="true" static="true"/>
|
||||
</display>
|
||||
</interface>
|
||||
<interface id="6" language="java" name="com.iluwatar.acyclicvisitor.ZoomVisitor" project="acyclic-visitor"
|
||||
file="/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ZoomVisitor.java" binary="false"
|
||||
corner="BOTTOM_RIGHT">
|
||||
<position height="-1" width="-1" x="758" y="467"/>
|
||||
<display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
|
||||
sort-features="false" accessors="true" visibility="true">
|
||||
<attributes public="true" package="true" protected="true" private="true" static="true"/>
|
||||
<operations public="true" package="true" protected="true" private="true" static="true"/>
|
||||
</display>
|
||||
</interface>
|
||||
<class id="7" language="java" name="com.iluwatar.acyclicvisitor.Hayes" project="acyclic-visitor"
|
||||
file="/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Hayes.java" binary="false" corner="BOTTOM_RIGHT">
|
||||
<position height="-1" width="-1" x="479" y="307"/>
|
||||
<display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
|
||||
sort-features="false" accessors="true" visibility="true">
|
||||
<attributes public="true" package="true" protected="true" private="true" static="true"/>
|
||||
<operations public="true" package="true" protected="true" private="true" static="true"/>
|
||||
</display>
|
||||
</class>
|
||||
<class id="8" language="java" name="com.iluwatar.acyclicvisitor.ConfigureForDosVisitor" project="acyclic-visitor"
|
||||
file="/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ConfigureForDosVisitor.java" binary="false"
|
||||
corner="BOTTOM_RIGHT">
|
||||
<position height="142" width="192" x="883" y="225"/>
|
||||
<display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
|
||||
sort-features="false" accessors="true" visibility="true">
|
||||
<attributes public="true" package="true" protected="true" private="true" static="true"/>
|
||||
<operations public="true" package="true" protected="true" private="true" static="true"/>
|
||||
</display>
|
||||
</class>
|
||||
<generalization id="9">
|
||||
<end type="SOURCE" refId="7"/>
|
||||
<end type="TARGET" refId="2"/>
|
||||
</generalization>
|
||||
<realization id="10">
|
||||
<end type="SOURCE" refId="8"/>
|
||||
<end type="TARGET" refId="6"/>
|
||||
</realization>
|
||||
<realization id="11">
|
||||
<end type="SOURCE" refId="8"/>
|
||||
<end type="TARGET" refId="5"/>
|
||||
</realization>
|
||||
<realization id="12">
|
||||
<end type="SOURCE" refId="3"/>
|
||||
<end type="TARGET" refId="6"/>
|
||||
</realization>
|
||||
<realization id="13">
|
||||
<end type="SOURCE" refId="3"/>
|
||||
<end type="TARGET" refId="1"/>
|
||||
</realization>
|
||||
<realization id="14">
|
||||
<end type="SOURCE" refId="8"/>
|
||||
<end type="TARGET" refId="1"/>
|
||||
</realization>
|
||||
<generalization id="15">
|
||||
<end type="SOURCE" refId="4"/>
|
||||
<end type="TARGET" refId="2"/>
|
||||
</generalization>
|
||||
<classifier-display autosize="true" stereotype="true" package="true" initial-value="false" signature="true"
|
||||
sort-features="false" accessors="true" visibility="true">
|
||||
<attributes public="true" package="true" protected="true" private="true" static="true"/>
|
||||
<operations public="true" package="true" protected="true" private="true" static="true"/>
|
||||
</classifier-display>
|
||||
<association-display labels="true" multiplicity="true"/>
|
||||
</class-diagram>
|
||||
Binary file not shown.
|
Before Width: | Height: | Size: 26 KiB After Width: | Height: | Size: 48 KiB |
@ -1,26 +0,0 @@
|
||||
/*
|
||||
* 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.
|
||||
*/
|
||||
|
||||
module com.iluwatar.acyclicvisitor {
|
||||
requires org.slf4j;
|
||||
}
|
||||
@ -37,7 +37,7 @@ import uk.org.lidalia.slf4jtest.TestLoggerFactory;
|
||||
*/
|
||||
public class ConfigureForDosVisitorTest {
|
||||
|
||||
private TestLogger logger = TestLoggerFactory.getTestLogger(ConfigureForDosVisitor.class);
|
||||
private final TestLogger logger = TestLoggerFactory.getTestLogger(ConfigureForDosVisitor.class);
|
||||
|
||||
@Test
|
||||
public void testVisitForZoom() {
|
||||
|
||||
@ -12,9 +12,8 @@ tags:
|
||||
Wrapper
|
||||
|
||||
## Intent
|
||||
Convert the interface of a class into another interface the clients
|
||||
expect. Adapter lets classes work together that couldn't otherwise because of
|
||||
incompatible interfaces.
|
||||
Convert the interface of a class into another interface the clients expect. Adapter lets classes work together that
|
||||
couldn't otherwise because of incompatible interfaces.
|
||||
|
||||
## Explanation
|
||||
|
||||
@ -56,7 +55,7 @@ And captain expects an implementation of `RowingBoat` interface to be able to mo
|
||||
```java
|
||||
public class Captain {
|
||||
|
||||
private RowingBoat rowingBoat;
|
||||
private final RowingBoat rowingBoat;
|
||||
// default constructor and setter for rowingBoat
|
||||
public Captain(RowingBoat rowingBoat) {
|
||||
this.rowingBoat = rowingBoat;
|
||||
@ -75,7 +74,7 @@ public class FishingBoatAdapter implements RowingBoat {
|
||||
|
||||
private static final Logger LOGGER = LoggerFactory.getLogger(FishingBoatAdapter.class);
|
||||
|
||||
private FishingBoat boat;
|
||||
private final FishingBoat boat;
|
||||
|
||||
public FishingBoatAdapter() {
|
||||
boat = new FishingBoat();
|
||||
|
||||
@ -29,7 +29,7 @@ package com.iluwatar.adapter;
|
||||
*/
|
||||
public class FishingBoatAdapter implements RowingBoat {
|
||||
|
||||
private FishingBoat boat;
|
||||
private final FishingBoat boat;
|
||||
|
||||
public FishingBoatAdapter() {
|
||||
boat = new FishingBoat();
|
||||
|
||||
@ -10,16 +10,91 @@ tags:
|
||||
|
||||
## Intent
|
||||
|
||||
The user makes a single call to the Aggregator, and the aggregator then calls each relevant microservice and collects
|
||||
the data, apply business logic to it, and further publish is as a REST Endpoint.
|
||||
More variations of the aggregator are:
|
||||
- Proxy Microservice Design Pattern: A different microservice is called upon the business need.
|
||||
- Chained Microservice Design Pattern: In this case each microservice is dependent/ chained to a series
|
||||
of other microservices.
|
||||
The user makes a single call to the aggregator service, and the aggregator then calls each relevant microservice.
|
||||
|
||||
## Explanation
|
||||
|
||||
Real world example
|
||||
|
||||
> Our web marketplace needs information about products and their current inventory. It makes a call to an aggregator
|
||||
> service which in turn calls the product information microservice and product inventory microservice returning the
|
||||
> combined information.
|
||||
|
||||
In plain words
|
||||
|
||||
> Aggregator Microservice collects pieces of data from various microservices and returns an aggregate for processing.
|
||||
|
||||
Stack Overflow says
|
||||
|
||||
> Aggregator Microservice invokes multiple services to achieve the functionality required by the application.
|
||||
|
||||
**Programmatic Example**
|
||||
|
||||
Let's start from the data model. Here's our `Product`.
|
||||
|
||||
```java
|
||||
public class Product {
|
||||
private String title;
|
||||
private int productInventories;
|
||||
// getters and setters ->
|
||||
...
|
||||
}
|
||||
```
|
||||
|
||||
Next we can introduce our `Aggregator` microservice. It contains clients `ProductInformationClient` and
|
||||
`ProductInventoryClient` for calling respective microservices.
|
||||
|
||||
```java
|
||||
@RestController
|
||||
public class Aggregator {
|
||||
|
||||
@Resource
|
||||
private ProductInformationClient informationClient;
|
||||
|
||||
@Resource
|
||||
private ProductInventoryClient inventoryClient;
|
||||
|
||||
@RequestMapping(path = "/product", method = RequestMethod.GET)
|
||||
public Product getProduct() {
|
||||
|
||||
var product = new Product();
|
||||
var productTitle = informationClient.getProductTitle();
|
||||
var productInventory = inventoryClient.getProductInventories();
|
||||
|
||||
//Fallback to error message
|
||||
product.setTitle(requireNonNullElse(productTitle, "Error: Fetching Product Title Failed"));
|
||||
|
||||
//Fallback to default error inventory
|
||||
product.setProductInventories(requireNonNullElse(productInventory, -1));
|
||||
|
||||
return product;
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
Here's the essence of information microservice implementation. Inventory microservice is similar, it just returns
|
||||
inventory counts.
|
||||
|
||||
```java
|
||||
@RestController
|
||||
public class InformationController {
|
||||
@RequestMapping(value = "/information", method = RequestMethod.GET)
|
||||
public String getProductTitle() {
|
||||
return "The Product Title.";
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
Now calling our `Aggregator` REST API returns the product information.
|
||||
|
||||
```bash
|
||||
curl http://localhost:50004/product
|
||||
{"title":"The Product Title.","productInventories":5}
|
||||
```
|
||||
|
||||
## Class diagram
|
||||
|
||||
|
||||
|
||||
|
||||
## Applicability
|
||||
|
||||
@ -28,3 +103,5 @@ Use the Aggregator Microservices pattern when you need a unified API for various
|
||||
## Credits
|
||||
|
||||
* [Microservice Design Patterns](http://web.archive.org/web/20190705163602/http://blog.arungupta.me/microservice-design-patterns/)
|
||||
* [Microservices Patterns: With examples in Java](https://www.amazon.com/gp/product/1617294543/ref=as_li_qf_asin_il_tl?ie=UTF8&tag=javadesignpat-20&creative=9325&linkCode=as2&creativeASIN=1617294543&linkId=8b4e570267bc5fb8b8189917b461dc60)
|
||||
* [Architectural Patterns: Uncover essential patterns in the most indispensable realm of enterprise architecture](https://www.amazon.com/gp/product/B077T7V8RC/ref=as_li_qf_asin_il_tl?ie=UTF8&tag=javadesignpat-20&creative=9325&linkCode=as2&creativeASIN=B077T7V8RC&linkId=c34d204bfe1b277914b420189f09c1a4)
|
||||
|
||||
Binary file not shown.
|
After Width: | Height: | Size: 40 KiB |
Binary file not shown.
|
Before Width: | Height: | Size: 40 KiB |
@ -5,33 +5,42 @@ folder: ambassador
|
||||
permalink: /patterns/ambassador/
|
||||
categories: Structural
|
||||
tags:
|
||||
- Decoupling
|
||||
- Decoupling
|
||||
- Cloud distributed
|
||||
---
|
||||
|
||||
## Intent
|
||||
|
||||
Provide a helper service instance on a client and offload common functionality away from a shared resource.
|
||||
|
||||
## Explanation
|
||||
|
||||
Real world example
|
||||
|
||||
> A remote service has many clients accessing a function it provides. The service is a legacy application and is impossible to update. Large numbers of requests from users are causing connectivity issues. New rules for request frequency should be implemented along with latency checks and client-side logging.
|
||||
> A remote service has many clients accessing a function it provides. The service is a legacy application and is
|
||||
> impossible to update. Large numbers of requests from users are causing connectivity issues. New rules for request
|
||||
> frequency should be implemented along with latency checks and client-side logging.
|
||||
|
||||
In plain words
|
||||
|
||||
> Using the ambassador pattern, we can implement less-frequent polling from clients along with latency checks and logging.
|
||||
> With the Ambassador pattern, we can implement less-frequent polling from clients along with latency checks and
|
||||
> logging.
|
||||
|
||||
Microsoft documentation states
|
||||
|
||||
> An ambassador service can be thought of as an out-of-process proxy that is co-located with the client.
|
||||
This pattern can be useful for offloading common client connectivity tasks such as monitoring, logging, routing, security (such as TLS), and resiliency patterns in a language agnostic way. It is often used with legacy applications, or other applications that are difficult to modify, in order to extend their networking capabilities. It can also enable a specialized team to implement those features.
|
||||
> An ambassador service can be thought of as an out-of-process proxy which is co-located with the client. This pattern
|
||||
> can be useful for offloading common client connectivity tasks such as monitoring, logging, routing,
|
||||
> security (such as TLS), and resiliency patterns in a language agnostic way. It is often used with legacy applications,
|
||||
> or other applications that are difficult to modify, in order to extend their networking capabilities. It can also
|
||||
> enable a specialized team to implement those features.
|
||||
|
||||
**Programmatic Example**
|
||||
|
||||
With the above example in mind we will imitate the functionality in a simple manner. We have an interface implemented by the remote service as well as the ambassador service:
|
||||
With the above introduction in mind we will imitate the functionality in this example. We have an interface implemented
|
||||
by the remote service as well as the ambassador service:
|
||||
|
||||
```java
|
||||
interface RemoteServiceInterface {
|
||||
|
||||
long doRemoteFunction(int value) throws Exception;
|
||||
}
|
||||
```
|
||||
@ -136,7 +145,7 @@ public class Client {
|
||||
}
|
||||
```
|
||||
|
||||
And here are two clients using the service.
|
||||
Here are two clients using the service.
|
||||
|
||||
```java
|
||||
public class App {
|
||||
@ -149,13 +158,29 @@ public class App {
|
||||
}
|
||||
```
|
||||
|
||||
Here's the output for running the example:
|
||||
|
||||
```java
|
||||
Time taken (ms): 111
|
||||
Service result: 120
|
||||
Time taken (ms): 931
|
||||
Failed to reach remote: (1)
|
||||
Time taken (ms): 665
|
||||
Failed to reach remote: (2)
|
||||
Time taken (ms): 538
|
||||
Failed to reach remote: (3)
|
||||
Service result: -1
|
||||
```
|
||||
|
||||
## Class diagram
|
||||
|
||||
|
||||
|
||||
## Applicability
|
||||
Ambassador is applicable when working with a legacy remote service that cannot
|
||||
be modified or would be extremely difficult to modify. Connectivity features can
|
||||
be implemented on the client avoiding the need for changes on the remote service.
|
||||
|
||||
Ambassador is applicable when working with a legacy remote service which cannot be modified or would be extremely
|
||||
difficult to modify. Connectivity features can be implemented on the client avoiding the need for changes on the remote
|
||||
service.
|
||||
|
||||
* Ambassador provides a local interface for a remote service.
|
||||
* Ambassador provides logging, circuit breaking, retries and security on the client.
|
||||
@ -168,10 +193,14 @@ be implemented on the client avoiding the need for changes on the remote service
|
||||
* Offload remote service tasks
|
||||
* Facilitate network connection
|
||||
|
||||
## Real world examples
|
||||
## Known uses
|
||||
|
||||
* [Kubernetes-native API gateway for microservices](https://github.com/datawire/ambassador)
|
||||
|
||||
## Related patterns
|
||||
|
||||
* [Proxy](https://java-design-patterns.com/patterns/proxy/)
|
||||
|
||||
## Credits
|
||||
|
||||
* [Ambassador pattern](https://docs.microsoft.com/en-us/azure/architecture/patterns/ambassador)
|
||||
|
||||
@ -29,5 +29,5 @@ package com.iluwatar.ambassador;
|
||||
interface RemoteServiceInterface {
|
||||
int FAILURE = -1;
|
||||
|
||||
long doRemoteFunction(int value) throws Exception;
|
||||
long doRemoteFunction(int value);
|
||||
}
|
||||
|
||||
@ -48,7 +48,7 @@ class RemoteServiceTest {
|
||||
}
|
||||
|
||||
private static class StaticRandomProvider implements RandomProvider {
|
||||
private double value;
|
||||
private final double value;
|
||||
|
||||
StaticRandomProvider(double value) {
|
||||
this.value = value;
|
||||
|
||||
@ -5,14 +5,142 @@ folder: api-gateway
|
||||
permalink: /patterns/api-gateway/
|
||||
categories: Architectural
|
||||
tags:
|
||||
- Cloud distributed
|
||||
- Decoupling
|
||||
- Cloud distributed
|
||||
- Decoupling
|
||||
- Microservices
|
||||
---
|
||||
|
||||
## Intent
|
||||
|
||||
Aggregate calls to microservices in a single location: the API Gateway. The user makes a single
|
||||
call to the API Gateway, and the API Gateway then calls each relevant microservice.
|
||||
Aggregate calls to microservices in a single location: the API Gateway. The user makes a single call to the API Gateway,
|
||||
and the API Gateway then calls each relevant microservice.
|
||||
|
||||
## Explanation
|
||||
|
||||
With the Microservices pattern, a client may need data from multiple different microservices. If the client called each
|
||||
microservice directly, that could contribute to longer load times, since the client would have to make a network request
|
||||
for each microservice called. Moreover, having the client call each microservice directly ties the client to that
|
||||
microservice - if the internal implementations of the microservices change (for example, if two microservices are
|
||||
combined sometime in the future) or if the location (host and port) of a microservice changes, then every client that
|
||||
makes use of those microservices must be updated.
|
||||
|
||||
The intent of the API Gateway pattern is to alleviate some of these issues. In the API Gateway pattern, an additional
|
||||
entity (the API Gateway) is placed between the client and the microservices. The job of the API Gateway is to aggregate
|
||||
the calls to the microservices. Rather than the client calling each microservice individually, the client calls the
|
||||
API Gateway a single time. The API Gateway then calls each of the microservices that the client needs.
|
||||
|
||||
Real world example
|
||||
|
||||
> We are implementing microservices and API Gateway pattern for an e-commerce site. In this system the API Gateway makes
|
||||
calls to the Image and Price microservices.
|
||||
|
||||
In plain words
|
||||
|
||||
> For a system implemented using microservices architecture, API Gateway is the single entry point that aggregates the
|
||||
calls to the individual microservices.
|
||||
|
||||
Wikipedia says
|
||||
|
||||
> API Gateway is a server that acts as an API front-end, receives API requests, enforces throttling and security
|
||||
policies, passes requests to the back-end service and then passes the response back to the requester. A gateway often
|
||||
includes a transformation engine to orchestrate and modify the requests and responses on the fly. A gateway can also
|
||||
provide functionality such as collecting analytics data and providing caching. The gateway can provide functionality to
|
||||
support authentication, authorization, security, audit and regulatory compliance.
|
||||
|
||||
**Programmatic Example**
|
||||
|
||||
This implementation shows what the API Gateway pattern could look like for an e-commerce site. The `ApiGateway` makes
|
||||
calls to the Image and Price microservices using the `ImageClientImpl` and `PriceClientImpl` respectively. Customers
|
||||
viewing the site on a desktop device can see both price information and an image of a product, so the `ApiGateway` calls
|
||||
both of the microservices and aggregates the data in the `DesktopProduct` model. However, mobile users only see price
|
||||
information; they do not see a product image. For mobile users, the `ApiGateway` only retrieves price information, which
|
||||
it uses to populate the `MobileProduct`.
|
||||
|
||||
Here's the Image microservice implementation.
|
||||
|
||||
```java
|
||||
public interface ImageClient {
|
||||
String getImagePath();
|
||||
}
|
||||
|
||||
public class ImageClientImpl implements ImageClient {
|
||||
|
||||
@Override
|
||||
public String getImagePath() {
|
||||
var httpClient = HttpClient.newHttpClient();
|
||||
var httpGet = HttpRequest.newBuilder()
|
||||
.GET()
|
||||
.uri(URI.create("http://localhost:50005/image-path"))
|
||||
.build();
|
||||
|
||||
try {
|
||||
var httpResponse = httpClient.send(httpGet, BodyHandlers.ofString());
|
||||
return httpResponse.body();
|
||||
} catch (IOException | InterruptedException e) {
|
||||
e.printStackTrace();
|
||||
}
|
||||
|
||||
return null;
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
Here's the Price microservice implementation.
|
||||
|
||||
```java
|
||||
public interface PriceClient {
|
||||
String getPrice();
|
||||
}
|
||||
|
||||
public class PriceClientImpl implements PriceClient {
|
||||
|
||||
@Override
|
||||
public String getPrice() {
|
||||
var httpClient = HttpClient.newHttpClient();
|
||||
var httpGet = HttpRequest.newBuilder()
|
||||
.GET()
|
||||
.uri(URI.create("http://localhost:50006/price"))
|
||||
.build();
|
||||
|
||||
try {
|
||||
var httpResponse = httpClient.send(httpGet, BodyHandlers.ofString());
|
||||
return httpResponse.body();
|
||||
} catch (IOException | InterruptedException e) {
|
||||
e.printStackTrace();
|
||||
}
|
||||
|
||||
return null;
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
And here we can see how API Gateway maps the requests to the microservices.
|
||||
|
||||
```java
|
||||
public class ApiGateway {
|
||||
|
||||
@Resource
|
||||
private ImageClient imageClient;
|
||||
|
||||
@Resource
|
||||
private PriceClient priceClient;
|
||||
|
||||
@RequestMapping(path = "/desktop", method = RequestMethod.GET)
|
||||
public DesktopProduct getProductDesktop() {
|
||||
var desktopProduct = new DesktopProduct();
|
||||
desktopProduct.setImagePath(imageClient.getImagePath());
|
||||
desktopProduct.setPrice(priceClient.getPrice());
|
||||
return desktopProduct;
|
||||
}
|
||||
|
||||
@RequestMapping(path = "/mobile", method = RequestMethod.GET)
|
||||
public MobileProduct getProductMobile() {
|
||||
var mobileProduct = new MobileProduct();
|
||||
mobileProduct.setPrice(priceClient.getPrice());
|
||||
return mobileProduct;
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
## Class diagram
|
||||
|
||||
@ -21,10 +149,11 @@ call to the API Gateway, and the API Gateway then calls each relevant microservi
|
||||
|
||||
Use the API Gateway pattern when
|
||||
|
||||
* you're also using the Microservices pattern and need a single point of aggregation for your
|
||||
microservice calls
|
||||
* You're using microservices architecture and need a single point of aggregation for your microservice calls.
|
||||
|
||||
## Credits
|
||||
|
||||
* [microservices.io - API Gateway](http://microservices.io/patterns/apigateway.html)
|
||||
* [NGINX - Building Microservices: Using an API Gateway](https://www.nginx.com/blog/building-microservices-using-an-api-gateway/)
|
||||
* [Microservices Patterns: With examples in Java](https://www.amazon.com/gp/product/1617294543/ref=as_li_qf_asin_il_tl?ie=UTF8&tag=javadesignpat-20&creative=9325&linkCode=as2&creativeASIN=1617294543&linkId=ac7b6a57f866ac006a309d9086e8cfbd)
|
||||
* [Building Microservices: Designing Fine-Grained Systems](https://www.amazon.com/gp/product/1491950358/ref=as_li_qf_asin_il_tl?ie=UTF8&tag=javadesignpat-20&creative=9325&linkCode=as2&creativeASIN=1491950358&linkId=4c95ca9831e05e3f0dadb08841d77bf1)
|
||||
|
||||
@ -9,22 +9,137 @@ tags:
|
||||
---
|
||||
|
||||
## Also known as
|
||||
|
||||
Given/When/Then
|
||||
|
||||
## Intent
|
||||
The Arrange/Act/Assert (AAA) is a pattern for organizing unit tests.
|
||||
|
||||
Arrange/Act/Assert (AAA) is a pattern for organizing unit tests.
|
||||
It breaks tests down into three clear and distinct steps:
|
||||
|
||||
1. Arrange: Perform the setup and initialization required for the test.
|
||||
2. Act: Take action(s) required for the test.
|
||||
3. Assert: Verify the outcome(s) of the test.
|
||||
|
||||
## Explanation
|
||||
|
||||
This pattern has several significant benefits. It creates a clear separation between a test's
|
||||
setup, operations, and results. This structure makes the code easier to read and understand. If
|
||||
you place the steps in order and format your code to separate them, you can scan a test and
|
||||
quickly comprehend what it does.
|
||||
|
||||
It also enforces a certain degree of discipline when you write your tests. You have to think
|
||||
clearly about the three steps your test will perform. It makes tests more natural to write at
|
||||
the same time since you already have an outline.
|
||||
|
||||
Real world example
|
||||
|
||||
> We need to write comprehensive and clear unit test suite for a class.
|
||||
|
||||
In plain words
|
||||
|
||||
> Arrange/Act/Assert is a testing pattern that organizes tests into three clear steps for easy
|
||||
> maintenance.
|
||||
|
||||
WikiWikiWeb says
|
||||
|
||||
> Arrange/Act/Assert is a pattern for arranging and formatting code in UnitTest methods.
|
||||
|
||||
**Programmatic Example**
|
||||
|
||||
Let's first introduce our `Cash` class to be unit tested.
|
||||
|
||||
```java
|
||||
public class Cash {
|
||||
|
||||
private int amount;
|
||||
|
||||
Cash(int amount) {
|
||||
this.amount = amount;
|
||||
}
|
||||
|
||||
void plus(int addend) {
|
||||
amount += addend;
|
||||
}
|
||||
|
||||
boolean minus(int subtrahend) {
|
||||
if (amount >= subtrahend) {
|
||||
amount -= subtrahend;
|
||||
return true;
|
||||
} else {
|
||||
return false;
|
||||
}
|
||||
}
|
||||
|
||||
int count() {
|
||||
return amount;
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
Then we write our unit tests according to Arrange/Act/Assert pattern. Notice the clearly
|
||||
separated steps for each unit test.
|
||||
|
||||
```java
|
||||
public class CashAAATest {
|
||||
|
||||
@Test
|
||||
public void testPlus() {
|
||||
//Arrange
|
||||
var cash = new Cash(3);
|
||||
//Act
|
||||
cash.plus(4);
|
||||
//Assert
|
||||
assertEquals(7, cash.count());
|
||||
}
|
||||
|
||||
@Test
|
||||
public void testMinus() {
|
||||
//Arrange
|
||||
var cash = new Cash(8);
|
||||
//Act
|
||||
var result = cash.minus(5);
|
||||
//Assert
|
||||
assertTrue(result);
|
||||
assertEquals(3, cash.count());
|
||||
}
|
||||
|
||||
@Test
|
||||
public void testInsufficientMinus() {
|
||||
//Arrange
|
||||
var cash = new Cash(1);
|
||||
//Act
|
||||
var result = cash.minus(6);
|
||||
//Assert
|
||||
assertFalse(result);
|
||||
assertEquals(1, cash.count());
|
||||
}
|
||||
|
||||
@Test
|
||||
public void testUpdate() {
|
||||
//Arrange
|
||||
var cash = new Cash(5);
|
||||
//Act
|
||||
cash.plus(6);
|
||||
var result = cash.minus(3);
|
||||
//Assert
|
||||
assertTrue(result);
|
||||
assertEquals(8, cash.count());
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
## Applicability
|
||||
|
||||
Use Arrange/Act/Assert pattern when
|
||||
|
||||
* you need to structure your unit tests so they're easier to read, maintain, and enhance.
|
||||
* You need to structure your unit tests so that they're easier to read, maintain, and enhance.
|
||||
|
||||
## Credits
|
||||
|
||||
* [Arrange, Act, Assert: What is AAA Testing?](https://blog.ncrunch.net/post/arrange-act-assert-aaa-testing.aspx)
|
||||
* [Bill Wake: 3A – Arrange, Act, Assert](https://xp123.com/articles/3a-arrange-act-assert/)
|
||||
* [Martin Fowler: GivenWhenThen](https://martinfowler.com/bliki/GivenWhenThen.html)
|
||||
* [xUnit Test Patterns: Refactoring Test Code](https://www.amazon.com/gp/product/0131495054/ref=as_li_qf_asin_il_tl?ie=UTF8&tag=javadesignpat-20&creative=9325&linkCode=as2&creativeASIN=0131495054&linkId=99701e8f4af2f7e8dd50d720c9b63dbf)
|
||||
* [Unit Testing Principles, Practices, and Patterns](https://www.amazon.com/gp/product/1617296279/ref=as_li_qf_asin_il_tl?ie=UTF8&tag=javadesignpat-20&creative=9325&linkCode=as2&creativeASIN=1617296279&linkId=74c75cf22a63c3e4758ae08aa0a0cc35)
|
||||
* [Test Driven Development: By Example](https://www.amazon.com/gp/product/0321146530/ref=as_li_qf_asin_il_tl?ie=UTF8&tag=javadesignpat-20&creative=9325&linkCode=as2&creativeASIN=0321146530&linkId=5c63a93d8c1175b84ca5087472ef0e05)
|
||||
|
||||
@ -60,7 +60,7 @@ public class CashAAATest {
|
||||
//Act
|
||||
cash.plus(4);
|
||||
//Assert
|
||||
assertEquals(cash.count(), 7);
|
||||
assertEquals(7, cash.count());
|
||||
}
|
||||
|
||||
@Test
|
||||
@ -71,7 +71,7 @@ public class CashAAATest {
|
||||
var result = cash.minus(5);
|
||||
//Assert
|
||||
assertTrue(result);
|
||||
assertEquals(cash.count(), 3);
|
||||
assertEquals(3, cash.count());
|
||||
}
|
||||
|
||||
@Test
|
||||
@ -82,7 +82,7 @@ public class CashAAATest {
|
||||
var result = cash.minus(6);
|
||||
//Assert
|
||||
assertFalse(result);
|
||||
assertEquals(cash.count(), 1);
|
||||
assertEquals(1, cash.count());
|
||||
}
|
||||
|
||||
@Test
|
||||
@ -94,6 +94,6 @@ public class CashAAATest {
|
||||
var result = cash.minus(3);
|
||||
//Assert
|
||||
assertTrue(result);
|
||||
assertEquals(cash.count(), 8);
|
||||
assertEquals(8, cash.count());
|
||||
}
|
||||
}
|
||||
|
||||
@ -44,16 +44,16 @@ public class CashAntiAAATest {
|
||||
var cash = new Cash(3);
|
||||
//test plus
|
||||
cash.plus(4);
|
||||
assertEquals(cash.count(), 7);
|
||||
assertEquals(7, cash.count());
|
||||
//test minus
|
||||
cash = new Cash(8);
|
||||
assertTrue(cash.minus(5));
|
||||
assertEquals(cash.count(), 3);
|
||||
assertEquals(3, cash.count());
|
||||
assertFalse(cash.minus(6));
|
||||
assertEquals(cash.count(), 3);
|
||||
assertEquals(3, cash.count());
|
||||
//test update
|
||||
cash.plus(5);
|
||||
assertTrue(cash.minus(5));
|
||||
assertEquals(cash.count(), 3);
|
||||
assertEquals(3, cash.count());
|
||||
}
|
||||
}
|
||||
|
||||
@ -100,7 +100,7 @@ public class ThreadAsyncExecutor implements AsyncExecutor {
|
||||
void setValue(T value) {
|
||||
this.value = value;
|
||||
this.state = COMPLETED;
|
||||
this.callback.ifPresent(ac -> ac.onComplete(value, Optional.<Exception>empty()));
|
||||
this.callback.ifPresent(ac -> ac.onComplete(value, Optional.empty()));
|
||||
synchronized (lock) {
|
||||
lock.notifyAll();
|
||||
}
|
||||
|
||||
@ -28,7 +28,7 @@ package com.iluwatar.business.delegate;
|
||||
*/
|
||||
public class Client {
|
||||
|
||||
private BusinessDelegate businessDelegate;
|
||||
private final BusinessDelegate businessDelegate;
|
||||
|
||||
public Client(BusinessDelegate businessDelegate) {
|
||||
this.businessDelegate = businessDelegate;
|
||||
|
||||
@ -28,5 +28,5 @@ package com.iluwatar.business.delegate;
|
||||
*/
|
||||
public enum ServiceType {
|
||||
|
||||
EJB, JMS;
|
||||
EJB, JMS
|
||||
}
|
||||
|
||||
@ -1,26 +0,0 @@
|
||||
/*
|
||||
* 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.
|
||||
*/
|
||||
|
||||
module com.iluwatar.business.delegate {
|
||||
requires org.slf4j;
|
||||
}
|
||||
@ -30,9 +30,9 @@ import java.util.Stack;
|
||||
*/
|
||||
public class VirtualMachine {
|
||||
|
||||
private Stack<Integer> stack = new Stack<>();
|
||||
private final Stack<Integer> stack = new Stack<>();
|
||||
|
||||
private Wizard[] wizards = new Wizard[2];
|
||||
private final Wizard[] wizards = new Wizard[2];
|
||||
|
||||
/**
|
||||
* Constructor.
|
||||
|
||||
@ -104,7 +104,7 @@ public class VirtualMachineTest {
|
||||
bytecode[2] = LITERAL.getIntValue();
|
||||
bytecode[3] = 50; // health amount
|
||||
bytecode[4] = SET_HEALTH.getIntValue();
|
||||
bytecode[5] = LITERAL.getIntValue();;
|
||||
bytecode[5] = LITERAL.getIntValue();
|
||||
bytecode[6] = wizardNumber;
|
||||
bytecode[7] = GET_HEALTH.getIntValue();
|
||||
|
||||
|
||||
@ -5,7 +5,8 @@ folder: caching
|
||||
permalink: /patterns/caching/
|
||||
categories: Behavioral
|
||||
tags:
|
||||
- Performance
|
||||
- Performance
|
||||
- Cloud distributed
|
||||
---
|
||||
|
||||
## Intent
|
||||
@ -25,4 +26,4 @@ Use the Caching pattern(s) when
|
||||
|
||||
* [Write-through, write-around, write-back: Cache explained](http://www.computerweekly.com/feature/Write-through-write-around-write-back-Cache-explained)
|
||||
* [Read-Through, Write-Through, Write-Behind, and Refresh-Ahead Caching](https://docs.oracle.com/cd/E15357_01/coh.360/e15723/cache_rtwtwbra.htm#COHDG5177)
|
||||
* [Cache-Aside](https://msdn.microsoft.com/en-us/library/dn589799.aspx)
|
||||
* [Cache-Aside pattern](https://docs.microsoft.com/en-us/azure/architecture/patterns/cache-aside)
|
||||
|
||||
@ -29,7 +29,7 @@ package com.iluwatar.caching;
|
||||
public enum CachingPolicy {
|
||||
THROUGH("through"), AROUND("around"), BEHIND("behind"), ASIDE("aside");
|
||||
|
||||
private String policy;
|
||||
private final String policy;
|
||||
|
||||
CachingPolicy(String policy) {
|
||||
this.policy = policy;
|
||||
|
||||
@ -1,26 +0,0 @@
|
||||
/*
|
||||
* 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.
|
||||
*/
|
||||
|
||||
module com.iluwatar.callback {
|
||||
requires org.slf4j;
|
||||
}
|
||||
@ -65,7 +65,7 @@ Then the request handler hierarchy
|
||||
```java
|
||||
public abstract class RequestHandler {
|
||||
private static final Logger LOGGER = LoggerFactory.getLogger(RequestHandler.class);
|
||||
private RequestHandler next;
|
||||
private final RequestHandler next;
|
||||
|
||||
public RequestHandler(RequestHandler next) {
|
||||
this.next = next;
|
||||
|
||||
@ -33,7 +33,7 @@ public abstract class RequestHandler {
|
||||
|
||||
private static final Logger LOGGER = LoggerFactory.getLogger(RequestHandler.class);
|
||||
|
||||
private RequestHandler next;
|
||||
private final RequestHandler next;
|
||||
|
||||
public RequestHandler(RequestHandler next) {
|
||||
this.next = next;
|
||||
|
||||
@ -1,26 +0,0 @@
|
||||
/*
|
||||
* 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.
|
||||
*/
|
||||
|
||||
module com.iluwatar.chain {
|
||||
requires org.slf4j;
|
||||
}
|
||||
@ -5,8 +5,9 @@ folder: circuit-breaker
|
||||
permalink: /patterns/circuit-breaker/
|
||||
categories: Behavioral
|
||||
tags:
|
||||
- Performance
|
||||
- Decoupling
|
||||
- Performance
|
||||
- Decoupling
|
||||
- Cloud distributed
|
||||
---
|
||||
|
||||
## Intent
|
||||
@ -187,4 +188,4 @@ Use the Circuit Breaker pattern when
|
||||
* [Understanding Circuit Breaker Pattern](https://itnext.io/understand-circuitbreaker-design-pattern-with-simple-practical-example-92a752615b42)
|
||||
* [Martin Fowler on Circuit Breaker](https://martinfowler.com/bliki/CircuitBreaker.html)
|
||||
* [Fault tolerance in a high volume, distributed system](https://medium.com/netflix-techblog/fault-tolerance-in-a-high-volume-distributed-system-91ab4faae74a)
|
||||
* [Microsoft docs](https://docs.microsoft.com/en-us/azure/architecture/patterns/circuit-breaker)
|
||||
* [Circuit Breaker pattern](https://docs.microsoft.com/en-us/azure/architecture/patterns/circuit-breaker)
|
||||
|
||||
@ -87,10 +87,7 @@ public class Car {
|
||||
} else if (!model.equals(other.model)) {
|
||||
return false;
|
||||
}
|
||||
if (year != other.year) {
|
||||
return false;
|
||||
}
|
||||
return true;
|
||||
return year == other.year;
|
||||
}
|
||||
|
||||
public String getMake() {
|
||||
|
||||
@ -29,7 +29,7 @@ import java.util.List;
|
||||
* A Person class that has the list of cars that the person owns and use.
|
||||
*/
|
||||
public class Person {
|
||||
private List<Car> cars;
|
||||
private final List<Car> cars;
|
||||
|
||||
/**
|
||||
* Constructor to create an instance of person.
|
||||
|
||||
@ -1,26 +0,0 @@
|
||||
/*
|
||||
* 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.
|
||||
*/
|
||||
|
||||
module com.iluwatar.collectionpipeline {
|
||||
requires org.slf4j;
|
||||
}
|
||||
@ -37,7 +37,7 @@ import org.slf4j.LoggerFactory;
|
||||
public class AppTest {
|
||||
private static final Logger LOGGER = LoggerFactory.getLogger(AppTest.class);
|
||||
|
||||
private List<Car> cars = CarFactory.createCars();
|
||||
private final List<Car> cars = CarFactory.createCars();
|
||||
|
||||
@Test
|
||||
public void testGetModelsAfter2000UsingFor() {
|
||||
|
||||
@ -36,8 +36,8 @@ public class Wizard {
|
||||
|
||||
private static final Logger LOGGER = LoggerFactory.getLogger(Wizard.class);
|
||||
|
||||
private Deque<Command> undoStack = new LinkedList<>();
|
||||
private Deque<Command> redoStack = new LinkedList<>();
|
||||
private final Deque<Command> undoStack = new LinkedList<>();
|
||||
private final Deque<Command> redoStack = new LinkedList<>();
|
||||
|
||||
public Wizard() {}
|
||||
|
||||
@ -75,19 +75,18 @@ public class Wizard {
|
||||
Next we present the spell hierarchy.
|
||||
|
||||
```java
|
||||
public abstract class Command {
|
||||
public interface Command {
|
||||
|
||||
public abstract void execute(Target target);
|
||||
void execute(Target target);
|
||||
|
||||
public abstract void undo();
|
||||
void undo();
|
||||
|
||||
public abstract void redo();
|
||||
void redo();
|
||||
|
||||
@Override
|
||||
public abstract String toString();
|
||||
String toString();
|
||||
}
|
||||
|
||||
public class InvisibilitySpell extends Command {
|
||||
public class InvisibilitySpell implements Command {
|
||||
|
||||
private Target target;
|
||||
|
||||
@ -117,7 +116,7 @@ public class InvisibilitySpell extends Command {
|
||||
}
|
||||
}
|
||||
|
||||
public class ShrinkSpell extends Command {
|
||||
public class ShrinkSpell implements Command {
|
||||
|
||||
private Size oldSize;
|
||||
private Target target;
|
||||
|
||||
Binary file not shown.
|
Before Width: | Height: | Size: 27 KiB After Width: | Height: | Size: 75 KiB |
@ -4,7 +4,7 @@ package com.iluwatar.command {
|
||||
+ App()
|
||||
+ main(args : String[]) {static}
|
||||
}
|
||||
abstract class Command {
|
||||
interface Command {
|
||||
+ Command()
|
||||
+ execute(Target) {abstract}
|
||||
+ redo() {abstract}
|
||||
@ -77,7 +77,7 @@ ShrinkSpell --> "-oldSize" Size
|
||||
InvisibilitySpell --> "-target" Target
|
||||
ShrinkSpell --> "-target" Target
|
||||
Target --> "-visibility" Visibility
|
||||
Goblin --|> Target
|
||||
InvisibilitySpell --|> Command
|
||||
ShrinkSpell --|> Command
|
||||
@enduml
|
||||
Goblin --|> Target
|
||||
InvisibilitySpell ..|> Command
|
||||
ShrinkSpell ..|> Command
|
||||
@enduml
|
||||
|
||||
@ -26,15 +26,12 @@ package com.iluwatar.command;
|
||||
/**
|
||||
* Interface for Commands.
|
||||
*/
|
||||
public abstract class Command {
|
||||
public interface Command {
|
||||
void execute(Target target);
|
||||
|
||||
public abstract void execute(Target target);
|
||||
void undo();
|
||||
|
||||
public abstract void undo();
|
||||
|
||||
public abstract void redo();
|
||||
|
||||
@Override
|
||||
public abstract String toString();
|
||||
void redo();
|
||||
|
||||
String toString();
|
||||
}
|
||||
|
||||
@ -26,7 +26,7 @@ package com.iluwatar.command;
|
||||
/**
|
||||
* InvisibilitySpell is a concrete command.
|
||||
*/
|
||||
public class InvisibilitySpell extends Command {
|
||||
public class InvisibilitySpell implements Command {
|
||||
|
||||
private Target target;
|
||||
|
||||
|
||||
@ -26,7 +26,7 @@ package com.iluwatar.command;
|
||||
/**
|
||||
* ShrinkSpell is a concrete command.
|
||||
*/
|
||||
public class ShrinkSpell extends Command {
|
||||
public class ShrinkSpell implements Command {
|
||||
|
||||
private Size oldSize;
|
||||
private Target target;
|
||||
|
||||
@ -1,43 +1,43 @@
|
||||
/*
|
||||
* 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.command;
|
||||
|
||||
/**
|
||||
* Enumeration for target size.
|
||||
*/
|
||||
public enum Size {
|
||||
|
||||
SMALL("small"), NORMAL("normal");
|
||||
|
||||
private String title;
|
||||
|
||||
Size(String title) {
|
||||
this.title = title;
|
||||
}
|
||||
|
||||
@Override
|
||||
public String toString() {
|
||||
return title;
|
||||
}
|
||||
}
|
||||
/*
|
||||
* 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.command;
|
||||
|
||||
/**
|
||||
* Enumeration for target size.
|
||||
*/
|
||||
public enum Size {
|
||||
|
||||
SMALL("small"), NORMAL("normal");
|
||||
|
||||
private final String title;
|
||||
|
||||
Size(String title) {
|
||||
this.title = title;
|
||||
}
|
||||
|
||||
@Override
|
||||
public String toString() {
|
||||
return title;
|
||||
}
|
||||
}
|
||||
|
||||
@ -1,43 +1,43 @@
|
||||
/*
|
||||
* 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.command;
|
||||
|
||||
/**
|
||||
* Enumeration for target visibility.
|
||||
*/
|
||||
public enum Visibility {
|
||||
|
||||
VISIBLE("visible"), INVISIBLE("invisible");
|
||||
|
||||
private String title;
|
||||
|
||||
Visibility(String title) {
|
||||
this.title = title;
|
||||
}
|
||||
|
||||
@Override
|
||||
public String toString() {
|
||||
return title;
|
||||
}
|
||||
}
|
||||
/*
|
||||
* 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.command;
|
||||
|
||||
/**
|
||||
* Enumeration for target visibility.
|
||||
*/
|
||||
public enum Visibility {
|
||||
|
||||
VISIBLE("visible"), INVISIBLE("invisible");
|
||||
|
||||
private final String title;
|
||||
|
||||
Visibility(String title) {
|
||||
this.title = title;
|
||||
}
|
||||
|
||||
@Override
|
||||
public String toString() {
|
||||
return title;
|
||||
}
|
||||
}
|
||||
|
||||
@ -35,8 +35,8 @@ public class Wizard {
|
||||
|
||||
private static final Logger LOGGER = LoggerFactory.getLogger(Wizard.class);
|
||||
|
||||
private Deque<Command> undoStack = new LinkedList<>();
|
||||
private Deque<Command> redoStack = new LinkedList<>();
|
||||
private final Deque<Command> undoStack = new LinkedList<>();
|
||||
private final Deque<Command> redoStack = new LinkedList<>();
|
||||
|
||||
public Wizard() {
|
||||
// comment to ignore sonar issue: LEVEL critical
|
||||
|
||||
@ -1,26 +0,0 @@
|
||||
/*
|
||||
* 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.
|
||||
*/
|
||||
|
||||
module com.iluwatar.command {
|
||||
requires org.slf4j;
|
||||
}
|
||||
@ -33,7 +33,7 @@ import java.util.Hashtable;
|
||||
*/
|
||||
|
||||
public class EmployeeDatabase extends Database<Order> {
|
||||
private Hashtable<String, Order> data;
|
||||
private final Hashtable<String, Order> data;
|
||||
|
||||
public EmployeeDatabase() {
|
||||
this.data = new Hashtable<>();
|
||||
|
||||
@ -33,7 +33,7 @@ import java.util.Hashtable;
|
||||
*/
|
||||
|
||||
public class MessagingDatabase extends Database<MessageRequest> {
|
||||
private Hashtable<String, MessageRequest> data;
|
||||
private final Hashtable<String, MessageRequest> data;
|
||||
|
||||
public MessagingDatabase() {
|
||||
this.data = new Hashtable<>();
|
||||
|
||||
@ -34,7 +34,7 @@ import java.util.Hashtable;
|
||||
|
||||
public class PaymentDatabase extends Database<PaymentRequest> {
|
||||
|
||||
private Hashtable<String, PaymentRequest> data;
|
||||
private final Hashtable<String, PaymentRequest> data;
|
||||
|
||||
public PaymentDatabase() {
|
||||
this.data = new Hashtable<>();
|
||||
|
||||
@ -35,7 +35,7 @@ import java.util.List;
|
||||
|
||||
public class QueueDatabase extends Database<QueueTask> {
|
||||
|
||||
private Queue<QueueTask> data;
|
||||
private final Queue<QueueTask> data;
|
||||
public List<Exception> exceptionsList;
|
||||
|
||||
public QueueDatabase(Exception... exc) {
|
||||
|
||||
@ -34,7 +34,7 @@ import java.util.Hashtable;
|
||||
|
||||
public class ShippingDatabase extends Database<ShippingRequest> {
|
||||
|
||||
private Hashtable<String, ShippingRequest> data;
|
||||
private final Hashtable<String, ShippingRequest> data;
|
||||
|
||||
public ShippingDatabase() {
|
||||
this.data = new Hashtable<>();
|
||||
|
||||
@ -34,7 +34,7 @@ Taking our sentence example from above. Here we have the base class and differen
|
||||
```java
|
||||
public abstract class LetterComposite {
|
||||
|
||||
private List<LetterComposite> children = new ArrayList<>();
|
||||
private final List<LetterComposite> children = new ArrayList<>();
|
||||
|
||||
public void add(LetterComposite letter) {
|
||||
children.add(letter);
|
||||
@ -59,7 +59,7 @@ public abstract class LetterComposite {
|
||||
|
||||
public class Letter extends LetterComposite {
|
||||
|
||||
private char character;
|
||||
private final char character;
|
||||
|
||||
public Letter(char c) {
|
||||
this.character = c;
|
||||
|
||||
@ -28,7 +28,7 @@ package com.iluwatar.composite;
|
||||
*/
|
||||
public class Letter extends LetterComposite {
|
||||
|
||||
private char character;
|
||||
private final char character;
|
||||
|
||||
public Letter(char c) {
|
||||
this.character = c;
|
||||
|
||||
@ -1,58 +1,58 @@
|
||||
/*
|
||||
* 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.composite;
|
||||
|
||||
import java.util.ArrayList;
|
||||
import java.util.List;
|
||||
|
||||
/**
|
||||
* Composite interface.
|
||||
*/
|
||||
public abstract class LetterComposite {
|
||||
|
||||
private List<LetterComposite> children = new ArrayList<>();
|
||||
|
||||
public void add(LetterComposite letter) {
|
||||
children.add(letter);
|
||||
}
|
||||
|
||||
public int count() {
|
||||
return children.size();
|
||||
}
|
||||
|
||||
protected void printThisBefore() {
|
||||
}
|
||||
|
||||
protected void printThisAfter() {
|
||||
}
|
||||
|
||||
/**
|
||||
* Print.
|
||||
*/
|
||||
public void print() {
|
||||
printThisBefore();
|
||||
children.forEach(LetterComposite::print);
|
||||
printThisAfter();
|
||||
}
|
||||
}
|
||||
/*
|
||||
* 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.composite;
|
||||
|
||||
import java.util.ArrayList;
|
||||
import java.util.List;
|
||||
|
||||
/**
|
||||
* Composite interface.
|
||||
*/
|
||||
public abstract class LetterComposite {
|
||||
|
||||
private final List<LetterComposite> children = new ArrayList<>();
|
||||
|
||||
public void add(LetterComposite letter) {
|
||||
children.add(letter);
|
||||
}
|
||||
|
||||
public int count() {
|
||||
return children.size();
|
||||
}
|
||||
|
||||
protected void printThisBefore() {
|
||||
}
|
||||
|
||||
protected void printThisAfter() {
|
||||
}
|
||||
|
||||
/**
|
||||
* Print.
|
||||
*/
|
||||
public void print() {
|
||||
printThisBefore();
|
||||
children.forEach(LetterComposite::print);
|
||||
printThisAfter();
|
||||
}
|
||||
}
|
||||
|
||||
@ -1,26 +0,0 @@
|
||||
/*
|
||||
* 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.
|
||||
*/
|
||||
|
||||
module com.iluwatar.composite {
|
||||
requires org.slf4j;
|
||||
}
|
||||
@ -29,10 +29,10 @@ import java.util.Objects;
|
||||
* User class.
|
||||
*/
|
||||
public class User {
|
||||
private String firstName;
|
||||
private String lastName;
|
||||
private boolean isActive;
|
||||
private String userId;
|
||||
private final String firstName;
|
||||
private final String lastName;
|
||||
private final boolean isActive;
|
||||
private final String userId;
|
||||
|
||||
/**
|
||||
* Constructor.
|
||||
|
||||
@ -30,10 +30,10 @@ import java.util.Objects;
|
||||
*/
|
||||
public class UserDto {
|
||||
|
||||
private String firstName;
|
||||
private String lastName;
|
||||
private boolean isActive;
|
||||
private String email;
|
||||
private final String firstName;
|
||||
private final String lastName;
|
||||
private final boolean isActive;
|
||||
private final String email;
|
||||
|
||||
/**
|
||||
* Constructor.
|
||||
|
||||
@ -1,26 +0,0 @@
|
||||
/*
|
||||
* 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.
|
||||
*/
|
||||
|
||||
module com.iluwatar.converter {
|
||||
requires org.slf4j;
|
||||
}
|
||||
@ -34,7 +34,7 @@ import org.junit.jupiter.api.Test;
|
||||
*/
|
||||
public class ConverterTest {
|
||||
|
||||
private UserConverter userConverter = new UserConverter();
|
||||
private final UserConverter userConverter = new UserConverter();
|
||||
|
||||
/**
|
||||
* Tests whether a converter created of opposite functions holds equality as a bijection.
|
||||
|
||||
@ -5,8 +5,8 @@ folder: cqrs
|
||||
permalink: /patterns/cqrs/
|
||||
categories: Architectural
|
||||
tags:
|
||||
- Performance
|
||||
- Cloud distributed
|
||||
- Performance
|
||||
- Cloud distributed
|
||||
---
|
||||
|
||||
## Intent
|
||||
@ -18,12 +18,13 @@ CQRS Command Query Responsibility Segregation - Separate the query side from the
|
||||
## Applicability
|
||||
Use the CQRS pattern when
|
||||
|
||||
* you want to scale the queries and commands independently.
|
||||
* you want to use different data models for queries and commands. Useful when dealing with complex domains.
|
||||
* you want to use architectures like event sourcing or task based UI.
|
||||
* You want to scale the queries and commands independently.
|
||||
* You want to use different data models for queries and commands. Useful when dealing with complex domains.
|
||||
* You want to use architectures like event sourcing or task based UI.
|
||||
|
||||
## Credits
|
||||
|
||||
* [Greg Young - CQRS, Task Based UIs, Event Sourcing agh!](http://codebetter.com/gregyoung/2010/02/16/cqrs-task-based-uis-event-sourcing-agh/)
|
||||
* [Martin Fowler - CQRS](https://martinfowler.com/bliki/CQRS.html)
|
||||
* [Oliver Wolf - CQRS for Great Good](https://www.youtube.com/watch?v=Ge53swja9Dw)
|
||||
* [Command and Query Responsibility Segregation (CQRS) pattern](https://docs.microsoft.com/en-us/azure/architecture/patterns/cqrs)
|
||||
|
||||
@ -34,7 +34,7 @@ import org.hibernate.SessionFactory;
|
||||
*/
|
||||
public class CommandServiceImpl implements ICommandService {
|
||||
|
||||
private SessionFactory sessionFactory = HibernateUtil.getSessionFactory();
|
||||
private final SessionFactory sessionFactory = HibernateUtil.getSessionFactory();
|
||||
|
||||
private Author getAuthorByUsername(String username) {
|
||||
Author author;
|
||||
|
||||
@ -38,7 +38,7 @@ import org.hibernate.transform.Transformers;
|
||||
*/
|
||||
public class QueryServiceImpl implements IQueryService {
|
||||
|
||||
private SessionFactory sessionFactory = HibernateUtil.getSessionFactory();
|
||||
private final SessionFactory sessionFactory = HibernateUtil.getSessionFactory();
|
||||
|
||||
@Override
|
||||
public Author getAuthorByUsername(String username) {
|
||||
|
||||
@ -112,7 +112,7 @@ public interface CustomerDao {
|
||||
|
||||
public class InMemoryCustomerDao implements CustomerDao {
|
||||
|
||||
private Map<Integer, Customer> idToCustomer = new HashMap<>();
|
||||
private final Map<Integer, Customer> idToCustomer = new HashMap<>();
|
||||
|
||||
@Override
|
||||
public Stream<Customer> getAll() {
|
||||
|
||||
@ -44,7 +44,7 @@ import org.slf4j.LoggerFactory;
|
||||
*/
|
||||
public class App {
|
||||
private static final String DB_URL = "jdbc:h2:~/dao";
|
||||
private static Logger log = LoggerFactory.getLogger(App.class);
|
||||
private static final Logger log = LoggerFactory.getLogger(App.class);
|
||||
private static final String ALL_CUSTOMERS = "customerDao.getAllCustomers(): ";
|
||||
|
||||
/**
|
||||
|
||||
@ -36,7 +36,7 @@ import java.util.stream.Stream;
|
||||
*/
|
||||
public class InMemoryCustomerDao implements CustomerDao {
|
||||
|
||||
private Map<Integer, Customer> idToCustomer = new HashMap<>();
|
||||
private final Map<Integer, Customer> idToCustomer = new HashMap<>();
|
||||
|
||||
/**
|
||||
* An eagerly evaluated stream of customers stored in memory.
|
||||
|
||||
@ -1,29 +0,0 @@
|
||||
/*
|
||||
* 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.
|
||||
*/
|
||||
|
||||
module com.iluwatar.dao {
|
||||
requires org.slf4j;
|
||||
requires java.sql;
|
||||
requires h2;
|
||||
requires java.naming;
|
||||
}
|
||||
@ -50,7 +50,7 @@ public class DbCustomerDaoTest {
|
||||
|
||||
private static final String DB_URL = "jdbc:h2:~/dao";
|
||||
private DbCustomerDao dao;
|
||||
private Customer existingCustomer = new Customer(1, "Freddy", "Krueger");
|
||||
private final Customer existingCustomer = new Customer(1, "Freddy", "Krueger");
|
||||
|
||||
/**
|
||||
* Creates customers schema.
|
||||
|
||||
@ -41,7 +41,7 @@ public class MessageCollectorMember implements Member {
|
||||
|
||||
private final String name;
|
||||
|
||||
private List<String> messages = new ArrayList<>();
|
||||
private final List<String> messages = new ArrayList<>();
|
||||
|
||||
public MessageCollectorMember(String name) {
|
||||
this.name = name;
|
||||
|
||||
@ -1,83 +1,83 @@
|
||||
/*
|
||||
* 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.datamapper;
|
||||
|
||||
import org.slf4j.Logger;
|
||||
import org.slf4j.LoggerFactory;
|
||||
|
||||
/**
|
||||
* The Data Mapper (DM) is a layer of software that separates the in-memory objects from the
|
||||
* database. Its responsibility is to transfer data between the two and also to isolate them from
|
||||
* each other. With Data Mapper the in-memory objects needn't know even that there's a database
|
||||
* present; they need no SQL interface code, and certainly no knowledge of the database schema. (The
|
||||
* database schema is always ignorant of the objects that use it.) Since it's a form of Mapper ,
|
||||
* Data Mapper itself is even unknown to the domain layer.
|
||||
*
|
||||
* <p>The below example demonstrates basic CRUD operations: Create, Read, Update, and Delete.
|
||||
*/
|
||||
public final class App {
|
||||
|
||||
private static Logger log = LoggerFactory.getLogger(App.class);
|
||||
private static final String STUDENT_STRING = "App.main(), student : ";
|
||||
|
||||
|
||||
/**
|
||||
* Program entry point.
|
||||
*
|
||||
* @param args command line args.
|
||||
*/
|
||||
public static void main(final String... args) {
|
||||
|
||||
/* Create new data mapper for type 'first' */
|
||||
final var mapper = new StudentDataMapperImpl();
|
||||
|
||||
/* Create new student */
|
||||
var student = new Student(1, "Adam", 'A');
|
||||
|
||||
/* Add student in respectibe store */
|
||||
mapper.insert(student);
|
||||
|
||||
log.debug(STUDENT_STRING + student + ", is inserted");
|
||||
|
||||
/* Find this student */
|
||||
final var studentToBeFound = mapper.find(student.getStudentId());
|
||||
|
||||
log.debug(STUDENT_STRING + studentToBeFound + ", is searched");
|
||||
|
||||
/* Update existing student object */
|
||||
student = new Student(student.getStudentId(), "AdamUpdated", 'A');
|
||||
|
||||
/* Update student in respectibe db */
|
||||
mapper.update(student);
|
||||
|
||||
log.debug(STUDENT_STRING + student + ", is updated");
|
||||
log.debug(STUDENT_STRING + student + ", is going to be deleted");
|
||||
|
||||
/* Delete student in db */
|
||||
mapper.delete(student);
|
||||
}
|
||||
|
||||
private App() {
|
||||
}
|
||||
}
|
||||
/*
|
||||
* 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.datamapper;
|
||||
|
||||
import org.slf4j.Logger;
|
||||
import org.slf4j.LoggerFactory;
|
||||
|
||||
/**
|
||||
* The Data Mapper (DM) is a layer of software that separates the in-memory objects from the
|
||||
* database. Its responsibility is to transfer data between the two and also to isolate them from
|
||||
* each other. With Data Mapper the in-memory objects needn't know even that there's a database
|
||||
* present; they need no SQL interface code, and certainly no knowledge of the database schema. (The
|
||||
* database schema is always ignorant of the objects that use it.) Since it's a form of Mapper ,
|
||||
* Data Mapper itself is even unknown to the domain layer.
|
||||
*
|
||||
* <p>The below example demonstrates basic CRUD operations: Create, Read, Update, and Delete.
|
||||
*/
|
||||
public final class App {
|
||||
|
||||
private static final Logger log = LoggerFactory.getLogger(App.class);
|
||||
private static final String STUDENT_STRING = "App.main(), student : ";
|
||||
|
||||
|
||||
/**
|
||||
* Program entry point.
|
||||
*
|
||||
* @param args command line args.
|
||||
*/
|
||||
public static void main(final String... args) {
|
||||
|
||||
/* Create new data mapper for type 'first' */
|
||||
final var mapper = new StudentDataMapperImpl();
|
||||
|
||||
/* Create new student */
|
||||
var student = new Student(1, "Adam", 'A');
|
||||
|
||||
/* Add student in respectibe store */
|
||||
mapper.insert(student);
|
||||
|
||||
log.debug(STUDENT_STRING + student + ", is inserted");
|
||||
|
||||
/* Find this student */
|
||||
final var studentToBeFound = mapper.find(student.getStudentId());
|
||||
|
||||
log.debug(STUDENT_STRING + studentToBeFound + ", is searched");
|
||||
|
||||
/* Update existing student object */
|
||||
student = new Student(student.getStudentId(), "AdamUpdated", 'A');
|
||||
|
||||
/* Update student in respectibe db */
|
||||
mapper.update(student);
|
||||
|
||||
log.debug(STUDENT_STRING + student + ", is updated");
|
||||
log.debug(STUDENT_STRING + student + ", is going to be deleted");
|
||||
|
||||
/* Delete student in db */
|
||||
mapper.delete(student);
|
||||
}
|
||||
|
||||
private App() {
|
||||
}
|
||||
}
|
||||
|
||||
@ -33,7 +33,7 @@ import java.util.Optional;
|
||||
public final class StudentDataMapperImpl implements StudentDataMapper {
|
||||
|
||||
/* Note: Normally this would be in the form of an actual database */
|
||||
private List<Student> students = new ArrayList<>();
|
||||
private final List<Student> students = new ArrayList<>();
|
||||
|
||||
@Override
|
||||
public Optional<Student> find(int studentId) {
|
||||
|
||||
@ -1,26 +0,0 @@
|
||||
/*
|
||||
* 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.
|
||||
*/
|
||||
|
||||
module com.iluwatar.datamapper {
|
||||
requires org.slf4j;
|
||||
}
|
||||
@ -64,7 +64,7 @@ Customer resource class acts as the server for customer information.
|
||||
|
||||
```java
|
||||
public class CustomerResource {
|
||||
private List<CustomerDto> customers;
|
||||
private final List<CustomerDto> customers;
|
||||
|
||||
public CustomerResource(List<CustomerDto> customers) {
|
||||
this.customers = customers;
|
||||
|
||||
@ -30,7 +30,7 @@ import java.util.List;
|
||||
* has all customer details.
|
||||
*/
|
||||
public class CustomerResource {
|
||||
private List<CustomerDto> customers;
|
||||
private final List<CustomerDto> customers;
|
||||
|
||||
/**
|
||||
* Initialise resource with existing customers.
|
||||
|
||||
@ -1,26 +0,0 @@
|
||||
/*
|
||||
* 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.
|
||||
*/
|
||||
|
||||
module com.iluwatar.datatransfer {
|
||||
requires org.slf4j;
|
||||
}
|
||||
@ -70,7 +70,7 @@ public class ClubbedTroll implements Troll {
|
||||
|
||||
private static final Logger LOGGER = LoggerFactory.getLogger(ClubbedTroll.class);
|
||||
|
||||
private Troll decorated;
|
||||
private final Troll decorated;
|
||||
|
||||
public ClubbedTroll(Troll decorated) {
|
||||
this.decorated = decorated;
|
||||
|
||||
@ -33,7 +33,7 @@ public class ClubbedTroll implements Troll {
|
||||
|
||||
private static final Logger LOGGER = LoggerFactory.getLogger(ClubbedTroll.class);
|
||||
|
||||
private Troll decorated;
|
||||
private final Troll decorated;
|
||||
|
||||
public ClubbedTroll(Troll decorated) {
|
||||
this.decorated = decorated;
|
||||
|
||||
@ -1,26 +0,0 @@
|
||||
/*
|
||||
* 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.
|
||||
*/
|
||||
|
||||
module com.iluwatar.decorator {
|
||||
requires org.slf4j;
|
||||
}
|
||||
@ -68,7 +68,7 @@ public class SimpleTrollTest {
|
||||
|
||||
private class InMemoryAppender extends AppenderBase<ILoggingEvent> {
|
||||
|
||||
private List<ILoggingEvent> log = new LinkedList<>();
|
||||
private final List<ILoggingEvent> log = new LinkedList<>();
|
||||
|
||||
public InMemoryAppender(Class clazz) {
|
||||
((Logger) LoggerFactory.getLogger(clazz)).addAppender(this);
|
||||
|
||||
@ -1,26 +0,0 @@
|
||||
/*
|
||||
* 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.
|
||||
*/
|
||||
|
||||
module com.iluwatar.delegation {
|
||||
requires org.slf4j;
|
||||
}
|
||||
@ -86,7 +86,7 @@ public class DelegateTest {
|
||||
*/
|
||||
private class InMemoryAppender extends AppenderBase<ILoggingEvent> {
|
||||
|
||||
private List<ILoggingEvent> log = new LinkedList<>();
|
||||
private final List<ILoggingEvent> log = new LinkedList<>();
|
||||
|
||||
public InMemoryAppender() {
|
||||
((Logger) LoggerFactory.getLogger("root")).addAppender(this);
|
||||
|
||||
@ -9,12 +9,78 @@ tags:
|
||||
---
|
||||
|
||||
## Intent
|
||||
Dependency Injection is a software design pattern in which one or
|
||||
more dependencies (or services) are injected, or passed by reference, into a
|
||||
dependent object (or client) and are made part of the client's state. The
|
||||
pattern separates the creation of a client's dependencies from its own
|
||||
behavior, which allows program designs to be loosely coupled and to follow the
|
||||
inversion of control and single responsibility principles.
|
||||
Dependency Injection is a software design pattern in which one or more dependencies (or services) are injected, or
|
||||
passed by reference, into a dependent object (or client) and are made part of the client's state. The pattern separates
|
||||
the creation of a client's dependencies from its own behavior, which allows program designs to be loosely coupled and
|
||||
to follow the inversion of control and single responsibility principles.
|
||||
|
||||
## Explanation
|
||||
Real world example
|
||||
|
||||
> The old wizard likes to fill his pipe and smoke tobacco once in a while. However, he doesn't want to depend on a single tobacco brand only but likes to be able to enjoy them all interchangeably.
|
||||
|
||||
In plain words
|
||||
|
||||
> Dependency Injection separates creation of client's dependencies from its own behavior.
|
||||
|
||||
Wikipedia says
|
||||
|
||||
> In software engineering, dependency injection is a technique in which an object receives other objects that it depends on. These other objects are called dependencies.
|
||||
|
||||
**Programmatic Example**
|
||||
|
||||
Let's first introduce the tobacco brands.
|
||||
|
||||
```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 {
|
||||
}
|
||||
```
|
||||
|
||||
Next here's the wizard class hierarchy.
|
||||
|
||||
```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);
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
And lastly we can show how easy it is to give the old wizard any brand of tobacco.
|
||||
|
||||
```java
|
||||
var advancedWizard = new AdvancedWizard(new SecondBreakfastTobacco());
|
||||
advancedWizard.smoke();
|
||||
```
|
||||
|
||||
## Class diagram
|
||||
|
||||
@ -22,5 +88,12 @@ inversion of control and single responsibility principles.
|
||||
## Applicability
|
||||
Use the Dependency Injection pattern when
|
||||
|
||||
* when you need to remove knowledge of concrete implementation from object
|
||||
* to enable unit testing of classes in isolation using mock objects or stubs
|
||||
* When you need to remove knowledge of concrete implementation from object
|
||||
* To enable unit testing of classes in isolation using mock objects or stubs
|
||||
|
||||
## Credits
|
||||
|
||||
* [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)
|
||||
|
||||
@ -29,7 +29,7 @@ package com.iluwatar.dependency.injection;
|
||||
*/
|
||||
public class AdvancedWizard implements Wizard {
|
||||
|
||||
private Tobacco tobacco;
|
||||
private final Tobacco tobacco;
|
||||
|
||||
public AdvancedWizard(Tobacco tobacco) {
|
||||
this.tobacco = tobacco;
|
||||
|
||||
@ -31,7 +31,7 @@ import javax.inject.Inject;
|
||||
*/
|
||||
public class GuiceWizard implements Wizard {
|
||||
|
||||
private Tobacco tobacco;
|
||||
private final Tobacco tobacco;
|
||||
|
||||
@Inject
|
||||
public GuiceWizard(Tobacco tobacco) {
|
||||
|
||||
@ -29,7 +29,7 @@ package com.iluwatar.dependency.injection;
|
||||
*/
|
||||
public class SimpleWizard implements Wizard {
|
||||
|
||||
private OldTobyTobacco tobacco = new OldTobyTobacco();
|
||||
private final OldTobyTobacco tobacco = new OldTobyTobacco();
|
||||
|
||||
public void smoke() {
|
||||
tobacco.smoke(this);
|
||||
|
||||
@ -37,7 +37,7 @@ import java.util.List;
|
||||
*/
|
||||
public class InMemoryAppender extends AppenderBase<ILoggingEvent> {
|
||||
|
||||
private List<ILoggingEvent> log = new LinkedList<>();
|
||||
private final List<ILoggingEvent> log = new LinkedList<>();
|
||||
|
||||
public InMemoryAppender(Class clazz) {
|
||||
((Logger) LoggerFactory.getLogger(clazz)).addAppender(this);
|
||||
|
||||
@ -34,7 +34,7 @@ import java.util.List;
|
||||
public class World {
|
||||
|
||||
private List<String> countries;
|
||||
private DataFetcher df;
|
||||
private final DataFetcher df;
|
||||
|
||||
public World() {
|
||||
this.countries = new ArrayList<String>();
|
||||
|
||||
@ -1,26 +0,0 @@
|
||||
/*
|
||||
* 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.
|
||||
*/
|
||||
|
||||
module com.iluwatar.dirtyflag {
|
||||
requires org.slf4j;
|
||||
}
|
||||
@ -33,7 +33,7 @@ public class FrameBuffer implements Buffer {
|
||||
public static final int WIDTH = 10;
|
||||
public static final int HEIGHT = 8;
|
||||
|
||||
private Pixel[] pixels = new Pixel[WIDTH * HEIGHT];
|
||||
private final Pixel[] pixels = new Pixel[WIDTH * HEIGHT];
|
||||
|
||||
public FrameBuffer() {
|
||||
clearAll();
|
||||
|
||||
@ -31,7 +31,7 @@ public enum Pixel {
|
||||
WHITE(0),
|
||||
BLACK(1);
|
||||
|
||||
private int color;
|
||||
private final int color;
|
||||
|
||||
Pixel(int color) {
|
||||
this.color = color;
|
||||
|
||||
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Reference in New Issue
Block a user