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Merge branch 'master' of https://github.com/iluwatar/java-design-patterns

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George Aristy
2017-12-27 15:22:02 -04:00
parent f7c396b0fd 6b4ae0d0b1
commit 144db43ad4
381 changed files with 3736 additions and 5691 deletions
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15
PULL_REQUEST_TEMPLATE.md Normal file
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@ -0,0 +1,15 @@
Pull request title
- Clearly and concisely describes what it does
- Refer to the issue that it solves, if available
Pull request description
- Describes the main changes that come with the pull request
- Any relevant additional information is provided
> For detailed contributing instructions see https://github.com/iluwatar/java-design-patterns/wiki/01.-How-to-contribute

1
README.md
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@ -8,6 +8,7 @@
[![License MIT](https://img.shields.io/badge/license-MIT-blue.svg)](https://raw.githubusercontent.com/iluwatar/java-design-patterns/master/LICENSE.md)
[![Join the chat at https://gitter.im/iluwatar/java-design-patterns](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/iluwatar/java-design-patterns?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
[![Quality Gate](https://sonarqube.com/api/badges/gate?key=com.iluwatar%3Ajava-design-patterns)](https://sonarqube.com/dashboard/index/com.iluwatar%3Ajava-design-patterns)
[![CII Best Practices](https://bestpractices.coreinfrastructure.org/projects/1503/badge)](https://bestpractices.coreinfrastructure.org/projects/1503)
# Introduction

67
_scripts/postPumlsToServer.py
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@ -1,67 +0,0 @@
#
# The MIT License
# Copyright (c) 2014-2016 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.
#
import requests, glob, re, os
# taken from here: http://stackoverflow.com/a/13641746
def replace(file, pattern, subst):
# Read contents from file as a single string
file_handle = open(file, 'r')
file_string = file_handle.read()
file_handle.close()
# Use RE package to allow for replacement (also allowing for (multiline) REGEX)
file_string = (re.sub(pattern, subst, file_string))
# Write contents to file.
# Using mode 'w' truncates the file.
file_handle = open(file, 'w')
file_handle.write(file_string)
file_handle.close()
# list of all puml files
fileList = glob.glob('*/etc/*.puml')
for puml in fileList:
pathSplit = puml.split("/")
# parent folder
parent = pathSplit[0]
# individual artifact/project name
artifact = pathSplit[2].replace(".urm.puml", "")
print "parent: " + parent + "; artifact: " + artifact
# do a POST to the official plantuml hosting site with a little trick "!includeurl" and raw github content
data = {
'text': "!includeurl https://raw.githubusercontent.com/iluwatar/java-design-patterns/master/" + puml
}
r = requests.post('http://plantuml.com/plantuml/uml', data=data)
pumlId = r.url.replace("http://plantuml.com/plantuml/uml/", "")
# the only thing needed to get a png/svg/ascii from the server back
print "Puml Server ID: " + pumlId
# add the id so jekyll/liquid can use it
if (parent == artifact):
replace("./" + parent + "/README.md", "categories:", "pumlid: {}\\ncategories:".format(pumlId))
else:
print "I dont want to program this, just add the following lines to the README.md file that corresponds to this puml file '" + puml + "'\npumlid: {}".format(pumlId)

1
abstract-document/README.md
View File

@ -3,7 +3,6 @@ layout: pattern
title: Abstract Document
folder: abstract-document
permalink: /patterns/abstract-document/
pumlid: PSjB3eCm34NHhPG599vtDyQn85L-ifzX-p3lxEf8Twj3MXGDQvyJMFubChxpKN767gucSq07iinEjSNDOACVNvoAUZr6MWoe3QVE_WRnxZ0Mf38b-hkIGlurX_MyehS7
categories: Structural
tags:
- Java

59
abstract-document/etc/abstract-document.urm.puml
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@ -1,59 +0,0 @@
@startuml
package com.iluwatar.abstractdocument.domain {
class Car {
+ Car(properties : Map<String, Object>)
}
interface HasModel {
+ PROPERTY : String {static}
+ getModel() : Optional<String>
}
interface HasParts {
+ PROPERTY : String {static}
+ getParts() : Stream<Part>
}
interface HasPrice {
+ PROPERTY : String {static}
+ getPrice() : Optional<Number>
}
interface HasType {
+ PROPERTY : String {static}
+ getType() : Optional<String>
}
class Part {
+ Part(properties : Map<String, Object>)
}
}
package com.iluwatar.abstractdocument {
abstract class AbstractDocument {
- properties : Map<String, Object>
# AbstractDocument(properties : Map<String, Object>)
+ children(key : String, constructor : Function<Map<String, Object>, T>) : Stream<T>
+ get(key : String) : Object
+ put(key : String, value : Object)
+ toString() : String
}
class App {
- LOGGER : Logger {static}
+ App()
+ main(args : String[]) {static}
}
interface Document {
+ children(String, Function<Map<String, Object>, T>) : Stream<T> {abstract}
+ get(String) : Object {abstract}
+ put(String, Object) {abstract}
}
}
AbstractDocument ..|> Document
Car ..|> HasModel
Car ..|> HasPrice
Car ..|> HasParts
Car --|> AbstractDocument
HasModel --|> Document
HasParts --|> Document
HasPrice --|> Document
HasType --|> Document
Part ..|> HasType
Part ..|> HasModel
Part ..|> HasPrice
Part --|> AbstractDocument
@enduml

2
abstract-document/pom.xml
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@ -29,7 +29,7 @@
<parent>
<artifactId>java-design-patterns</artifactId>
<groupId>com.iluwatar</groupId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<artifactId>abstract-document</artifactId>
<dependencies>

44
abstract-factory/README.md
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@ -3,7 +3,6 @@ layout: pattern
title: Abstract Factory
folder: abstract-factory
permalink: /patterns/abstract-factory/
pumlid: PSZB3OD034NHLa81Czwd6sCC39gVxEUWT1_ssLmTtQLqgR5fM7sTmFGtaV6TZu8prd0r6HtQaMKqAZLk1XjT_E6qgPUZfyc0MdTgx0-8LuUn8ErFXdr98NypXxKyezKV
categories: Creational
tags:
- Java
@ -120,6 +119,45 @@ king.getDescription(); // Output: This is the Elven king!
army.getDescription(); // Output: 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.
The client can use FactoryMaker to create the desired concrete factory which, in turn, will produce different concrete objects (Army, King, Castle).
In this example, we also used an enum to parameterize which type of kingdom factory the client will ask for.
```
public static class FactoryMaker {
public enum KingdomType {
ELF, ORC
}
public static KingdomFactory makeFactory(KingdomType type) {
switch (type) {
case ELF:
return new ElfKingdomFactory();
case ORC:
return new OrcKingdomFactory();
default:
throw new IllegalArgumentException("KingdomType not supported.");
}
}
}
public static void main(String[] args) {
App app = new App();
LOGGER.info("Elf Kingdom");
app.createKingdom(FactoryMaker.makeFactory(KingdomType.ELF));
LOGGER.info(app.getArmy().getDescription());
LOGGER.info(app.getCastle().getDescription());
LOGGER.info(app.getKing().getDescription());
LOGGER.info("Orc Kingdom");
app.createKingdom(FactoryMaker.makeFactory(KingdomType.ORC));
-- similar use of the orc factory
}
```
## Applicability
Use the Abstract Factory pattern when
@ -141,6 +179,10 @@ Use the Abstract Factory pattern when
* Dependency injection in java hides the service class dependencies that can lead to runtime errors that would have been caught at compile time.
## Presentations
* [Abstract Factory Pattern](etc/presentation.html)
## Real world examples
* [javax.xml.parsers.DocumentBuilderFactory](http://docs.oracle.com/javase/8/docs/api/javax/xml/parsers/DocumentBuilderFactory.html)

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abstract-factory/etc/presentation.html Normal file
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<!--
The MIT License
Copyright (c) 2017 Rodolfo Forte
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.
-->
<!DOCTYPE html>
<html>
<head>
<title>Design Patterns - Abstract Factory Presentation</title>
<meta charset="utf-8">
<style>
@import url(https://fonts.googleapis.com/css?family=Yanone+Kaffeesatz);
@import url(https://fonts.googleapis.com/css?family=Droid+Serif:400,700,400italic);
@import url(https://fonts.googleapis.com/css?family=Ubuntu+Mono:400,700,400italic);
body { font-family: 'Droid Serif'; }
h1, h2, h3 {
font-family: 'Yanone Kaffeesatz';
font-weight: normal;
}
.remark-code, .remark-inline-code { font-family: 'Ubuntu Mono'; }
blockquote {
border-left: 0.3em solid rgba(0,0,0,0.5);
padding: 0 15px;
font-style: italic;
}
img {
max-width:100%;
}
</style>
</head>
<body>
<textarea id="source">
class: center, middle
# Abstract Factory
---
# Also known as
* Kit
---
# Intent
* Provide an interface for creating families of related or dependent objects without specifying their concrete classes
---
# Explanation
* [Wikipedia](https://en.wikipedia.org/wiki/Abstract_factory_pattern) says:
> "The abstract factory pattern provides a way to encapsulate a group of individual factories that have a common theme without specifying their concrete classes"
<br />
* In plain words:
* A factory that groups individual but related/dependent factories together without specifying their concrete classes;
* A factory of factories;
---
# Example
* In a factory that creates kingdoms, we need objects with common theme:
* Elven kingdom needs an Elven king, Elven castle and Elven army;
* Orcish kingdom needs an Orcish king, Orcish castle and Orcish army;
<br />
* There is a dependency between the objects in the kingdom;
---
# Diagram
* Based on the kingdom example, the diagram below showcases the different concrete factories and their concrete products:
.center[![Diagram](diagram1.png)]
---
# Diagram
* The class diagram below showcases the factory of factories;
* At runtime, we can define which Kingdom type is needed and pass it as a parameter to define which concrete KingdomFactory to instantiate;
* The concrete factory returned will then be able to produce the related objects of the specified type;
.center[![Diagram](diagram2.png)]
---
# 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;
---
# Applicability
Use the Abstract Factory pattern when:
* 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;
---
#Use Cases
* Selecting to call the appropriate implementation of FileSystemAcmeService or DatabaseAcmeService or NetworkAcmeService at runtime;
* Unit test case writing becomes much easier;
---
# Consequences
* Dependency injection in java hides the service class dependencies that can lead to runtime errors that would have been caught at compile time
---
# Real world examples
[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--)
---
# Credits
* [Design Patterns: Elements of Reusable Object-Oriented Software](http://www.amazon.com/Design-Patterns-Elements-Reusable-Object-Oriented/dp/0201633612)
---
# Tutorials
* Source code http://java-design-patterns.com/patterns/abstract-factory/
</textarea>
<script src="https://gnab.github.io/remark/downloads/remark-latest.min.js">
</script>
<script>
var slideshow = remark.create();
</script>
</body>
</html>

2
abstract-factory/pom.xml
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@ -29,7 +29,7 @@
<parent>
<groupId>com.iluwatar</groupId>
<artifactId>java-design-patterns</artifactId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<artifactId>abstract-factory</artifactId>
<dependencies>

37
abstract-factory/src/main/java/com/iluwatar/abstractfactory/App.java
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@ -25,6 +25,8 @@ package com.iluwatar.abstractfactory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.iluwatar.abstractfactory.App.FactoryMaker.KingdomType;
/**
*
* The Abstract Factory pattern provides a way to encapsulate a group of individual factories that have a common theme
@ -94,7 +96,34 @@ public class App {
}
/**
* Program entry point
* The factory of kingdom factories.
*/
public static class FactoryMaker {
/**
* Enumeration for the different types of Kingdoms.
*/
public enum KingdomType {
ELF, ORC
}
/**
* The factory method to create KingdomFactory concrete objects.
*/
public static KingdomFactory makeFactory(KingdomType type) {
switch (type) {
case ELF:
return new ElfKingdomFactory();
case ORC:
return new OrcKingdomFactory();
default:
throw new IllegalArgumentException("KingdomType not supported.");
}
}
}
/**
* Program entry point.
*
* @param args
* command line args
@ -104,17 +133,15 @@ public class App {
App app = new App();
LOGGER.info("Elf Kingdom");
app.createKingdom(new ElfKingdomFactory());
app.createKingdom(FactoryMaker.makeFactory(KingdomType.ELF));
LOGGER.info(app.getArmy().getDescription());
LOGGER.info(app.getCastle().getDescription());
LOGGER.info(app.getKing().getDescription());
LOGGER.info("Orc Kingdom");
app.createKingdom(new OrcKingdomFactory());
app.createKingdom(FactoryMaker.makeFactory(KingdomType.ORC));
LOGGER.info(app.getArmy().getDescription());
LOGGER.info(app.getCastle().getDescription());
LOGGER.info(app.getKing().getDescription());
}
}

7
abstract-factory/src/test/java/com/iluwatar/abstractfactory/AbstractFactoryTest.java
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@ -25,6 +25,9 @@ package com.iluwatar.abstractfactory;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import com.iluwatar.abstractfactory.App.FactoryMaker;
import com.iluwatar.abstractfactory.App.FactoryMaker.KingdomType;
import org.junit.Before;
import org.junit.Test;
@ -39,8 +42,8 @@ public class AbstractFactoryTest {
@Before
public void setUp() {
elfFactory = new ElfKingdomFactory();
orcFactory = new OrcKingdomFactory();
elfFactory = FactoryMaker.makeFactory(KingdomType.ELF);
orcFactory = FactoryMaker.makeFactory(KingdomType.ORC);
}
@Test

1
adapter/README.md
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@ -3,7 +3,6 @@ layout: pattern
title: Adapter
folder: adapter
permalink: /patterns/adapter/
pumlid: DSR14S8m30J0Lg20M7-wEMnDOiPMFDA9j0yyUEtUkzMHJTF7xI1NF4GSLzaxZtncgDVJgCPIpobzv0N2vOKtjgRHTziMI7KBcOXl10thfxB-Nz9dMJd71m00
categories: Structural
tags:
- Java

2
adapter/pom.xml
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@ -29,7 +29,7 @@
<parent>
<groupId>com.iluwatar</groupId>
<artifactId>java-design-patterns</artifactId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<artifactId>adapter</artifactId>
<dependencies>

1
aggregator-microservices/README.md
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@ -3,7 +3,6 @@ layout: pattern
title: Aggregator Microservices
folder: aggregator-microservices
permalink: /patterns/aggregator-microservices/
pumlid: JOov3SCm301NIGQGs7iRXYPa1g8ayB7NjuiKwGvtmBrbKC-Tq_hhY5Y-0HXUjKaS-Kbdepc2HrIQ2jBpma23BvvOTdPfeooCO1iEYlu0O6l63MDQKI6Rp-CKOWSE-ey_NzEqhjH-0m00
categories: Architectural
tags:
- Java

2
aggregator-microservices/aggregator-service/pom.xml
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@ -29,7 +29,7 @@
<parent>
<artifactId>aggregator-microservices</artifactId>
<groupId>com.iluwatar</groupId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>

43
aggregator-microservices/etc/aggregator-service.urm.puml
View File

@ -1,43 +0,0 @@
@startuml
package com.iluwatar.aggregator.microservices {
class Aggregator {
- informationClient : ProductInformationClient
- inventoryClient : ProductInventoryClient
+ Aggregator()
+ getProduct() : Product
}
class App {
+ App()
+ main(args : String[]) {static}
}
class Product {
- productInventories : int
- title : String
+ Product()
+ getProductInventories() : int
+ getTitle() : String
+ setProductInventories(productInventories : int)
+ setTitle(title : String)
}
interface ProductInformationClient {
+ getProductTitle() : String {abstract}
}
class ProductInformationClientImpl {
- LOGGER : Logger {static}
+ ProductInformationClientImpl()
+ getProductTitle() : String
}
interface ProductInventoryClient {
+ getProductInventories() : int {abstract}
}
class ProductInventoryClientImpl {
- LOGGER : Logger {static}
+ ProductInventoryClientImpl()
+ getProductInventories() : int
}
}
Aggregator --> "-informationClient" ProductInformationClient
Aggregator --> "-inventoryClient" ProductInventoryClient
ProductInformationClientImpl ..|> ProductInformationClient
ProductInventoryClientImpl ..|> ProductInventoryClient
@enduml

12
aggregator-microservices/etc/information-microservice.urm.puml
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@ -1,12 +0,0 @@
@startuml
package com.iluwatar.information.microservice {
class InformationApplication {
+ InformationApplication()
+ main(args : String[]) {static}
}
class InformationController {
+ InformationController()
+ getProductTitle() : String
}
}
@enduml

12
aggregator-microservices/etc/inventory-microservice.urm.puml
View File

@ -1,12 +0,0 @@
@startuml
package com.iluwatar.inventory.microservice {
class InventoryApplication {
+ InventoryApplication()
+ main(args : String[]) {static}
}
class InventoryController {
+ InventoryController()
+ getProductInventories() : int
}
}
@enduml

2
aggregator-microservices/information-microservice/pom.xml
View File

@ -29,7 +29,7 @@
<parent>
<artifactId>aggregator-microservices</artifactId>
<groupId>com.iluwatar</groupId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>

2
aggregator-microservices/inventory-microservice/pom.xml
View File

@ -29,7 +29,7 @@
<parent>
<artifactId>aggregator-microservices</artifactId>
<groupId>com.iluwatar</groupId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>

23
aggregator-microservices/pom.xml
View File

@ -29,32 +29,11 @@
<parent>
<artifactId>java-design-patterns</artifactId>
<groupId>com.iluwatar</groupId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>aggregator-microservices</artifactId>
<packaging>pom</packaging>
<build>
<plugins>
<plugin>
<groupId>com.github.markusmo3.urm</groupId>
<artifactId>urm-maven-plugin</artifactId>
<version>${urm.version}</version>
<configuration combine.self="override">
<outputDirectory>${project.basedir}/../etc</outputDirectory>
<packages>
<param>com.iluwatar</param>
</packages>
<skipForProjects>
<!-- skip for parent project -->
<param>aggregator-microservices</param>
</skipForProjects>
</configuration>
</plugin>
</plugins>
</build>
<modules>
<module>information-microservice</module>
<module>aggregator-service</module>

1
api-gateway/README.md
View File

@ -3,7 +3,6 @@ layout: pattern
title: API Gateway
folder: api-gateway
permalink: /patterns/api-gateway/
pumlid: JSox3SCm303HLP819FRUXg49cO542_nOyFPncUvUSszHwhbpMdyT4TCt0CDLcyIHdtGsEZLOez8vG7ek33JuueLbPvUcPM84cpeCz2S0fvI6mGjluA1_b-Tt2N5D6tNcw3y0
categories: Architectural
tags:
- Java

2
api-gateway/api-gateway-service/pom.xml
View File

@ -29,7 +29,7 @@
<parent>
<artifactId>api-gateway</artifactId>
<groupId>com.iluwatar</groupId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>api-gateway-service</artifactId>

48
api-gateway/etc/api-gateway-service.urm.puml
View File

@ -1,48 +0,0 @@
@startuml
package com.iluwatar.api.gateway {
class ApiGateway {
- imageClient : ImageClient
- priceClient : PriceClient
+ ApiGateway()
+ getProductDesktop() : DesktopProduct
+ getProductMobile() : MobileProduct
}
class App {
+ App()
+ main(args : String[]) {static}
}
class DesktopProduct {
- imagePath : String
- price : String
+ DesktopProduct()
+ getImagePath() : String
+ getPrice() : String
+ setImagePath(imagePath : String)
+ setPrice(price : String)
}
interface ImageClient {
+ getImagePath() : String {abstract}
}
class ImageClientImpl {
+ ImageClientImpl()
+ getImagePath() : String
}
class MobileProduct {
- price : String
+ MobileProduct()
+ getPrice() : String
+ setPrice(price : String)
}
interface PriceClient {
+ getPrice() : String {abstract}
}
class PriceClientImpl {
+ PriceClientImpl()
+ getPrice() : String
}
}
ApiGateway --> "-imageClient" ImageClient
ApiGateway --> "-priceClient" PriceClient
ImageClientImpl ..|> ImageClient
PriceClientImpl ..|> PriceClient
@enduml

12
api-gateway/etc/image-microservice.urm.puml
View File

@ -1,12 +0,0 @@
@startuml
package com.iluwatar.image.microservice {
class ImageApplication {
+ ImageApplication()
+ main(args : String[]) {static}
}
class ImageController {
+ ImageController()
+ getImagePath() : String
}
}
@enduml

12
api-gateway/etc/price-microservice.urm.puml
View File

@ -1,12 +0,0 @@
@startuml
package com.iluwatar.price.microservice {
class PriceApplication {
+ PriceApplication()
+ main(args : String[]) {static}
}
class PriceController {
+ PriceController()
+ getPrice() : String
}
}
@enduml

2
api-gateway/image-microservice/pom.xml
View File

@ -29,7 +29,7 @@
<parent>
<artifactId>api-gateway</artifactId>
<groupId>com.iluwatar</groupId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>

23
api-gateway/pom.xml
View File

@ -29,32 +29,11 @@
<parent>
<artifactId>java-design-patterns</artifactId>
<groupId>com.iluwatar</groupId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>api-gateway</artifactId>
<packaging>pom</packaging>
<build>
<plugins>
<plugin>
<groupId>com.github.markusmo3.urm</groupId>
<artifactId>urm-maven-plugin</artifactId>
<version>${urm.version}</version>
<configuration combine.self="override">
<outputDirectory>${project.basedir}/../etc</outputDirectory>
<packages>
<param>com.iluwatar</param>
</packages>
<skipForProjects>
<!-- skip for parent project -->
<param>api-gateway</param>
</skipForProjects>
</configuration>
</plugin>
</plugins>
</build>
<modules>
<module>image-microservice</module>
<module>price-microservice</module>

2
api-gateway/price-microservice/pom.xml
View File

@ -29,7 +29,7 @@
<parent>
<artifactId>api-gateway</artifactId>
<groupId>com.iluwatar</groupId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>

1
async-method-invocation/README.md
View File

@ -3,7 +3,6 @@ layout: pattern
title: Async Method Invocation
folder: async-method-invocation
permalink: /patterns/async-method-invocation/
pumlid: TSdB3SCW303GLTe1mFTkunWhk0A3_4dKxTi5UdlIUuhIoCPfuz4Zjhy03EzwIlGyqjbeQR16fJL1HjuOQF362qjZbrFBnWWsTPZeFm3wHwbCZhvQ4RqMOSXIuA1_LzDctJd75m00
categories: Concurrency
tags:
- Java

51
async-method-invocation/etc/async-method-invocation.urm.puml
View File

@ -1,51 +0,0 @@
@startuml
package com.iluwatar.async.method.invocation {
class App {
- LOGGER : Logger {static}
+ App()
- callback(name : String) : AsyncCallback<T> {static}
- lazyval(value : T, delayMillis : long) : Callable<T> {static}
- log(msg : String) {static}
+ main(args : String[]) {static}
}
interface AsyncCallback<T> {
+ onComplete(T, Optional<Exception>) {abstract}
}
interface AsyncExecutor {
+ endProcess(AsyncResult<T>) : T {abstract}
+ startProcess(Callable<T>) : AsyncResult<T> {abstract}
+ startProcess(Callable<T>, AsyncCallback<T>) : AsyncResult<T> {abstract}
}
interface AsyncResult<T> {
+ await() {abstract}
+ getValue() : T {abstract}
+ isCompleted() : boolean {abstract}
}
class ThreadAsyncExecutor {
- idx : AtomicInteger
+ ThreadAsyncExecutor()
+ endProcess(asyncResult : AsyncResult<T>) : T
+ startProcess(task : Callable<T>) : AsyncResult<T>
+ startProcess(task : Callable<T>, callback : AsyncCallback<T>) : AsyncResult<T>
}
-class CompletableResult<T> {
~ COMPLETED : int {static}
~ FAILED : int {static}
~ RUNNING : int {static}
~ callback : Optional<AsyncCallback<T>>
~ exception : Exception
~ lock : Object
~ state : int
~ value : T
~ CompletableResult<T>(callback : AsyncCallback<T>)
+ await()
+ getValue() : T
+ isCompleted() : boolean
~ setException(exception : Exception)
~ setValue(value : T)
}
}
CompletableResult ..+ ThreadAsyncExecutor
ThreadAsyncExecutor ..|> AsyncExecutor
CompletableResult ..|> AsyncResult
@enduml

2
async-method-invocation/pom.xml
View File

@ -29,7 +29,7 @@
<parent>
<groupId>com.iluwatar</groupId>
<artifactId>java-design-patterns</artifactId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<artifactId>async-method-invocation</artifactId>
<dependencies>

24
balking/etc/balking.urm.puml
View File

@ -1,24 +0,0 @@
@startuml
package com.iluwatar.balking {
class App {
- LOGGER : Logger {static}
+ App()
+ main(args : String[]) {static}
}
class WashingMachine {
- LOGGER : Logger {static}
- washingMachineState : WashingMachineState
+ WashingMachine()
+ endOfWashing()
+ getWashingMachineState() : WashingMachineState
+ wash()
}
enum WashingMachineState {
+ ENABLED {static}
+ WASHING {static}
+ valueOf(name : String) : WashingMachineState {static}
+ values() : WashingMachineState[] {static}
}
}
WashingMachine --> "-washingMachineState" WashingMachineState
@enduml

2
balking/pom.xml
View File

@ -29,7 +29,7 @@
<parent>
<artifactId>java-design-patterns</artifactId>
<groupId>com.iluwatar</groupId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>

1
bridge/README.md
View File

@ -3,7 +3,6 @@ layout: pattern
title: Bridge
folder: bridge
permalink: /patterns/bridge/
pumlid: BSR14SCm20J0Lf82BFxf1akCJ4R26ZZYzkE7zxLljJgoIVfu7S2A3v7pLRhYo3r3l9u6CPHwJjAH5uETllpZhKbejsqn86v1a-CExQwj2mdgqv8-oyev_W00
categories: Structural
tags:
- Java

2
bridge/pom.xml
View File

@ -29,7 +29,7 @@
<parent>
<groupId>com.iluwatar</groupId>
<artifactId>java-design-patterns</artifactId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<artifactId>bridge</artifactId>
<dependencies>

6
bridge/src/test/java/com/iluwatar/bridge/WeaponTest.java
View File

@ -44,15 +44,15 @@ public abstract class WeaponTest {
assertNotNull(weapon.getEnchantment());
weapon.swing();
verify(enchantment, times(1)).apply();
verify(enchantment).apply();
verifyNoMoreInteractions(enchantment);
weapon.wield();
verify(enchantment, times(1)).onActivate();
verify(enchantment).onActivate();
verifyNoMoreInteractions(enchantment);
weapon.unwield();
verify(enchantment, times(1)).onDeactivate();
verify(enchantment).onDeactivate();
verifyNoMoreInteractions(enchantment);
}

1
builder/README.md
View File

@ -3,7 +3,6 @@ layout: pattern
title: Builder
folder: builder
permalink: /patterns/builder/
pumlid: DSR94O0m2030LhG0mzzkC64KXs26GzlNZw_TcRLADagJwOWOlW8OFcNdE79B9wkN1ccKUdLWoGS33KwySMdalEioC89C7Jhw5zYIfNrIrFybhPUHNLu0
categories: Creational
tags:
- Java

2
builder/pom.xml
View File

@ -29,7 +29,7 @@
<parent>
<groupId>com.iluwatar</groupId>
<artifactId>java-design-patterns</artifactId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<artifactId>builder</artifactId>
<dependencies>

1
business-delegate/README.md
View File

@ -3,7 +3,6 @@ layout: pattern
title: Business Delegate
folder: business-delegate
permalink: /patterns/business-delegate/
pumlid: POl13SCm3CHMQGU8zUysgYCuBcJ5a4x9-l6_Fu84tzsgvYxf-Zg06HyYvxkqZYE_6UBrD8YXr7DGrxmPxFJZYxTTeZVR9WFY5ZGu5j2wkad4wYgD8IIe_xQaZp9pw0C0
categories: Business Tier
tags:
- Java

57
business-delegate/etc/business-delegate.urm.puml
View File

@ -1,57 +0,0 @@
@startuml
package com.iluwatar.business.delegate {
class App {
+ App()
+ main(args : String[]) {static}
}
class BusinessDelegate {
- businessService : BusinessService
- lookupService : BusinessLookup
- serviceType : ServiceType
+ BusinessDelegate()
+ doTask()
+ setLookupService(businessLookup : BusinessLookup)
+ setServiceType(serviceType : ServiceType)
}
class BusinessLookup {
- ejbService : EjbService
- jmsService : JmsService
+ BusinessLookup()
+ getBusinessService(serviceType : ServiceType) : BusinessService
+ setEjbService(ejbService : EjbService)
+ setJmsService(jmsService : JmsService)
}
interface BusinessService {
+ doProcessing() {abstract}
}
class Client {
- businessDelegate : BusinessDelegate
+ Client(businessDelegate : BusinessDelegate)
+ doTask()
}
class EjbService {
- LOGGER : Logger {static}
+ EjbService()
+ doProcessing()
}
class JmsService {
- LOGGER : Logger {static}
+ JmsService()
+ doProcessing()
}
enum ServiceType {
+ EJB {static}
+ JMS {static}
+ valueOf(name : String) : ServiceType {static}
+ values() : ServiceType[] {static}
}
}
BusinessLookup --> "-ejbService" EjbService
BusinessDelegate --> "-serviceType" ServiceType
Client --> "-businessDelegate" BusinessDelegate
BusinessDelegate --> "-businessService" BusinessService
BusinessDelegate --> "-lookupService" BusinessLookup
BusinessLookup --> "-jmsService" JmsService
EjbService ..|> BusinessService
JmsService ..|> BusinessService
@enduml

2
business-delegate/pom.xml
View File

@ -30,7 +30,7 @@
<parent>
<groupId>com.iluwatar</groupId>
<artifactId>java-design-patterns</artifactId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<artifactId>business-delegate</artifactId>
<dependencies>

1
caching/README.md
View File

@ -3,7 +3,6 @@ layout: pattern
title: Caching
folder: caching
permalink: /patterns/caching/
pumlid: DSRB4OKm2030LhG0m_rrWyWaE0bc-6ZxpujxsbMKUXwSrfSMCVq7OFYKAj5oJsUZIuCr2bq3fEU3WGOdthWTx59rcnZ1fWu3_GqGKXEjm47VIzeeCqV_0m00
categories: Other
tags:
- Java

110
caching/etc/caching.urm.puml
View File

@ -1,110 +0,0 @@
@startuml
package com.iluwatar.caching {
class App {
- LOGGER : Logger {static}
+ App()
+ main(args : String[]) {static}
+ useCacheAsideStategy()
+ useReadAndWriteThroughStrategy()
+ useReadThroughAndWriteAroundStrategy()
+ useReadThroughAndWriteBehindStrategy()
}
class AppManager {
- cachingPolicy : CachingPolicy {static}
- AppManager()
+ find(userId : String) : UserAccount {static}
- findAside(userId : String) : UserAccount {static}
+ initCacheCapacity(capacity : int) {static}
+ initCachingPolicy(policy : CachingPolicy) {static}
+ initDb(useMongoDb : boolean) {static}
+ printCacheContent() : String {static}
+ save(userAccount : UserAccount) {static}
- saveAside(userAccount : UserAccount) {static}
}
class CacheStore {
- LOGGER : Logger {static}
~ cache : LruCache {static}
- CacheStore()
+ clearCache() {static}
+ flushCache() {static}
+ get(userId : String) : UserAccount {static}
+ initCapacity(capacity : int) {static}
+ invalidate(userId : String) {static}
+ print() : String {static}
+ readThrough(userId : String) : UserAccount {static}
+ readThroughWithWriteBackPolicy(userId : String) : UserAccount {static}
+ set(userId : String, userAccount : UserAccount) {static}
+ writeAround(userAccount : UserAccount) {static}
+ writeBehind(userAccount : UserAccount) {static}
+ writeThrough(userAccount : UserAccount) {static}
}
enum CachingPolicy {
+ AROUND {static}
+ ASIDE {static}
+ BEHIND {static}
+ THROUGH {static}
- policy : String
+ getPolicy() : String
+ valueOf(name : String) : CachingPolicy {static}
+ values() : CachingPolicy[] {static}
}
class DbManager {
- db : MongoDatabase {static}
- mongoClient : MongoClient {static}
- useMongoDB : boolean {static}
- virtualDB : Map<String, UserAccount> {static}
- DbManager()
+ connect() {static}
+ createVirtualDb() {static}
+ readFromDb(userId : String) : UserAccount {static}
+ updateDb(userAccount : UserAccount) {static}
+ upsertDb(userAccount : UserAccount) {static}
+ writeToDb(userAccount : UserAccount) {static}
}
class LruCache {
- LOGGER : Logger {static}
~ cache : Map<String, Node>
~ capacity : int
~ end : Node
~ head : Node
+ LruCache(capacity : int)
+ clear()
+ contains(userId : String) : boolean
+ get(userId : String) : UserAccount
+ getCacheDataInListForm() : List<UserAccount>
+ getLruData() : UserAccount
+ invalidate(userId : String)
+ isFull() : boolean
+ remove(node : Node)
+ set(userId : String, userAccount : UserAccount)
+ setCapacity(newCapacity : int)
+ setHead(node : Node)
}
~class Node {
~ next : Node
~ previous : Node
~ userAccount : UserAccount
~ userId : String
+ Node(this$0 : String, userId : UserAccount)
}
class UserAccount {
- additionalInfo : String
- userId : String
- userName : String
+ UserAccount(userId : String, userName : String, additionalInfo : String)
+ getAdditionalInfo() : String
+ getUserId() : String
+ getUserName() : String
+ setAdditionalInfo(additionalInfo : String)
+ setUserId(userId : String)
+ setUserName(userName : String)
+ toString() : String
}
}
LruCache --> "-head" Node
Node --+ LruCache
Node --> "-previous" Node
AppManager --> "-cachingPolicy" CachingPolicy
Node --> "-userAccount" UserAccount
CacheStore --> "-cache" LruCache
@enduml

2
caching/pom.xml
View File

@ -29,7 +29,7 @@
<parent>
<groupId>com.iluwatar</groupId>
<artifactId>java-design-patterns</artifactId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<artifactId>caching</artifactId>
<dependencies>

1
callback/README.md
View File

@ -3,7 +3,6 @@ layout: pattern
title: Callback
folder: callback
permalink: /patterns/callback/
pumlid: FSVB4S8m30N0Lg20M7UwUL4qYOciUFGXxSE9s-wp6sjjKgwF8tF6YyXnjxtdKMk5E5-MOjdu6jIrRYIStlXWsIJwRij4fhW53SGFn51TmIT9yZ-jVBHPGxy0
categories: Other
tags:
- Java

28
callback/etc/callback.urm.puml
View File

@ -1,28 +0,0 @@
@startuml
package com.iluwatar.callback {
class App {
- LOGGER : Logger {static}
+ App()
+ main(args : String[]) {static}
}
interface Callback {
+ call() {abstract}
}
class LambdasApp {
- LOGGER : Logger {static}
+ LambdasApp()
+ main(args : String[]) {static}
}
class SimpleTask {
- LOGGER : Logger {static}
+ SimpleTask()
+ execute()
}
abstract class Task {
+ Task()
+ execute() {abstract}
+ executeWith(callback : Callback)
}
}
SimpleTask --|> Task
@enduml

2
callback/pom.xml
View File

@ -29,7 +29,7 @@
<parent>
<groupId>com.iluwatar</groupId>
<artifactId>java-design-patterns</artifactId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<artifactId>callback</artifactId>
<dependencies>

127
chain/README.md
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@ -3,7 +3,6 @@ layout: pattern
title: Chain of responsibility
folder: chain
permalink: /patterns/chain/
pumlid: 9SR13SCm20NGLTe1OkxTXX0KKzd4Wa-pVYlrdTxJN4OTMZ4U7LZv8Wg-ssdejLTgoELGHvDhaesw6HpqvWzlXwQTlYq6D3nfSlv2qjcS5F9VgvXjrHnV
categories: Behavioral
tags:
- Java
@ -16,7 +15,131 @@ Avoid coupling the sender of a request to its receiver by giving
more than one object a chance to handle the request. Chain the receiving
objects and pass the request along the chain until an object handles it.
![alt text](./etc/chain_1.png "Chain of Responsibility")
## Explanation
Real world example
> The Orc King gives loud orders to his army. The closest one to react is the commander, then officer and then soldier. The commander, officer and soldier here form a chain of responsibility.
In plain words
> It helps building a chain of objects. Request enters from one end and keeps going from object to object till it finds the suitable handler.
Wikipedia says
> In object-oriented design, the chain-of-responsibility pattern is a design pattern consisting of a source of command objects and a series of processing objects. Each processing object contains logic that defines the types of command objects that it can handle; the rest are passed to the next processing object in the chain.
**Programmatic Example**
Translating our example with orcs from above. First we have the request class
```
public class Request {
private final RequestType requestType;
private final String requestDescription;
private boolean handled;
public Request(final RequestType requestType, final String requestDescription) {
this.requestType = Objects.requireNonNull(requestType);
this.requestDescription = Objects.requireNonNull(requestDescription);
}
public String getRequestDescription() { return requestDescription; }
public RequestType getRequestType() { return requestType; }
public void markHandled() { this.handled = true; }
public boolean isHandled() { return this.handled; }
@Override
public String toString() { return getRequestDescription(); }
}
public enum RequestType {
DEFEND_CASTLE, TORTURE_PRISONER, COLLECT_TAX
}
```
Then the request handler hierarchy
```
public abstract class RequestHandler {
private static final Logger LOGGER = LoggerFactory.getLogger(RequestHandler.class);
private RequestHandler next;
public RequestHandler(RequestHandler next) {
this.next = next;
}
public void handleRequest(Request req) {
if (next != null) {
next.handleRequest(req);
}
}
protected void printHandling(Request req) {
LOGGER.info("{} handling request \"{}\"", this, req);
}
@Override
public abstract String toString();
}
public class OrcCommander extends RequestHandler {
public OrcCommander(RequestHandler handler) {
super(handler);
}
@Override
public void handleRequest(Request req) {
if (req.getRequestType().equals(RequestType.DEFEND_CASTLE)) {
printHandling(req);
req.markHandled();
} else {
super.handleRequest(req);
}
}
@Override
public String toString() {
return "Orc commander";
}
}
// OrcOfficer and OrcSoldier are defined similarly as OrcCommander
```
Then we have the Orc King who gives the orders and forms the chain
```
public class OrcKing {
RequestHandler chain;
public OrcKing() {
buildChain();
}
private void buildChain() {
chain = new OrcCommander(new OrcOfficer(new OrcSoldier(null)));
}
public void makeRequest(Request req) {
chain.handleRequest(req);
}
}
```
Then it is used as follows
```
OrcKing king = new OrcKing();
king.makeRequest(new Request(RequestType.DEFEND_CASTLE, "defend castle")); // Orc commander handling request "defend castle"
king.makeRequest(new Request(RequestType.TORTURE_PRISONER, "torture prisoner")); // Orc officer handling request "torture prisoner"
king.makeRequest(new Request(RequestType.COLLECT_TAX, "collect tax")); // Orc soldier handling request "collect tax"
```
## Applicability
Use Chain of Responsibility when

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chain/etc/chain.ucls
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@ -1,109 +0,0 @@
<?xml version="1.0" encoding="UTF-8"?>
<class-diagram version="1.1.8" icons="true" automaticImage="PNG" always-add-relationships="false" generalizations="true"
realizations="true" associations="true" dependencies="false" nesting-relationships="true">
<class id="1" language="java" name="com.iluwatar.chain.Request" project="chain"
file="/chain/src/main/java/com/iluwatar/chain/Request.java" binary="false" corner="BOTTOM_RIGHT">
<position height="196" width="228" x="168" y="182"/>
<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="2" language="java" name="com.iluwatar.chain.OrcOfficer" project="chain"
file="/chain/src/main/java/com/iluwatar/chain/OrcOfficer.java" binary="false" corner="BOTTOM_RIGHT">
<position height="124" width="194" x="168" y="609"/>
<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.chain.OrcCommander" project="chain"
file="/chain/src/main/java/com/iluwatar/chain/OrcCommander.java" binary="false" corner="BOTTOM_RIGHT">
<position height="124" width="217" x="402" y="609"/>
<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.chain.RequestHandler" project="chain"
file="/chain/src/main/java/com/iluwatar/chain/RequestHandler.java" binary="false" corner="BOTTOM_RIGHT">
<position height="141" width="218" x="451" y="418"/>
<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="5" language="java" name="com.iluwatar.chain.OrcSoldier" project="chain"
file="/chain/src/main/java/com/iluwatar/chain/OrcSoldier.java" binary="false" corner="BOTTOM_RIGHT">
<position height="124" width="194" x="659" y="609"/>
<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="6" language="java" name="com.iluwatar.chain.OrcKing" project="chain"
file="/chain/src/main/java/com/iluwatar/chain/OrcKing.java" binary="false" corner="BOTTOM_RIGHT">
<position height="124" width="188" x="451" y="182"/>
<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>
<enumeration id="7" language="java" name="com.iluwatar.chain.RequestType" project="chain"
file="/chain/src/main/java/com/iluwatar/chain/RequestType.java" binary="false" corner="BOTTOM_RIGHT">
<position height="142" width="243" x="168" y="418"/>
<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>
</enumeration>
<association id="8">
<end type="SOURCE" refId="6" navigable="false">
<attribute id="9" name="chain"/>
<multiplicity id="10" minimum="0" maximum="1"/>
</end>
<end type="TARGET" refId="4" navigable="true"/>
<display labels="true" multiplicity="true"/>
</association>
<association id="11">
<end type="SOURCE" refId="4" navigable="false">
<attribute id="12" name="next"/>
<multiplicity id="13" minimum="0" maximum="1"/>
</end>
<end type="TARGET" refId="4" navigable="true"/>
<display labels="true" multiplicity="true"/>
</association>
<generalization id="14">
<end type="SOURCE" refId="5"/>
<end type="TARGET" refId="4"/>
</generalization>
<association id="15">
<end type="SOURCE" refId="1" navigable="false">
<attribute id="16" name="requestType"/>
<multiplicity id="17" minimum="0" maximum="1"/>
</end>
<end type="TARGET" refId="7" navigable="true"/>
<display labels="true" multiplicity="true"/>
</association>
<generalization id="18">
<end type="SOURCE" refId="2"/>
<end type="TARGET" refId="4"/>
</generalization>
<generalization id="19">
<end type="SOURCE" refId="3"/>
<end type="TARGET" refId="4"/>
</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>

61
chain/etc/chain.urm.puml
View File

@ -1,61 +0,0 @@
@startuml
package com.iluwatar.chain {
class App {
+ App()
+ main(args : String[]) {static}
}
class OrcCommander {
+ OrcCommander(handler : RequestHandler)
+ handleRequest(req : Request)
+ toString() : String
}
class OrcKing {
~ chain : RequestHandler
+ OrcKing()
- buildChain()
+ makeRequest(req : Request)
}
class OrcOfficer {
+ OrcOfficer(handler : RequestHandler)
+ handleRequest(req : Request)
+ toString() : String
}
class OrcSoldier {
+ OrcSoldier(handler : RequestHandler)
+ handleRequest(req : Request)
+ toString() : String
}
class Request {
- handled : boolean
- requestDescription : String
- requestType : RequestType
+ Request(requestType : RequestType, requestDescription : String)
+ getRequestDescription() : String
+ getRequestType() : RequestType
+ isHandled() : boolean
+ markHandled()
+ toString() : String
}
abstract class RequestHandler {
- LOGGER : Logger {static}
- next : RequestHandler
+ RequestHandler(next : RequestHandler)
+ handleRequest(req : Request)
# printHandling(req : Request)
+ toString() : String {abstract}
}
enum RequestType {
+ COLLECT_TAX {static}
+ DEFEND_CASTLE {static}
+ TORTURE_PRISONER {static}
+ valueOf(name : String) : RequestType {static}
+ values() : RequestType[] {static}
}
}
RequestHandler --> "-next" RequestHandler
Request --> "-requestType" RequestType
OrcKing --> "-chain" RequestHandler
OrcCommander --|> RequestHandler
OrcOfficer --|> RequestHandler
OrcSoldier --|> RequestHandler
@enduml

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2
chain/pom.xml
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@ -29,7 +29,7 @@
<parent>
<groupId>com.iluwatar</groupId>
<artifactId>java-design-patterns</artifactId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<artifactId>chain</artifactId>
<dependencies>

4
checkstyle.xml
View File

@ -85,9 +85,7 @@
value="LITERAL_TRY, LITERAL_CATCH, LITERAL_FINALLY, LITERAL_IF, LITERAL_ELSE, LITERAL_SWITCH"/>
</module>
<module name="NeedBraces"/>
<module name="LeftCurly">
<property name="maxLineLength" value="120"/>
</module>
<module name="LeftCurly"/>
<module name="RightCurly"/>
<module name="RightCurly">
<property name="option" value="alone"/>

5
command/README.md
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@ -3,7 +3,6 @@ layout: pattern
title: Command
folder: command
permalink: /patterns/command/
pumlid: DSgn4OCm30NGLM00h3xR25i7vYpXaxx2-g59zugtTgiZcwIFvGHcV8YSdt9qdBbdYDVR88PIRwK-yc6mqyLVtff4FsoR38XRa7Aye3SgMoD1_RkaQvcfumS0
categories: Behavioral
tags:
- Java
@ -37,6 +36,10 @@ Use the Command pattern when you want to
* implement callback functionality
* implement the undo functionality
## Presentations
* [Command Pattern](etc/presentation.html)
## Real world examples
* [java.lang.Runnable](http://docs.oracle.com/javase/8/docs/api/java/lang/Runnable.html)

86
command/etc/command.urm.puml
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@ -1,86 +0,0 @@
@startuml
package com.iluwatar.command {
class App {
+ App()
+ main(args : String[]) {static}
}
abstract class Command {
+ Command()
+ execute(Target) {abstract}
+ redo() {abstract}
+ toString() : String {abstract}
+ undo() {abstract}
}
class Goblin {
+ Goblin()
+ toString() : String
}
class InvisibilitySpell {
- target : Target
+ InvisibilitySpell()
+ execute(target : Target)
+ redo()
+ toString() : String
+ undo()
}
class ShrinkSpell {
- oldSize : Size
- target : Target
+ ShrinkSpell()
+ execute(target : Target)
+ redo()
+ toString() : String
+ undo()
}
enum Size {
+ LARGE {static}
+ NORMAL {static}
+ SMALL {static}
+ UNDEFINED {static}
- title : String
+ toString() : String
+ valueOf(name : String) : Size {static}
+ values() : Size[] {static}
}
abstract class Target {
- LOGGER : Logger {static}
- size : Size
- visibility : Visibility
+ Target()
+ getSize() : Size
+ getVisibility() : Visibility
+ printStatus()
+ setSize(size : Size)
+ setVisibility(visibility : Visibility)
+ toString() : String {abstract}
}
enum Visibility {
+ INVISIBLE {static}
+ UNDEFINED {static}
+ VISIBLE {static}
- title : String
+ toString() : String
+ valueOf(name : String) : Visibility {static}
+ values() : Visibility[] {static}
}
class Wizard {
- LOGGER : Logger {static}
- redoStack : Deque<Command>
- undoStack : Deque<Command>
+ Wizard()
+ castSpell(command : Command, target : Target)
+ redoLastSpell()
+ toString() : String
+ undoLastSpell()
}
}
Target --> "-size" Size
Wizard --> "-undoStack" Command
ShrinkSpell --> "-oldSize" Size
InvisibilitySpell --> "-target" Target
ShrinkSpell --> "-target" Target
Target --> "-visibility" Visibility
Goblin --|> Target
InvisibilitySpell --|> Command
ShrinkSpell --|> Command
@enduml

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<!--
The MIT License
Copyright (c) 2017 Rodolfo Forte
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.
-->
<!DOCTYPE html>
<html>
<head>
<title>Design Patterns - Command Presentation</title>
<meta charset="utf-8">
<style>
@import url(https://fonts.googleapis.com/css?family=Yanone+Kaffeesatz);
@import url(https://fonts.googleapis.com/css?family=Droid+Serif:400,700,400italic);
@import url(https://fonts.googleapis.com/css?family=Ubuntu+Mono:400,700,400italic);
body { font-family: 'Droid Serif'; }
h1, h2, h3 {
font-family: 'Yanone Kaffeesatz';
font-weight: normal;
}
.remark-code, .remark-inline-code { font-family: 'Ubuntu Mono'; }
blockquote {
border-left: 0.3em solid rgba(0,0,0,0.5);
padding: 0 15px;
font-style: italic;
}
img {
max-width:100%;
}
</style>
</head>
<body>
<textarea id="source">
class: center, middle
# Command
---
# Also known as
* Action, Transaction
---
# Intent
* Encapsulate a request as an object, thereby letting you parameterize clients with different requests, queue or log requests, and support undoable operations.
---
# Explanation
* [Wikipedia](https://en.wikipedia.org/wiki/Command_pattern) says:
> In object-oriented programming, the command pattern is a behavioral design pattern in which an object is used to encapsulate all information needed to perform an action or trigger an event at a later time. This information includes the method name, the object that owns the method and values for the method parameters.
<br />
* In plain words:
* Enable the construction of components that are able to delegate, sequence or execute method calls at a time of their choosing;
---
# Explanation
Four terms always associated with the pattern:
* Command
* Object that knows about the receiver and invokes a method of the receiver;
* Receiver
* Object that does the work;
* Invoker
* Knows how to execute a command, and optionally does the bookkeeping about the command execution;
* Client
* Decides which commands to execute at which points, passing the command object to the invoker object;
---
# Example
In our example, a Wizard can cast spells on targets.
* Spell will be the command (implements the Command interface);
* Goblin (a Target object) will be the receiver;
* Wizard will be the invoker;
* App will be the client;
```
//App.java
public static void main(String[] args) {
Wizard wizard = new Wizard();
Goblin goblin = new Goblin();
goblin.printStatus(); //Goblin, [size=normal] [visibility=visible]
wizard.castSpell(new ShrinkSpell(), goblin);
wizard.castSpell(new InvisibilitySpell(), goblin);
goblin.printStatus(); //Goblin, [size=small] [visibility=invisible]
wizard.undoLastSpell();
goblin.printStatus(); //Goblin, [size=small] [visibility=visible]
wizard.redoLastSpell();
goblin.printStatus(); //Goblin, [size=small] [visibility=invisible]
}
```
---
# Diagram
.center[![Diagram](diagram.png)]
---
# Applicability
Use the Command pattern when you want to:
* Parameterize objects by an action to perform;
* You can express such parameterization in a procedural language with a callback function, that is, a function that's registered somewhere to be called at a later point;
* Commands are an object-oriented replacement for callbacks;
<br />
* Specify, queue, and execute requests at different times;
* A Command object can have a lifetime independent of the original request;
* If the receiver of a request can be represented in an address space-independent way, then you can transfer a command object for the request to a different process and fulfill the request there;
---
# Applicability
Use the Command pattern when you want to:
* Support undo;
* The Command's execute() operation can store state for reversing its effects in the command itself;
* The Command interface must have an added unexecute() operation that reverses the effects of a previous call to execute;
* Executed commands are stored in a history list;
* Unlimited-level undo and redo is achieved by traversing this list backwards and forwards calling unexecute() and execute(), respectively;
---
# Applicability
Use the Command pattern when you want to:
* Support logging changes so that they can be reapplied in case of a system crash;
* By augmenting the Command interface with load() and store() operations, you can keep a persistent log of changes;
* Recovering from a crash involves reloading logged commands from disk and re-executing them with the execute operation;
---
# Applicability
Use the Command pattern when you want to:
* Structure a system around high-level operations build on primitive operations;
* Such a structure is common in information systems that support transactions;
* A transaction encapsulates a set of changes to data;
* The Command pattern offers a way to model transactions;
* Commands have a common interface, letting you invoke all transactions the same way;
* The pattern also makes it easy to extend the system with new transactions
---
# Use Cases
* To keep a history of requests;
* Implement callback functionality;
* Implement the undo functionality;
---
# Real world examples
[java.lang.Runnable](http://docs.oracle.com/javase/8/docs/api/java/lang/Runnable.html)
[Netflix Hystrix](https://github.com/Netflix/Hystrix/wiki)
[javax.swing.Action](http://docs.oracle.com/javase/8/docs/api/javax/swing/Action.html)
---
# Credits
* [Design Patterns: Elements of Reusable Object-Oriented Software](http://www.amazon.com/Design-Patterns-Elements-Reusable-Object-Oriented/dp/0201633612)
---
# Tutorials
* Source code http://java-design-patterns.com/patterns/command/
</textarea>
<script src="https://gnab.github.io/remark/downloads/remark-latest.min.js">
</script>
<script>
var slideshow = remark.create();
</script>
</body>
</html>

2
command/pom.xml
View File

@ -29,7 +29,7 @@
<parent>
<groupId>com.iluwatar</groupId>
<artifactId>java-design-patterns</artifactId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<artifactId>command</artifactId>
<dependencies>

2
command/src/main/java/com/iluwatar/command/Size.java
View File

@ -29,7 +29,7 @@ package com.iluwatar.command;
*/
public enum Size {
SMALL("small"), NORMAL("normal"), LARGE("large"), UNDEFINED("");
SMALL("small"), NORMAL("normal");
private String title;

2
command/src/main/java/com/iluwatar/command/Visibility.java
View File

@ -29,7 +29,7 @@ package com.iluwatar.command;
*/
public enum Visibility {
VISIBLE("visible"), INVISIBLE("invisible"), UNDEFINED("");
VISIBLE("visible"), INVISIBLE("invisible");
private String title;

4
command/src/main/java/com/iluwatar/command/Wizard.java
View File

@ -40,7 +40,9 @@ public class Wizard {
private Deque<Command> undoStack = new LinkedList<>();
private Deque<Command> redoStack = new LinkedList<>();
public Wizard() {}
public Wizard() {
// comment to ignore sonar issue: LEVEL critical
}
/**
* Cast spell

6
command/src/test/java/com/iluwatar/command/CommandTest.java
View File

@ -81,13 +81,13 @@ public class CommandTest {
* @param goblin a goblin object whose state is to be verified against other parameters
* @param expectedName expectedName of the goblin
* @param expectedSize expected size of the goblin
* @param expectedVisibilty exepcted visibility of the goblin
* @param expectedVisibility expected visibility of the goblin
*/
private void verifyGoblin(Goblin goblin, String expectedName, Size expectedSize,
Visibility expectedVisibilty) {
Visibility expectedVisibility) {
assertEquals("Goblin's name must be same as expectedName", expectedName, goblin.toString());
assertEquals("Goblin's size must be same as expectedSize", expectedSize, goblin.getSize());
assertEquals("Goblin's visibility must be same as expectedVisibility", expectedVisibilty,
assertEquals("Goblin's visibility must be same as expectedVisibility", expectedVisibility,
goblin.getVisibility());
}
}

1
composite/README.md
View File

@ -3,7 +3,6 @@ layout: pattern
title: Composite
folder: composite
permalink: /patterns/composite/
pumlid: HSf13eCm30NHgy01YFUzZGaM62LEP7-NwvTTT_EaMTLgoqFIst81Cpv4payv5LVk6U9r6CHGwkYaBHy6EztyvUsGqDEsoO2u1NMED-WTvmY5aA3-LT9xcTdR3m00
categories: Structural
tags:
- Java

2
composite/pom.xml
View File

@ -29,7 +29,7 @@
<parent>
<groupId>com.iluwatar</groupId>
<artifactId>java-design-patterns</artifactId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<artifactId>composite</artifactId>
<dependencies>

2
converter/README.md
View File

@ -3,7 +3,7 @@ layout: pattern
title: Converter
folder: converter
permalink: /patterns/converter/
categories:
categories: Business Tier
tags:
- Java
- Difficulty-Beginner

49
converter/etc/converter.urm.puml
View File

@ -1,49 +0,0 @@
@startuml
package com.iluwatar.converter {
class App {
+ App()
+ main(args : String[]) {static}
}
class Converter<T, U> {
- fromDto : Function<T, U>
- fromEntity : Function<U, T>
+ Converter<T, U>(fromDto : Function<T, U>, fromEntity : Function<U, T>)
+ convertFromDto(userDto : T) : U
+ convertFromEntity(user : U) : T
+ createFromDtos(dtoUsers : Collection<T>) : List<U>
+ createFromEntities(users : Collection<U>) : List<T>
}
class User {
- firstName : String
- isActive : boolean
- lastName : String
- userId : String
+ User(firstName : String, lastName : String, isActive : boolean, userId : String)
+ equals(o : Object) : boolean
+ getFirstName() : String
+ getLastName() : String
+ getUserId() : String
+ hashCode() : int
+ isActive() : boolean
+ toString() : String
}
class UserConverter {
+ UserConverter()
}
class UserDto {
- email : String
- firstName : String
- isActive : boolean
- lastName : String
+ UserDto(firstName : String, lastName : String, isActive : boolean, email : String)
+ equals(o : Object) : boolean
+ getEmail() : String
+ getFirstName() : String
+ getLastName() : String
+ hashCode() : int
+ isActive() : boolean
+ toString() : String
}
}
UserConverter --|> Converter
@enduml

2
converter/pom.xml
View File

@ -29,7 +29,7 @@
<parent>
<artifactId>java-design-patterns</artifactId>
<groupId>com.iluwatar</groupId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<dependencies>

5
converter/src/main/java/com/iluwatar/converter/App.java
View File

@ -41,10 +41,7 @@ public class App {
* @param args command line args
*/
public static void main(String[] args) {
Converter<UserDto, User> userConverter = new Converter<>(
userDto -> new User(userDto.getFirstName(), userDto.getLastName(), userDto.isActive(),
userDto.getEmail()),
user -> new UserDto(user.getFirstName(), user.getLastName(), user.isActive(), user.getUserId()));
Converter<UserDto, User> userConverter = new UserConverter();
UserDto dtoUser = new UserDto("John", "Doe", true, "whatever[at]wherever.com");
User user = userConverter.convertFromDto(dtoUser);

4
converter/src/main/java/com/iluwatar/converter/Converter.java
View File

@ -68,7 +68,7 @@ public class Converter<T, U> {
/**
* @param dtoUsers collection of DTO entities
* @return List of domain representation of provided entities retrieved by
* mapping each of them with the convertion function
* mapping each of them with the conversion function
*/
public final List<U> createFromDtos(final Collection<T> dtoUsers) {
return dtoUsers.stream().map(this::convertFromDto).collect(Collectors.toList());
@ -77,7 +77,7 @@ public class Converter<T, U> {
/**
* @param users collection of domain entities
* @return List of domain representation of provided entities retrieved by
* mapping each of them with the convertion function
* mapping each of them with the conversion function
*/
public final List<T> createFromEntities(final Collection<U> users) {
return users.stream().map(this::convertFromEntity).collect(Collectors.toList());

1
cqrs/README.md
View File

@ -3,7 +3,6 @@ layout: pattern
title: CQRS
folder: cqrs
permalink: /patterns/cqrs/
pumlid: 7SPR4a0m3030gt00pR_RH6I8QQFouFgC_TfHb6gkd5Q7FQBx363ub4rYpoMTZKuDrYXqDX37HIuuyCPfPPTDfuuHREhGqBy0NUR0GNzAMYizMtq1
categories: Architectural
tags:
- Java

124
cqrs/etc/cqrs.urm.puml
View File

@ -1,124 +0,0 @@
@startuml
package com.iluwatar.cqrs.util {
class HibernateUtil {
- LOGGER : Logger {static}
- SESSIONFACTORY : SessionFactory {static}
+ HibernateUtil()
- buildSessionFactory() : SessionFactory {static}
+ getSessionFactory() : SessionFactory {static}
}
}
package com.iluwatar.cqrs.app {
class App {
+ App()
+ main(args : String[]) {static}
}
}
package com.iluwatar.cqrs.dto {
class Author {
- email : String
- name : String
- username : String
+ Author()
+ Author(name : String, email : String, username : String)
+ equals(obj : Object) : boolean
+ getEmail() : String
+ getName() : String
+ getUsername() : String
+ hashCode() : int
+ toString() : String
}
class Book {
- price : double
- title : String
+ Book()
+ Book(title : String, price : double)
+ equals(obj : Object) : boolean
+ getPrice() : double
+ getTitle() : String
+ hashCode() : int
+ toString() : String
}
}
package com.iluwatar.cqrs.commandes {
class CommandServiceImpl {
- sessionFactory : SessionFactory
+ CommandServiceImpl()
+ authorCreated(username : String, name : String, email : String)
+ authorEmailUpdated(username : String, email : String)
+ authorNameUpdated(username : String, name : String)
+ authorUsernameUpdated(oldUsername : String, newUsername : String)
+ bookAddedToAuthor(title : String, price : double, username : String)
+ bookPriceUpdated(title : String, price : double)
+ bookTitleUpdated(oldTitle : String, newTitle : String)
- getAuthorByUsername(username : String) : Author
- getBookByTitle(title : String) : Book
}
interface ICommandService {
+ authorCreated(String, String, String) {abstract}
+ authorEmailUpdated(String, String) {abstract}
+ authorNameUpdated(String, String) {abstract}
+ authorUsernameUpdated(String, String) {abstract}
+ bookAddedToAuthor(String, double, String) {abstract}
+ bookPriceUpdated(String, double) {abstract}
+ bookTitleUpdated(String, String) {abstract}
}
}
package com.iluwatar.cqrs.queries {
interface IQueryService {
+ getAuthorBooks(String) : List<Book> {abstract}
+ getAuthorBooksCount(String) : BigInteger {abstract}
+ getAuthorByUsername(String) : Author {abstract}
+ getAuthorsCount() : BigInteger {abstract}
+ getBook(String) : Book {abstract}
}
class QueryServiceImpl {
- sessionFactory : SessionFactory
+ QueryServiceImpl()
+ getAuthorBooks(username : String) : List<Book>
+ getAuthorBooksCount(username : String) : BigInteger
+ getAuthorByUsername(username : String) : Author
+ getAuthorsCount() : BigInteger
+ getBook(title : String) : Book
}
}
package com.iluwatar.cqrs.domain.model {
class Author {
- email : String
- id : long
- name : String
- username : String
# Author()
+ Author(username : String, name : String, email : String)
+ getEmail() : String
+ getId() : long
+ getName() : String
+ getUsername() : String
+ setEmail(email : String)
+ setId(id : long)
+ setName(name : String)
+ setUsername(username : String)
+ toString() : String
}
class Book {
- author : Author
- id : long
- price : double
- title : String
# Book()
+ Book(title : String, price : double, author : Author)
+ getAuthor() : Author
+ getId() : long
+ getPrice() : double
+ getTitle() : String
+ setAuthor(author : Author)
+ setId(id : long)
+ setPrice(price : double)
+ setTitle(title : String)
+ toString() : String
}
}
Book --> "-author" Author
CommandServiceImpl ..|> ICommandService
QueryServiceImpl ..|> IQueryService
@enduml

2
cqrs/pom.xml
View File

@ -21,7 +21,7 @@
<parent>
<groupId>com.iluwatar</groupId>
<artifactId>java-design-patterns</artifactId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<artifactId>cqrs</artifactId>
<dependencies>

1
dao/README.md
View File

@ -3,7 +3,6 @@ layout: pattern
title: Data Access Object
folder: dao
permalink: /patterns/dao/
pumlid: 5SR14OKW30N0LhG0oVrt4o6ZE12Ov4NR_thQNQlc5aN2sd82qtz4naywAixOmyNoK8WYvT6fjdWOR7JnpLiHhuTkam4nTUhiRwZm847-J64zpUZj3m00
categories: Persistence Tier
tags:
- Java

66
dao/etc/dao.urm.puml
View File

@ -1,66 +0,0 @@
@startuml
package com.iluwatar.dao {
class App {
- DB_URL : String {static}
- log : Logger {static}
+ App()
- addCustomers(customerDao : CustomerDao) {static}
- createDataSource() : DataSource {static}
- createSchema(dataSource : DataSource) {static}
- deleteSchema(dataSource : DataSource) {static}
+ generateSampleCustomers() : List<Customer> {static}
+ main(args : String[]) {static}
- performOperationsUsing(customerDao : CustomerDao) {static}
}
class Customer {
- firstName : String
- id : int
- lastName : String
+ Customer(id : int, firstName : String, lastName : String)
+ equals(that : Object) : boolean
+ getFirstName() : String
+ getId() : int
+ getLastName() : String
+ hashCode() : int
+ setFirstName(firstName : String)
+ setId(id : int)
+ setLastName(lastName : String)
+ toString() : String
}
interface CustomerDao {
+ add(Customer) : boolean {abstract}
+ delete(Customer) : boolean {abstract}
+ getAll() : Stream<Customer> {abstract}
+ getById(int) : Optional<Customer> {abstract}
+ update(Customer) : boolean {abstract}
}
class CustomerSchemaSql {
+ CREATE_SCHEMA_SQL : String {static}
+ DELETE_SCHEMA_SQL : String {static}
- CustomerSchemaSql()
}
class DbCustomerDao {
- dataSource : DataSource
+ DbCustomerDao(dataSource : DataSource)
+ add(customer : Customer) : boolean
- createCustomer(resultSet : ResultSet) : Customer
+ delete(customer : Customer) : boolean
+ getAll() : Stream<Customer>
+ getById(id : int) : Optional<Customer>
- getConnection() : Connection
- mutedClose(connection : Connection)
+ update(customer : Customer) : boolean
}
class InMemoryCustomerDao {
- idToCustomer : Map<Integer, Customer>
+ InMemoryCustomerDao()
+ add(customer : Customer) : boolean
+ delete(customer : Customer) : boolean
+ getAll() : Stream<Customer>
+ getById(id : int) : Optional<Customer>
+ update(customer : Customer) : boolean
}
}
DbCustomerDao ..|> CustomerDao
InMemoryCustomerDao ..|> CustomerDao
@enduml

2
dao/pom.xml
View File

@ -30,7 +30,7 @@
<parent>
<groupId>com.iluwatar</groupId>
<artifactId>java-design-patterns</artifactId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<artifactId>dao</artifactId>

43
dao/src/main/java/com/iluwatar/dao/CustomException.java Normal file
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@ -0,0 +1,43 @@
/**
* The MIT License
* Copyright (c) 2014 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.dao;
/**
*
* Custom exception
*
*/
public class CustomException extends Exception {
private static final long serialVersionUID = 1L;
public CustomException() {}
public CustomException(String message) {
super(message);
}
public CustomException(String message, Throwable cause) {
super(message, cause);
}
}

27
dao/src/main/java/com/iluwatar/dao/DbCustomerDao.java
View File

@ -36,12 +36,16 @@ import java.util.stream.StreamSupport;
import javax.sql.DataSource;
import org.apache.log4j.Logger;
/**
* An implementation of {@link CustomerDao} that persists customers in RDBMS.
*
*/
public class DbCustomerDao implements CustomerDao {
private static final Logger LOGGER = Logger.getLogger(DbCustomerDao.class);
private final DataSource dataSource;
/**
@ -79,12 +83,12 @@ public class DbCustomerDao implements CustomerDao {
action.accept(createCustomer(resultSet));
return true;
} catch (SQLException e) {
throw new RuntimeException(e);
throw new RuntimeException(e); // NOSONAR
}
}
}, false).onClose(() -> mutedClose(connection, statement, resultSet));
} catch (SQLException e) {
throw new Exception(e.getMessage(), e);
throw new CustomException(e.getMessage(), e);
}
}
@ -98,7 +102,7 @@ public class DbCustomerDao implements CustomerDao {
statement.close();
connection.close();
} catch (SQLException e) {
e.printStackTrace();
LOGGER.info("Exception thrown " + e.getMessage());
}
}
@ -113,19 +117,26 @@ public class DbCustomerDao implements CustomerDao {
*/
@Override
public Optional<Customer> getById(int id) throws Exception {
ResultSet resultSet = null;
try (Connection connection = getConnection();
PreparedStatement statement =
connection.prepareStatement("SELECT * FROM CUSTOMERS WHERE ID = ?")) {
statement.setInt(1, id);
ResultSet resultSet = statement.executeQuery();
resultSet = statement.executeQuery();
if (resultSet.next()) {
return Optional.of(createCustomer(resultSet));
} else {
return Optional.empty();
}
} catch (SQLException ex) {
throw new Exception(ex.getMessage(), ex);
throw new CustomException(ex.getMessage(), ex);
} finally {
if (resultSet != null) {
resultSet.close();
}
}
}
@ -147,7 +158,7 @@ public class DbCustomerDao implements CustomerDao {
statement.execute();
return true;
} catch (SQLException ex) {
throw new Exception(ex.getMessage(), ex);
throw new CustomException(ex.getMessage(), ex);
}
}
@ -164,7 +175,7 @@ public class DbCustomerDao implements CustomerDao {
statement.setInt(3, customer.getId());
return statement.executeUpdate() > 0;
} catch (SQLException ex) {
throw new Exception(ex.getMessage(), ex);
throw new CustomException(ex.getMessage(), ex);
}
}
@ -179,7 +190,7 @@ public class DbCustomerDao implements CustomerDao {
statement.setInt(1, customer.getId());
return statement.executeUpdate() > 0;
} catch (SQLException ex) {
throw new Exception(ex.getMessage(), ex);
throw new CustomException(ex.getMessage(), ex);
}
}
}

77
data-bus/etc/data-bus.urm.puml
View File

@ -1,77 +0,0 @@
@startuml
package com.iluwatar.databus {
class AbstractDataType {
- dataBus : DataBus
+ AbstractDataType()
+ getDataBus() : DataBus
+ setDataBus(dataBus : DataBus)
}
~class App {
- log : Logger {static}
~ App()
+ main(args : String[]) {static}
}
class DataBus {
- INSTANCE : DataBus {static}
- listeners : Set<Member>
+ DataBus()
+ getInstance() : DataBus {static}
+ publish(event : DataType)
+ subscribe(member : Member)
+ unsubscribe(member : Member)
}
interface DataType {
+ getDataBus() : DataBus {abstract}
+ setDataBus(DataBus) {abstract}
}
interface Member {
+ accept(DataType) {abstract}
}
}
package com.iluwatar.databus.data {
class MessageData {
- message : String
+ MessageData(message : String)
+ getMessage() : String
+ of(message : String) : DataType {static}
}
class StartingData {
- when : LocalDateTime
+ StartingData(when : LocalDateTime)
+ getWhen() : LocalDateTime
+ of(when : LocalDateTime) : DataType {static}
}
class StoppingData {
- when : LocalDateTime
+ StoppingData(when : LocalDateTime)
+ getWhen() : LocalDateTime
+ of(when : LocalDateTime) : DataType {static}
}
}
package com.iluwatar.databus.members {
class CounterMember {
- log : Logger {static}
- name : String
+ CounterMember(name : String)
+ accept(data : DataType)
- handleEvent(data : MessageData)
}
class StatusMember {
- id : int
- log : Logger {static}
+ StatusMember(id : int)
+ accept(data : DataType)
- handleEvent(data : StartingData)
- handleEvent(data : StoppingData)
}
}
AbstractDataType --> "-dataBus" DataBus
DataBus --> "-INSTANCE" DataBus
DataBus --> "-listeners" Member
AbstractDataType ..|> DataType
MessageData --|> AbstractDataType
StartingData --|> AbstractDataType
StoppingData --|> AbstractDataType
CounterMember ..|> Member
StatusMember ..|> Member
@enduml

2
data-bus/pom.xml
View File

@ -33,7 +33,7 @@
<parent>
<groupId>com.iluwatar</groupId>
<artifactId>java-design-patterns</artifactId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<artifactId>data-bus</artifactId>
<dependencies>

1
data-mapper/README.md
View File

@ -3,7 +3,6 @@ layout: pattern
title: Data Mapper
folder: data-mapper
permalink: /patterns/data-mapper/
pumlid: JShB3OGm303HLg20nFVjnYGM1CN6ycTfVtFSsnjfzY5jPgUqkLqHwXy0mxUU8wuyqidQ8q4IjJqCO-QBWGOtVh5qyd5AKOmW4mT6Nu2-ZiAekapH_hkcSTNa-GC0
categories: Persistence Tier
tags:
- Java

42
data-mapper/etc/data-mapper.urm.puml
View File

@ -1,42 +0,0 @@
@startuml
package com.iluwatar.datamapper {
class App {
- log : Logger {static}
- App()
+ main(args : String[]) {static}
}
class Student {
- grade : char
- name : String
- serialVersionUID : long {static}
- studentId : int
+ Student(studentId : int, name : String, grade : char)
+ equals(inputObject : Object) : boolean
+ getGrade() : char
+ getName() : String
+ getStudentId() : int
+ hashCode() : int
+ setGrade(grade : char)
+ setName(name : String)
+ setStudentId(studentId : int)
+ toString() : String
}
interface StudentDataMapper {
+ delete(Student) {abstract}
+ find(int) : Optional<Student> {abstract}
+ insert(Student) {abstract}
+ update(Student) {abstract}
}
class StudentDataMapperImpl {
- students : List<Student>
+ StudentDataMapperImpl()
+ delete(studentToBeDeleted : Student)
+ find(studentId : int) : Optional<Student>
+ getStudents() : List<Student>
+ insert(studentToBeInserted : Student)
+ update(studentToBeUpdated : Student)
}
}
StudentDataMapperImpl --> "-students" Student
StudentDataMapperImpl ..|> StudentDataMapper
@enduml

2
data-mapper/pom.xml
View File

@ -28,7 +28,7 @@
<parent>
<groupId>com.iluwatar</groupId>
<artifactId>java-design-patterns</artifactId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<artifactId>data-mapper</artifactId>
<dependencies>

1
data-transfer-object/README.md
View File

@ -3,7 +3,6 @@ layout: pattern
title: Data Transfer Object
folder: data-transfer-object
permalink: /patterns/data-transfer-object/
pumlid: RSh14SCW30NHLk82GFTq8uDYum71I5zn-t41kUtCswrfwL4bhBzEOFcRoFZEHyCPUxXOcGfHv387jHutWuqk_dAguktGj1WGKwV1_WJLvqWmLl-8fRbVKa22yXTosCWhHly1
categories: Architectural
tags:
- Java

26
data-transfer-object/etc/data-transfer-object.urm.puml
View File

@ -1,26 +0,0 @@
@startuml
package com.iluwatar.datatransfer {
class CustomerClientApp {
+ CustomerClientApp()
+ main(args : String[]) {static}
- printCustomerDetails(allCustomers : List<CustomerDto>) {static}
}
class CustomerDto {
- firstName : String
- id : String
- lastName : String
+ CustomerDto(id : String, firstName : String, lastName : String)
+ getFirstName() : String
+ getId() : String
+ getLastName() : String
}
class CustomerResource {
- customers : List<CustomerDto>
+ CustomerResource(customers : List<CustomerDto>)
+ delete(customerId : String)
+ getAllCustomers() : List<CustomerDto>
+ save(customer : CustomerDto)
}
}
CustomerResource --> "-customers" CustomerDto
@enduml

2
data-transfer-object/pom.xml
View File

@ -28,7 +28,7 @@
<parent>
<groupId>com.iluwatar</groupId>
<artifactId>java-design-patterns</artifactId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<artifactId>data-transfer-object</artifactId>
<dependencies>

9
decorator/README.md
View File

@ -3,7 +3,6 @@ layout: pattern
title: Decorator
folder: decorator
permalink: /patterns/decorator/
pumlid: HSV14SCm20J0Lk82BFxf1YF6LaP26ZZizfDVVhjRC-bPDRs_Bc35cyZvAMV3bKU6kao36ehCGQtdms2d3z-yLursshuOKBUWmV43LPNfZEcaaFzA-YWhH_y2
categories: Structural
tags:
- Java
@ -35,7 +34,7 @@ Wikipedia says
**Programmatic Example**
Lets take the troll example. First of all we have a simple troll implementing the troll interface
Let's take the troll example. First of all we have a simple troll implementing the troll interface
```
public interface Troll {
@ -105,9 +104,9 @@ troll.attack(); // The troll tries to grab you!
troll.fleeBattle(); // The troll shrieks in horror and runs away!
// change the behavior of the simple troll by adding a decorator
Troll clubbed = new ClubbedTroll(troll);
clubbed.attack(); // The troll tries to grab you! The troll swings at you with a club!
clubbed.fleeBattle(); // The troll shrieks in horror and runs away!
troll = new ClubbedTroll(troll);
troll.attack(); // The troll tries to grab you! The troll swings at you with a club!
troll.fleeBattle(); // The troll shrieks in horror and runs away!
```
## Applicability

2
decorator/pom.xml
View File

@ -29,7 +29,7 @@
<parent>
<groupId>com.iluwatar</groupId>
<artifactId>java-design-patterns</artifactId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<artifactId>decorator</artifactId>
<dependencies>

8
decorator/src/main/java/com/iluwatar/decorator/App.java
View File

@ -57,9 +57,9 @@ public class App {
// change the behavior of the simple troll by adding a decorator
LOGGER.info("A troll with huge club surprises you.");
Troll clubbed = new ClubbedTroll(troll);
clubbed.attack();
clubbed.fleeBattle();
LOGGER.info("Clubbed troll power {}.\n", clubbed.getAttackPower());
troll = new ClubbedTroll(troll);
troll.attack();
troll.fleeBattle();
LOGGER.info("Clubbed troll power {}.\n", troll.getAttackPower());
}
}

1
delegation/README.md
View File

@ -3,7 +3,6 @@ layout: pattern
title: Delegation
folder: delegation
permalink: /patterns/delegation/
pumlid: JSV14GCX20NGLf82LkxfXbN69OFeu2VRVdBCxRsdUhLiac6F2rZxHHHybwwuyimjKQT37ANEGMfvCpZepHy-ccpjVYm697pJuFq3DJ7f39rEWlhNaZ7Aoc5V
categories: Behavioral
tags:
- Java

39
delegation/etc/delegation.urm.puml
View File

@ -1,39 +0,0 @@
@startuml
package com.iluwatar.delegation.simple.printers {
class CanonPrinter {
- LOGGER : Logger {static}
+ CanonPrinter()
+ print(message : String)
}
class EpsonPrinter {
- LOGGER : Logger {static}
+ EpsonPrinter()
+ print(message : String)
}
class HpPrinter {
- LOGGER : Logger {static}
+ HpPrinter()
+ print(message : String)
}
}
package com.iluwatar.delegation.simple {
class App {
+ MESSAGE_TO_PRINT : String {static}
+ App()
+ main(args : String[]) {static}
}
interface Printer {
+ print(String) {abstract}
}
class PrinterController {
- printer : Printer
+ PrinterController(printer : Printer)
+ print(message : String)
}
}
PrinterController --> "-printer" Printer
PrinterController ..|> Printer
CanonPrinter ..|> Printer
EpsonPrinter ..|> Printer
HpPrinter ..|> Printer
@enduml

2
delegation/pom.xml
View File

@ -30,7 +30,7 @@
<parent>
<artifactId>java-design-patterns</artifactId>
<groupId>com.iluwatar</groupId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>

1
dependency-injection/README.md
View File

@ -3,7 +3,6 @@ layout: pattern
title: Dependency Injection
folder: dependency-injection
permalink: /patterns/dependency-injection/
pumlid: RSdB3SCW303GLPe1mFTkunWhSGG6-PEesxS3zFQajubIpyPf_NL6B7y363xra3XpJsUZgS4QbUO0wVbWeC65DvR6BeUMXH5iwZ3GVu36YxMnqgU8NamXKu63_aPD6tNbw5y0
categories: Behavioral
tags:
- Java

49
dependency-injection/etc/dependency-injection.urm.puml
View File

@ -1,49 +0,0 @@
@startuml
package com.iluwatar.dependency.injection {
class AdvancedWizard {
- tobacco : Tobacco
+ AdvancedWizard(tobacco : Tobacco)
+ smoke()
}
class App {
+ App()
+ main(args : String[]) {static}
}
class GuiceWizard {
- tobacco : Tobacco
+ GuiceWizard(tobacco : Tobacco)
+ smoke()
}
class OldTobyTobacco {
+ OldTobyTobacco()
}
class RivendellTobacco {
+ RivendellTobacco()
}
class SecondBreakfastTobacco {
+ SecondBreakfastTobacco()
}
class SimpleWizard {
- tobacco : OldTobyTobacco
+ SimpleWizard()
+ smoke()
}
abstract class Tobacco {
- LOGGER : Logger {static}
+ Tobacco()
+ smoke(wizard : Wizard)
}
interface Wizard {
+ smoke() {abstract}
}
}
SimpleWizard --> "-tobacco" OldTobyTobacco
AdvancedWizard --> "-tobacco" Tobacco
GuiceWizard --> "-tobacco" Tobacco
AdvancedWizard ..|> Wizard
GuiceWizard ..|> Wizard
OldTobyTobacco --|> Tobacco
RivendellTobacco --|> Tobacco
SecondBreakfastTobacco --|> Tobacco
SimpleWizard ..|> Wizard
@enduml

2
dependency-injection/pom.xml
View File

@ -29,7 +29,7 @@
<parent>
<groupId>com.iluwatar</groupId>
<artifactId>java-design-patterns</artifactId>
<version>1.17.0-SNAPSHOT</version>
<version>1.18.0-SNAPSHOT</version>
</parent>
<artifactId>dependency-injection</artifactId>
<dependencies>

1
double-checked-locking/README.md
View File

@ -3,7 +3,6 @@ layout: pattern
title: Double Checked Locking
folder: double-checked-locking
permalink: /patterns/double-checked-locking/
pumlid: TSdH4SCW203GLTe1bFzkGv1J6qGFeLc_MI1_x-wzkv94uJ1vDVUrFm26LwxTMnonsMYgitgcEQ1BNEXeyCKVfiAxLqqBtTbqmy1z0ygCGpXHOpgv99bqTgt0JW-LmqPUCUGF
categories: Concurrency
tags:
- Java

22
double-checked-locking/etc/double-checked-locking.urm.puml
View File

@ -1,22 +0,0 @@
@startuml
package com.iluwatar.doublechecked.locking {
class App {
- LOGGER : Logger {static}
+ App()
+ main(args : String[]) {static}
}
class Inventory {
- LOGGER : Logger {static}
- inventorySize : int
- items : List<Item>
- lock : Lock
+ Inventory(inventorySize : int)
+ addItem(item : Item) : boolean
+ getItems() : List<Item>
}
class Item {
+ Item()
}
}
Inventory --> "-items" Item
@enduml

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