Achieved milestone 1.10.0

Feature Toogle PR

.travis.yml

@@ -1,20 +1,18 @@
 language: java
-
 jdk:
-  - oraclejdk8
+- oraclejdk8
 
 env:
   global:
   - GH_REF: github.com/iluwatar/java-design-patterns.git
-  - secure: "LxTDuNS/rBWIvKkaEqr79ImZAe48mCdoYCF41coxNXgNoippo4GIBArknqtv+XvdkiuRZ1yGyj6pn8GU33c/yn+krddTUkVCwTbVatbalW5jhQjDbHYym/JcxaK9ZS/3JTeGcWrBgiPqHEEDhCf26vPZsXoMSeVCEORVKTp1BSg="
-
-before_install:
-  - "export DISPLAY=:99.0"
-  - "sh -e /etc/init.d/xvfb start"
+  - secure: LxTDuNS/rBWIvKkaEqr79ImZAe48mCdoYCF41coxNXgNoippo4GIBArknqtv+XvdkiuRZ1yGyj6pn8GU33c/yn+krddTUkVCwTbVatbalW5jhQjDbHYym/JcxaK9ZS/3JTeGcWrBgiPqHEEDhCf26vPZsXoMSeVCEORVKTp1BSg=
   
-after_success:
-  - mvn clean test jacoco:report coveralls:report
-  - bash update-ghpages.sh
+before_install:
+- export DISPLAY=:99.0
+- sh -e /etc/init.d/xvfb start
+
+after_success:
+- mvn clean test jacoco:report coveralls:report
+- bash update-ghpages.sh
 
-# Migration to container-based infrastructure  
 sudo: false

CODE_COVERAGE.md

@@ -0,0 +1,13 @@
+# Code Coverage Report generation
+
+To generate the code coverage report, execute the following command:
+> mvn clean verify
+
+This will generate code coverage report in each of the modules. In order to view the same, open the following file in your browser.
+> target/site/jacoco/index.html 
+
+Please note that the above folder is created under each of the modules. For example:
+* adapter/target/site/jacoco/index.html 
+* busniess-delegate/target/site/jacoco/index.html 
+
+

CONTRIBUTING.MD

@@ -0,0 +1,4 @@
+This is great you have something to contribute! 
+
+Before going any further please read the [wiki](https://github.com/iluwatar/java-design-patterns/wiki)
+with conventions and rules we used for this project.

README.md

@@ -2,11 +2,10 @@
      that smart and dearly wants an empty line before a heading to be able to
      display it as such, e.g. website) -->
 
-# Design pattern samples in Java
+# Design patterns implemented in Java
 
 [![Build status](https://travis-ci.org/iluwatar/java-design-patterns.svg?branch=master)](https://travis-ci.org/iluwatar/java-design-patterns)
 [![Coverage Status](https://coveralls.io/repos/iluwatar/java-design-patterns/badge.svg?branch=master)](https://coveralls.io/r/iluwatar/java-design-patterns?branch=master)
-[![Coverity Scan Build Status](https://scan.coverity.com/projects/5634/badge.svg)](https://scan.coverity.com/projects/5634)
 [![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)
 
 # Introduction
@@ -23,10 +22,16 @@ are familiar with the patterns.
 
 # Getting started
 
-Before you dive into the material, you should be familiar with various 
-[Programming/Software Design Principles](http://webpro.github.io/programming-principles/). 
+Before you dive into the material, you should be familiar with various
+[Programming/Software Design Principles](http://webpro.github.io/programming-principles/).
 
-Once you are familiar with these concepts you can start drilling down into patterns by any of the following approaches
+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
 
  - Using difficulty tags, `Difficulty-Beginner`, `Difficulty-Intermediate` & `Difficulty-Expert`.
  - Using pattern categories, `Creational`, `Behavioral` and others.
@@ -34,21 +39,7 @@ Once you are familiar with these concepts you can start drilling down into patte
 
 # How to contribute
 
-If you are willing to contribute to the project you will find the relevant information in our [developer wiki](https://github.com/iluwatar/java-design-patterns/wiki).
-
-# Credits
-
-* [Design Patterns: Elements of Reusable Object-Oriented Software](http://www.amazon.com/Design-Patterns-Elements-Reusable-Object-Oriented/dp/0201633612)
-* [Effective Java (2nd Edition)](http://www.amazon.com/Effective-Java-Edition-Joshua-Bloch/dp/0321356683)
-* [Java Generics and Collections](http://www.amazon.com/Java-Generics-Collections-Maurice-Naftalin/dp/0596527756/)
-* [Let's Modify the Objects-First Approach into Design-Patterns-First](http://edu.pecinovsky.cz/papers/2006_ITiCSE_Design_Patterns_First.pdf)
-* [Pattern Languages of Program Design](http://www.amazon.com/Pattern-Languages-Program-Design-Coplien/dp/0201607344/ref=sr_1_1)
-* [Presentation Tier Patterns](http://www.javagyan.com/tutorials/corej2eepatterns/presentation-tier-patterns)
-* [Functional Programming in Java: Harnessing the Power of Java 8 Lambda Expressions](http://www.amazon.com/Functional-Programming-Java-Harnessing-Expressions/dp/1937785467/ref=sr_1_1)
-* [Patterns of Enterprise Application Architecture](http://www.amazon.com/Patterns-Enterprise-Application-Architecture-Martin/dp/0321127420)
-* [Spring Data](http://www.amazon.com/Spring-Data-Mark-Pollack/dp/1449323952/ref=sr_1_1)
-* [J2EE Design Patterns](http://www.amazon.com/J2EE-Design-Patterns-William-Crawford/dp/0596004273/ref=sr_1_2)
-* [Pattern Oriented Software Architecture Vol I-V](http://www.amazon.com/Pattern-Oriented-Software-Architecture-Volume-Patterns/dp/0471958697)
+If you are willing to contribute to the project you will find the relevant information in our [developer wiki](https://github.com/iluwatar/java-design-patterns/wiki). We will help you and answer your questions in the [Gitter chatroom](https://gitter.im/iluwatar/java-design-patterns).
 
 # License
 

abstract-factory/index.md

@@ -4,21 +4,33 @@ title: Abstract Factory
 folder: abstract-factory
 permalink: /patterns/abstract-factory/
 categories: Creational
-tags: Java
+tags: 
+ - Java
+ - Gang Of Four
+ - Difficulty-Intermediate
 ---
 
-**Intent:** Provide an interface for creating families of related or dependent
+## Also known as
+Kit
+
+## Intent
+Provide an interface for creating families of related or dependent
 objects without specifying their concrete classes.
 
 ![alt text](./etc/abstract-factory_1.png "Abstract Factory")
 
-**Applicability:** Use the Abstract Factory pattern when
+## 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
 
-**Real world examples:**
+## Real world examples
 
 * [javax.xml.parsers.DocumentBuilderFactory](http://docs.oracle.com/javase/8/docs/api/javax/xml/parsers/DocumentBuilderFactory.html)
+
+## Credits
+
+* [Design Patterns: Elements of Reusable Object-Oriented Software](http://www.amazon.com/Design-Patterns-Elements-Reusable-Object-Oriented/dp/0201633612)

abstract-factory/pom.xml

@@ -1,19 +1,42 @@
 <?xml version="1.0"?>
-<project
-	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
-	xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
-	<modelVersion>4.0.0</modelVersion>
-	<parent>
-		<groupId>com.iluwatar</groupId>
-		<artifactId>java-design-patterns</artifactId>
-		<version>1.6.0</version>
-	</parent>
-	<artifactId>abstract-factory</artifactId>
-	<dependencies>
-		<dependency>
-			<groupId>junit</groupId>
-			<artifactId>junit</artifactId>
-			<scope>test</scope>
-		</dependency>
-	</dependencies>
+<!--
+
+    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.
+
+-->
+<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>com.iluwatar</groupId>
+    <artifactId>java-design-patterns</artifactId>
+    <version>1.10.0</version>
+  </parent>
+  <artifactId>abstract-factory</artifactId>
+  <dependencies>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
 </project>

abstract-factory/src/main/java/com/iluwatar/abstractfactory/App.java

@@ -1,73 +1,127 @@
+/**
+ * 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.abstractfactory;
 
-
 /**
  * 
- * The essence of the Abstract Factory pattern is a factory interface
- * ({@link KingdomFactory}) and its implementations ({@link ElfKingdomFactory},
- * {@link OrcKingdomFactory}).
+ * The Abstract Factory pattern provides a way to encapsulate a group of individual factories that have a common theme
+ * without specifying their concrete classes. In normal usage, the client software creates a concrete implementation of
+ * the abstract factory and then uses the generic interface of the factory to create the concrete objects that are part
+ * of the theme. The client does not know (or care) which concrete objects it gets from each of these internal
+ * factories, since it uses only the generic interfaces of their products. This pattern separates the details of
+ * implementation of a set of objects from their general usage and relies on object composition, as object creation is
+ * implemented in methods exposed in the factory interface.
  * <p>
- * The example uses both concrete implementations to create a king, a castle and
- * an army.
+ * The essence of the Abstract Factory pattern is a factory interface ({@link KingdomFactory}) and its implementations (
+ * {@link ElfKingdomFactory}, {@link OrcKingdomFactory}). The example uses both concrete implementations to create a
+ * king, a castle and an army.
  * 
  */
 public class App {
 
-	private King king;
-	private Castle castle;
-	private Army army;
+  private King king;
+  private Castle castle;
+  private Army army;
+
+  /**
+   * Creates kingdom
+   */
+  public void createKingdom(final KingdomFactory factory) {
+    setKing(factory.createKing());
+    setCastle(factory.createCastle());
+    setArmy(factory.createArmy());
+  }
+
+  ElfKingdomFactory getElfKingdomFactory() {
+    return new ElfKingdomFactory();
+  }
+
+  OrcKingdomFactory getOrcKingdomFactory() {
+    return new OrcKingdomFactory();
+  }
+
+  King getKing(final KingdomFactory factory) {
+    return factory.createKing();
+  }
+
+  public King getKing() {
+    return king;
+  }
+
+  private void setKing(final King king) {
+    this.king = king;
+  }
+  
+  Castle getCastle(final KingdomFactory factory) {
+    return factory.createCastle();
+  }
+
+  public Castle getCastle() {
+    return castle;
+  }
+
+  private void setCastle(final Castle castle) {
+    this.castle = castle;
+  }
+  
+  Army getArmy(final KingdomFactory factory) {
+    return factory.createArmy();
+  }
+
+  public Army getArmy() {
+    return army;
+  }
+
+  private void setArmy(final Army army) {
+    this.army = army;
+  }
+  
+  /**
+   * Program entry point
+   * 
+   * @param args
+   *          command line args
+   */
+  public static void main(String[] args) {
+
+    App app = new App();
+
+    System.out.println("Elf Kingdom");
+    KingdomFactory elfKingdomFactory;
+    elfKingdomFactory = app.getElfKingdomFactory();
+    app.createKingdom(elfKingdomFactory);
+    System.out.println(app.getArmy().getDescription());
+    System.out.println(app.getCastle().getDescription());
+    System.out.println(app.getKing().getDescription());
+
+    System.out.println("\nOrc Kingdom");
+    KingdomFactory orcKingdomFactory;
+    orcKingdomFactory = app.getOrcKingdomFactory();
+    app.createKingdom(orcKingdomFactory);
+    System.out.println(app.getArmy().getDescription());
+    System.out.println(app.getCastle().getDescription());
+    System.out.println(app.getKing().getDescription());
+
+  }
 
-	/**
-	 * Creates kingdom
-	 * @param factory
-	 */
-	public void createKingdom(final KingdomFactory factory) {
-		setKing(factory.createKing());
-		setCastle(factory.createCastle());
-		setArmy(factory.createArmy());
-	}
-	
-	ElfKingdomFactory getElfKingdomFactory() {
-		return new ElfKingdomFactory();
-	}
-	
-	OrcKingdomFactory getOrcKingdomFactory() {
-		return new OrcKingdomFactory();
-	}
-	
-	King getKing(final KingdomFactory factory) {
-		return factory.createKing();
-	}
-	
-	Castle getCastle(final KingdomFactory factory) {
-		return factory.createCastle();
-	}
-	
-	Army getArmy(final KingdomFactory factory) {
-		return factory.createArmy();
-	}
-	
-	public King getKing() {
-		return king;
-	}
-	
-	private void setKing(final King king) {
-		this.king = king;
-	}
-	
-	public Castle getCastle() {
-		return castle;
-	}
-	
-	private void setCastle(final Castle castle) {
-		this.castle = castle;
-	}
-	
-	public Army getArmy() {
-		return army;
-	}
-	
-	private void setArmy(final Army army) {
-		this.army = army;
-	}
 }

abstract-factory/src/main/java/com/iluwatar/abstractfactory/Army.java

@@ -1,3 +1,25 @@
+/**
+ * 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.abstractfactory;
 
 /**
@@ -7,5 +29,5 @@ package com.iluwatar.abstractfactory;
  */
 public interface Army {
 
-	String getDescription();
+  String getDescription();
 }

abstract-factory/src/main/java/com/iluwatar/abstractfactory/Castle.java

@@ -1,3 +1,25 @@
+/**
+ * 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.abstractfactory;
 
 /**
@@ -7,5 +29,5 @@ package com.iluwatar.abstractfactory;
  */
 public interface Castle {
 
-	String getDescription();
+  String getDescription();
 }

abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfArmy.java

@@ -1,3 +1,25 @@
+/**
+ * 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.abstractfactory;
 
 /**
@@ -7,10 +29,10 @@ package com.iluwatar.abstractfactory;
  */
 public class ElfArmy implements Army {
 
-	static final String DESCRIPTION = "This is the Elven Army!";
+  static final String DESCRIPTION = "This is the Elven Army!";
 
-	@Override
-	public String getDescription() {
-		return DESCRIPTION;
-	}
+  @Override
+  public String getDescription() {
+    return DESCRIPTION;
+  }
 }

abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfCastle.java

@@ -1,3 +1,25 @@
+/**
+ * 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.abstractfactory;
 
 /**
@@ -7,10 +29,10 @@ package com.iluwatar.abstractfactory;
  */
 public class ElfCastle implements Castle {
 
-	static final String DESCRIPTION = "This is the Elven castle!";
+  static final String DESCRIPTION = "This is the Elven castle!";
 
-	@Override
-	public String getDescription() {
-		return DESCRIPTION;
-	}
+  @Override
+  public String getDescription() {
+    return DESCRIPTION;
+  }
 }

abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfKing.java

@@ -1,3 +1,25 @@
+/**
+ * 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.abstractfactory;
 
 /**
@@ -7,10 +29,10 @@ package com.iluwatar.abstractfactory;
  */
 public class ElfKing implements King {
 
-	static final String DESCRIPTION = "This is the Elven king!";
-	
-	@Override
-	public String getDescription() {
-		return DESCRIPTION;
-	}
+  static final String DESCRIPTION = "This is the Elven king!";
+
+  @Override
+  public String getDescription() {
+    return DESCRIPTION;
+  }
 }

abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfKingdomFactory.java

@@ -1,3 +1,25 @@
+/**
+ * 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.abstractfactory;
 
 /**
@@ -7,16 +29,16 @@ package com.iluwatar.abstractfactory;
  */
 public class ElfKingdomFactory implements KingdomFactory {
 
-	public Castle createCastle() {
-		return new ElfCastle();
-	}
+  public Castle createCastle() {
+    return new ElfCastle();
+  }
 
-	public King createKing() {
-		return new ElfKing();
-	}
+  public King createKing() {
+    return new ElfKing();
+  }
 
-	public Army createArmy() {
-		return new ElfArmy();
-	}
+  public Army createArmy() {
+    return new ElfArmy();
+  }
 
 }

abstract-factory/src/main/java/com/iluwatar/abstractfactory/King.java

@@ -1,3 +1,25 @@
+/**
+ * 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.abstractfactory;
 
 /**
@@ -7,5 +29,5 @@ package com.iluwatar.abstractfactory;
  */
 public interface King {
 
-	String getDescription();
+  String getDescription();
 }

abstract-factory/src/main/java/com/iluwatar/abstractfactory/KingdomFactory.java

@@ -1,3 +1,25 @@
+/**
+ * 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.abstractfactory;
 
 /**
@@ -7,10 +29,10 @@ package com.iluwatar.abstractfactory;
  */
 public interface KingdomFactory {
 
-	Castle createCastle();
+  Castle createCastle();
 
-	King createKing();
+  King createKing();
 
-	Army createArmy();
+  Army createArmy();
 
 }

abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcArmy.java

@@ -1,3 +1,25 @@
+/**
+ * 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.abstractfactory;
 
 /**
@@ -7,10 +29,10 @@ package com.iluwatar.abstractfactory;
  */
 public class OrcArmy implements Army {
 
-	static final String DESCRIPTION = "This is the Orc Army!";
+  static final String DESCRIPTION = "This is the Orc Army!";
 
-	@Override
-	public String getDescription() {
-		return DESCRIPTION;
-	}
+  @Override
+  public String getDescription() {
+    return DESCRIPTION;
+  }
 }

abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcCastle.java

@@ -1,3 +1,25 @@
+/**
+ * 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.abstractfactory;
 
 /**
@@ -7,10 +29,10 @@ package com.iluwatar.abstractfactory;
  */
 public class OrcCastle implements Castle {
 
-	static final String DESCRIPTION = "This is the Orc castle!";
+  static final String DESCRIPTION = "This is the Orc castle!";
 
-	@Override
-	public String getDescription() {
-		return DESCRIPTION;
-	}
+  @Override
+  public String getDescription() {
+    return DESCRIPTION;
+  }
 }

abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcKing.java

@@ -1,3 +1,25 @@
+/**
+ * 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.abstractfactory;
 
 /**
@@ -7,10 +29,10 @@ package com.iluwatar.abstractfactory;
  */
 public class OrcKing implements King {
 
-static final String DESCRIPTION = "This is the Orc king!";
-	
-	@Override
-	public String getDescription() {
-		return DESCRIPTION;
-	}
+  static final String DESCRIPTION = "This is the Orc king!";
+
+  @Override
+  public String getDescription() {
+    return DESCRIPTION;
+  }
 }

abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcKingdomFactory.java

@@ -1,3 +1,25 @@
+/**
+ * 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.abstractfactory;
 
 /**
@@ -7,16 +29,15 @@ package com.iluwatar.abstractfactory;
  */
 public class OrcKingdomFactory implements KingdomFactory {
 
-	public Castle createCastle() {
-		return new OrcCastle();
-	}
+  public Castle createCastle() {
+    return new OrcCastle();
+  }
 
-	public King createKing() {
-		return new OrcKing();
-	}
-
-	public Army createArmy() {
-		return new OrcArmy();
-	}
+  public King createKing() {
+    return new OrcKing();
+  }
 
+  public Army createArmy() {
+    return new OrcArmy();
+  }
 }

abstract-factory/src/test/java/com/iluwatar/abstractfactory/AbstractFactoryTest.java

@@ -0,0 +1,100 @@
+/**
+ * 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.abstractfactory;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Before;
+import org.junit.Test;
+
+public class AbstractFactoryTest {
+
+  private App app = new App();
+  private KingdomFactory elfFactory;
+  private KingdomFactory orcFactory;
+
+  @Before
+  public void setUp() {
+    elfFactory = app.getElfKingdomFactory();
+    orcFactory = app.getOrcKingdomFactory();
+  }
+
+  @Test
+  public void king() {
+    final King elfKing = app.getKing(elfFactory);
+    assertTrue(elfKing instanceof ElfKing);
+    assertEquals(ElfKing.DESCRIPTION, elfKing.getDescription());
+    final King orcKing = app.getKing(orcFactory);
+    assertTrue(orcKing instanceof OrcKing);
+    assertEquals(OrcKing.DESCRIPTION, orcKing.getDescription());
+  }
+
+  @Test
+  public void castle() {
+    final Castle elfCastle = app.getCastle(elfFactory);
+    assertTrue(elfCastle instanceof ElfCastle);
+    assertEquals(ElfCastle.DESCRIPTION, elfCastle.getDescription());
+    final Castle orcCastle = app.getCastle(orcFactory);
+    assertTrue(orcCastle instanceof OrcCastle);
+    assertEquals(OrcCastle.DESCRIPTION, orcCastle.getDescription());
+  }
+
+  @Test
+  public void army() {
+    final Army elfArmy = app.getArmy(elfFactory);
+    assertTrue(elfArmy instanceof ElfArmy);
+    assertEquals(ElfArmy.DESCRIPTION, elfArmy.getDescription());
+    final Army orcArmy = app.getArmy(orcFactory);
+    assertTrue(orcArmy instanceof OrcArmy);
+    assertEquals(OrcArmy.DESCRIPTION, orcArmy.getDescription());
+  }
+
+  @Test
+  public void createElfKingdom() {
+    app.createKingdom(elfFactory);
+    final King king = app.getKing();
+    final Castle castle = app.getCastle();
+    final Army army = app.getArmy();
+    assertTrue(king instanceof ElfKing);
+    assertEquals(ElfKing.DESCRIPTION, king.getDescription());
+    assertTrue(castle instanceof ElfCastle);
+    assertEquals(ElfCastle.DESCRIPTION, castle.getDescription());
+    assertTrue(army instanceof ElfArmy);
+    assertEquals(ElfArmy.DESCRIPTION, army.getDescription());
+  }
+
+  @Test
+  public void createOrcKingdom() {
+    app.createKingdom(orcFactory);
+    final King king = app.getKing();
+    final Castle castle = app.getCastle();
+    final Army army = app.getArmy();
+    assertTrue(king instanceof OrcKing);
+    assertEquals(OrcKing.DESCRIPTION, king.getDescription());
+    assertTrue(castle instanceof OrcCastle);
+    assertEquals(OrcCastle.DESCRIPTION, castle.getDescription());
+    assertTrue(army instanceof OrcArmy);
+    assertEquals(OrcArmy.DESCRIPTION, army.getDescription());
+  }
+}

abstract-factory/src/test/java/com/iluwatar/abstractfactory/AppTest.java

@@ -1,77 +1,38 @@
+/**
+ * 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.abstractfactory;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
 
-import org.junit.Before;
 import org.junit.Test;
 
-public class AppTest {
+import java.io.IOException;
 
-	private App app = new App();;
-	private KingdomFactory elfFactory;
-	private KingdomFactory orcFactory;
-	
-	@Before
-	public void setUp() {
-		elfFactory = app.getElfKingdomFactory();
-		orcFactory = app.getOrcKingdomFactory();
-	}
-	
-	@Test
-	public void king() {
-		final King elfKing = app.getKing(elfFactory);
-		assertTrue(elfKing instanceof ElfKing);
-		assertEquals(ElfKing.DESCRIPTION, elfKing.getDescription());
-		final King orcKing = app.getKing(orcFactory);
-		assertTrue(orcKing instanceof OrcKing);
-		assertEquals(OrcKing.DESCRIPTION, orcKing.getDescription());
-	}
-	
-	@Test
-	public void castle() {
-		final Castle elfCastle = app.getCastle(elfFactory);
-		assertTrue(elfCastle instanceof ElfCastle);
-		assertEquals(ElfCastle.DESCRIPTION, elfCastle.getDescription());
-		final Castle orcCastle = app.getCastle(orcFactory);
-		assertTrue(orcCastle instanceof OrcCastle);
-		assertEquals(OrcCastle.DESCRIPTION, orcCastle.getDescription());
-	}
-	
-	@Test
-	public void army() {
-		final Army elfArmy = app.getArmy(elfFactory);
-		assertTrue(elfArmy instanceof ElfArmy);
-		assertEquals(ElfArmy.DESCRIPTION, elfArmy.getDescription());
-		final Army orcArmy = app.getArmy(orcFactory);
-		assertTrue(orcArmy instanceof OrcArmy);
-		assertEquals(OrcArmy.DESCRIPTION, orcArmy.getDescription());
-	}
-	
-	@Test
-	public void createElfKingdom() {
-		app.createKingdom(elfFactory);
-		final King king = app.getKing();
-		final Castle castle = app.getCastle();
-		final Army army = app.getArmy();
-		assertTrue(king instanceof ElfKing);
-		assertEquals(ElfKing.DESCRIPTION, king.getDescription());
-		assertTrue(castle instanceof ElfCastle);
-		assertEquals(ElfCastle.DESCRIPTION, castle.getDescription());
-		assertTrue(army instanceof ElfArmy);
-		assertEquals(ElfArmy.DESCRIPTION, army.getDescription());
-	}
-	
-	@Test
-	public void createOrcKingdom() {
-		app.createKingdom(orcFactory);
-		final King king = app.getKing();
-		final Castle castle = app.getCastle();
-		final Army army = app.getArmy();
-		assertTrue(king instanceof OrcKing);
-		assertEquals(OrcKing.DESCRIPTION, king.getDescription());
-		assertTrue(castle instanceof OrcCastle);
-		assertEquals(OrcCastle.DESCRIPTION, castle.getDescription());
-		assertTrue(army instanceof OrcArmy);
-		assertEquals(OrcArmy.DESCRIPTION, army.getDescription());
-	}
+/**
+ * Tests that Abstract Factory example runs without errors.
+ */
+public class AppTest {
+  @Test
+  public void test() throws IOException {
+    String[] args = {};
+    App.main(args);
+  }
 }

adapter/etc/adapter.ucls

@@ -1,61 +1,61 @@
 <?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.adapter.GnomeEngineeringManager" project="adapter" 
-    file="/adapter/src/main/java/com/iluwatar/adapter/GnomeEngineeringManager.java" binary="false" corner="BOTTOM_RIGHT">    
-    <position height="106" width="224" x="110" y="210"/>    
+<class-diagram version="1.1.9" icons="true" always-add-relationships="false" generalizations="true" realizations="true" 
+  associations="true" dependencies="false" nesting-relationships="true" router="FAN">  
+  <class id="1" language="java" name="com.iluwatar.adapter.FishingBoat" project="adapter" 
+    file="/adapter/src/main/java/com/iluwatar/adapter/FishingBoat.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="656" y="355"/>    
     <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="2" language="java" name="com.iluwatar.adapter.Engineer" project="adapter" 
-    file="/adapter/src/main/java/com/iluwatar/adapter/Engineer.java" binary="false" corner="BOTTOM_RIGHT">    
-    <position height="88" width="141" x="110" y="356"/>    
+  <class id="2" language="java" name="com.iluwatar.adapter.Captain" project="adapter" 
+    file="/adapter/src/main/java/com/iluwatar/adapter/Captain.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="228" y="185"/>    
+    <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.adapter.BattleFishingBoat" project="adapter" 
+    file="/adapter/src/main/java/com/iluwatar/adapter/BattleFishingBoat.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="463" y="357"/>    
+    <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="4" language="java" name="com.iluwatar.adapter.BattleShip" project="adapter" 
+    file="/adapter/src/main/java/com/iluwatar/adapter/BattleShip.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="466" y="170"/>    
     <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="3" language="java" name="com.iluwatar.adapter.GnomeEngineer" project="adapter" 
-    file="/adapter/src/main/java/com/iluwatar/adapter/GnomeEngineer.java" binary="false" corner="BOTTOM_RIGHT">    
-    <position height="106" width="141" x="374" y="210"/>    
-    <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.adapter.GoblinGlider" project="adapter" 
-    file="/adapter/src/main/java/com/iluwatar/adapter/GoblinGlider.java" binary="false" corner="BOTTOM_RIGHT">    
-    <position height="142" width="130" x="374" y="356"/>    
-    <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>  
   <realization id="5">    
-    <end type="SOURCE" refId="1"/>    
-    <end type="TARGET" refId="2"/>  
+    <end type="SOURCE" refId="2"/>    
+    <end type="TARGET" refId="4"/>  
   </realization>  
-  <realization id="6">    
-    <end type="SOURCE" refId="3"/>    
-    <end type="TARGET" refId="2"/>  
-  </realization>  
-  <association id="7">    
-    <end type="SOURCE" refId="1" navigable="false">      
-      <attribute id="8" name="engineer"/>      
-      <multiplicity id="9" minimum="0" maximum="1"/>    
+  <association id="6">    
+    <end type="SOURCE" refId="3" navigable="false">      
+      <attribute id="7" name="boat"/>      
+      <multiplicity id="8" minimum="0" maximum="1"/>    
     </end>    
-    <end type="TARGET" refId="2" navigable="true"/>    
+    <end type="TARGET" refId="1" navigable="true"/>    
     <display labels="true" multiplicity="true"/>  
   </association>  
+  <realization id="9">    
+    <end type="SOURCE" refId="3"/>    
+    <end type="TARGET" refId="4"/>  
+  </realization>  
   <association id="10">    
-    <end type="SOURCE" refId="3" navigable="false">      
-      <attribute id="11" name="glider"/>      
+    <end type="SOURCE" refId="2" navigable="false">      
+      <attribute id="11" name="battleship"/>      
       <multiplicity id="12" minimum="0" maximum="1"/>    
     </end>    
     <end type="TARGET" refId="4" navigable="true"/>    

adapter/index.md

@@ -4,21 +4,34 @@ title: Adapter
 folder: adapter
 permalink: /patterns/adapter/
 categories: Structural
-tags: Java
+tags:
+ - Java
+ - Gang Of Four
+ - Difficulty-Beginner
 ---
 
-**Intent:** Convert the interface of a class into another interface the clients
+## Also known as
+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.
 
-![alt text](./etc/adapter_1.png "Adapter")
+![alt text](./etc/adapter.png "Adapter")
 
-**Applicability:** Use the Adapter pattern when
+## Applicability
+Use the Adapter pattern when
 
 * you want to use an existing class, and its interface does not match the one you need
 * you want to create a reusable class that cooperates with unrelated or unforeseen classes, that is, classes that don't necessarily have compatible interfaces
 * you need to use several existing subclasses, but it's impractical to adapt their interface by subclassing every one. An object adapter can adapt the interface of its parent class.
 
-**Real world examples:**
+## Real world examples
 
 * [java.util.Arrays#asList()](http://docs.oracle.com/javase/8/docs/api/java/util/Arrays.html#asList%28T...%29)
+
+## Credits
+
+* [Design Patterns: Elements of Reusable Object-Oriented Software](http://www.amazon.com/Design-Patterns-Elements-Reusable-Object-Oriented/dp/0201633612)
+* [J2EE Design Patterns](http://www.amazon.com/J2EE-Design-Patterns-William-Crawford/dp/0596004273/ref=sr_1_2)

adapter/pom.xml

@@ -1,19 +1,47 @@
 <?xml version="1.0"?>
-<project
-	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
-	xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
-	<modelVersion>4.0.0</modelVersion>
-	<parent>
-		<groupId>com.iluwatar</groupId>
-		<artifactId>java-design-patterns</artifactId>
-		<version>1.6.0</version>
-	</parent>
-	<artifactId>adapter</artifactId>
-	<dependencies>
-		<dependency>
-			<groupId>junit</groupId>
-			<artifactId>junit</artifactId>
-			<scope>test</scope>
-		</dependency>
-	</dependencies>
+<!--
+
+    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.
+
+-->
+<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>com.iluwatar</groupId>
+    <artifactId>java-design-patterns</artifactId>
+    <version>1.10.0</version>
+  </parent>
+  <artifactId>adapter</artifactId>
+  <dependencies>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.mockito</groupId>
+      <artifactId>mockito-core</artifactId>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
 </project>

adapter/src/main/java/com/iluwatar/adapter/App.java

@@ -1,25 +1,60 @@
+/**
+ * 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.adapter;
 
 /**
- * 
- * There are two variations of the Adapter pattern: The class adapter implements
- * the adaptee's interface whereas the object adapter uses composition to
- * contain the adaptee in the adapter object. This example uses the object
- * adapter approach.
+ * An adapter helps two incompatible interfaces to work together. This is the real world definition
+ * for an adapter. Interfaces may be incompatible but the inner functionality should suit the need.
+ * The Adapter design pattern allows otherwise incompatible classes to work together by converting
+ * the interface of one class into an interface expected by the clients.
+ *
  * <p>
- * The Adapter ({@link GnomeEngineer}) converts the interface of the target class
- * ({@link GoblinGlider}) into a suitable one expected by the client
- * ({@link GnomeEngineeringManager}).
- * 
+ * There are two variations of the Adapter pattern: The class adapter implements the adaptee's
+ * interface whereas the object adapter uses composition to contain the adaptee in the adapter
+ * object. This example uses the object adapter approach.
+ *
+ * <p>
+ * The Adapter ({@link BattleFishingBoat}) converts the interface of the adaptee class (
+ * {@link FishingBoat}) into a suitable one expected by the client ( {@link BattleShip} ).
+ *
+ * <p>
+ * The story of this implementation is this. <br>
+ * Pirates are coming! we need a {@link BattleShip} to fight! We have a {@link FishingBoat} and our
+ * captain. We have no time to make up a new ship! we need to reuse this {@link FishingBoat}. The
+ * captain needs a battleship which can fire and move. The spec is in {@link BattleShip}. We will
+ * use the Adapter pattern to reuse {@link FishingBoat}.
+ *
  */
 public class App {
 
-	/**
-	 * Program entry point
-	 * @param args command line args
-	 */
-	public static void main(String[] args) {
-		Engineer manager = new GnomeEngineeringManager();
-		manager.operateDevice();
-	}
+  /**
+   * Program entry point.
+   *
+   * @param args command line args
+   */
+  public static void main(String[] args) {
+    Captain captain = new Captain(new BattleFishingBoat());
+    captain.move();
+    captain.fire();
+  }
 }

adapter/src/main/java/com/iluwatar/adapter/BattleFishingBoat.java

@@ -0,0 +1,51 @@
+/**
+ * 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.adapter;
+
+/**
+ *
+ * Adapter class. Adapts the interface of the device ({@link FishingBoat}) into {@link BattleShip}
+ * interface expected by the client ({@link Captain}). <br>
+ * In this case we added a new function fire to suit the interface. We are reusing the
+ * {@link FishingBoat} without changing itself. The Adapter class can just map the functions of the
+ * Adaptee or add, delete features of the Adaptee.
+ *
+ */
+public class BattleFishingBoat implements BattleShip {
+
+  private FishingBoat boat;
+
+  public BattleFishingBoat() {
+    boat = new FishingBoat();
+  }
+
+  @Override
+  public void fire() {
+    System.out.println("fire!");
+  }
+
+  @Override
+  public void move() {
+    boat.sail();
+  }
+}

adapter/src/main/java/com/iluwatar/adapter/BattleShip.java

@@ -0,0 +1,36 @@
+/**
+ * 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.adapter;
+
+/**
+ * The interface expected by the client.<br>
+ * A Battleship can fire and move.
+ *
+ */
+public interface BattleShip {
+
+  void fire();
+
+  void move();
+
+}

adapter/src/main/java/com/iluwatar/adapter/Captain.java

@@ -0,0 +1,55 @@
+/**
+ * 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.adapter;
+
+/**
+ * The Captain uses {@link BattleShip} to fight. <br>
+ * This is the client in the pattern.
+ */
+public class Captain implements BattleShip {
+
+  private BattleShip battleship;
+
+  public Captain() {
+
+  }
+
+  public Captain(BattleShip battleship) {
+    this.battleship = battleship;
+  }
+
+  public void setBattleship(BattleShip battleship) {
+    this.battleship = battleship;
+  }
+
+  @Override
+  public void fire() {
+    battleship.fire();
+  }
+
+  @Override
+  public void move() {
+    battleship.move();
+  }
+
+}

adapter/src/main/java/com/iluwatar/adapter/Engineer.java

@@ -1,12 +0,0 @@
-package com.iluwatar.adapter;
-
-/**
- * 
- * Engineers can operate devices.
- * 
- */
-public interface Engineer {
-
-	void operateDevice();
-
-}

adapter/src/main/java/com/iluwatar/adapter/FishingBoat.java

@@ -0,0 +1,40 @@
+/**
+ * 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.adapter;
+
+/**
+ *
+ * Device class (adaptee in the pattern). We want to reuse this class
+ *
+ */
+public class FishingBoat {
+
+  public void sail() {
+    System.out.println("The Boat is moving to that place");
+  }
+
+  public void fish() {
+    System.out.println("fishing ...");
+  }
+
+}

adapter/src/main/java/com/iluwatar/adapter/GnomeEngineer.java

@@ -1,24 +0,0 @@
-package com.iluwatar.adapter;
-
-/**
- * 
- * Adapter class. Adapts the interface of the device ({@link GoblinGlider}) into
- * {@link Engineer} interface expected by the client ({@link GnomeEngineeringManager}).
- * 
- */
-public class GnomeEngineer implements Engineer {
-
-	private GoblinGlider glider;
-
-	public GnomeEngineer() {
-		glider = new GoblinGlider();
-	}
-
-	@Override
-	public void operateDevice() {
-		glider.attachGlider();
-		glider.gainSpeed();
-		glider.takeOff();
-	}
-
-}

adapter/src/main/java/com/iluwatar/adapter/GnomeEngineeringManager.java

@@ -1,20 +0,0 @@
-package com.iluwatar.adapter;
-
-/**
- * 
- * GnomeEngineering manager uses {@link Engineer} to operate devices.
- * 
- */
-public class GnomeEngineeringManager implements Engineer {
-
-	private Engineer engineer;
-
-	public GnomeEngineeringManager() {
-		engineer = new GnomeEngineer();
-	}
-
-	@Override
-	public void operateDevice() {
-		engineer.operateDevice();
-	}
-}

adapter/src/main/java/com/iluwatar/adapter/GoblinGlider.java

@@ -1,21 +0,0 @@
-package com.iluwatar.adapter;
-
-/**
- * 
- * Device class (adaptee in the pattern).
- * 
- */
-public class GoblinGlider {
-
-	public void attachGlider() {
-		System.out.println("Glider attached.");
-	}
-
-	public void gainSpeed() {
-		System.out.println("Gaining speed.");
-	}
-
-	public void takeOff() {
-		System.out.println("Lift-off!");
-	}
-}

adapter/src/test/java/com/iluwatar/adapter/AdapterPatternTest.java

@@ -0,0 +1,83 @@
+/**
+ * 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.adapter;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verify;
+
+/**
+ * Test class
+ * 
+ */
+public class AdapterPatternTest {
+
+  private Map<String, Object> beans;
+
+  private static final String BATTLESHIP_BEAN = "engineer";
+
+  private static final String CAPTAIN_BEAN = "captain";
+
+  /**
+   * This method runs before the test execution and sets the bean objects in the beans Map.
+   */
+  @Before
+  public void setup() {
+    beans = new HashMap<>();
+
+    BattleFishingBoat battleFishingBoat = spy(new BattleFishingBoat());
+    beans.put(BATTLESHIP_BEAN, battleFishingBoat);
+
+    Captain captain = new Captain();
+    captain.setBattleship((BattleFishingBoat) beans.get(BATTLESHIP_BEAN));
+    beans.put(CAPTAIN_BEAN, captain);
+  }
+
+  /**
+   * This test asserts that when we use the move() method on a captain bean(client), it is
+   * internally calling move method on the battleship object. The Adapter ({@link BattleFishingBoat}
+   * ) converts the interface of the target class ( {@link FishingBoat}) into a suitable one
+   * expected by the client ({@link Captain} ).
+   */
+  @Test
+  public void testAdapter() {
+    BattleShip captain = (BattleShip) beans.get(CAPTAIN_BEAN);
+
+    // when captain moves
+    captain.move();
+
+    // the captain internally calls the battleship object to move
+    BattleShip battleship = (BattleShip) beans.get(BATTLESHIP_BEAN);
+    verify(battleship).move();
+
+    // same with above with firing
+    captain.fire();
+    verify(battleship).fire();
+
+  }
+}

adapter/src/test/java/com/iluwatar/adapter/AppTest.java

@@ -1,19 +1,38 @@
+/**
+ * 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.adapter;
 
 import org.junit.Test;
 
-import com.iluwatar.adapter.App;
+import java.io.IOException;
 
 /**
- * 
- * Application test
- *
+ * Tests that Adapter example runs without errors.
  */
 public class AppTest {
-
-	@Test
-	public void test() {
-		String[] args = {};
-		App.main(args);
-	}
+  @Test
+  public void test() throws IOException {
+    String[] args = {};
+    App.main(args);
+  }
 }

async-method-invocation/index.md

@@ -4,24 +4,29 @@ title: Async Method Invocation
 folder: async-method-invocation
 permalink: /patterns/async-method-invocation/
 categories: Concurrency
-tags: Java
+tags:
+ - Java
+ - Difficulty-Intermediate
+ - Functional
 ---
 
-**Intent:** Asynchronous method invocation is pattern where the calling thread
+## Intent
+Asynchronous method invocation is pattern where the calling thread
 is not blocked while waiting results of tasks. The pattern provides parallel
 processing of multiple independent tasks and retrieving the results via
 callbacks or waiting until everything is done. 
 
 ![alt text](./etc/async-method-invocation.png "Async Method Invocation")
 
-**Applicability:** Use async method invocation pattern when
+## Applicability
+Use async method invocation pattern when
 
 * you have multiple independent tasks that can run in parallel
 * you need to improve the performance of a group of sequential tasks
 * you have limited amount of processing capacity or long running tasks and the
   caller should not wait the tasks to be ready
 
-**Real world examples:**
+## Real world examples
 
 * [FutureTask](http://docs.oracle.com/javase/8/docs/api/java/util/concurrent/FutureTask.html), [CompletableFuture](https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/CompletableFuture.html) and [ExecutorService](http://docs.oracle.com/javase/8/docs/api/java/util/concurrent/ExecutorService.html) (Java)
 * [Task-based Asynchronous Pattern](https://msdn.microsoft.com/en-us/library/hh873175.aspx) (.NET)

async-method-invocation/pom.xml

@@ -1,19 +1,47 @@
 <?xml version="1.0"?>
-<project
-	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
-	xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
-	<modelVersion>4.0.0</modelVersion>
-	<parent>
-		<groupId>com.iluwatar</groupId>
-		<artifactId>java-design-patterns</artifactId>
-		<version>1.6.0</version>
-	</parent>
-	<artifactId>async-method-invocation</artifactId>
-	<dependencies>
-		<dependency>
-			<groupId>junit</groupId>
-			<artifactId>junit</artifactId>
-			<scope>test</scope>
-		</dependency>
-	</dependencies>
+<!--
+
+    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.
+
+-->
+<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>com.iluwatar</groupId>
+    <artifactId>java-design-patterns</artifactId>
+    <version>1.10.0</version>
+  </parent>
+  <artifactId>async-method-invocation</artifactId>
+  <dependencies>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.mockito</groupId>
+      <artifactId>mockito-core</artifactId>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
 </project>

async-method-invocation/src/main/java/com/iluwatar/async/method/invocation/App.java

@@ -1,3 +1,25 @@
+/**
+ * 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.async.method.invocation;
 
 import java.util.concurrent.Callable;
@@ -5,22 +27,22 @@ import java.util.concurrent.Callable;
 /**
  * This application demonstrates the async method invocation pattern. Key parts of the pattern are
  * <code>AsyncResult</code> which is an intermediate container for an asynchronously evaluated value,
- * <code>AsyncCallback</code> which can be provided to be executed on task completion and
- * <code>AsyncExecutor</code> that manages the execution of the async tasks.
+ * <code>AsyncCallback</code> which can be provided to be executed on task completion and <code>AsyncExecutor</code>
+ * that manages the execution of the async tasks.
  * <p>
- * The main method shows example flow of async invocations. The main thread starts multiple tasks with
- * variable durations and then continues its own work. When the main thread has done it's job it collects
- * the results of the async tasks. Two of the tasks are handled with callbacks, meaning the callbacks are
- * executed immediately when the tasks complete.
+ * The main method shows example flow of async invocations. The main thread starts multiple tasks with variable
+ * durations and then continues its own work. When the main thread has done it's job it collects the results of the
+ * async tasks. Two of the tasks are handled with callbacks, meaning the callbacks are executed immediately when the
+ * tasks complete.
  * <p>
- * Noteworthy difference of thread usage between the async results and callbacks is that the async results
- * are collected in the main thread but the callbacks are executed within the worker threads. This should be
- * noted when working with thread pools.
+ * Noteworthy difference of thread usage between the async results and callbacks is that the async results are collected
+ * in the main thread but the callbacks are executed within the worker threads. This should be noted when working with
+ * thread pools.
  * <p>
- * Java provides its own implementations of async method invocation pattern. FutureTask, CompletableFuture
- * and ExecutorService are the real world implementations of this pattern. But due to the nature of parallel
- * programming, the implementations are not trivial. This example does not take all possible scenarios into
- * account but rather provides a simple version that helps to understand the pattern.
+ * Java provides its own implementations of async method invocation pattern. FutureTask, CompletableFuture and
+ * ExecutorService are the real world implementations of this pattern. But due to the nature of parallel programming,
+ * the implementations are not trivial. This example does not take all possible scenarios into account but rather
+ * provides a simple version that helps to understand the pattern.
  *
  * @see AsyncResult
  * @see AsyncCallback
@@ -32,66 +54,72 @@ import java.util.concurrent.Callable;
  */
 public class App {
 
-	public static void main(String[] args) throws Exception {
-		// construct a new executor that will run async tasks
-		AsyncExecutor executor = new ThreadAsyncExecutor();
+  /**
+   * Program entry point
+   */
+  public static void main(String[] args) throws Exception {
+    // construct a new executor that will run async tasks
+    AsyncExecutor executor = new ThreadAsyncExecutor();
 
-		// start few async tasks with varying processing times, two last with callback handlers
-		AsyncResult<Integer> asyncResult1 = executor.startProcess(lazyval(10, 500));
-		AsyncResult<String> asyncResult2 = executor.startProcess(lazyval("test", 300));
-		AsyncResult<Long> asyncResult3 = executor.startProcess(lazyval(50L, 700));
-		AsyncResult<Integer> asyncResult4 = executor.startProcess(lazyval(20, 400), callback("Callback result 4"));
-		AsyncResult<String> asyncResult5 = executor.startProcess(lazyval("callback", 600), callback("Callback result 5"));
+    // start few async tasks with varying processing times, two last with callback handlers
+    AsyncResult<Integer> asyncResult1 = executor.startProcess(lazyval(10, 500));
+    AsyncResult<String> asyncResult2 = executor.startProcess(lazyval("test", 300));
+    AsyncResult<Long> asyncResult3 = executor.startProcess(lazyval(50L, 700));
+    AsyncResult<Integer> asyncResult4 = executor.startProcess(lazyval(20, 400), callback("Callback result 4"));
+    AsyncResult<String> asyncResult5 = executor.startProcess(lazyval("callback", 600), callback("Callback result 5"));
 
-		// emulate processing in the current thread while async tasks are running in their own threads
-		Thread.sleep(350); // Oh boy I'm working hard here
-		log("Some hard work done");
+    // emulate processing in the current thread while async tasks are running in their own threads
+    Thread.sleep(350); // Oh boy I'm working hard here
+    log("Some hard work done");
 
-		// wait for completion of the tasks
-		Integer result1 = executor.endProcess(asyncResult1);
-		String result2 = executor.endProcess(asyncResult2);
-		Long result3 = executor.endProcess(asyncResult3);
-		asyncResult4.await();
-		asyncResult5.await();
+    // wait for completion of the tasks
+    Integer result1 = executor.endProcess(asyncResult1);
+    String result2 = executor.endProcess(asyncResult2);
+    Long result3 = executor.endProcess(asyncResult3);
+    asyncResult4.await();
+    asyncResult5.await();
 
-		// log the results of the tasks, callbacks log immediately when complete
-		log("Result 1: " + result1);
-		log("Result 2: " + result2);
-		log("Result 3: " + result3);
-	}
+    // log the results of the tasks, callbacks log immediately when complete
+    log("Result 1: " + result1);
+    log("Result 2: " + result2);
+    log("Result 3: " + result3);
+  }
 
-	/**
-	 * Creates a callable that lazily evaluates to given value with artificial delay.
-	 *
-	 * @param value value to evaluate
-	 * @param delayMillis artificial delay in milliseconds
-	 * @return new callable for lazy evaluation
-	 */
-	private static <T> Callable<T> lazyval(T value, long delayMillis) {
-		return () -> {
-			Thread.sleep(delayMillis);
-			log("Task completed with: " + value);
-			return value;
-		};
-	}
+  /**
+   * Creates a callable that lazily evaluates to given value with artificial delay.
+   *
+   * @param value
+   *          value to evaluate
+   * @param delayMillis
+   *          artificial delay in milliseconds
+   * @return new callable for lazy evaluation
+   */
+  private static <T> Callable<T> lazyval(T value, long delayMillis) {
+    return () -> {
+      Thread.sleep(delayMillis);
+      log("Task completed with: " + value);
+      return value;
+    };
+  }
 
-	/**
-	 * Creates a simple callback that logs the complete status of the async result.
-	 *
-	 * @param name callback name
-	 * @return new async callback
-	 */
-	private static <T> AsyncCallback<T> callback(String name) {
-		return (value, ex) -> {
-			if (ex.isPresent()) {
-				log(name + " failed: " + ex.map(Exception::getMessage).orElse(""));
-			} else {
-				log(name + ": " + value);
-			}
-		};
-	}
+  /**
+   * Creates a simple callback that logs the complete status of the async result.
+   *
+   * @param name
+   *          callback name
+   * @return new async callback
+   */
+  private static <T> AsyncCallback<T> callback(String name) {
+    return (value, ex) -> {
+      if (ex.isPresent()) {
+        log(name + " failed: " + ex.map(Exception::getMessage).orElse(""));
+      } else {
+        log(name + ": " + value);
+      }
+    };
+  }
 
-	private static void log(String msg) {
-		System.out.println(String.format("[%1$-10s] - %2$s", Thread.currentThread().getName(), msg));
-	}
+  private static void log(String msg) {
+    System.out.println(String.format("[%1$-10s] - %2$s", Thread.currentThread().getName(), msg));
+  }
 }

async-method-invocation/src/main/java/com/iluwatar/async/method/invocation/AsyncCallback.java

@@ -1,3 +1,25 @@
+/**
+ * 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.async.method.invocation;
 
 import java.util.Optional;
@@ -11,12 +33,11 @@ import java.util.Optional;
  */
 public interface AsyncCallback<T> {
 
-	/**
-	 * Complete handler which is executed when async task is completed or fails execution.
-	 *
-	 * @param value the evaluated value from async task, undefined when execution fails
-	 * @param ex empty value if execution succeeds, some exception if executions fails
-	 */
-	void onComplete(T value, Optional<Exception> ex);
-
+  /**
+   * Complete handler which is executed when async task is completed or fails execution.
+   *
+   * @param value the evaluated value from async task, undefined when execution fails
+   * @param ex empty value if execution succeeds, some exception if executions fails
+   */
+  void onComplete(T value, Optional<Exception> ex);
 }

async-method-invocation/src/main/java/com/iluwatar/async/method/invocation/AsyncExecutor.java

@@ -1,3 +1,25 @@
+/**
+ * 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.async.method.invocation;
 
 import java.util.concurrent.Callable;
@@ -10,33 +32,32 @@ import java.util.concurrent.ExecutionException;
  */
 public interface AsyncExecutor {
 
-	/**
-	 * Starts processing of an async task. Returns immediately with async result.
-	 *
-	 * @param task task to be executed asynchronously
-	 * @return async result for the task
-	 */
-	<T> AsyncResult<T> startProcess(Callable<T> task);
+  /**
+   * Starts processing of an async task. Returns immediately with async result.
+   *
+   * @param task task to be executed asynchronously
+   * @return async result for the task
+   */
+  <T> AsyncResult<T> startProcess(Callable<T> task);
 
-	/**
-	 * Starts processing of an async task. Returns immediately with async result. Executes callback
-	 * when the task is completed.
-	 *
-	 * @param task task to be executed asynchronously
-	 * @param callback callback to be executed on task completion
-	 * @return async result for the task
-	 */
-	<T> AsyncResult<T> startProcess(Callable<T> task, AsyncCallback<T> callback);
-
-	/**
-	 * Ends processing of an async task. Blocks the current thread if necessary and returns the
-	 * evaluated value of the completed task.
-	 *
-	 * @param asyncResult async result of a task
-	 * @return evaluated value of the completed task
-	 * @throws ExecutionException if execution has failed, containing the root cause
-	 * @throws InterruptedException if the execution is interrupted
-	 */
-	<T> T endProcess(AsyncResult<T> asyncResult) throws ExecutionException, InterruptedException;
+  /**
+   * Starts processing of an async task. Returns immediately with async result. Executes callback
+   * when the task is completed.
+   *
+   * @param task task to be executed asynchronously
+   * @param callback callback to be executed on task completion
+   * @return async result for the task
+   */
+  <T> AsyncResult<T> startProcess(Callable<T> task, AsyncCallback<T> callback);
 
+  /**
+   * Ends processing of an async task. Blocks the current thread if necessary and returns the
+   * evaluated value of the completed task.
+   *
+   * @param asyncResult async result of a task
+   * @return evaluated value of the completed task
+   * @throws ExecutionException if execution has failed, containing the root cause
+   * @throws InterruptedException if the execution is interrupted
+   */
+  <T> T endProcess(AsyncResult<T> asyncResult) throws ExecutionException, InterruptedException;
 }

async-method-invocation/src/main/java/com/iluwatar/async/method/invocation/AsyncResult.java

@@ -1,3 +1,25 @@
+/**
+ * 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.async.method.invocation;
 
 import java.util.concurrent.ExecutionException;
@@ -5,31 +27,29 @@ import java.util.concurrent.ExecutionException;
 /**
  * 
  * AsyncResult interface
- *
- * @param <T>
  */
 public interface AsyncResult<T> {
 
-	/**
-	 * Status of the async task execution.
-	 *
-	 * @return <code>true</code> if execution is completed or failed
-	 */
-	boolean isCompleted();
+  /**
+   * Status of the async task execution.
+   *
+   * @return <code>true</code> if execution is completed or failed
+   */
+  boolean isCompleted();
 
-	/**
-	 * Gets the value of completed async task.
-	 *
-	 * @return evaluated value or throws ExecutionException if execution has failed
-	 * @throws ExecutionException if execution has failed, containing the root cause
-	 * @throws IllegalStateException if execution is not completed
-	 */
-	T getValue() throws ExecutionException;
+  /**
+   * Gets the value of completed async task.
+   *
+   * @return evaluated value or throws ExecutionException if execution has failed
+   * @throws ExecutionException if execution has failed, containing the root cause
+   * @throws IllegalStateException if execution is not completed
+   */
+  T getValue() throws ExecutionException;
 
-	/**
-	 * Blocks the current thread until the async task is completed.
-	 *
-	 * @throws InterruptedException if the execution is interrupted
-	 */
-	void await() throws InterruptedException;
+  /**
+   * Blocks the current thread until the async task is completed.
+   *
+   * @throws InterruptedException if the execution is interrupted
+   */
+  void await() throws InterruptedException;
 }

async-method-invocation/src/main/java/com/iluwatar/async/method/invocation/ThreadAsyncExecutor.java

@@ -1,3 +1,25 @@
+/**
+ * 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.async.method.invocation;
 
 import java.util.Optional;
@@ -12,116 +34,117 @@ import java.util.concurrent.atomic.AtomicInteger;
  */
 public class ThreadAsyncExecutor implements AsyncExecutor {
 
-	/** Index for thread naming */
-	private final AtomicInteger idx = new AtomicInteger(0);
+  /** Index for thread naming */
+  private final AtomicInteger idx = new AtomicInteger(0);
 
-	@Override
-	public <T> AsyncResult<T> startProcess(Callable<T> task) {
-		return startProcess(task, null);
-	}
+  @Override
+  public <T> AsyncResult<T> startProcess(Callable<T> task) {
+    return startProcess(task, null);
+  }
 
-	@Override
-	public <T> AsyncResult<T> startProcess(Callable<T> task, AsyncCallback<T> callback) {
-		CompletableResult<T> result = new CompletableResult<>(callback);
-		new Thread(() -> {
-			try {
-				result.setValue(task.call());
-			} catch (Exception ex) {
-				result.setException(ex);
-			}
-		}, "executor-" + idx.incrementAndGet()).start();
-		return result;
-	}
+  @Override
+  public <T> AsyncResult<T> startProcess(Callable<T> task, AsyncCallback<T> callback) {
+    CompletableResult<T> result = new CompletableResult<>(callback);
+    new Thread(() -> {
+      try {
+        result.setValue(task.call());
+      } catch (Exception ex) {
+        result.setException(ex);
+      }
+    } , "executor-" + idx.incrementAndGet()).start();
+    return result;
+  }
 
-	@Override
-	public <T> T endProcess(AsyncResult<T> asyncResult) throws ExecutionException, InterruptedException {
-		if (asyncResult.isCompleted()) {
-			return asyncResult.getValue();
-		} else {
-			asyncResult.await();
-			return asyncResult.getValue();
-		}
-	}
+  @Override
+  public <T> T endProcess(AsyncResult<T> asyncResult) throws ExecutionException, InterruptedException {
+    if (asyncResult.isCompleted()) {
+      return asyncResult.getValue();
+    } else {
+      asyncResult.await();
+      return asyncResult.getValue();
+    }
+  }
 
-	/**
-	 * Simple implementation of async result that allows completing it successfully with a value
-	 * or exceptionally with an exception. A really simplified version from its real life cousins
-	 * FutureTask and CompletableFuture.
-	 *
-	 * @see java.util.concurrent.FutureTask
-	 * @see java.util.concurrent.CompletableFuture
-	 */
-	private static class CompletableResult<T> implements AsyncResult<T> {
+  /**
+   * Simple implementation of async result that allows completing it successfully with a value or exceptionally with an
+   * exception. A really simplified version from its real life cousins FutureTask and CompletableFuture.
+   *
+   * @see java.util.concurrent.FutureTask
+   * @see java.util.concurrent.CompletableFuture
+   */
+  private static class CompletableResult<T> implements AsyncResult<T> {
 
-		static final int RUNNING = 1;
-		static final int FAILED = 2;
-		static final int COMPLETED = 3;
+    static final int RUNNING = 1;
+    static final int FAILED = 2;
+    static final int COMPLETED = 3;
 
-		final Object lock;
-		final Optional<AsyncCallback<T>> callback;
+    final Object lock;
+    final Optional<AsyncCallback<T>> callback;
 
-		volatile int state = RUNNING;
-		T value;
-		Exception exception;
+    volatile int state = RUNNING;
+    T value;
+    Exception exception;
 
-		CompletableResult(AsyncCallback<T> callback) {
-			this.lock = new Object();
-			this.callback = Optional.ofNullable(callback);
-		}
+    CompletableResult(AsyncCallback<T> callback) {
+      this.lock = new Object();
+      this.callback = Optional.ofNullable(callback);
+    }
 
-		/**
-		 * Sets the value from successful execution and executes callback if available. Notifies
-		 * any thread waiting for completion.
-		 *
-		 * @param value value of the evaluated task
-		 */
-		void setValue(T value) {
-			this.value = value;
-			this.state = COMPLETED;
-			this.callback.ifPresent(ac -> ac.onComplete(value, Optional.<Exception>empty()));
-			synchronized (lock) {
-				lock.notifyAll();
-			}
-		}
+    /**
+     * Sets the value from successful execution and executes callback if available. Notifies any thread waiting for
+     * completion.
+     *
+     * @param value
+     *          value of the evaluated task
+     */
+    void setValue(T value) {
+      this.value = value;
+      this.state = COMPLETED;
+      this.callback.ifPresent(ac -> ac.onComplete(value, Optional.<Exception>empty()));
+      synchronized (lock) {
+        lock.notifyAll();
+      }
+    }
 
-		/**
-		 * Sets the exception from failed execution and executes callback if available. Notifies
-		 * any thread waiting for completion.
-		 *
-		 * @param exception exception of the failed task
-		 */
-		void setException(Exception exception) {
-			this.exception = exception;
-			this.state = FAILED;
-			this.callback.ifPresent(ac -> ac.onComplete(null, Optional.of(exception)));
-			synchronized (lock) {
-				lock.notifyAll();
-			}
-		}
+    /**
+     * Sets the exception from failed execution and executes callback if available. Notifies any thread waiting for
+     * completion.
+     *
+     * @param exception
+     *          exception of the failed task
+     */
+    void setException(Exception exception) {
+      this.exception = exception;
+      this.state = FAILED;
+      this.callback.ifPresent(ac -> ac.onComplete(null, Optional.of(exception)));
+      synchronized (lock) {
+        lock.notifyAll();
+      }
+    }
 
-		@Override
-		public boolean isCompleted() {
-			return (state > RUNNING);
-		}
+    @Override
+    public boolean isCompleted() {
+      return state > RUNNING;
+    }
 
-		@Override
-		public T getValue() throws ExecutionException {
-			if (state == COMPLETED) {
-				return value;
-			} else if (state == FAILED) {
-				throw new ExecutionException(exception);
-			} else {
-				throw new IllegalStateException("Execution not completed yet");
-			}
-		}
+    @Override
+    public T getValue() throws ExecutionException {
+      if (state == COMPLETED) {
+        return value;
+      } else if (state == FAILED) {
+        throw new ExecutionException(exception);
+      } else {
+        throw new IllegalStateException("Execution not completed yet");
+      }
+    }
 
-		@Override
-		public void await() throws InterruptedException {
-			synchronized (lock) {
-				if (!isCompleted()) {
-					lock.wait();
-				}
-			}
-		}
-	}
+    @Override
+    public void await() throws InterruptedException {
+      synchronized (lock) {
+        if (!isCompleted()) {
+          lock.wait();
+        }
+      }
+    }
+  }
 }

async-method-invocation/src/test/java/com/iluwatar/async/method/invocation/AppTest.java

@@ -1,3 +1,25 @@
+/**
+ * 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.async.method.invocation;
 
 import org.junit.Test;
@@ -9,10 +31,9 @@ import org.junit.Test;
  */
 public class AppTest {
 
-	@Test
-	public void test() throws Exception {
-		String[] args = {};
-		App.main(args);
-	}
-
+  @Test
+  public void test() throws Exception {
+    String[] args = {};
+    App.main(args);
+  }
 }

async-method-invocation/src/test/java/com/iluwatar/async/method/invocation/ThreadAsyncExecutorTest.java

@@ -0,0 +1,312 @@
+/**
+ * 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.async.method.invocation;
+
+import org.junit.Test;
+import org.mockito.ArgumentCaptor;
+import org.mockito.Matchers;
+
+import java.util.Optional;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutionException;
+
+import static org.junit.Assert.*;
+import static org.mockito.Matchers.eq;
+import static org.mockito.Mockito.*;
+import static org.mockito.internal.verification.VerificationModeFactory.times;
+
+/**
+ * Date: 12/6/15 - 10:49 AM
+ *
+ * @author Jeroen Meulemeester
+ */
+public class ThreadAsyncExecutorTest {
+
+  /**
+   * Test used to verify the happy path of {@link ThreadAsyncExecutor#startProcess(Callable)}
+   */
+  @Test(timeout = 3000)
+  public void testSuccessfulTaskWithoutCallback() throws Exception {
+    // Instantiate a new executor and start a new 'null' task ...
+    final ThreadAsyncExecutor executor = new ThreadAsyncExecutor();
+
+    final Object result = new Object();
+    final Callable<Object> task = mock(Callable.class);
+    when(task.call()).thenReturn(result);
+
+    final AsyncResult<Object> asyncResult = executor.startProcess(task);
+    assertNotNull(asyncResult);
+    asyncResult.await(); // Prevent timing issues, and wait until the result is available
+    assertTrue(asyncResult.isCompleted());
+
+    // Our task should only execute once ...
+    verify(task, times(1)).call();
+
+    // ... and the result should be exactly the same object
+    assertSame(result, asyncResult.getValue());
+  }
+
+  /**
+   * Test used to verify the happy path of {@link ThreadAsyncExecutor#startProcess(Callable, AsyncCallback)}
+   */
+  @Test(timeout = 3000)
+  public void testSuccessfulTaskWithCallback() throws Exception {
+    // Instantiate a new executor and start a new 'null' task ...
+    final ThreadAsyncExecutor executor = new ThreadAsyncExecutor();
+
+    final Object result = new Object();
+    final Callable<Object> task = mock(Callable.class);
+    when(task.call()).thenReturn(result);
+
+    final AsyncCallback callback = mock(AsyncCallback.class);
+    final AsyncResult<Object> asyncResult = executor.startProcess(task, callback);
+    assertNotNull(asyncResult);
+    asyncResult.await(); // Prevent timing issues, and wait until the result is available
+    assertTrue(asyncResult.isCompleted());
+
+    // Our task should only execute once ...
+    verify(task, times(1)).call();
+
+    // ... same for the callback, we expect our object
+    final ArgumentCaptor<Optional<Exception>> optionalCaptor = ArgumentCaptor.forClass((Class) Optional.class);
+    verify(callback, times(1)).onComplete(eq(result), optionalCaptor.capture());
+
+    final Optional<Exception> optionalException = optionalCaptor.getValue();
+    assertNotNull(optionalException);
+    assertFalse(optionalException.isPresent());
+
+    // ... and the result should be exactly the same object
+    assertSame(result, asyncResult.getValue());
+  }
+
+  /**
+   * Test used to verify the happy path of {@link ThreadAsyncExecutor#startProcess(Callable)} when a task takes a while
+   * to execute
+   */
+  @Test(timeout = 5000)
+  public void testLongRunningTaskWithoutCallback() throws Exception {
+    // Instantiate a new executor and start a new 'null' task ...
+    final ThreadAsyncExecutor executor = new ThreadAsyncExecutor();
+
+    final Object result = new Object();
+    final Callable<Object> task = mock(Callable.class);
+    when(task.call()).thenAnswer(i -> {
+      Thread.sleep(1500);
+      return result;
+    });
+
+    final AsyncResult<Object> asyncResult = executor.startProcess(task);
+    assertNotNull(asyncResult);
+    assertFalse(asyncResult.isCompleted());
+
+    try {
+      asyncResult.getValue();
+      fail("Expected IllegalStateException when calling AsyncResult#getValue on a non-completed task");
+    } catch (IllegalStateException e) {
+      assertNotNull(e.getMessage());
+    }
+
+    // Our task should only execute once, but it can take a while ...
+    verify(task, timeout(3000).times(1)).call();
+
+    // Prevent timing issues, and wait until the result is available
+    asyncResult.await();
+    assertTrue(asyncResult.isCompleted());
+    verifyNoMoreInteractions(task);
+
+    // ... and the result should be exactly the same object
+    assertSame(result, asyncResult.getValue());
+  }
+
+  /**
+   * Test used to verify the happy path of {@link ThreadAsyncExecutor#startProcess(Callable, AsyncCallback)} when a task
+   * takes a while to execute
+   */
+  @Test(timeout = 5000)
+  public void testLongRunningTaskWithCallback() throws Exception {
+    // Instantiate a new executor and start a new 'null' task ...
+    final ThreadAsyncExecutor executor = new ThreadAsyncExecutor();
+
+    final Object result = new Object();
+    final Callable<Object> task = mock(Callable.class);
+    when(task.call()).thenAnswer(i -> {
+      Thread.sleep(1500);
+      return result;
+    });
+
+    final AsyncCallback<Object> callback = mock(AsyncCallback.class);
+    final AsyncResult<Object> asyncResult = executor.startProcess(task, callback);
+    assertNotNull(asyncResult);
+    assertFalse(asyncResult.isCompleted());
+
+    verifyZeroInteractions(callback);
+
+    try {
+      asyncResult.getValue();
+      fail("Expected IllegalStateException when calling AsyncResult#getValue on a non-completed task");
+    } catch (IllegalStateException e) {
+      assertNotNull(e.getMessage());
+    }
+
+    // Our task should only execute once, but it can take a while ...
+    verify(task, timeout(3000).times(1)).call();
+
+    final ArgumentCaptor<Optional<Exception>> optionalCaptor = ArgumentCaptor.forClass((Class) Optional.class);
+    verify(callback, timeout(3000).times(1)).onComplete(eq(result), optionalCaptor.capture());
+
+    final Optional<Exception> optionalException = optionalCaptor.getValue();
+    assertNotNull(optionalException);
+    assertFalse(optionalException.isPresent());
+
+    // Prevent timing issues, and wait until the result is available
+    asyncResult.await();
+    assertTrue(asyncResult.isCompleted());
+    verifyNoMoreInteractions(task, callback);
+
+    // ... and the result should be exactly the same object
+    assertSame(result, asyncResult.getValue());
+  }
+
+  /**
+   * Test used to verify the happy path of {@link ThreadAsyncExecutor#startProcess(Callable)} when a task takes a while
+   * to execute, while waiting on the result using {@link ThreadAsyncExecutor#endProcess(AsyncResult)}
+   */
+  @Test(timeout = 5000)
+  public void testEndProcess() throws Exception {
+    // Instantiate a new executor and start a new 'null' task ...
+    final ThreadAsyncExecutor executor = new ThreadAsyncExecutor();
+
+    final Object result = new Object();
+    final Callable<Object> task = mock(Callable.class);
+    when(task.call()).thenAnswer(i -> {
+      Thread.sleep(1500);
+      return result;
+    });
+
+    final AsyncResult<Object> asyncResult = executor.startProcess(task);
+    assertNotNull(asyncResult);
+    assertFalse(asyncResult.isCompleted());
+
+    try {
+      asyncResult.getValue();
+      fail("Expected IllegalStateException when calling AsyncResult#getValue on a non-completed task");
+    } catch (IllegalStateException e) {
+      assertNotNull(e.getMessage());
+    }
+
+    assertSame(result, executor.endProcess(asyncResult));
+    verify(task, times(1)).call();
+    assertTrue(asyncResult.isCompleted());
+
+    // Calling end process a second time while already finished should give the same result
+    assertSame(result, executor.endProcess(asyncResult));
+    verifyNoMoreInteractions(task);
+  }
+
+  /**
+   * Test used to verify the behaviour of {@link ThreadAsyncExecutor#startProcess(Callable)} when the callable is 'null'
+   */
+  @Test(timeout = 3000)
+  public void testNullTask() throws Exception {
+    // Instantiate a new executor and start a new 'null' task ...
+    final ThreadAsyncExecutor executor = new ThreadAsyncExecutor();
+    final AsyncResult<Object> asyncResult = executor.startProcess(null);
+
+    assertNotNull("The AsyncResult should not be 'null', even though the task was 'null'.", asyncResult);
+    asyncResult.await(); // Prevent timing issues, and wait until the result is available
+    assertTrue(asyncResult.isCompleted());
+
+    try {
+      asyncResult.getValue();
+      fail("Expected ExecutionException with NPE as cause");
+    } catch (final ExecutionException e) {
+      assertNotNull(e.getMessage());
+      assertNotNull(e.getCause());
+      assertEquals(NullPointerException.class, e.getCause().getClass());
+    }
+
+  }
+
+  /**
+   * Test used to verify the behaviour of {@link ThreadAsyncExecutor#startProcess(Callable, AsyncCallback)} when the
+   * callable is 'null', but the asynchronous callback is provided
+   */
+  @Test(timeout = 3000)
+  public void testNullTaskWithCallback() throws Exception {
+    // Instantiate a new executor and start a new 'null' task ...
+    final ThreadAsyncExecutor executor = new ThreadAsyncExecutor();
+    final AsyncCallback<Object> callback = mock(AsyncCallback.class);
+    final AsyncResult<Object> asyncResult = executor.startProcess(null, callback);
+
+    assertNotNull("The AsyncResult should not be 'null', even though the task was 'null'.", asyncResult);
+    asyncResult.await(); // Prevent timing issues, and wait until the result is available
+    assertTrue(asyncResult.isCompleted());
+
+    final ArgumentCaptor<Optional<Exception>> optionalCaptor = ArgumentCaptor.forClass((Class) Optional.class);
+    verify(callback, times(1)).onComplete(Matchers.isNull(), optionalCaptor.capture());
+
+    final Optional<Exception> optionalException = optionalCaptor.getValue();
+    assertNotNull(optionalException);
+    assertTrue(optionalException.isPresent());
+
+    final Exception exception = optionalException.get();
+    assertNotNull(exception);
+    assertEquals(NullPointerException.class, exception.getClass());
+
+    try {
+      asyncResult.getValue();
+      fail("Expected ExecutionException with NPE as cause");
+    } catch (final ExecutionException e) {
+      assertNotNull(e.getMessage());
+      assertNotNull(e.getCause());
+      assertEquals(NullPointerException.class, e.getCause().getClass());
+    }
+
+  }
+
+  /**
+   * Test used to verify the behaviour of {@link ThreadAsyncExecutor#startProcess(Callable, AsyncCallback)} when both
+   * the callable and the asynchronous callback are 'null'
+   */
+  @Test(timeout = 3000)
+  public void testNullTaskWithNullCallback() throws Exception {
+    // Instantiate a new executor and start a new 'null' task ...
+    final ThreadAsyncExecutor executor = new ThreadAsyncExecutor();
+    final AsyncResult<Object> asyncResult = executor.startProcess(null, null);
+
+    assertNotNull("The AsyncResult should not be 'null', even though the task and callback were 'null'.", asyncResult);
+    asyncResult.await(); // Prevent timing issues, and wait until the result is available
+    assertTrue(asyncResult.isCompleted());
+
+    try {
+      asyncResult.getValue();
+      fail("Expected ExecutionException with NPE as cause");
+    } catch (final ExecutionException e) {
+      assertNotNull(e.getMessage());
+      assertNotNull(e.getCause());
+      assertEquals(NullPointerException.class, e.getCause().getClass());
+    }
+
+  }
+
+}

bridge/index.md

@@ -4,19 +4,30 @@ title: Bridge
 folder: bridge
 permalink: /patterns/bridge/
 categories: Structural
-tags: Java
+tags:
+ - Java
+ - Gang Of Four
+ - Difficulty-Intermediate
 ---
 
-**Intent:** Decouple an abstraction from its implementation so that the two can
-vary independently.
+## Also known as
+Handle/Body
 
+## Intent
+Decouple an abstraction from its implementation so that the two can
+vary independently.
 
 ![alt text](./etc/bridge.png "Bridge")
 
-**Applicability:** Use the Bridge pattern when
+## Applicability
+Use the Bridge pattern when
 
 * you want to avoid a permanent binding between an abstraction and its implementation. This might be the case, for example, when the implementation must be selected or switched at run-time.
 * both the abstractions and their implementations should be extensible by subclassing. In this case, the Bridge pattern lets you combine the different abstractions and implementations and extend them independently
 * changes in the implementation of an abstraction should have no impact on clients; that is, their code should not have to be recompiled.
 * you have a proliferation of classes. Such a class hierarchy indicates the need for splitting an object into two parts. Rumbaugh uses the term "nested generalizations" to refer to such class hierarchies
 * you want to share an implementation among multiple objects (perhaps using reference counting), and this fact should be hidden from the client. A simple example is Coplien's String class, in which multiple objects can share the same string representation.
+
+## Credits
+
+* [Design Patterns: Elements of Reusable Object-Oriented Software](http://www.amazon.com/Design-Patterns-Elements-Reusable-Object-Oriented/dp/0201633612)

bridge/pom.xml

@@ -1,19 +1,47 @@
 <?xml version="1.0"?>
-<project
-	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
-	xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
-	<modelVersion>4.0.0</modelVersion>
-	<parent>
-		<groupId>com.iluwatar</groupId>
-		<artifactId>java-design-patterns</artifactId>
-		<version>1.6.0</version>
-	</parent>
-	<artifactId>bridge</artifactId>
-	<dependencies>
-		<dependency>
-			<groupId>junit</groupId>
-			<artifactId>junit</artifactId>
-			<scope>test</scope>
-		</dependency>
-	</dependencies>
+<!--
+
+    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.
+
+-->
+<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>com.iluwatar</groupId>
+    <artifactId>java-design-patterns</artifactId>
+    <version>1.10.0</version>
+  </parent>
+  <artifactId>bridge</artifactId>
+  <dependencies>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.mockito</groupId>
+      <artifactId>mockito-core</artifactId>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
 </project>

bridge/src/main/java/com/iluwatar/bridge/App.java

@@ -1,39 +1,61 @@
+/**
+ * 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.bridge;
 
 /**
  * 
- * In Bridge pattern both abstraction ({@link MagicWeapon}) and implementation
- * ({@link MagicWeaponImpl}) have their own class hierarchies. The interface of the
- * implementations can be changed without affecting the clients.
+ * The Bridge pattern can also be thought of as two layers of abstraction. With Bridge, you can
+ * decouple an abstraction from its implementation so that the two can vary independently.
+ * <p>
+ * In Bridge pattern both abstraction ({@link MagicWeapon}) and implementation (
+ * {@link MagicWeaponImpl}) have their own class hierarchies. The interface of the implementations
+ * can be changed without affecting the clients.
  * 
  */
 public class App {
 
-	/**
-	 * Program entry point
-	 * @param args command line args
-	 */
-	public static void main(String[] args) {
-		BlindingMagicWeapon blindingMagicWeapon = new BlindingMagicWeapon(
-				new Excalibur());
-		blindingMagicWeapon.wield();
-		blindingMagicWeapon.blind();
-		blindingMagicWeapon.swing();
-		blindingMagicWeapon.unwield();
+  /**
+   * Program entry point
+   * 
+   * @param args command line args
+   */
+  public static void main(String[] args) {
+    BlindingMagicWeapon blindingMagicWeapon = new BlindingMagicWeapon(new Excalibur());
+    blindingMagicWeapon.wield();
+    blindingMagicWeapon.blind();
+    blindingMagicWeapon.swing();
+    blindingMagicWeapon.unwield();
 
-		FlyingMagicWeapon flyingMagicWeapon = new FlyingMagicWeapon(
-				new Mjollnir());
-		flyingMagicWeapon.wield();
-		flyingMagicWeapon.fly();
-		flyingMagicWeapon.swing();
-		flyingMagicWeapon.unwield();
+    FlyingMagicWeapon flyingMagicWeapon = new FlyingMagicWeapon(new Mjollnir());
+    flyingMagicWeapon.wield();
+    flyingMagicWeapon.fly();
+    flyingMagicWeapon.swing();
+    flyingMagicWeapon.unwield();
 
-		SoulEatingMagicWeapon soulEatingMagicWeapon = new SoulEatingMagicWeapon(
-				new Stormbringer());
-		soulEatingMagicWeapon.wield();
-		soulEatingMagicWeapon.swing();
-		soulEatingMagicWeapon.eatSoul();
-		soulEatingMagicWeapon.unwield();
-
-	}
+    SoulEatingMagicWeapon soulEatingMagicWeapon = new SoulEatingMagicWeapon(new Stormbringer());
+    soulEatingMagicWeapon.wield();
+    soulEatingMagicWeapon.swing();
+    soulEatingMagicWeapon.eatSoul();
+    soulEatingMagicWeapon.unwield();
+  }
 }

bridge/src/main/java/com/iluwatar/bridge/BlindingMagicWeapon.java

@@ -1,3 +1,25 @@
+/**
+ * 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.bridge;
 
 /**
@@ -7,32 +29,31 @@ package com.iluwatar.bridge;
  */
 public class BlindingMagicWeapon extends MagicWeapon {
 
-	public BlindingMagicWeapon(BlindingMagicWeaponImpl imp) {
-		super(imp);
-	}
+  public BlindingMagicWeapon(BlindingMagicWeaponImpl imp) {
+    super(imp);
+  }
 
-	@Override
-	public BlindingMagicWeaponImpl getImp() {
-		return (BlindingMagicWeaponImpl) imp;
-	}
+  @Override
+  public BlindingMagicWeaponImpl getImp() {
+    return (BlindingMagicWeaponImpl) imp;
+  }
 
-	@Override
-	public void wield() {
-		getImp().wieldImp();
-	}
+  @Override
+  public void wield() {
+    getImp().wieldImp();
+  }
 
-	@Override
-	public void swing() {
-		getImp().swingImp();
-	}
+  @Override
+  public void swing() {
+    getImp().swingImp();
+  }
 
-	@Override
-	public void unwield() {
-		getImp().unwieldImp();
-	}
-
-	public void blind() {
-		getImp().blindImp();
-	}
+  @Override
+  public void unwield() {
+    getImp().unwieldImp();
+  }
 
+  public void blind() {
+    getImp().blindImp();
+  }
 }

bridge/src/main/java/com/iluwatar/bridge/BlindingMagicWeaponImpl.java

@@ -1,3 +1,25 @@
+/**
+ * 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.bridge;
 
 /**
@@ -7,6 +29,6 @@ package com.iluwatar.bridge;
  */
 public abstract class BlindingMagicWeaponImpl extends MagicWeaponImpl {
 
-	public abstract void blindImp();
+  public abstract void blindImp();
 
 }

bridge/src/main/java/com/iluwatar/bridge/Excalibur.java

@@ -1,3 +1,25 @@
+/**
+ * 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.bridge;
 
 /**
@@ -7,25 +29,23 @@ package com.iluwatar.bridge;
  */
 public class Excalibur extends BlindingMagicWeaponImpl {
 
-	@Override
-	public void wieldImp() {
-		System.out.println("wielding Excalibur");
-	}
+  @Override
+  public void wieldImp() {
+    System.out.println("wielding Excalibur");
+  }
 
-	@Override
-	public void swingImp() {
-		System.out.println("swinging Excalibur");
-	}
+  @Override
+  public void swingImp() {
+    System.out.println("swinging Excalibur");
+  }
 
-	@Override
-	public void unwieldImp() {
-		System.out.println("unwielding Excalibur");
-	}
-
-	@Override
-	public void blindImp() {
-		System.out
-				.println("bright light streams from Excalibur blinding the enemy");
-	}
+  @Override
+  public void unwieldImp() {
+    System.out.println("unwielding Excalibur");
+  }
 
+  @Override
+  public void blindImp() {
+    System.out.println("bright light streams from Excalibur blinding the enemy");
+  }
 }

bridge/src/main/java/com/iluwatar/bridge/FlyingMagicWeapon.java

@@ -1,3 +1,25 @@
+/**
+ * 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.bridge;
 
 /**
@@ -7,31 +29,31 @@ package com.iluwatar.bridge;
  */
 public class FlyingMagicWeapon extends MagicWeapon {
 
-	public FlyingMagicWeapon(FlyingMagicWeaponImpl imp) {
-		super(imp);
-	}
+  public FlyingMagicWeapon(FlyingMagicWeaponImpl imp) {
+    super(imp);
+  }
 
-	public FlyingMagicWeaponImpl getImp() {
-		return (FlyingMagicWeaponImpl) imp;
-	}
+  public FlyingMagicWeaponImpl getImp() {
+    return (FlyingMagicWeaponImpl) imp;
+  }
 
-	@Override
-	public void wield() {
-		getImp().wieldImp();
-	}
+  @Override
+  public void wield() {
+    getImp().wieldImp();
+  }
 
-	@Override
-	public void swing() {
-		getImp().swingImp();
-	}
+  @Override
+  public void swing() {
+    getImp().swingImp();
+  }
 
-	@Override
-	public void unwield() {
-		getImp().unwieldImp();
-	}
+  @Override
+  public void unwield() {
+    getImp().unwieldImp();
+  }
 
-	public void fly() {
-		getImp().flyImp();
-	}
+  public void fly() {
+    getImp().flyImp();
+  }
 
 }

bridge/src/main/java/com/iluwatar/bridge/FlyingMagicWeaponImpl.java

@@ -1,3 +1,25 @@
+/**
+ * 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.bridge;
 
 /**
@@ -7,6 +29,6 @@ package com.iluwatar.bridge;
  */
 public abstract class FlyingMagicWeaponImpl extends MagicWeaponImpl {
 
-	public abstract void flyImp();
+  public abstract void flyImp();
 
 }

bridge/src/main/java/com/iluwatar/bridge/MagicWeapon.java

@@ -1,3 +1,25 @@
+/**
+ * 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.bridge;
 
 /**
@@ -7,20 +29,19 @@ package com.iluwatar.bridge;
  */
 public abstract class MagicWeapon {
 
-	protected MagicWeaponImpl imp;
+  protected MagicWeaponImpl imp;
 
-	public MagicWeapon(MagicWeaponImpl imp) {
-		this.imp = imp;
-	}
+  public MagicWeapon(MagicWeaponImpl imp) {
+    this.imp = imp;
+  }
 
-	public abstract void wield();
+  public abstract void wield();
 
-	public abstract void swing();
+  public abstract void swing();
 
-	public abstract void unwield();
-
-	public MagicWeaponImpl getImp() {
-		return imp;
-	}
+  public abstract void unwield();
 
+  public MagicWeaponImpl getImp() {
+    return imp;
+  }
 }

bridge/src/main/java/com/iluwatar/bridge/MagicWeaponImpl.java

@@ -1,3 +1,25 @@
+/**
+ * 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.bridge;
 
 /**
@@ -7,10 +29,10 @@ package com.iluwatar.bridge;
  */
 public abstract class MagicWeaponImpl {
 
-	public abstract void wieldImp();
+  public abstract void wieldImp();
 
-	public abstract void swingImp();
+  public abstract void swingImp();
 
-	public abstract void unwieldImp();
+  public abstract void unwieldImp();
 
 }

bridge/src/main/java/com/iluwatar/bridge/Mjollnir.java

@@ -1,3 +1,25 @@
+/**
+ * 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.bridge;
 
 /**
@@ -7,25 +29,23 @@ package com.iluwatar.bridge;
  */
 public class Mjollnir extends FlyingMagicWeaponImpl {
 
-	@Override
-	public void wieldImp() {
-		System.out.println("wielding Mjollnir");
-	}
+  @Override
+  public void wieldImp() {
+    System.out.println("wielding Mjollnir");
+  }
 
-	@Override
-	public void swingImp() {
-		System.out.println("swinging Mjollnir");
-	}
+  @Override
+  public void swingImp() {
+    System.out.println("swinging Mjollnir");
+  }
 
-	@Override
-	public void unwieldImp() {
-		System.out.println("unwielding Mjollnir");
-	}
-
-	@Override
-	public void flyImp() {
-		System.out
-				.println("Mjollnir hits the enemy in the air and returns back to the owner's hand");
-	}
+  @Override
+  public void unwieldImp() {
+    System.out.println("unwielding Mjollnir");
+  }
 
+  @Override
+  public void flyImp() {
+    System.out.println("Mjollnir hits the enemy in the air and returns back to the owner's hand");
+  }
 }

bridge/src/main/java/com/iluwatar/bridge/SoulEatingMagicWeapon.java

@@ -1,3 +1,25 @@
+/**
+ * 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.bridge;
 
 /**
@@ -7,32 +29,32 @@ package com.iluwatar.bridge;
  */
 public class SoulEatingMagicWeapon extends MagicWeapon {
 
-	public SoulEatingMagicWeapon(SoulEatingMagicWeaponImpl imp) {
-		super(imp);
-	}
+  public SoulEatingMagicWeapon(SoulEatingMagicWeaponImpl imp) {
+    super(imp);
+  }
 
-	@Override
-	public SoulEatingMagicWeaponImpl getImp() {
-		return (SoulEatingMagicWeaponImpl) imp;
-	}
+  @Override
+  public SoulEatingMagicWeaponImpl getImp() {
+    return (SoulEatingMagicWeaponImpl) imp;
+  }
 
-	@Override
-	public void wield() {
-		getImp().wieldImp();
-	}
+  @Override
+  public void wield() {
+    getImp().wieldImp();
+  }
 
-	@Override
-	public void swing() {
-		getImp().swingImp();
-	}
+  @Override
+  public void swing() {
+    getImp().swingImp();
+  }
 
-	@Override
-	public void unwield() {
-		getImp().unwieldImp();
-	}
+  @Override
+  public void unwield() {
+    getImp().unwieldImp();
+  }
 
-	public void eatSoul() {
-		getImp().eatSoulImp();
-	}
+  public void eatSoul() {
+    getImp().eatSoulImp();
+  }
 
 }

bridge/src/main/java/com/iluwatar/bridge/SoulEatingMagicWeaponImpl.java

@@ -1,3 +1,25 @@
+/**
+ * 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.bridge;
 
 /**
@@ -7,6 +29,6 @@ package com.iluwatar.bridge;
  */
 public abstract class SoulEatingMagicWeaponImpl extends MagicWeaponImpl {
 
-	public abstract void eatSoulImp();
+  public abstract void eatSoulImp();
 
 }

bridge/src/main/java/com/iluwatar/bridge/Stormbringer.java

@@ -1,3 +1,25 @@
+/**
+ * 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.bridge;
 
 /**
@@ -7,24 +29,23 @@ package com.iluwatar.bridge;
  */
 public class Stormbringer extends SoulEatingMagicWeaponImpl {
 
-	@Override
-	public void wieldImp() {
-		System.out.println("wielding Stormbringer");
-	}
+  @Override
+  public void wieldImp() {
+    System.out.println("wielding Stormbringer");
+  }
 
-	@Override
-	public void swingImp() {
-		System.out.println("swinging Stormbringer");
-	}
+  @Override
+  public void swingImp() {
+    System.out.println("swinging Stormbringer");
+  }
 
-	@Override
-	public void unwieldImp() {
-		System.out.println("unwielding Stormbringer");
-	}
-
-	@Override
-	public void eatSoulImp() {
-		System.out.println("Stormbringer devours the enemy's soul");
-	}
+  @Override
+  public void unwieldImp() {
+    System.out.println("unwielding Stormbringer");
+  }
 
+  @Override
+  public void eatSoulImp() {
+    System.out.println("Stormbringer devours the enemy's soul");
+  }
 }

bridge/src/test/java/com/iluwatar/bridge/AppTest.java

@@ -1,9 +1,29 @@
+/**
+ * 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.bridge;
 
 import org.junit.Test;
 
-import com.iluwatar.bridge.App;
-
 /**
  * 
  * Application test
@@ -11,9 +31,9 @@ import com.iluwatar.bridge.App;
  */
 public class AppTest {
 
-	@Test
-	public void test() {
-		String[] args = {};
-		App.main(args);
-	}
+  @Test
+  public void test() {
+    String[] args = {};
+    App.main(args);
+  }
 }

bridge/src/test/java/com/iluwatar/bridge/BlindingMagicWeaponTest.java

@@ -0,0 +1,55 @@
+/**
+ * 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.bridge;
+
+import org.junit.Test;
+
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+import static org.mockito.internal.verification.VerificationModeFactory.times;
+
+/**
+ * Date: 12/6/15 - 11:15 PM
+ *
+ * @author Jeroen Meulemeester
+ */
+public class BlindingMagicWeaponTest extends MagicWeaponTest {
+
+  /**
+   * Invoke all possible actions on the weapon and check if the actions are executed on the actual
+   * underlying weapon implementation.
+   */
+  @Test
+  public void testExcalibur() throws Exception {
+    final Excalibur excalibur = spy(new Excalibur());
+    final BlindingMagicWeapon blindingMagicWeapon = new BlindingMagicWeapon(excalibur);
+
+    testBasicWeaponActions(blindingMagicWeapon, excalibur);
+
+    blindingMagicWeapon.blind();
+    verify(excalibur, times(1)).blindImp();
+    verifyNoMoreInteractions(excalibur);
+  }
+
+}

bridge/src/test/java/com/iluwatar/bridge/FlyingMagicWeaponTest.java

@@ -0,0 +1,55 @@
+/**
+ * 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.bridge;
+
+import org.junit.Test;
+
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+import static org.mockito.internal.verification.VerificationModeFactory.times;
+
+/**
+ * Date: 12/6/15 - 11:26 PM
+ *
+ * @author Jeroen Meulemeester
+ */
+public class FlyingMagicWeaponTest extends MagicWeaponTest {
+
+  /**
+   * Invoke all possible actions on the weapon and check if the actions are executed on the actual
+   * underlying weapon implementation.
+   */
+  @Test
+  public void testMjollnir() throws Exception {
+    final Mjollnir mjollnir = spy(new Mjollnir());
+    final FlyingMagicWeapon flyingMagicWeapon = new FlyingMagicWeapon(mjollnir);
+
+    testBasicWeaponActions(flyingMagicWeapon, mjollnir);
+
+    flyingMagicWeapon.fly();
+    verify(mjollnir, times(1)).flyImp();
+    verifyNoMoreInteractions(mjollnir);
+  }
+
+}

bridge/src/test/java/com/iluwatar/bridge/MagicWeaponTest.java

@@ -0,0 +1,64 @@
+/**
+ * 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.bridge;
+
+import static org.junit.Assert.assertNotNull;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+import static org.mockito.internal.verification.VerificationModeFactory.times;
+
+/**
+ * Date: 12/6/15 - 11:28 PM
+ *
+ * @author Jeroen Meulemeester
+ */
+public abstract class MagicWeaponTest {
+
+  /**
+   * Invoke the basic actions of the given weapon, and test if the underlying weapon implementation
+   * is invoked
+   *
+   * @param weaponImpl The spied weapon implementation where actions are bridged to
+   * @param weapon               The weapon, handled by the app
+   */
+  protected final void testBasicWeaponActions(final MagicWeapon weapon,
+                                              final MagicWeaponImpl weaponImpl) {
+    assertNotNull(weapon);
+    assertNotNull(weaponImpl);
+    assertNotNull(weapon.getImp());
+
+    weapon.swing();
+    verify(weaponImpl, times(1)).swingImp();
+    verifyNoMoreInteractions(weaponImpl);
+
+    weapon.wield();
+    verify(weaponImpl, times(1)).wieldImp();
+    verifyNoMoreInteractions(weaponImpl);
+
+    weapon.unwield();
+    verify(weaponImpl, times(1)).unwieldImp();
+    verifyNoMoreInteractions(weaponImpl);
+
+  }
+
+}

bridge/src/test/java/com/iluwatar/bridge/SoulEatingMagicWeaponTest.java

@@ -0,0 +1,55 @@
+/**
+ * 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.bridge;
+
+import org.junit.Test;
+
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyNoMoreInteractions;
+import static org.mockito.internal.verification.VerificationModeFactory.times;
+
+/**
+ * Date: 12/6/15 - 11:43 PM
+ *
+ * @author Jeroen Meulemeester
+ */
+public class SoulEatingMagicWeaponTest extends MagicWeaponTest {
+
+  /**
+   * Invoke all possible actions on the weapon and check if the actions are executed on the actual
+   * underlying weapon implementation.
+   */
+  @Test
+  public void testStormBringer() throws Exception {
+    final Stormbringer stormbringer = spy(new Stormbringer());
+    final SoulEatingMagicWeapon soulEatingMagicWeapon = new SoulEatingMagicWeapon(stormbringer);
+
+    testBasicWeaponActions(soulEatingMagicWeapon, stormbringer);
+
+    soulEatingMagicWeapon.eatSoul();
+    verify(stormbringer, times(1)).eatSoulImp();
+    verifyNoMoreInteractions(stormbringer);
+  }
+
+}

builder/index.md

@@ -4,21 +4,31 @@ title: Builder
 folder: builder
 permalink: /patterns/builder/
 categories: Creational
-tags: Java
+tags:
+ - Java
+ - Gang Of Four
+ - Difficulty-Intermediate
 ---
 
-**Intent:** Separate the construction of a complex object from its
+## Intent
+Separate the construction of a complex object from its
 representation so that the same construction process can create different
 representations.
 
 ![alt text](./etc/builder_1.png "Builder")
 
-**Applicability:** Use the Builder pattern when
+## Applicability
+Use the Builder pattern when
 
 * the algorithm for creating a complex object should be independent of the parts that make up the object and how they're assembled
 * the construction process must allow different representations for the object that's constructed
 
-**Real world examples:**
+## Real world examples
 
 * [java.lang.StringBuilder](http://docs.oracle.com/javase/8/docs/api/java/lang/StringBuilder.html)
 * [Apache Camel builders](https://github.com/apache/camel/tree/0e195428ee04531be27a0b659005e3aa8d159d23/camel-core/src/main/java/org/apache/camel/builder)
+
+## Credits
+
+* [Design Patterns: Elements of Reusable Object-Oriented Software](http://www.amazon.com/Design-Patterns-Elements-Reusable-Object-Oriented/dp/0201633612)
+* [Effective Java (2nd Edition)](http://www.amazon.com/Effective-Java-Edition-Joshua-Bloch/dp/0321356683)

builder/pom.xml

@@ -1,19 +1,42 @@
 <?xml version="1.0"?>
-<project
-	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
-	xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
-	<modelVersion>4.0.0</modelVersion>
-	<parent>
-		<groupId>com.iluwatar</groupId>
-		<artifactId>java-design-patterns</artifactId>
-		<version>1.6.0</version>
-	</parent>
-	<artifactId>builder</artifactId>
-	<dependencies>
-		<dependency>
-			<groupId>junit</groupId>
-			<artifactId>junit</artifactId>
-			<scope>test</scope>
-		</dependency>
-	</dependencies>
+<!--
+
+    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.
+
+-->
+<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>com.iluwatar</groupId>
+    <artifactId>java-design-patterns</artifactId>
+    <version>1.10.0</version>
+  </parent>
+  <artifactId>builder</artifactId>
+  <dependencies>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
 </project>

builder/src/main/java/com/iluwatar/builder/App.java

@@ -1,42 +1,77 @@
+/**
+ * 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.builder;
 
-import com.iluwatar. builder.Hero.HeroBuilder;
+import com.iluwatar.builder.Hero.HeroBuilder;
 
 /**
  * 
- * This is the Builder pattern variation as described by Joshua Bloch in
- * Effective Java 2nd Edition.
+ * The intention of the Builder pattern is to find a solution to the telescoping constructor
+ * anti-pattern. The telescoping constructor anti-pattern occurs when the increase of object
+ * constructor parameter combination leads to an exponential list of constructors. Instead of using
+ * numerous constructors, the builder pattern uses another object, a builder, that receives each
+ * initialization parameter step by step and then returns the resulting constructed object at once.
  * <p>
- * We want to build {@link Hero} objects, but its construction is complex because of the
- * many parameters needed. To aid the user we introduce {@link HeroBuilder} class.
- * {@link HeroBuilder} takes the minimum parameters to build {@link Hero} object in its
- * constructor. After that additional configuration for the {@link Hero} object can be
- * done using the fluent {@link HeroBuilder} interface. When configuration is ready the
- * build method is called to receive the final {@link Hero} object.
+ * The Builder pattern has another benefit. It can be used for objects that contain flat data (html
+ * code, SQL query, X.509 certificate...), that is to say, data that can't be easily edited. This
+ * type of data cannot be edited step by step and must be edited at once. The best way to construct
+ * such an object is to use a builder class.
+ * <p>
+ * In this example we have the Builder pattern variation as described by Joshua Bloch in Effective
+ * Java 2nd Edition.
+ * <p>
+ * We want to build {@link Hero} objects, but its construction is complex because of the many
+ * parameters needed. To aid the user we introduce {@link HeroBuilder} class. {@link HeroBuilder}
+ * takes the minimum parameters to build {@link Hero} object in its constructor. After that
+ * additional configuration for the {@link Hero} object can be done using the fluent
+ * {@link HeroBuilder} interface. When configuration is ready the build method is called to receive
+ * the final {@link Hero} object.
  * 
  */
 public class App {
 
-	/**
-	 * Program entry point
-	 * @param args command line args
-	 */
-	public static void main(String[] args) {
+  /**
+   * Program entry point
+   * 
+   * @param args command line args
+   */
+  public static void main(String[] args) {
 
-		Hero mage = new HeroBuilder(Profession.MAGE, "Riobard")
-				.withHairColor(HairColor.BLACK).withWeapon(Weapon.DAGGER)
-				.build();
-		System.out.println(mage);
+    Hero mage =
+        new HeroBuilder(Profession.MAGE, "Riobard").withHairColor(HairColor.BLACK)
+            .withWeapon(Weapon.DAGGER).build();
+    System.out.println(mage);
 
-		Hero warrior = new HeroBuilder(Profession.WARRIOR, "Amberjill")
-				.withHairColor(HairColor.BLOND)
-				.withHairType(HairType.LONG_CURLY).withArmor(Armor.CHAIN_MAIL)
-				.withWeapon(Weapon.SWORD).build();
-		System.out.println(warrior);
+    Hero warrior =
+        new HeroBuilder(Profession.WARRIOR, "Amberjill").withHairColor(HairColor.BLOND)
+            .withHairType(HairType.LONG_CURLY).withArmor(Armor.CHAIN_MAIL).withWeapon(Weapon.SWORD)
+            .build();
+    System.out.println(warrior);
 
-		Hero thief = new HeroBuilder(Profession.THIEF, "Desmond")
-				.withHairType(HairType.BALD).withWeapon(Weapon.BOW).build();
-		System.out.println(thief);
+    Hero thief =
+        new HeroBuilder(Profession.THIEF, "Desmond").withHairType(HairType.BALD)
+            .withWeapon(Weapon.BOW).build();
+    System.out.println(thief);
 
-	}
+  }
 }

builder/src/main/java/com/iluwatar/builder/Armor.java

@@ -1,3 +1,25 @@
+/**
+ * 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.builder;
 
 /**
@@ -7,16 +29,16 @@ package com.iluwatar.builder;
  */
 public enum Armor {
 
-	CLOTHES("clothes"), LEATHER("leather"), CHAIN_MAIL("chain mail"), PLATE_MAIL("plate mail");
+  CLOTHES("clothes"), LEATHER("leather"), CHAIN_MAIL("chain mail"), PLATE_MAIL("plate mail");
 
-    private String title;
+  private String title;
 
-    Armor(String title) {
-        this.title = title;
-    }
+  Armor(String title) {
+    this.title = title;
+  }
 
-    @Override
-	public String toString() {
-		return title;
-	}
+  @Override
+  public String toString() {
+    return title;
+  }
 }

builder/src/main/java/com/iluwatar/builder/HairColor.java

@@ -1,3 +1,25 @@
+/**
+ * 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.builder;
 
 /**
@@ -7,11 +29,11 @@ package com.iluwatar.builder;
  */
 public enum HairColor {
 
-	WHITE, BLOND, RED, BROWN, BLACK;
+  WHITE, BLOND, RED, BROWN, BLACK;
 
-	@Override
-	public String toString() {
-		return name().toLowerCase();
-	}
+  @Override
+  public String toString() {
+    return name().toLowerCase();
+  }
 
 }

builder/src/main/java/com/iluwatar/builder/HairType.java

@@ -1,3 +1,25 @@
+/**
+ * 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.builder;
 
 /**
@@ -7,16 +29,17 @@ package com.iluwatar.builder;
  */
 public enum HairType {
 
-	BALD("bald"), SHORT("short"), CURLY("curly"), LONG_STRAIGHT("long straight"), LONG_CURLY("long curly");
+  BALD("bald"), SHORT("short"), CURLY("curly"), LONG_STRAIGHT("long straight"), LONG_CURLY(
+      "long curly");
 
-    private String title;
+  private String title;
 
-    HairType(String title) {
-        this.title = title;
-    }
+  HairType(String title) {
+    this.title = title;
+  }
 
-    @Override
-	public String toString() {
-		return title;
-	}
+  @Override
+  public String toString() {
+    return title;
+  }
 }

builder/src/main/java/com/iluwatar/builder/Hero.java

@@ -1,3 +1,25 @@
+/**
+ * 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.builder;
 
 /**
@@ -7,123 +29,121 @@ package com.iluwatar.builder;
  */
 public class Hero {
 
-	private final Profession profession;
-	private final String name;
-	private final HairType hairType;
-	private final HairColor hairColor;
-	private final Armor armor;
-	private final Weapon weapon;
+  private final Profession profession;
+  private final String name;
+  private final HairType hairType;
+  private final HairColor hairColor;
+  private final Armor armor;
+  private final Weapon weapon;
 
-	public Profession getProfession() {
-		return profession;
-	}
+  public Profession getProfession() {
+    return profession;
+  }
 
-	public String getName() {
-		return name;
-	}
+  public String getName() {
+    return name;
+  }
 
-	public HairType getHairType() {
-		return hairType;
-	}
+  public HairType getHairType() {
+    return hairType;
+  }
 
-	public HairColor getHairColor() {
-		return hairColor;
-	}
+  public HairColor getHairColor() {
+    return hairColor;
+  }
 
-	public Armor getArmor() {
-		return armor;
-	}
+  public Armor getArmor() {
+    return armor;
+  }
 
-	public Weapon getWeapon() {
-		return weapon;
-	}
+  public Weapon getWeapon() {
+    return weapon;
+  }
 
-	@Override
-	public String toString() {
+  @Override
+  public String toString() {
 
-		StringBuilder sb = new StringBuilder();
-		sb.append("This is a ");
-		sb.append(profession);
-		sb.append(" named ");
-		sb.append(name);
-		if (hairColor != null || hairType != null) {
-			sb.append(" with ");
-			if (hairColor != null) {
-				sb.append(hairColor);
-				sb.append(" ");
-			}
-			if (hairType != null) {
-				sb.append(hairType);
-				sb.append(" ");
-			}
-			sb.append(hairType != HairType.BALD ? "hair" : "head");
-		}
-		if (armor != null) {
-			sb.append(" wearing ");
-			sb.append(armor);
-		}
-		if (weapon != null) {
-			sb.append(" and wielding a ");
-			sb.append(weapon);
-		}
-		sb.append(".");
-		return sb.toString();
-	}
+    StringBuilder sb = new StringBuilder();
+    sb.append("This is a ")
+            .append(profession)
+            .append(" named ")
+            .append(name);
+    if (hairColor != null || hairType != null) {
+      sb.append(" with ");
+      if (hairColor != null) {
+        sb.append(hairColor).append(' ');
+      }
+      if (hairType != null) {
+        sb.append(hairType).append(' ');
+      }
+      sb.append(hairType != HairType.BALD ? "hair" : "head");
+    }
+    if (armor != null) {
+      sb.append(" wearing ").append(armor);
+    }
+    if (weapon != null) {
+      sb.append(" and wielding a ").append(weapon);
+    }
+    sb.append('.');
+    return sb.toString();
+  }
 
-	private Hero(HeroBuilder builder) {
-		this.profession = builder.profession;
-		this.name = builder.name;
-		this.hairColor = builder.hairColor;
-		this.hairType = builder.hairType;
-		this.weapon = builder.weapon;
-		this.armor = builder.armor;
-	}
+  private Hero(HeroBuilder builder) {
+    this.profession = builder.profession;
+    this.name = builder.name;
+    this.hairColor = builder.hairColor;
+    this.hairType = builder.hairType;
+    this.weapon = builder.weapon;
+    this.armor = builder.armor;
+  }
 
-	/**
-	 * 
-	 * The builder class.
-	 * 
-	 */
-	public static class HeroBuilder {
+  /**
+   * 
+   * The builder class.
+   * 
+   */
+  public static class HeroBuilder {
 
-		private final Profession profession;
-		private final String name;
-		private HairType hairType;
-		private HairColor hairColor;
-		private Armor armor;
-		private Weapon weapon;
+    private final Profession profession;
+    private final String name;
+    private HairType hairType;
+    private HairColor hairColor;
+    private Armor armor;
+    private Weapon weapon;
 
-		public HeroBuilder(Profession profession, String name) {
-			if (profession == null || name == null) {
-				throw new IllegalArgumentException(
-						"profession and name can not be null");
-			}
-			this.profession = profession;
-			this.name = name;
-		}
+    /**
+     * Constructor
+     */
+    public HeroBuilder(Profession profession, String name) {
+      if (profession == null || name == null) {
+        throw new IllegalArgumentException("profession and name can not be null");
+      }
+      this.profession = profession;
+      this.name = name;
+    }
 
-		public HeroBuilder withHairType(HairType hairType) {
-			this.hairType = hairType;
-			return this;
-		}
+    public HeroBuilder withHairType(HairType hairType) {
+      this.hairType = hairType;
+      return this;
+    }
 
-		public HeroBuilder withHairColor(HairColor hairColor) {
-			this.hairColor = hairColor;
-			return this;
-		}
+    public HeroBuilder withHairColor(HairColor hairColor) {
+      this.hairColor = hairColor;
+      return this;
+    }
 
-		public HeroBuilder withArmor(Armor armor) {
-			this.armor = armor;
-			return this;
-		}
+    public HeroBuilder withArmor(Armor armor) {
+      this.armor = armor;
+      return this;
+    }
 
-		public HeroBuilder withWeapon(Weapon weapon) {
-			this.weapon = weapon;
-			return this;
-		}
+    public HeroBuilder withWeapon(Weapon weapon) {
+      this.weapon = weapon;
+      return this;
+    }
 
-		public Hero build() {
-			return new Hero(this);
-		}
-	}
+    public Hero build() {
+      return new Hero(this);
+    }
+  }
 }

builder/src/main/java/com/iluwatar/builder/Profession.java

@@ -1,3 +1,25 @@
+/**
+ * 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.builder;
 
 /**
@@ -7,11 +29,10 @@ package com.iluwatar.builder;
  */
 public enum Profession {
 
-	WARRIOR, THIEF, MAGE, PRIEST;
-
-	@Override
-	public String toString() {
-		return name().toLowerCase();
-	}
+  WARRIOR, THIEF, MAGE, PRIEST;
 
+  @Override
+  public String toString() {
+    return name().toLowerCase();
+  }
 }

builder/src/main/java/com/iluwatar/builder/Weapon.java

@@ -1,3 +1,25 @@
+/**
+ * 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.builder;
 
 /**
@@ -7,11 +29,10 @@ package com.iluwatar.builder;
  */
 public enum Weapon {
 
-	DAGGER, SWORD, AXE, WARHAMMER, BOW;
-
-	@Override
-	public String toString() {
-		return name().toLowerCase();
-	}
+  DAGGER, SWORD, AXE, WARHAMMER, BOW;
 
+  @Override
+  public String toString() {
+    return name().toLowerCase();
+  }
 }

builder/src/test/java/com/iluwatar/builder/AppTest.java

@@ -1,9 +1,29 @@
+/**
+ * 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.builder;
 
 import org.junit.Test;
 
-import com.iluwatar. builder.App;
-
 /**
  * 
  * Application test
@@ -11,9 +31,9 @@ import com.iluwatar. builder.App;
  */
 public class AppTest {
 
-	@Test
-	public void test() {
-		String[] args = {};
-		App.main(args);
-	}
+  @Test
+  public void test() {
+    String[] args = {};
+    App.main(args);
+  }
 }

builder/src/test/java/com/iluwatar/builder/HeroTest.java

@@ -0,0 +1,78 @@
+/**
+ * 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.builder;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+
+/**
+ * Date: 12/6/15 - 11:01 PM
+ *
+ * @author Jeroen Meulemeester
+ */
+public class HeroTest {
+
+  /**
+   * Test if we get the expected exception when trying to create a hero without a profession
+   */
+  @Test(expected = IllegalArgumentException.class)
+  public void testMissingProfession() throws Exception {
+    new Hero.HeroBuilder(null, "Sir without a job");
+  }
+
+  /**
+   * Test if we get the expected exception when trying to create a hero without a name
+   */
+  @Test(expected = IllegalArgumentException.class)
+  public void testMissingName() throws Exception {
+    new Hero.HeroBuilder(Profession.THIEF, null);
+  }
+
+  /**
+   * Test if the hero build by the builder has the correct attributes, as requested
+   */
+  @Test
+  public void testBuildHero() throws Exception {
+    final String heroName = "Sir Lancelot";
+
+    final Hero hero = new Hero.HeroBuilder(Profession.WARRIOR, heroName)
+        .withArmor(Armor.CHAIN_MAIL)
+        .withWeapon(Weapon.SWORD)
+        .withHairType(HairType.LONG_CURLY)
+        .withHairColor(HairColor.BLOND)
+        .build();
+
+    assertNotNull(hero);
+    assertNotNull(hero.toString());
+    assertEquals(Profession.WARRIOR, hero.getProfession());
+    assertEquals(heroName, hero.getName());
+    assertEquals(Armor.CHAIN_MAIL, hero.getArmor());
+    assertEquals(Weapon.SWORD, hero.getWeapon());
+    assertEquals(HairType.LONG_CURLY, hero.getHairType());
+    assertEquals(HairColor.BLOND, hero.getHairColor());
+
+  }
+
+}

business-delegate/index.md

@@ -4,18 +4,25 @@ title: Business Delegate
 folder: business-delegate
 permalink: /patterns/business-delegate/
 categories: Business Tier
-tags: Java
+tags:
+ - Java
+ - Difficulty-Intermediate
 ---
 
-**Intent:** The Business Delegate pattern adds an abstraction layer between
+## Intent
+The Business Delegate pattern adds an abstraction layer between
 presentation and business tiers. By using the pattern we gain loose coupling
 between the tiers and encapsulate knowledge about how to locate, connect to,
 and interact with the business objects that make up the application.
 
 ![alt text](./etc/business-delegate.png "Business Delegate")
 
-**Applicability:** Use the Business Delegate pattern when
+## Applicability
+Use the Business Delegate pattern when
 
 * you want loose coupling between presentation and business tiers
 * you want to orchestrate calls to multiple business services
 * you want to encapsulate service lookups and service calls
+
+##Credits
+* [J2EE Design Patterns](http://www.amazon.com/J2EE-Design-Patterns-William-Crawford/dp/0596004273/ref=sr_1_2)

business-delegate/pom.xml

@@ -1,4 +1,28 @@
 <?xml version="1.0"?>
+<!--
+
+    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.
+
+-->
 <project
 	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
 	xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
@@ -6,7 +30,7 @@
 	<parent>
 		<groupId>com.iluwatar</groupId>
 		<artifactId>java-design-patterns</artifactId>
-		<version>1.6.0</version>
+		<version>1.10.0</version>
 	</parent>
 	<artifactId>business-delegate</artifactId>
 	<dependencies>
@@ -15,5 +39,10 @@
 			<artifactId>junit</artifactId>
 			<scope>test</scope>
 		</dependency>
+		<dependency>
+			<groupId>org.mockito</groupId>
+			<artifactId>mockito-core</artifactId>
+			<scope>test</scope>
+		</dependency>
 	</dependencies>
 </project>

business-delegate/src/main/java/com/iluwatar/business/delegate/App.java

@@ -1,35 +1,62 @@
+/**
+ * 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.business.delegate;
 
 /**
+ * The Business Delegate pattern adds an abstraction layer between the presentation and business
+ * tiers. By using the pattern we gain loose coupling between the tiers. The Business Delegate
+ * encapsulates knowledge about how to locate, connect to, and interact with the business objects
+ * that make up the application.
  * 
- * The Business Delegate pattern adds an abstraction layer between the presentation and business tiers.
- * By using the pattern we gain loose coupling between the tiers. The Business Delegate encapsulates
- * knowledge about how to locate, connect to, and interact with the business objects that make up
- * the application.
- * <p>
- * Some of the services the Business Delegate uses are instantiated directly, and some can be retrieved
- * through service lookups. The Business Delegate itself may contain business logic too potentially tying
- * together multiple service calls, exception handling, retrying etc.
- * <p>
- * In this example the client ({@link Client}) utilizes a business delegate ({@link BusinessDelegate}) to execute a task.
- * The Business Delegate then selects the appropriate service and makes the service call.
- *
+ * <p>Some of the services the Business Delegate uses are instantiated directly, and some can be
+ * retrieved through service lookups. The Business Delegate itself may contain business logic too
+ * potentially tying together multiple service calls, exception handling, retrying etc.
+ * 
+ * <p>In this example the client ({@link Client}) utilizes a business delegate (
+ * {@link BusinessDelegate}) to execute a task. The Business Delegate then selects the appropriate
+ * service and makes the service call.
  */
 public class App {
-	
-	/**
-	 * Program entry point
-	 * @param args command line args
-	 */
-	public static void main(String[] args) {
-		
-		BusinessDelegate businessDelegate = new BusinessDelegate();
-		businessDelegate.setServiceType(ServiceType.EJB);
 
-		Client client = new Client(businessDelegate);
-		client.doTask();
+  /**
+   * Program entry point.
+   *
+   * @param args command line args
+   */
+  public static void main(String[] args) {
 
-		businessDelegate.setServiceType(ServiceType.JMS);
-		client.doTask();
-	}
+    BusinessDelegate businessDelegate = new BusinessDelegate();
+    BusinessLookup businessLookup = new BusinessLookup();
+    businessLookup.setEjbService(new EjbService());
+    businessLookup.setJmsService(new JmsService());
+
+    businessDelegate.setLookupService(businessLookup);
+    businessDelegate.setServiceType(ServiceType.EJB);
+
+    Client client = new Client(businessDelegate);
+    client.doTask();
+
+    businessDelegate.setServiceType(ServiceType.JMS);
+    client.doTask();
+  }
 }

business-delegate/src/main/java/com/iluwatar/business/delegate/BusinessDelegate.java

@@ -1,22 +1,46 @@
+/**
+ * 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.business.delegate;
 
 /**
- * 
  * BusinessDelegate separates the presentation and business tiers
- *
  */
 public class BusinessDelegate {
-	
-	private BusinessLookup lookupService = new BusinessLookup();
-	private BusinessService businessService;
-	private ServiceType serviceType;
 
-	public void setServiceType(ServiceType serviceType) {
-		this.serviceType = serviceType;
-	}
+  private BusinessLookup lookupService;
+  private BusinessService businessService;
+  private ServiceType serviceType;
 
-	public void doTask() {
-		businessService = lookupService.getBusinessService(serviceType);
-		businessService.doProcessing();
-	}
+  public void setLookupService(BusinessLookup businessLookup) {
+    this.lookupService = businessLookup;
+  }
+
+  public void setServiceType(ServiceType serviceType) {
+    this.serviceType = serviceType;
+  }
+
+  public void doTask() {
+    businessService = lookupService.getBusinessService(serviceType);
+    businessService.doProcessing();
+  }
 }

business-delegate/src/main/java/com/iluwatar/business/delegate/BusinessLookup.java

@@ -1,17 +1,53 @@
+/**
+ * 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.business.delegate;
 
 /**
- * 
- * Class for performing service lookups
- *
+ * Class for performing service lookups.
  */
 public class BusinessLookup {
 
-	public BusinessService getBusinessService(ServiceType serviceType) {
-		if (serviceType.equals(ServiceType.EJB)) {
-			return new EjbService();
-		} else {
-			return new JmsService();
-		}
-	}
+  private EjbService ejbService;
+
+  private JmsService jmsService;
+
+  /**
+   * @param serviceType Type of service instance to be returned.
+   * @return Service instance.
+   */
+  public BusinessService getBusinessService(ServiceType serviceType) {
+    if (serviceType.equals(ServiceType.EJB)) {
+      return ejbService;
+    } else {
+      return jmsService;
+    }
+  }
+
+  public void setJmsService(JmsService jmsService) {
+    this.jmsService = jmsService;
+  }
+
+  public void setEjbService(EjbService ejbService) {
+    this.ejbService = ejbService;
+  }
 }

business-delegate/src/main/java/com/iluwatar/business/delegate/BusinessService.java

@@ -1,3 +1,25 @@
+/**
+ * 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.business.delegate;
 
 /**
@@ -7,5 +29,5 @@ package com.iluwatar.business.delegate;
  */
 public interface BusinessService {
 
-	void doProcessing();
+  void doProcessing();
 }

business-delegate/src/main/java/com/iluwatar/business/delegate/Client.java

@@ -1,3 +1,25 @@
+/**
+ * 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.business.delegate;
 
 /**
@@ -7,13 +29,13 @@ package com.iluwatar.business.delegate;
  */
 public class Client {
 
-	private BusinessDelegate businessDelegate;
+  private BusinessDelegate businessDelegate;
 
-	public Client(BusinessDelegate businessDelegate) {
-		this.businessDelegate = businessDelegate;
-	}
+  public Client(BusinessDelegate businessDelegate) {
+    this.businessDelegate = businessDelegate;
+  }
 
-	public void doTask() {
-		businessDelegate.doTask();
-	}
+  public void doTask() {
+    businessDelegate.doTask();
+  }
 }

business-delegate/src/main/java/com/iluwatar/business/delegate/EjbService.java

@@ -1,3 +1,25 @@
+/**
+ * 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.business.delegate;
 
 /**
@@ -7,8 +29,8 @@ package com.iluwatar.business.delegate;
  */
 public class EjbService implements BusinessService {
 
-	@Override
-	public void doProcessing() {
-		System.out.println("EjbService is now processing");
-	}
+  @Override
+  public void doProcessing() {
+    System.out.println("EjbService is now processing");
+  }
 }

business-delegate/src/main/java/com/iluwatar/business/delegate/JmsService.java

@@ -1,3 +1,25 @@
+/**
+ * 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.business.delegate;
 
 /**
@@ -7,8 +29,8 @@ package com.iluwatar.business.delegate;
  */
 public class JmsService implements BusinessService {
 
-	@Override
-	public void doProcessing() {
-		System.out.println("JmsService is now processing");
-	}
+  @Override
+  public void doProcessing() {
+    System.out.println("JmsService is now processing");
+  }
 }

business-delegate/src/main/java/com/iluwatar/business/delegate/ServiceType.java

@@ -1,3 +1,25 @@
+/**
+ * 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.business.delegate;
 
 /**
@@ -6,6 +28,6 @@ package com.iluwatar.business.delegate;
  *
  */
 public enum ServiceType {
-	
-	EJB, JMS;
+
+  EJB, JMS;
 }

business-delegate/src/test/java/com/iluwatar/business/delegate/AppTest.java

@@ -1,19 +1,38 @@
+/**
+ * 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.business.delegate;
 
 import org.junit.Test;
 
-import com.iluwatar.business.delegate.App;
+import java.io.IOException;
 
 /**
- * 
- * Application test
- *
+ * Tests that Business Delegate example runs without errors.
  */
 public class AppTest {
-	
-	@Test
-	public void test() {
-		String[] args = {};
-		App.main(args);
-	}
+  @Test
+  public void test() throws IOException {
+    String[] args = {};
+    App.main(args);
+  }
 }

business-delegate/src/test/java/com/iluwatar/business/delegate/BusinessDelegateTest.java

@@ -0,0 +1,100 @@
+/**
+ * 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.business.delegate;
+
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * The Business Delegate pattern adds an abstraction layer between the presentation and business
+ * tiers. By using the pattern we gain loose coupling between the tiers. The Business Delegate
+ * encapsulates knowledge about how to locate, connect to, and interact with the business objects
+ * that make up the application.
+ * 
+ * <p>Some of the services the Business Delegate uses are instantiated directly, and some can be
+ * retrieved through service lookups. The Business Delegate itself may contain business logic too
+ * potentially tying together multiple service calls, exception handling, retrying etc.
+ */
+public class BusinessDelegateTest {
+
+  private EjbService ejbService;
+
+  private JmsService jmsService;
+
+  private BusinessLookup businessLookup;
+
+  private BusinessDelegate businessDelegate;
+
+  /**
+   * This method sets up the instance variables of this test class. It is executed before the
+   * execution of every test.
+   */
+  @Before
+  public void setup() {
+    ejbService = spy(new EjbService());
+    jmsService = spy(new JmsService());
+
+    businessLookup = spy(new BusinessLookup());
+    businessLookup.setEjbService(ejbService);
+    businessLookup.setJmsService(jmsService);
+
+    businessDelegate = spy(new BusinessDelegate());
+    businessDelegate.setLookupService(businessLookup);
+  }
+
+  /**
+   * In this example the client ({@link Client}) utilizes a business delegate (
+   * {@link BusinessDelegate}) to execute a task. The Business Delegate then selects the appropriate
+   * service and makes the service call.
+   */
+  @Test
+  public void testBusinessDelegate() {
+
+    // setup a client object
+    Client client = new Client(businessDelegate);
+
+    // set the service type
+    businessDelegate.setServiceType(ServiceType.EJB);
+
+    // action
+    client.doTask();
+
+    // verifying that the businessDelegate was used by client during doTask() method.
+    verify(businessDelegate).doTask();
+    verify(ejbService).doProcessing();
+
+    // set the service type
+    businessDelegate.setServiceType(ServiceType.JMS);
+
+    // action
+    client.doTask();
+
+    // verifying that the businessDelegate was used by client during doTask() method.
+    verify(businessDelegate, times(2)).doTask();
+    verify(jmsService).doProcessing();
+  }
+}

caching/.gitignore

@@ -0,0 +1 @@
+/target/

caching/etc/caching.ucls

@@ -0,0 +1,106 @@
+<?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="main.java.com.wssia.caching.App" project="CachingPatterns" 
+    file="/CachingPatterns/src/main/java/com/wssia/caching/App.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="249" y="150"/>    
+    <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="main.java.com.wssia.caching.AppManager" project="CachingPatterns" 
+    file="/CachingPatterns/src/main/java/com/wssia/caching/AppManager.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="502" y="163"/>    
+    <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="main.java.com.wssia.caching.CacheStore" project="CachingPatterns" 
+    file="/CachingPatterns/src/main/java/com/wssia/caching/CacheStore.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="537" y="436"/>    
+    <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="4" language="java" name="main.java.com.wssia.caching.CachingPolicy" project="CachingPatterns" 
+    file="/CachingPatterns/src/main/java/com/wssia/caching/CachingPolicy.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="789" y="162"/>    
+    <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>  
+  <class id="5" language="java" name="main.java.com.wssia.caching.DBManager" project="CachingPatterns" 
+    file="/CachingPatterns/src/main/java/com/wssia/caching/DBManager.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="1137" y="134"/>    
+    <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="main.java.com.wssia.caching.LRUCache" project="CachingPatterns" 
+    file="/CachingPatterns/src/main/java/com/wssia/caching/LRUCache.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="884" y="435"/>    
+    <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="7" language="java" name="main.java.com.wssia.caching.UserAccount" project="CachingPatterns" 
+    file="/CachingPatterns/src/main/java/com/wssia/caching/UserAccount.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="1140" y="405"/>    
+    <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="test.java.com.wssia.caching.AppTest" project="CachingPatterns" 
+    file="/CachingPatterns/src/test/java/com/wssia/caching/AppTest.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="251" y="374"/>    
+    <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>  
+  <association id="9">    
+    <end type="SOURCE" refId="2" navigable="false">      
+      <attribute id="10" name="cachingPolicy"/>      
+      <multiplicity id="11" minimum="0" maximum="1"/>    
+    </end>    
+    <end type="TARGET" refId="4" navigable="true"/>    
+    <display labels="true" multiplicity="true"/>  
+  </association>  
+  <association id="12">    
+    <end type="SOURCE" refId="8" navigable="false">      
+      <attribute id="13" name="app"/>      
+      <multiplicity id="14" minimum="0" maximum="1"/>    
+    </end>    
+    <end type="TARGET" refId="1" navigable="true"/>    
+    <display labels="true" multiplicity="true"/>  
+  </association>  
+  <association id="15">    
+    <end type="SOURCE" refId="3" navigable="false">      
+      <attribute id="16" name="cache"/>      
+      <multiplicity id="17" minimum="0" maximum="1"/>    
+    </end>    
+    <end type="TARGET" refId="6" navigable="true"/>    
+    <display labels="true" multiplicity="true"/>  
+  </association>  
+  <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>

caching/index.md

@@ -0,0 +1,28 @@
+---
+layout: pattern
+title: Caching
+folder: caching
+permalink: /patterns/caching/
+categories: Other
+tags:
+ - Java
+ - Difficulty-Intermediate
+ - Performance
+---
+
+## Intent
+To avoid expensive re-acquisition of resources by not releasing
+the resources immediately after their use. The resources retain their identity, are kept in some
+fast-access storage, and are re-used to avoid having to acquire them again.
+
+![alt text](./etc/caching.png "Caching")
+
+## Applicability
+Use the Caching pattern(s) when
+
+* Repetitious acquisition, initialization, and release of the same resource causes unnecessary performance overhead.
+
+## Credits
+
+* [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)

caching/pom.xml

@@ -0,0 +1,75 @@
+<?xml version="1.0"?>
+<!--
+
+    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.
+
+-->
+<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>com.iluwatar</groupId>
+    <artifactId>java-design-patterns</artifactId>
+    <version>1.10.0</version>
+  </parent>
+  <artifactId>caching</artifactId>
+  <dependencies>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.mongodb</groupId>
+      <artifactId>mongodb-driver</artifactId>
+      <version>3.0.4</version>
+    </dependency>
+    <dependency>
+      <groupId>org.mongodb</groupId>
+      <artifactId>mongodb-driver-core</artifactId>
+      <version>3.0.4</version>
+    </dependency>
+    <dependency>
+      <groupId>org.mongodb</groupId>
+      <artifactId>bson</artifactId>
+      <version>3.0.4</version>
+    </dependency>
+  </dependencies>
+  <!--
+    Due to the use of MongoDB in the test of this pattern, TRAVIS and/or MAVEN might fail if the DB connection is
+    not open for the JUnit test. To avoid disrupting the compilation process, the surefire plug-in was used
+    to SKIP the running of the JUnit tests for this pattern. To ACTIVATE the running of the tests, change the
+    skipTests (below) flag to 'false' and vice-versa.
+  -->
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-surefire-plugin</artifactId>
+        <version>2.19</version>
+        <configuration>
+          <skipTests>false</skipTests>
+        </configuration>
+      </plugin>
+    </plugins>
+  </build>
+</project>

caching/src/main/java/com/iluwatar/caching/App.java

@@ -0,0 +1,139 @@
+/**
+ * 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.caching;
+
+/**
+ *
+ * The Caching pattern describes how to avoid expensive re-acquisition of resources by not releasing
+ * the resources immediately after their use. The resources retain their identity, are kept in some
+ * fast-access storage, and are re-used to avoid having to acquire them again. There are three main
+ * caching strategies/techniques in this pattern; each with their own pros and cons. They are:
+ * <code>write-through</code> which writes data to the cache and DB in a single transaction,
+ * <code>write-around</code> which writes data immediately into the DB instead of the cache, and
+ * <code>write-behind</code> which writes data into the cache initially whilst the data is only
+ * written into the DB when the cache is full. The <code>read-through</code> strategy is also
+ * included in the mentioned three strategies -- returns data from the cache to the caller <b>if</b>
+ * it exists <b>else</b> queries from DB and stores it into the cache for future use. These
+ * strategies determine when the data in the cache should be written back to the backing store (i.e.
+ * Database) and help keep both data sources synchronized/up-to-date. This pattern can improve
+ * performance and also helps to maintain consistency between data held in the cache and the data in
+ * the underlying data store.
+ * <p>
+ * In this example, the user account ({@link UserAccount}) entity is used as the underlying
+ * application data. The cache itself is implemented as an internal (Java) data structure. It adopts
+ * a Least-Recently-Used (LRU) strategy for evicting data from itself when its full. The three
+ * strategies are individually tested. The testing of the cache is restricted towards saving and
+ * querying of user accounts from the underlying data store ( {@link DbManager}). The main class (
+ * {@link App} is not aware of the underlying mechanics of the application (i.e. save and query) and
+ * whether the data is coming from the cache or the DB (i.e. separation of concern). The AppManager
+ * ({@link AppManager}) handles the transaction of data to-and-from the underlying data store
+ * (depending on the preferred caching policy/strategy).
+ *
+ * <i>App --> AppManager --> CacheStore/LRUCache/CachingPolicy --> DBManager</i>
+ * </p>
+ *
+ * @see CacheStore
+ * @See LRUCache
+ * @see CachingPolicy
+ *
+ */
+public class App {
+
+  /**
+   * Program entry point
+   *
+   * @param args command line args
+   */
+  public static void main(String[] args) {
+    AppManager.initDb(false); // VirtualDB (instead of MongoDB) was used in running the JUnit tests
+                              // and the App class to avoid Maven compilation errors. Set flag to
+                              // true to run the tests with MongoDB (provided that MongoDB is
+                              // installed and socket connection is open).
+    AppManager.initCacheCapacity(3);
+    App app = new App();
+    app.useReadAndWriteThroughStrategy();
+    app.useReadThroughAndWriteAroundStrategy();
+    app.useReadThroughAndWriteBehindStrategy();
+  }
+
+  /**
+   * Read-through and write-through
+   */
+  public void useReadAndWriteThroughStrategy() {
+    System.out.println("# CachingPolicy.THROUGH");
+    AppManager.initCachingPolicy(CachingPolicy.THROUGH);
+
+    UserAccount userAccount1 = new UserAccount("001", "John", "He is a boy.");
+
+    AppManager.save(userAccount1);
+    System.out.println(AppManager.printCacheContent());
+    AppManager.find("001");
+    AppManager.find("001");
+  }
+
+  /**
+   * Read-through and write-around
+   */
+  public void useReadThroughAndWriteAroundStrategy() {
+    System.out.println("# CachingPolicy.AROUND");
+    AppManager.initCachingPolicy(CachingPolicy.AROUND);
+
+    UserAccount userAccount2 = new UserAccount("002", "Jane", "She is a girl.");
+
+    AppManager.save(userAccount2);
+    System.out.println(AppManager.printCacheContent());
+    AppManager.find("002");
+    System.out.println(AppManager.printCacheContent());
+    userAccount2 = AppManager.find("002");
+    userAccount2.setUserName("Jane G.");
+    AppManager.save(userAccount2);
+    System.out.println(AppManager.printCacheContent());
+    AppManager.find("002");
+    System.out.println(AppManager.printCacheContent());
+    AppManager.find("002");
+  }
+
+  /**
+   * Read-through and write-behind
+   */
+  public void useReadThroughAndWriteBehindStrategy() {
+    System.out.println("# CachingPolicy.BEHIND");
+    AppManager.initCachingPolicy(CachingPolicy.BEHIND);
+
+    UserAccount userAccount3 = new UserAccount("003", "Adam", "He likes food.");
+    UserAccount userAccount4 = new UserAccount("004", "Rita", "She hates cats.");
+    UserAccount userAccount5 = new UserAccount("005", "Isaac", "He is allergic to mustard.");
+
+    AppManager.save(userAccount3);
+    AppManager.save(userAccount4);
+    AppManager.save(userAccount5);
+    System.out.println(AppManager.printCacheContent());
+    AppManager.find("003");
+    System.out.println(AppManager.printCacheContent());
+    UserAccount userAccount6 = new UserAccount("006", "Yasha", "She is an only child.");
+    AppManager.save(userAccount6);
+    System.out.println(AppManager.printCacheContent());
+    AppManager.find("004");
+    System.out.println(AppManager.printCacheContent());
+  }
+}

caching/src/main/java/com/iluwatar/caching/AppManager.java

@@ -0,0 +1,109 @@
+/**
+ * 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.caching;
+
+import java.text.ParseException;
+
+/**
+ *
+ * AppManager helps to bridge the gap in communication between the main class and the application's
+ * back-end. DB connection is initialized through this class. The chosen caching strategy/policy is
+ * also initialized here. Before the cache can be used, the size of the cache has to be set.
+ * Depending on the chosen caching policy, AppManager will call the appropriate function in the
+ * CacheStore class.
+ *
+ */
+public class AppManager {
+
+  private static CachingPolicy cachingPolicy;
+
+  private AppManager() {
+  }
+
+  /**
+   *
+   * Developer/Tester is able to choose whether the application should use MongoDB as its underlying
+   * data storage or a simple Java data structure to (temporarily) store the data/objects during
+   * runtime.
+   */
+  public static void initDb(boolean useMongoDb) {
+    if (useMongoDb) {
+      try {
+        DbManager.connect();
+      } catch (ParseException e) {
+        e.printStackTrace();
+      }
+    } else {
+      DbManager.createVirtualDb();
+    }
+  }
+
+  /**
+   * Initialize caching policy
+   */
+  public static void initCachingPolicy(CachingPolicy policy) {
+    cachingPolicy = policy;
+    if (cachingPolicy == CachingPolicy.BEHIND) {
+      Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() {
+        @Override
+        public void run() {
+          CacheStore.flushCache();
+        }
+      }));
+    }
+    CacheStore.clearCache();
+  }
+
+  public static void initCacheCapacity(int capacity) {
+    CacheStore.initCapacity(capacity);
+  }
+
+  /**
+   * Find user account
+   */
+  public static UserAccount find(String userId) {
+    if (cachingPolicy == CachingPolicy.THROUGH || cachingPolicy == CachingPolicy.AROUND) {
+      return CacheStore.readThrough(userId);
+    } else if (cachingPolicy == CachingPolicy.BEHIND) {
+      return CacheStore.readThroughWithWriteBackPolicy(userId);
+    }
+    return null;
+  }
+
+  /**
+   * Save user account
+   */
+  public static void save(UserAccount userAccount) {
+    if (cachingPolicy == CachingPolicy.THROUGH) {
+      CacheStore.writeThrough(userAccount);
+    } else if (cachingPolicy == CachingPolicy.AROUND) {
+      CacheStore.writeAround(userAccount);
+    } else if (cachingPolicy == CachingPolicy.BEHIND) {
+      CacheStore.writeBehind(userAccount);
+    }
+  }
+
+  public static String printCacheContent() {
+    return CacheStore.print();
+  }
+}

caching/src/main/java/com/iluwatar/caching/CacheStore.java

@@ -0,0 +1,156 @@
+/**
+ * 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.caching;
+
+import java.util.ArrayList;
+
+/**
+ *
+ * The caching strategies are implemented in this class.
+ *
+ */
+public class CacheStore {
+
+  static LruCache cache = null;
+
+  private CacheStore() {
+  }
+
+  /**
+   * Init cache capacity
+   */
+  public static void initCapacity(int capacity) {
+    if (null == cache) {
+      cache = new LruCache(capacity);
+    } else {
+      cache.setCapacity(capacity);
+    }
+  }
+
+  /**
+   * Get user account using read-through cache
+   */
+  public static UserAccount readThrough(String userId) {
+    if (cache.contains(userId)) {
+      System.out.println("# Cache Hit!");
+      return cache.get(userId);
+    }
+    System.out.println("# Cache Miss!");
+    UserAccount userAccount = DbManager.readFromDb(userId);
+    cache.set(userId, userAccount);
+    return userAccount;
+  }
+
+  /**
+   * Get user account using write-through cache
+   */
+  public static void writeThrough(UserAccount userAccount) {
+    if (cache.contains(userAccount.getUserId())) {
+      DbManager.updateDb(userAccount);
+    } else {
+      DbManager.writeToDb(userAccount);
+    }
+    cache.set(userAccount.getUserId(), userAccount);
+  }
+
+  /**
+   * Get user account using write-around cache
+   */
+  public static void writeAround(UserAccount userAccount) {
+    if (cache.contains(userAccount.getUserId())) {
+      DbManager.updateDb(userAccount);
+      cache.invalidate(userAccount.getUserId()); // Cache data has been updated -- remove older
+                                                 // version from cache.
+    } else {
+      DbManager.writeToDb(userAccount);
+    }
+  }
+
+  /**
+   * Get user account using read-through cache with write-back policy
+   */
+  public static UserAccount readThroughWithWriteBackPolicy(String userId) {
+    if (cache.contains(userId)) {
+      System.out.println("# Cache Hit!");
+      return cache.get(userId);
+    }
+    System.out.println("# Cache Miss!");
+    UserAccount userAccount = DbManager.readFromDb(userId);
+    if (cache.isFull()) {
+      System.out.println("# Cache is FULL! Writing LRU data to DB...");
+      UserAccount toBeWrittenToDb = cache.getLruData();
+      DbManager.upsertDb(toBeWrittenToDb);
+    }
+    cache.set(userId, userAccount);
+    return userAccount;
+  }
+
+  /**
+   * Set user account
+   */
+  public static void writeBehind(UserAccount userAccount) {
+    if (cache.isFull() && !cache.contains(userAccount.getUserId())) {
+      System.out.println("# Cache is FULL! Writing LRU data to DB...");
+      UserAccount toBeWrittenToDb = cache.getLruData();
+      DbManager.upsertDb(toBeWrittenToDb);
+    }
+    cache.set(userAccount.getUserId(), userAccount);
+  }
+
+  /**
+   * Clears cache
+   */
+  public static void clearCache() {
+    if (null != cache) {
+      cache.clear();
+    }
+  }
+
+  /**
+   * Writes remaining content in the cache into the DB.
+   */
+  public static void flushCache() {
+    System.out.println("# flushCache...");
+    if (null == cache) {
+      return;
+    }
+    ArrayList<UserAccount> listOfUserAccounts = cache.getCacheDataInListForm();
+    for (UserAccount userAccount : listOfUserAccounts) {
+      DbManager.upsertDb(userAccount);
+    }
+  }
+
+  /**
+   * Print user accounts
+   */
+  public static String print() {
+    ArrayList<UserAccount> listOfUserAccounts = cache.getCacheDataInListForm();
+    StringBuilder sb = new StringBuilder();
+    sb.append("\n--CACHE CONTENT--\n");
+    for (UserAccount userAccount : listOfUserAccounts) {
+      sb.append(userAccount.toString() + "\n");
+    }
+    sb.append("----\n");
+    return sb.toString();
+  }
+}

caching/src/main/java/com/iluwatar/caching/CachingPolicy.java

@@ -0,0 +1,42 @@
+/**
+ * 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.caching;
+
+/**
+ *
+ * Enum class containing the three caching strategies implemented in the pattern.
+ *
+ */
+public enum CachingPolicy {
+  THROUGH("through"), AROUND("around"), BEHIND("behind");
+
+  private String policy;
+
+  private CachingPolicy(String policy) {
+    this.policy = policy;
+  }
+
+  public String getPolicy() {
+    return policy;
+  }
+}

caching/src/main/java/com/iluwatar/caching/DbManager.java

@@ -0,0 +1,163 @@
+/**
+ * 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.caching;
+
+import java.text.ParseException;
+import java.util.HashMap;
+
+import org.bson.Document;
+
+import com.mongodb.MongoClient;
+import com.mongodb.client.FindIterable;
+import com.mongodb.client.MongoDatabase;
+import com.mongodb.client.model.UpdateOptions;
+
+/**
+ *
+ * <p>DBManager handles the communication with the underlying data store i.e. Database. It contains the
+ * implemented methods for querying, inserting, and updating data. MongoDB was used as the database
+ * for the application.</p>
+ * 
+ * <p>Developer/Tester is able to choose whether the application should use MongoDB as its underlying
+ * data storage (connect()) or a simple Java data structure to (temporarily) store the data/objects
+ * during runtime (createVirtualDB()).</p>
+ * 
+ */
+public class DbManager {
+
+  private static MongoClient mongoClient;
+  private static MongoDatabase db;
+  private static boolean useMongoDB;
+
+  private static HashMap<String, UserAccount> virtualDB;
+
+  private DbManager() {
+  }
+
+  /**
+   * Create DB
+   */
+  public static void createVirtualDb() {
+    useMongoDB = false;
+    virtualDB = new HashMap<>();
+  }
+
+  /**
+   * Connect to DB
+   */
+  public static void connect() throws ParseException {
+    useMongoDB = true;
+    mongoClient = new MongoClient();
+    db = mongoClient.getDatabase("test");
+  }
+
+  /**
+   * Read user account from DB
+   */
+  public static UserAccount readFromDb(String userId) {
+    if (!useMongoDB) {
+      if (virtualDB.containsKey(userId)) {
+        return virtualDB.get(userId);
+      }
+      return null;
+    }
+    if (null == db) {
+      try {
+        connect();
+      } catch (ParseException e) {
+        e.printStackTrace();
+      }
+    }
+    FindIterable<Document> iterable =
+        db.getCollection("user_accounts").find(new Document("userID", userId));
+    if (iterable == null) {
+      return null;
+    }
+    Document doc = iterable.first();
+    return new UserAccount(userId, doc.getString("userName"), doc.getString("additionalInfo"));
+  }
+
+  /**
+   * Write user account to DB
+   */
+  public static void writeToDb(UserAccount userAccount) {
+    if (!useMongoDB) {
+      virtualDB.put(userAccount.getUserId(), userAccount);
+      return;
+    }
+    if (null == db) {
+      try {
+        connect();
+      } catch (ParseException e) {
+        e.printStackTrace();
+      }
+    }
+    db.getCollection("user_accounts").insertOne(
+        new Document("userID", userAccount.getUserId()).append("userName",
+            userAccount.getUserName()).append("additionalInfo", userAccount.getAdditionalInfo()));
+  }
+
+  /**
+   * Update DB
+   */
+  public static void updateDb(UserAccount userAccount) {
+    if (!useMongoDB) {
+      virtualDB.put(userAccount.getUserId(), userAccount);
+      return;
+    }
+    if (null == db) {
+      try {
+        connect();
+      } catch (ParseException e) {
+        e.printStackTrace();
+      }
+    }
+    db.getCollection("user_accounts").updateOne(
+        new Document("userID", userAccount.getUserId()),
+        new Document("$set", new Document("userName", userAccount.getUserName()).append(
+            "additionalInfo", userAccount.getAdditionalInfo())));
+  }
+
+  /**
+   *
+   * Insert data into DB if it does not exist. Else, update it.
+   */
+  public static void upsertDb(UserAccount userAccount) {
+    if (!useMongoDB) {
+      virtualDB.put(userAccount.getUserId(), userAccount);
+      return;
+    }
+    if (null == db) {
+      try {
+        connect();
+      } catch (ParseException e) {
+        e.printStackTrace();
+      }
+    }
+    db.getCollection("user_accounts").updateOne(
+        new Document("userID", userAccount.getUserId()),
+        new Document("$set", new Document("userID", userAccount.getUserId()).append("userName",
+            userAccount.getUserName()).append("additionalInfo", userAccount.getAdditionalInfo())),
+        new UpdateOptions().upsert(true));
+  }
+}

caching/src/main/java/com/iluwatar/caching/LruCache.java

@@ -0,0 +1,185 @@
+/**
+ * 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.caching;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+
+/**
+ *
+ * Data structure/implementation of the application's cache. The data structure consists of a hash
+ * table attached with a doubly linked-list. The linked-list helps in capturing and maintaining the
+ * LRU data in the cache. When a data is queried (from the cache), added (to the cache), or updated,
+ * the data is moved to the front of the list to depict itself as the most-recently-used data. The
+ * LRU data is always at the end of the list.
+ *
+ */
+public class LruCache {
+
+  class Node {
+    String userId;
+    UserAccount userAccount;
+    Node previous;
+    Node next;
+
+    public Node(String userId, UserAccount userAccount) {
+      this.userId = userId;
+      this.userAccount = userAccount;
+    }
+  }
+
+  int capacity;
+  HashMap<String, Node> cache = new HashMap<>();
+  Node head = null;
+  Node end = null;
+
+  public LruCache(int capacity) {
+    this.capacity = capacity;
+  }
+
+  /**
+   * Get user account
+   */
+  public UserAccount get(String userId) {
+    if (cache.containsKey(userId)) {
+      Node node = cache.get(userId);
+      remove(node);
+      setHead(node);
+      return node.userAccount;
+    }
+    return null;
+  }
+
+  /**
+   *
+   * Remove node from linked list.
+   */
+  public void remove(Node node) {
+    if (node.previous != null) {
+      node.previous.next = node.next;
+    } else {
+      head = node.next;
+    }
+    if (node.next != null) {
+      node.next.previous = node.previous;
+    } else {
+      end = node.previous;
+    }
+  }
+
+  /**
+   *
+   * Move node to the front of the list.
+   */
+  public void setHead(Node node) {
+    node.next = head;
+    node.previous = null;
+    if (head != null) {
+      head.previous = node;
+    }
+    head = node;
+    if (end == null) {
+      end = head;
+    }
+  }
+
+  /**
+   * Set user account
+   */
+  public void set(String userId, UserAccount userAccount) {
+    if (cache.containsKey(userId)) {
+      Node old = cache.get(userId);
+      old.userAccount = userAccount;
+      remove(old);
+      setHead(old);
+    } else {
+      Node newNode = new Node(userId, userAccount);
+      if (cache.size() >= capacity) {
+        System.out.println("# Cache is FULL! Removing " + end.userId + " from cache...");
+        cache.remove(end.userId); // remove LRU data from cache.
+        remove(end);
+        setHead(newNode);
+      } else {
+        setHead(newNode);
+      }
+      cache.put(userId, newNode);
+    }
+  }
+
+  public boolean contains(String userId) {
+    return cache.containsKey(userId);
+  }
+
+  /**
+   * Invalidate cache for user
+   */
+  public void invalidate(String userId) {
+    System.out.println("# " + userId + " has been updated! Removing older version from cache...");
+    Node toBeRemoved = cache.get(userId);
+    remove(toBeRemoved);
+    cache.remove(userId);
+  }
+
+  public boolean isFull() {
+    return cache.size() >= capacity;
+  }
+
+  public UserAccount getLruData() {
+    return end.userAccount;
+  }
+
+  /**
+   * Clear cache
+   */
+  public void clear() {
+    head = null;
+    end = null;
+    cache.clear();
+  }
+
+  /**
+   *
+   * Returns cache data in list form.
+   */
+  public ArrayList<UserAccount> getCacheDataInListForm() {
+    ArrayList<UserAccount> listOfCacheData = new ArrayList<>();
+    Node temp = head;
+    while (temp != null) {
+      listOfCacheData.add(temp.userAccount);
+      temp = temp.next;
+    }
+    return listOfCacheData;
+  }
+
+  /**
+   * Set cache capacity
+   */
+  public void setCapacity(int newCapacity) {
+    if (capacity > newCapacity) {
+      clear(); // Behavior can be modified to accommodate for decrease in cache size. For now, we'll
+               // just clear the cache.
+    } else {
+      this.capacity = newCapacity;
+    }
+  }
+}

caching/src/main/java/com/iluwatar/caching/UserAccount.java

@@ -0,0 +1,72 @@
+/**
+ * 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.caching;
+
+/**
+ *
+ * Entity class (stored in cache and DB) used in the application.
+ *
+ */
+public class UserAccount {
+  private String userId;
+  private String userName;
+  private String additionalInfo;
+
+  /**
+   * Constructor
+   */
+  public UserAccount(String userId, String userName, String additionalInfo) {
+    this.userId = userId;
+    this.userName = userName;
+    this.additionalInfo = additionalInfo;
+  }
+
+  public String getUserId() {
+    return userId;
+  }
+
+  public void setUserId(String userId) {
+    this.userId = userId;
+  }
+
+  public String getUserName() {
+    return userName;
+  }
+
+  public void setUserName(String userName) {
+    this.userName = userName;
+  }
+
+  public String getAdditionalInfo() {
+    return additionalInfo;
+  }
+
+  public void setAdditionalInfo(String additionalInfo) {
+    this.additionalInfo = additionalInfo;
+  }
+
+  @Override
+  public String toString() {
+    return userId + ", " + userName + ", " + additionalInfo;
+  }
+}