Reached milestone 1.12.0

implementation of microservices architectural pattern #296

.gitignore

@@ -11,4 +11,9 @@ target
 .idea
 *.iml
 *.swp
-datanucleus.log
+datanucleus.log
+/bin/
+/bin/
+/bin/
+
+data-mapper/src/main/resources/log4j.xml

.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
 
-# Migration to container-based infrastructure  
-sudo: false
+after_success:
+- mvn clean test jacoco:report coveralls:report
+- bash update-ghpages.sh
+
+sudo: false # route the build to the container-based infrastructure for a faster build

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.

LICENSE.md

@@ -1,6 +1,6 @@
 The MIT License (MIT)
 
-Copyright (c) 2014 Ilkka Seppälä
+Copyright (c) 2014-2016 Ilkka Seppälä
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

README.md

@@ -2,11 +2,11 @@
      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)
+[![License MIT](https://img.shields.io/badge/license-MIT-blue.svg)](https://raw.githubusercontent.com/iluwatar/java-design-patterns/master/LICENSE.md)
 [![Join the chat at https://gitter.im/iluwatar/java-design-patterns](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/iluwatar/java-design-patterns?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 
 # Introduction
@@ -23,10 +23,16 @@ 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 +40,7 @@ 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-document/README.md

@@ -0,0 +1,31 @@
+---
+layout: pattern
+title: Abstract Document
+folder: abstract-document
+permalink: /patterns/abstract-document/
+categories: Structural
+tags: 
+ - Java
+ - Difficulty-Intermediate
+---
+
+## Intent
+Achieve flexibility of untyped languages and keep the type-safety 
+
+![alt text](./etc/abstract-document-base.png "Abstract Document Base")
+
+![alt text](./etc/abstract-document.png "Abstract Document Traits and Domain")
+
+
+## Applicability
+Use the Abstract Document Pattern when
+
+* there is a need to add new properties on the fly
+* you want a flexible way to organize domain in tree like structure
+* you want more loosely coupled system
+
+
+## Credits
+
+* [Wikipedia: Abstract Document Pattern](https://en.wikipedia.org/wiki/Abstract_Document_Pattern)
+* [Martin Fowler: Dealing with properties](http://martinfowler.com/apsupp/properties.pdf)

abstract-document/etc/abstract-document-base.ucls

@@ -0,0 +1,58 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<class-diagram version="1.1.9" icons="true" automaticImage="PNG" always-add-relationships="false" generalizations="true" 
+  realizations="true" associations="true" dependencies="false" nesting-relationships="true" router="FAN">  
+  <interface id="1" language="java" name="com.iluwatar.abstractdocument.Document" project="design-patterns" 
+    file="/design-patterns/src/com/iluwatar/abstractdocument/Document.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="249" 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>  
+  </interface>  
+  <class id="2" language="java" name="com.iluwatar.abstractdocument.AbstractDocument" project="design-patterns" 
+    file="/design-patterns/src/com/iluwatar/abstractdocument/AbstractDocument.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="250" y="237"/>    
+    <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.abstractdocument.domain.Car" project="design-patterns" 
+    file="/design-patterns/src/com/iluwatar/abstractdocument/domain/Car.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="108" y="75"/>    
+    <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.abstractdocument.domain.Part" project="design-patterns" 
+    file="/design-patterns/src/com/iluwatar/abstractdocument/domain/Part.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="400" y="76"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </class>  
+  <generalization id="5">    
+    <end type="SOURCE" refId="4"/>    
+    <end type="TARGET" refId="2"/>  
+  </generalization>  
+  <realization id="6">    
+    <end type="SOURCE" refId="2"/>    
+    <end type="TARGET" refId="1"/>  
+  </realization>  
+  <generalization id="7">    
+    <end type="SOURCE" refId="3"/>    
+    <end type="TARGET" refId="2"/>  
+  </generalization>  
+  <classifier-display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+    sort-features="false" accessors="true" visibility="true">    
+    <attributes public="true" package="true" protected="true" private="true" static="true"/>    
+    <operations public="true" package="true" protected="true" private="true" static="true"/>  
+  </classifier-display>  
+  <association-display labels="true" multiplicity="true"/>
+</class-diagram>

abstract-document/etc/abstract-document.ucls

@@ -0,0 +1,96 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<class-diagram version="1.1.9" icons="true" automaticImage="PNG" always-add-relationships="false" generalizations="true" 
+  realizations="true" associations="true" dependencies="false" nesting-relationships="true" router="FAN">  
+  <interface id="1" language="java" name="com.iluwatar.abstractdocument.Document" project="design-patterns" 
+    file="/design-patterns/src/com/iluwatar/abstractdocument/Document.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="341" y="376"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </interface>  
+  <interface id="2" language="java" name="com.iluwatar.abstractdocument.domain.HasModel" project="design-patterns" 
+    file="/design-patterns/src/com/iluwatar/abstractdocument/domain/HasModel.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="81" width="173" x="41" y="194"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </interface>  
+  <interface id="3" language="java" name="com.iluwatar.abstractdocument.domain.HasPrice" project="design-patterns" 
+    file="/design-patterns/src/com/iluwatar/abstractdocument/domain/HasPrice.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="81" width="175" x="254" y="194"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </interface>  
+  <interface id="4" language="java" name="com.iluwatar.abstractdocument.domain.HasParts" project="design-patterns" 
+    file="/design-patterns/src/com/iluwatar/abstractdocument/domain/HasParts.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="81" width="173" x="469" y="194"/>    
+    <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="5" language="java" name="com.iluwatar.abstractdocument.domain.Car" project="design-patterns" 
+    file="/design-patterns/src/com/iluwatar/abstractdocument/domain/Car.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="99" width="173" x="254" y="37"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </class>  
+  <class id="6" language="java" name="com.iluwatar.abstractdocument.domain.Part" project="design-patterns" 
+    file="/design-patterns/src/com/iluwatar/abstractdocument/domain/Part.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="99" width="173" x="41" y="37"/>    
+    <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="7">    
+    <end type="SOURCE" refId="5"/>    
+    <end type="TARGET" refId="2"/>  
+  </realization>  
+  <realization id="8">    
+    <end type="SOURCE" refId="6"/>    
+    <end type="TARGET" refId="2"/>  
+  </realization>  
+  <generalization id="9">    
+    <end type="SOURCE" refId="2"/>    
+    <end type="TARGET" refId="1"/>  
+  </generalization>  
+  <realization id="10">    
+    <end type="SOURCE" refId="5"/>    
+    <end type="TARGET" refId="3"/>  
+  </realization>  
+  <realization id="11">    
+    <end type="SOURCE" refId="5"/>    
+    <end type="TARGET" refId="4"/>  
+  </realization>  
+  <generalization id="12">    
+    <end type="SOURCE" refId="3"/>    
+    <end type="TARGET" refId="1"/>  
+  </generalization>  
+  <generalization id="13">    
+    <end type="SOURCE" refId="4"/>    
+    <end type="TARGET" refId="1"/>  
+  </generalization>  
+  <realization id="14">    
+    <end type="SOURCE" refId="6"/>    
+    <end type="TARGET" refId="3"/>  
+  </realization>  
+  <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>

abstract-document/pom.xml

@@ -0,0 +1,42 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+    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 xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <artifactId>java-design-patterns</artifactId>
+        <groupId>com.iluwatar</groupId>
+        <version>1.12.0</version>
+    </parent>
+    <artifactId>abstract-document</artifactId>
+    <dependencies>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+</project>

abstract-document/src/main/java/com/iluwatar/abstractdocument/AbstractDocument.java

@@ -0,0 +1,72 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ * <p>
+ * 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:
+ * <p>
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * <p>
+ * 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.abstractdocument;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Optional;
+import java.util.function.Function;
+import java.util.stream.Stream;
+
+/**
+ * Abstract implementation of Document interface
+ */
+public abstract class AbstractDocument implements Document {
+
+  private final Map<String, Object> properties;
+
+  protected AbstractDocument(Map<String, Object> properties) {
+    Objects.requireNonNull(properties, "properties map is required");
+    this.properties = properties;
+  }
+
+  @Override
+  public Void put(String key, Object value) {
+    properties.put(key, value);
+    return null;
+  }
+
+  @Override
+  public Object get(String key) {
+    return properties.get(key);
+  }
+
+  @Override
+  public <T> Stream<T> children(String key, Function<Map<String, Object>, T> constructor) {
+    Optional<List<Map<String, Object>>> any = Stream.of(get(key)).filter(el -> el != null)
+        .map(el -> (List<Map<String, Object>>) el).findAny();
+    return any.isPresent() ? any.get().stream().map(constructor) : Stream.empty();
+  }
+
+  @Override
+  public String toString() {
+    StringBuilder builder = new StringBuilder();
+    builder.append(getClass().getName()).append("[");
+    properties.entrySet()
+        .forEach(e -> builder.append("[").append(e.getKey()).append(" : ").append(e.getValue()).append("]"));
+    builder.append("]");
+    return builder.toString();
+  }
+
+}

abstract-document/src/main/java/com/iluwatar/abstractdocument/App.java

@@ -0,0 +1,88 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ * <p>
+ * 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:
+ * <p>
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * <p>
+ * 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.abstractdocument;
+
+import com.iluwatar.abstractdocument.domain.Car;
+import com.iluwatar.abstractdocument.domain.HasModel;
+import com.iluwatar.abstractdocument.domain.HasParts;
+import com.iluwatar.abstractdocument.domain.HasPrice;
+import com.iluwatar.abstractdocument.domain.HasType;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * The Abstract Document pattern enables handling additional, non-static
+ * properties. This pattern uses concept of traits to enable type safety and
+ * separate properties of different classes into set of interfaces.
+ * <p>
+ * <p>
+ * In Abstract Document pattern,({@link AbstractDocument}) fully implements
+ * {@link Document}) interface. Traits are then defined to enable access to
+ * properties in usual, static way.
+ */
+public class App {
+
+  /**
+   * Executes the App
+   */
+  public App() {
+    System.out.println("Constructing parts and car");
+
+    Map<String, Object> carProperties = new HashMap<>();
+    carProperties.put(HasModel.PROPERTY, "300SL");
+    carProperties.put(HasPrice.PROPERTY, 10000L);
+
+    Map<String, Object> wheelProperties = new HashMap<>();
+    wheelProperties.put(HasType.PROPERTY, "wheel");
+    wheelProperties.put(HasModel.PROPERTY, "15C");
+    wheelProperties.put(HasPrice.PROPERTY, 100L);
+
+    Map<String, Object> doorProperties = new HashMap<>();
+    doorProperties.put(HasType.PROPERTY, "door");
+    doorProperties.put(HasModel.PROPERTY, "Lambo");
+    doorProperties.put(HasPrice.PROPERTY, 300L);
+
+    carProperties.put(HasParts.PROPERTY, Arrays.asList(wheelProperties, doorProperties));
+
+    Car car = new Car(carProperties);
+
+    System.out.println("Here is our car:");
+    System.out.println("-> model: " + car.getModel().get());
+    System.out.println("-> price: " + car.getPrice().get());
+    System.out.println("-> parts: ");
+    car.getParts().forEach(p -> System.out
+        .println("\t" + p.getType().get() + "/" + p.getModel().get() + "/" + p.getPrice().get()));
+  }
+
+  /**
+   * Program entry point
+   *
+   * @param args command line args
+   */
+  public static void main(String[] args) {
+    new App();
+  }
+
+}

abstract-document/src/main/java/com/iluwatar/abstractdocument/Document.java

@@ -0,0 +1,59 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ * <p>
+ * 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:
+ * <p>
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * <p>
+ * 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.abstractdocument;
+
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Stream;
+
+/**
+ * Document interface
+ */
+public interface Document {
+
+  /**
+   * Puts the value related to the key
+   *
+   * @param key   element key
+   * @param value element value
+   * @return Void
+   */
+  Void put(String key, Object value);
+
+  /**
+   * Gets the value for the key
+   *
+   * @param key element key
+   * @return value or null
+   */
+  Object get(String key);
+
+  /**
+   * Gets the stream of child documents
+   *
+   * @param key         element key
+   * @param constructor constructor of child class
+   * @return child documents
+   */
+  <T> Stream<T> children(String key, Function<Map<String, Object>, T> constructor);
+}

abstract-document/src/main/java/com/iluwatar/abstractdocument/domain/Car.java

@@ -0,0 +1,38 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ * <p>
+ * 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:
+ * <p>
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * <p>
+ * 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.abstractdocument.domain;
+
+import java.util.Map;
+
+import com.iluwatar.abstractdocument.AbstractDocument;
+
+/**
+ * Car entity
+ */
+public class Car extends AbstractDocument implements HasModel, HasPrice, HasParts {
+
+  public Car(Map<String, Object> properties) {
+    super(properties);
+  }
+
+}

abstract-document/src/main/java/com/iluwatar/abstractdocument/domain/HasModel.java

@@ -0,0 +1,40 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ * <p>
+ * 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:
+ * <p>
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * <p>
+ * 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.abstractdocument.domain;
+
+import java.util.Optional;
+
+import com.iluwatar.abstractdocument.Document;
+
+/**
+ * HasModel trait for static access to 'model' property
+ */
+public interface HasModel extends Document {
+
+  String PROPERTY = "model";
+
+  default Optional<String> getModel() {
+    return Optional.ofNullable((String) get(PROPERTY));
+  }
+
+}

abstract-document/src/main/java/com/iluwatar/abstractdocument/domain/HasParts.java

@@ -0,0 +1,40 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ * <p>
+ * 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:
+ * <p>
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * <p>
+ * 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.abstractdocument.domain;
+
+import java.util.stream.Stream;
+
+import com.iluwatar.abstractdocument.Document;
+
+/**
+ * HasParts trait for static access to 'parts' property
+ */
+public interface HasParts extends Document {
+
+  String PROPERTY = "parts";
+
+  default Stream<Part> getParts() {
+    return children(PROPERTY, Part::new);
+  }
+
+}

abstract-document/src/main/java/com/iluwatar/abstractdocument/domain/HasPrice.java

@@ -0,0 +1,40 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ * <p>
+ * 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:
+ * <p>
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * <p>
+ * 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.abstractdocument.domain;
+
+import java.util.Optional;
+
+import com.iluwatar.abstractdocument.Document;
+
+/**
+ * HasPrice trait for static access to 'price' property
+ */
+public interface HasPrice extends Document {
+
+  String PROPERTY = "price";
+
+  default Optional<Number> getPrice() {
+    return Optional.ofNullable((Number) get(PROPERTY));
+  }
+
+}

abstract-document/src/main/java/com/iluwatar/abstractdocument/domain/HasType.java

@@ -0,0 +1,40 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ * <p>
+ * 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:
+ * <p>
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * <p>
+ * 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.abstractdocument.domain;
+
+import com.iluwatar.abstractdocument.Document;
+
+import java.util.Optional;
+
+/**
+ * HasType trait for static access to 'type' property
+ */
+public interface HasType extends Document {
+
+  String PROPERTY = "type";
+
+  default Optional<String> getType() {
+    return Optional.ofNullable((String) get(PROPERTY));
+  }
+
+}

abstract-document/src/main/java/com/iluwatar/abstractdocument/domain/Part.java

@@ -0,0 +1,38 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ * <p>
+ * 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:
+ * <p>
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * <p>
+ * 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.abstractdocument.domain;
+
+import java.util.Map;
+
+import com.iluwatar.abstractdocument.AbstractDocument;
+
+/**
+ * Part entity
+ */
+public class Part extends AbstractDocument implements HasType, HasModel, HasPrice {
+
+  public Part(Map<String, Object> properties) {
+    super(properties);
+  }
+
+}

abstract-document/src/test/java/com/iluwatar/abstractdocument/AbstractDocumentTest.java

@@ -0,0 +1,88 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ * <p>
+ * 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:
+ * <p>
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * <p>
+ * 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.abstractdocument;
+
+import org.junit.Test;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Stream;
+
+import static junit.framework.TestCase.assertEquals;
+import static junit.framework.TestCase.assertNotNull;
+
+/**
+ * AbstractDocument test class
+ */
+public class AbstractDocumentTest {
+
+  private static final String KEY = "key";
+  private static final String VALUE = "value";
+
+  private class DocumentImplementation extends AbstractDocument {
+
+    DocumentImplementation(Map<String, Object> properties) {
+      super(properties);
+    }
+  }
+
+  private DocumentImplementation document = new DocumentImplementation(new HashMap<>());
+
+  @Test
+  public void shouldPutAndGetValue() {
+    document.put(KEY, VALUE);
+    assertEquals(VALUE, document.get(KEY));
+  }
+
+  @Test
+  public void shouldRetrieveChildren() {
+    Map<String, Object> child1 = new HashMap<>();
+    Map<String, Object> child2 = new HashMap<>();
+    List<Map<String, Object>> children = Arrays.asList(child1, child2);
+
+    document.put(KEY, children);
+
+    Stream<DocumentImplementation> childrenStream = document.children(KEY, DocumentImplementation::new);
+    assertNotNull(children);
+    assertEquals(2, childrenStream.count());
+  }
+
+  @Test
+  public void shouldRetrieveEmptyStreamForNonExistingChildren() {
+    Stream<DocumentImplementation> children = document.children(KEY, DocumentImplementation::new);
+    assertNotNull(children);
+    assertEquals(0, children.count());
+  }
+
+  @Test
+  public void shouldIncludePropsInToString() {
+    Map<String, Object> props = new HashMap<>();
+    props.put(KEY, VALUE);
+    DocumentImplementation document = new DocumentImplementation(props);
+    assertNotNull(document.toString().contains(KEY));
+    assertNotNull(document.toString().contains(VALUE));
+  }
+
+}

abstract-document/src/test/java/com/iluwatar/abstractdocument/AppTest.java

@@ -0,0 +1,37 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ * <p>
+ * 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:
+ * <p>
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * <p>
+ * 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.abstractdocument;
+
+import org.junit.Test;
+
+/**
+ * Simple App test
+ */
+public class AppTest {
+
+  @Test
+  public void shouldExecuteAppWithoutException() {
+    App.main(null);
+  }
+
+}

abstract-document/src/test/java/com/iluwatar/abstractdocument/DomainTest.java

@@ -0,0 +1,77 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ * <p>
+ * 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:
+ * <p>
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * <p>
+ * 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.abstractdocument;
+
+import com.iluwatar.abstractdocument.domain.Car;
+import com.iluwatar.abstractdocument.domain.HasModel;
+import com.iluwatar.abstractdocument.domain.HasParts;
+import com.iluwatar.abstractdocument.domain.HasPrice;
+import com.iluwatar.abstractdocument.domain.HasType;
+import com.iluwatar.abstractdocument.domain.Part;
+import org.junit.Test;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+
+import static junit.framework.TestCase.assertEquals;
+
+/**
+ * Test for Part and Car
+ */
+public class DomainTest {
+
+  private static final String TEST_PART_TYPE = "test-part-type";
+  private static final String TEST_PART_MODEL = "test-part-model";
+  private static final long TEST_PART_PRICE = 0L;
+
+  private static final String TEST_CAR_MODEL = "test-car-model";
+  private static final long TEST_CAR_PRICE = 1L;
+
+  @Test
+  public void shouldConstructPart() {
+    Map<String, Object> partProperties = new HashMap<>();
+    partProperties.put(HasType.PROPERTY, TEST_PART_TYPE);
+    partProperties.put(HasModel.PROPERTY, TEST_PART_MODEL);
+    partProperties.put(HasPrice.PROPERTY, TEST_PART_PRICE);
+    Part part = new Part(partProperties);
+
+    assertEquals(TEST_PART_TYPE, part.getType().get());
+    assertEquals(TEST_PART_MODEL, part.getModel().get());
+    assertEquals(TEST_PART_PRICE, part.getPrice().get());
+  }
+
+  @Test
+  public void shouldConstructCar() {
+    Map<String, Object> carProperties = new HashMap<>();
+    carProperties.put(HasModel.PROPERTY, TEST_CAR_MODEL);
+    carProperties.put(HasPrice.PROPERTY, TEST_CAR_PRICE);
+    carProperties.put(HasParts.PROPERTY, Arrays.asList(new HashMap<>(), new HashMap<>()));
+    Car car = new Car(carProperties);
+
+    assertEquals(TEST_CAR_MODEL, car.getModel().get());
+    assertEquals(TEST_CAR_PRICE, car.getPrice().get());
+    assertEquals(2, car.getParts().count());
+  }
+
+}

abstract-factory/README.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>1.12.0</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 +1,115 @@
+/**
+ * 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());
+  }
+
+  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");
+    app.createKingdom(new ElfKingdomFactory());
+    System.out.println(app.getArmy().getDescription());
+    System.out.println(app.getCastle().getDescription());
+    System.out.println(app.getKing().getDescription());
+
+    System.out.println("\nOrc Kingdom");
+    app.createKingdom(new 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 = new ElfKingdomFactory();
+    orcFactory = new OrcKingdomFactory();
+  }
+
+  @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/README.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/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/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>1.12.0</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);
+  }
 }

aggregator-microservices/README.md

@@ -0,0 +1,29 @@
+---
+layout: pattern
+title: Aggregator Microservices
+folder: aggregator-microservices
+permalink: /patterns/aggregator-microservices/
+categories: Architectural
+tags:
+- Java
+- Spring
+---
+
+## Intent
+
+The user makes a single call to the Aggregator, and the aggregator then calls each relevant microservice and collects
+the data, apply business logic to it, and further publish is as a REST Endpoint.
+More variations of the aggregator are: 
+- Proxy Microservice Design Pattern: A different microservice is called upon the business need. 
+- Chained Microservice Design Pattern: In this case each microservice is dependent/ chained to a series 
+of other microservices.
+
+![alt text](./etc/aggregator-microservice.png "Aggregator Microservice")
+
+## Applicability
+
+Use the Aggregator Microservices pattern when you need a unified API for various microservices, regardless the client device.
+
+## Credits
+
+* [Microservice Design Patterns](http://blog.arungupta.me/microservice-design-patterns/)

aggregator-microservices/aggregator-service/pom.xml

@@ -0,0 +1,88 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+    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 xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>aggregator-microservices</artifactId>
+        <groupId>com.iluwatar</groupId>
+        <version>1.12.0</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>aggregator-service</artifactId>
+    <packaging>jar</packaging>
+
+    <dependencyManagement>
+        <dependencies>
+            <dependency>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-dependencies</artifactId>
+            </dependency>
+        </dependencies>
+    </dependencyManagement>
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework</groupId>
+            <artifactId>spring-webmvc</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-core</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.httpcomponents</groupId>
+            <artifactId>httpclient</artifactId>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+                <version>${spring-boot.version}</version>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>repackage</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+</project>

aggregator-microservices/aggregator-service/src/main/java/com/iluwatar/aggregator/microservices/Aggregator.java

@@ -0,0 +1,58 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ * <p/>
+ * 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:
+ * <p/>
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * <p/>
+ * 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.aggregator.microservices;
+
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import javax.annotation.Resource;
+
+/**
+ * The aggregator aggregates calls on various micro-services, collects
+ * data and further publishes them under a REST endpoint.
+ */
+@RestController
+public class Aggregator {
+
+
+  @Resource
+  private ProductInformationClient informationClient;
+
+  @Resource
+  private ProductInventoryClient inventoryClient;
+
+
+  /**
+   * Retrieves product data.
+   *
+   * @return a Product.
+   */
+  @RequestMapping("/product")
+  public Product getProduct() {
+    Product product = new Product();
+    product.setTitle(informationClient.getProductTitle());
+    product.setProductInventories(inventoryClient.getProductInventories());
+    return product;
+  }
+
+}

aggregator-microservices/aggregator-service/src/main/java/com/iluwatar/aggregator/microservices/App.java

@@ -0,0 +1,39 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ * <p/>
+ * 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:
+ * <p/>
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * <p/>
+ * 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.aggregator.microservices;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class App {
+
+  /**
+   * Program entry point
+   *
+   * @param args command line args
+   */
+  public static void main(String[] args) {
+    SpringApplication.run(App.class, args);
+  }
+}

aggregator-microservices/aggregator-service/src/main/java/com/iluwatar/aggregator/microservices/Product.java

@@ -0,0 +1,57 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ * <p/>
+ * 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:
+ * <p/>
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * <p/>
+ * 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.aggregator.microservices;
+
+/**
+ * Encapsulates all the data for a Product that clients will request.
+ */
+public class Product {
+
+  /**
+   * The title of the product.
+   */
+  private String title;
+
+
+  /**
+   * The inventories of the product.
+   */
+  private int productInventories;
+
+  public String getTitle() {
+    return title;
+  }
+
+  public void setTitle(String title) {
+    this.title = title;
+  }
+
+  public int getProductInventories() {
+    return productInventories;
+  }
+
+  public void setProductInventories(int productInventories) {
+    this.productInventories = productInventories;
+  }
+
+}

aggregator-microservices/aggregator-service/src/main/java/com/iluwatar/aggregator/microservices/ProductInformationClient.java

@@ -0,0 +1,32 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ * <p/>
+ * 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:
+ * <p/>
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * <p/>
+ * 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.aggregator.microservices;
+
+/**
+ * Interface for the Information micro-service.
+ */
+public interface ProductInformationClient {
+
+  String getProductTitle();
+
+}

aggregator-microservices/aggregator-service/src/main/java/com/iluwatar/aggregator/microservices/ProductInformationClientImpl.java

@@ -0,0 +1,53 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ * <p/>
+ * 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:
+ * <p/>
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * <p/>
+ * 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.aggregator.microservices;
+
+import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.http.impl.client.HttpClients;
+import org.apache.http.util.EntityUtils;
+import org.springframework.stereotype.Component;
+
+import java.io.IOException;
+
+/**
+ * An adapter to communicate with information micro-service.
+ */
+@Component
+public class ProductInformationClientImpl implements ProductInformationClient {
+
+  @Override
+  public String getProductTitle() {
+    String response = null;
+    try (CloseableHttpClient httpClient = HttpClients.createDefault()) {
+      HttpGet httpGet = new HttpGet("http://localhost:51515/information");
+      try (CloseableHttpResponse httpResponse = httpClient.execute(httpGet)) {
+        response = EntityUtils.toString(httpResponse.getEntity());
+      }
+    } catch (IOException e) {
+      e.printStackTrace();
+    }
+    return response;
+  }
+}

aggregator-microservices/aggregator-service/src/main/java/com/iluwatar/aggregator/microservices/ProductInventoryClient.java

@@ -0,0 +1,31 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ * <p/>
+ * 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:
+ * <p/>
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * <p/>
+ * 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.aggregator.microservices;
+
+/**
+ * Interface to Inventory micro-service.
+ */
+public interface ProductInventoryClient {
+
+  int getProductInventories();
+}

aggregator-microservices/aggregator-service/src/main/java/com/iluwatar/aggregator/microservices/ProductInventoryClientImpl.java

@@ -0,0 +1,53 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ * <p/>
+ * 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:
+ * <p/>
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * <p/>
+ * 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.aggregator.microservices;
+
+import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.http.impl.client.HttpClients;
+import org.apache.http.util.EntityUtils;
+import org.springframework.stereotype.Component;
+
+import java.io.IOException;
+
+/**
+ * An adapter to communicate with inventory micro-service.
+ */
+@Component
+public class ProductInventoryClientImpl implements ProductInventoryClient {
+
+  @Override
+  public int getProductInventories() {
+    String response = "0";
+    try (CloseableHttpClient httpClient = HttpClients.createDefault()) {
+      HttpGet httpGet = new HttpGet("http://localhost:51516/inventories");
+      try (CloseableHttpResponse httpResponse = httpClient.execute(httpGet)) {
+        response = EntityUtils.toString(httpResponse.getEntity());
+      }
+    } catch (IOException e) {
+      e.printStackTrace();
+    }
+    return Integer.parseInt(response);
+  }
+}

aggregator-microservices/aggregator-service/src/main/resources/application.properties

@@ -0,0 +1,24 @@
+#
+# 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.
+#
+
+server.port=50004

aggregator-microservices/aggregator-service/src/test/java/com/iluwatar/aggregator/microservices/AggregatorTest.java

@@ -0,0 +1,67 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ * <p/>
+ * 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:
+ * <p/>
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * <p/>
+ * 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.aggregator.microservices;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+import static org.junit.Assert.assertEquals;
+import static org.mockito.Mockito.when;
+
+public class AggregatorTest {
+
+  @InjectMocks
+  private Aggregator aggregator;
+
+  @Mock
+  private ProductInformationClient informationClient;
+
+  @Mock
+  private ProductInventoryClient inventoryClient;
+
+  @Before
+  public void setup() {
+    MockitoAnnotations.initMocks(this);
+  }
+
+  /**
+   * Tests getting the data for a desktop client
+   */
+  @Test
+  public void testGetProduct() {
+    String title = "The Product Title.";
+    int inventories = 5;
+
+    when(informationClient.getProductTitle()).thenReturn(title);
+    when(inventoryClient.getProductInventories()).thenReturn(inventories);
+
+    Product testProduct = aggregator.getProduct();
+
+    assertEquals(title, testProduct.getTitle());
+    assertEquals(inventories, testProduct.getProductInventories());
+  }
+
+}

aggregator-microservices/information-microservice/pom.xml

@@ -0,0 +1,79 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+    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 xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>aggregator-microservices</artifactId>
+        <groupId>com.iluwatar</groupId>
+        <version>1.12.0</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>information-microservice</artifactId>
+    <packaging>jar</packaging>
+
+    <dependencyManagement>
+        <dependencies>
+            <dependency>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-dependencies</artifactId>
+            </dependency>
+        </dependencies>
+    </dependencyManagement>
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework</groupId>
+            <artifactId>spring-webmvc</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+                <version>${spring-boot.version}</version>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>repackage</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+</project>

aggregator-microservices/information-microservice/src/main/java/com/iluwatar/information/microservice/InformationApplication.java

@@ -0,0 +1,37 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ * <p/>
+ * 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:
+ * <p/>
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * <p/>
+ * 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.information.microservice;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+/**
+ * Inventory Application starts container (Spring Boot) and exposes the Inventory micro-service.
+ */
+@SpringBootApplication
+public class InformationApplication {
+
+  public static void main(String[] args) {
+    SpringApplication.run(InformationApplication.class, args);
+  }
+}

aggregator-microservices/information-microservice/src/main/java/com/iluwatar/information/microservice/InformationController.java

@@ -0,0 +1,41 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ * <p/>
+ * 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:
+ * <p/>
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * <p/>
+ * 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.information.microservice;
+
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class InformationController {
+
+  /**
+   * Endpoint to retrieve a product's informations.
+   *
+   * @return product inventory.
+   */
+  @RequestMapping(value = "/information", method = RequestMethod.GET)
+  public String getProductTitle() {
+    return "The Product Title.";
+  }
+}

aggregator-microservices/information-microservice/src/main/resources/application.properties

@@ -0,0 +1,24 @@
+#
+# 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.
+#
+
+server.port=51515

aggregator-microservices/information-microservice/src/test/java/com/iluwatar/information/microservice/InformationControllerTest.java

@@ -0,0 +1,39 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ * <p/>
+ * 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:
+ * <p/>
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * <p/>
+ * 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.information.microservice;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class InformationControllerTest {
+
+  @Test
+  public void shouldGetProductTitle() {
+    InformationController infoController = new InformationController();
+
+    String title = infoController.getProductTitle();
+
+    Assert.assertEquals("The Product Title.", title);
+  }
+
+}

aggregator-microservices/inventory-microservice/pom.xml

@@ -0,0 +1,79 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+    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 xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>aggregator-microservices</artifactId>
+        <groupId>com.iluwatar</groupId>
+        <version>1.12.0</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+
+    <artifactId>inventory-microservice</artifactId>
+    <packaging>jar</packaging>
+
+    <dependencyManagement>
+        <dependencies>
+            <dependency>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-dependencies</artifactId>
+            </dependency>
+        </dependencies>
+    </dependencyManagement>
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework</groupId>
+            <artifactId>spring-webmvc</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+                <version>${spring-boot.version}</version>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>repackage</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+</project>

aggregator-microservices/inventory-microservice/src/main/java/com/iluwatar/inventory/microservice/InventoryApplication.java

@@ -0,0 +1,38 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ * <p/>
+ * 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:
+ * <p/>
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * <p/>
+ * 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.inventory.microservice;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+/**
+ * Inventory Application starts container (Spring Boot) and exposes the Inventory micro-service.
+ */
+@SpringBootApplication
+public class InventoryApplication {
+
+  public static void main(String[] args) {
+    SpringApplication.run(InventoryApplication.class, args);
+  }
+
+}

aggregator-microservices/inventory-microservice/src/main/java/com/iluwatar/inventory/microservice/InventoryController.java

@@ -0,0 +1,42 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ * <p/>
+ * 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:
+ * <p/>
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * <p/>
+ * 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.inventory.microservice;
+
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class InventoryController {
+
+  /**
+   * Endpoint to retrieve a product's inventories.
+   *
+   * @return product inventory.
+   */
+  @RequestMapping(value = "/inventories", method = RequestMethod.GET)
+  public int getProductInventories() {
+    return 5;
+  }
+
+}

aggregator-microservices/inventory-microservice/src/main/resources/application.properties

@@ -0,0 +1,24 @@
+#
+# 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.
+#
+
+server.port=51516

aggregator-microservices/inventory-microservice/src/test/java/com/iluwatar/inventory/microservice/InventoryControllerTest.java

@@ -0,0 +1,38 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ * <p/>
+ * 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:
+ * <p/>
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ * <p/>
+ * 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.inventory.microservice;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class InventoryControllerTest {
+
+  @Test
+  public void testGetProductInventories() throws Exception {
+    InventoryController inventoryController = new InventoryController();
+
+    int numberOfInventories = inventoryController.getProductInventories();
+
+    Assert.assertEquals(5, numberOfInventories);
+  }
+}

aggregator-microservices/pom.xml

@@ -0,0 +1,43 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+    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 xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <parent>
+        <artifactId>java-design-patterns</artifactId>
+        <groupId>com.iluwatar</groupId>
+        <version>1.12.0</version>
+    </parent>
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>aggregator-microservices</artifactId>
+    <packaging>pom</packaging>
+
+    <modules>
+        <module>information-microservice</module>
+        <module>aggregator-service</module>
+        <module>inventory-microservice</module>
+    </modules>
+</project>

api-gateway/README.md

@@ -0,0 +1,30 @@
+---
+layout: pattern
+title: API Gateway
+folder: api-gateway
+permalink: /patterns/api-gateway/
+categories: Architectural
+tags:
+- Java
+- Difficulty-Intermediate
+- Spring
+---
+
+## Intent
+
+Aggregate calls to microservices in a single location: the API Gateway. The user makes a single
+call to the API Gateway, and the API Gateway then calls each relevant microservice.
+
+![alt text](./etc/api-gateway.png "API Gateway")
+
+## Applicability
+
+Use the API Gateway pattern when
+
+* you're also using the Microservices pattern and need a single point of aggregation for your
+microservice calls
+
+## Credits
+
+* [microservices.io - API Gateway](http://microservices.io/patterns/apigateway.html)
+* [NGINX - Building Microservices: Using an API Gateway](https://www.nginx.com/blog/building-microservices-using-an-api-gateway/)

api-gateway/api-gateway-service/pom.xml

@@ -0,0 +1,87 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+    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 xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <parent>
+    <artifactId>api-gateway</artifactId>
+    <groupId>com.iluwatar</groupId>
+    <version>1.12.0</version>
+  </parent>
+  <modelVersion>4.0.0</modelVersion>
+  <artifactId>api-gateway-service</artifactId>
+  <packaging>jar</packaging>
+
+  <dependencyManagement>
+    <dependencies>
+      <dependency>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-dependencies</artifactId>
+      </dependency>
+    </dependencies>
+  </dependencyManagement>
+  <dependencies>
+    <dependency>
+      <groupId>org.springframework</groupId>
+      <artifactId>spring-webmvc</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>org.springframework.boot</groupId>
+      <artifactId>spring-boot-starter-web</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.mockito</groupId>
+      <artifactId>mockito-core</artifactId>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.apache.httpcomponents</groupId>
+      <artifactId>httpclient</artifactId>
+    </dependency>
+  </dependencies>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-maven-plugin</artifactId>
+        <version>${spring-boot.version}</version>
+        <executions>
+          <execution>
+            <goals>
+              <goal>repackage</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+</project>

api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/ApiGateway.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.api.gateway;
+
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import javax.annotation.Resource;
+
+/**
+ * The ApiGateway aggregates calls to microservices based on the needs of the individual clients.
+ */
+@RestController
+public class ApiGateway {
+
+  @Resource
+  private ImageClient imageClient;
+
+  @Resource
+  private PriceClient priceClient;
+
+  /**
+   * Retrieves product information that desktop clients need
+   * @return Product information for clients on a desktop
+   */
+  @RequestMapping("/desktop")
+  public DesktopProduct getProductDesktop() {
+    DesktopProduct desktopProduct = new DesktopProduct();
+    desktopProduct.setImagePath(imageClient.getImagePath());
+    desktopProduct.setPrice(priceClient.getPrice());
+    return desktopProduct;
+  }
+
+  /**
+   * Retrieves product information that mobile clients need
+   * @return Product information for clients on a mobile device
+   */
+  @RequestMapping("/mobile")
+  public MobileProduct getProductMobile() {
+    MobileProduct mobileProduct = new MobileProduct();
+    mobileProduct.setPrice(priceClient.getPrice());
+    return mobileProduct;
+  }
+}

api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/App.java

@@ -0,0 +1,66 @@
+/**
+ * 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.api.gateway;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+/**
+ * With the Microservices pattern, a client may need data from multiple different microservices.
+ * If the client called each microservice directly, that could contribute to longer load times,
+ * since the client would have to make a network request for each microservice called. Moreover,
+ * having the client call each microservice directly ties the client to that microservice - if the
+ * internal implementations of the microservices change (for example, if two microservices are
+ * combined sometime in the future) or if the location (host and port) of a microservice changes,
+ * then every client that makes use of those microservices must be updated.
+ *
+ * <p>
+ * The intent of the API Gateway pattern is to alleviate some of these issues. In the API Gateway
+ * pattern, an additional entity (the API Gateway) is placed between the client and the
+ * microservices. The job of the API Gateway is to aggregate the calls to the microservices.
+ * Rather than the client calling each microservice individually, the client calls the API Gateway
+ * a single time. The API Gateway then calls each of the microservices that the client needs.
+ *
+ * <p>
+ * This implementation shows what the API Gateway pattern could look like for an e-commerce site.
+ * The {@link ApiGateway} makes calls to the Image and Price microservices using the
+ * {@link ImageClientImpl} and {@link PriceClientImpl} respectively. Customers viewing the site on a
+ * desktop device can see both price information and an image of a product, so the {@link ApiGateway}
+ * calls both of the microservices and aggregates the data in the {@link DesktopProduct} model.
+ * However, mobile users only see price information; they do not see a product image. For mobile
+ * users, the {@link ApiGateway} only retrieves price information, which it uses to populate the
+ * {@link MobileProduct}.
+ */
+@SpringBootApplication
+public class App {
+
+  /**
+   * Program entry point
+   *
+   * @param args
+   *          command line args
+   */
+  public static void main(String[] args) {
+    SpringApplication.run(App.class, args);
+  }
+}

api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/DesktopProduct.java

@@ -0,0 +1,54 @@
+/**
+ * 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.api.gateway;
+
+/**
+ * Encapsulates all of the information that a desktop client needs to display a product.
+ */
+public class DesktopProduct {
+  /**
+   * The price of the product
+   */
+  private String price;
+
+  /**
+   * The path to the image of the product
+   */
+  private String imagePath;
+
+  public String getPrice() {
+    return price;
+  }
+
+  public void setPrice(String price) {
+    this.price = price;
+  }
+
+  public String getImagePath() {
+    return imagePath;
+  }
+
+  public void setImagePath(String imagePath) {
+    this.imagePath = imagePath;
+  }
+}

api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/ImageClient.java

@@ -0,0 +1,30 @@
+/**
+ * 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.api.gateway;
+
+/**
+ * An interface used to communicate with the Image microservice
+ */
+public interface ImageClient {
+  String getImagePath();
+}

api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/ImageClientImpl.java

@@ -0,0 +1,56 @@
+/**
+ * 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.api.gateway;
+
+import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.http.impl.client.HttpClients;
+import org.apache.http.util.EntityUtils;
+import org.springframework.stereotype.Component;
+
+import java.io.IOException;
+
+/**
+ * An adapter to communicate with the Image microservice
+ */
+@Component
+public class ImageClientImpl implements ImageClient{
+  /**
+   * Makes a simple HTTP Get request to the Image microservice
+   * @return The path to the image
+   */
+  @Override
+  public String getImagePath() {
+    String response = null;
+    try (CloseableHttpClient httpClient = HttpClients.createDefault()) {
+      HttpGet httpGet = new HttpGet("http://localhost:50005/image-path");
+      try (CloseableHttpResponse httpResponse = httpClient.execute(httpGet)) {
+        response = EntityUtils.toString(httpResponse.getEntity());
+      }
+    } catch (IOException e) {
+      e.printStackTrace();
+    }
+    return response;
+  }
+}

api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/MobileProduct.java

@@ -0,0 +1,41 @@
+/**
+ * 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.api.gateway;
+
+/**
+ * Encapsulates all of the information that mobile client needs to display a product.
+ */
+public class MobileProduct {
+  /**
+   * The price of the product
+   */
+  private String price;
+
+  public String getPrice() {
+    return price;
+  }
+
+  public void setPrice(String price) {
+    this.price = price;
+  }
+}

api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/PriceClient.java

@@ -0,0 +1,30 @@
+/**
+ * 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.api.gateway;
+
+/**
+ * An interface used to communicate with the Price microservice
+ */
+public interface PriceClient {
+  String getPrice();
+}

api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/PriceClientImpl.java

@@ -0,0 +1,56 @@
+/**
+ * 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.api.gateway;
+
+import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.http.impl.client.HttpClients;
+import org.apache.http.util.EntityUtils;
+import org.springframework.stereotype.Component;
+
+import java.io.IOException;
+
+/**
+ * An adapter to communicate with the Price microservice
+ */
+@Component
+public class PriceClientImpl implements PriceClient{
+  /**
+   * Makes a simple HTTP Get request to the Price microservice
+   * @return The price of the product
+   */
+  @Override
+  public String getPrice() {
+    String response = null;
+    try (CloseableHttpClient httpClient = HttpClients.createDefault()) {
+      HttpGet httpGet = new HttpGet("http://localhost:50006/price");
+      try (CloseableHttpResponse httpResponse = httpClient.execute(httpGet)) {
+        response = EntityUtils.toString(httpResponse.getEntity());
+      }
+    } catch (IOException e) {
+      e.printStackTrace();
+    }
+    return response;
+  }
+}

api-gateway/api-gateway-service/src/main/resources/application.properties

@@ -0,0 +1,24 @@
+#
+# 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.
+#
+
+server.port=50004

api-gateway/api-gateway-service/src/test/java/com/iluwatar/api/gateway/ApiGatewayTest.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.api.gateway;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+import static org.junit.Assert.assertEquals;
+import static org.mockito.Mockito.when;
+
+public class ApiGatewayTest {
+
+  @InjectMocks
+  private ApiGateway apiGateway;
+
+  @Mock
+  private ImageClient imageClient;
+
+  @Mock
+  private PriceClient priceClient;
+
+  @Before
+  public void setup() {
+    MockitoAnnotations.initMocks(this);
+  }
+
+  /**
+   * Tests getting the data for a desktop client
+   */
+  @Test
+  public void testGetProductDesktop() {
+    String imagePath = "/product-image.png";
+    String price = "20";
+    when(imageClient.getImagePath()).thenReturn(imagePath);
+    when(priceClient.getPrice()).thenReturn(price);
+
+    DesktopProduct desktopProduct = apiGateway.getProductDesktop();
+
+    assertEquals(price, desktopProduct.getPrice());
+    assertEquals(imagePath, desktopProduct.getImagePath());
+  }
+
+  /**
+   * Tests getting the data for a mobile client
+   */
+  @Test
+  public void testGetProductMobile() {
+    String price = "20";
+    when(priceClient.getPrice()).thenReturn(price);
+
+    MobileProduct mobileProduct = apiGateway.getProductMobile();
+
+    assertEquals(price, mobileProduct.getPrice());
+  }
+}

api-gateway/etc/api-gateway.ucls

@@ -0,0 +1,97 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<class-diagram version="1.1.9" icons="true" automaticImage="PNG" 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.api.gateway.ApiGateway" project="api-gateway" 
+    file="/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/ApiGateway.java" binary="false" corner="BOTTOM_RIGHT">
+    <position height="-1" width="-1" x="125" y="87"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </class>  
+  <class id="2" language="java" name="com.iluwatar.api.gateway.DesktopProduct" project="api-gateway" 
+    file="/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/DesktopProduct.java" binary="false" corner="BOTTOM_RIGHT">
+    <position height="-1" width="-1" x="388" y="109"/>    
+    <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="3" language="java" name="com.iluwatar.api.gateway.ImageClient" project="api-gateway" 
+    file="/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/ImageClient.java" binary="false" corner="BOTTOM_RIGHT">
+    <position height="81" width="129" x="13" y="197"/>    
+    <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="4" language="java" name="com.iluwatar.api.gateway.ImageClientImpl" project="api-gateway" 
+    file="/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/ImageClientImpl.java" binary="false" corner="BOTTOM_RIGHT">
+    <position height="99" width="129" x="13" y="325"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </class>  
+  <class id="5" language="java" name="com.iluwatar.api.gateway.MobileProduct" project="api-gateway" 
+    file="/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/MobileProduct.java" binary="false" corner="BOTTOM_RIGHT">
+    <position height="-1" width="-1" x="376" y="293"/>    
+    <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="6" language="java" name="com.iluwatar.api.gateway.PriceClient" project="api-gateway" 
+    file="/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/PriceClient.java" binary="false" corner="BOTTOM_RIGHT">
+    <position height="-1" width="-1" x="222" y="231"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </interface>  
+  <class id="7" language="java" name="com.iluwatar.api.gateway.PriceClientImpl" project="api-gateway" 
+    file="/api-gateway/api-gateway-service/src/main/java/com/iluwatar/api/gateway/PriceClientImpl.java" binary="false" corner="BOTTOM_RIGHT">
+    <position height="-1" width="-1" x="223" 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="8">    
+    <end type="SOURCE" refId="1" navigable="false">      
+      <attribute id="9" name="imageClient"/>      
+      <multiplicity id="10" minimum="0" maximum="1"/>    
+    </end>    
+    <end type="TARGET" refId="3" navigable="true"/>    
+    <display labels="true" multiplicity="true"/>  
+  </association>  
+  <realization id="11">    
+    <end type="SOURCE" refId="4"/>    
+    <end type="TARGET" refId="3"/>  
+  </realization>  
+  <association id="12">    
+    <end type="SOURCE" refId="1" navigable="false">      
+      <attribute id="13" name="priceClient"/>      
+      <multiplicity id="14" minimum="0" maximum="1"/>    
+    </end>    
+    <end type="TARGET" refId="6" navigable="true"/>    
+    <display labels="true" multiplicity="true"/>  
+  </association>  
+  <realization id="15">    
+    <end type="SOURCE" refId="7"/>    
+    <end type="TARGET" refId="6"/>  
+  </realization>  
+  <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>

api-gateway/image-microservice/etc/image-microservice.ucls

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<class-diagram version="1.1.9" icons="true" automaticImage="PNG" 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.image.microservice.ImageController" project="image-microservice" 
+    file="/image-microservice/src/main/java/com/iluwatar/image/microservice/ImageController.java" binary="false" 
+    corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="87" y="61"/>    
+    <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>  
+  <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>

api-gateway/image-microservice/pom.xml

@@ -0,0 +1,79 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+    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 xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <parent>
+    <artifactId>api-gateway</artifactId>
+    <groupId>com.iluwatar</groupId>
+    <version>1.12.0</version>
+  </parent>
+
+  <modelVersion>4.0.0</modelVersion>
+  <artifactId>image-microservice</artifactId>
+  <packaging>jar</packaging>
+
+  <dependencyManagement>
+    <dependencies>
+      <dependency>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-dependencies</artifactId>
+      </dependency>
+    </dependencies>
+  </dependencyManagement>
+  <dependencies>
+    <dependency>
+      <groupId>org.springframework</groupId>
+      <artifactId>spring-webmvc</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>org.springframework.boot</groupId>
+      <artifactId>spring-boot-starter-web</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-maven-plugin</artifactId>
+        <version>${spring-boot.version}</version>
+        <executions>
+          <execution>
+            <goals>
+              <goal>repackage</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+</project>

api-gateway/image-microservice/src/main/java/com/iluwatar/image/microservice/ImageApplication.java

@@ -0,0 +1,43 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.image.microservice;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+/**
+ * ImageApplication starts up Spring Boot, exposing endpoints for the Image microservice through
+ * the {@link ImageController}.
+ */
+@SpringBootApplication
+public class ImageApplication {
+
+  /**
+   * Microservice entry point
+   * @param args
+   *          command line args
+   */
+  public static void main(String[] args) {
+    SpringApplication.run(ImageApplication.class, args);
+  }
+}

api-gateway/image-microservice/src/main/java/com/iluwatar/image/microservice/ImageController.java

@@ -0,0 +1,43 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.image.microservice;
+
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.RestController;
+
+/**
+ * Exposes the Image microservice's endpoints
+ */
+@RestController
+public class ImageController {
+
+  /**
+   * An endpoint for a user to retrieve an image path
+   * @return An image path
+   */
+  @RequestMapping(value = "/image-path", method = RequestMethod.GET)
+  public String getImagePath() {
+    return "/product-image.png";
+  }
+}

api-gateway/image-microservice/src/main/resources/application.properties

@@ -0,0 +1,24 @@
+#
+# 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.
+#
+
+server.port=50005