Resolved checkstyle issues

Execute Around - use lambda

.gitignore

@@ -1,14 +1,20 @@
-target
-.metadata
-.settings
-.classpath
-.project
-*.class
-# Package Files #
-*.jar
-*.war
-*.ear
-.idea
-*.iml
-*.swp
-datanucleus.log
+target
+.metadata
+.settings
+.classpath
+.project
+*.class
+# Package Files #
+*.jar
+*.war
+*.ear
+.idea
+*.iml
+*.swp
+datanucleus.log
+/bin/
+/bin/
+/bin/
+*.log
+data-mapper/src/main/resources/log4j.xml
+event-sourcing/Journal.json

.travis.yml

@@ -1,20 +1,39 @@
 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=
+  - secure: "eoWlW9GyTJY04P8K3pxayXwU9/hmptQg/LfirispQkV9YvmziCfSzXnatnBhNfud98sCzY8BScXnb+OWLTnjLKpId4rtEqb0aJ40Jc32cUKzgzFAUn7cNcDAbUIfyPAGVqyQqfj/11wYSADwWMMOPlW97ExUtoyiH2WenXuRHso="
   
-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
+# default install command is just "mvn install -DskipTests=true -Dmaven.javadoc.skip=true -B -V"
+install:
+- mvn install -DskipTests=true -Dmaven.javadoc.skip=true -B -V -e
+
+after_success:
+- mvn clean org.jacoco:jacoco-maven-plugin:prepare-agent package sonar:sonar -Dsonar.host.url=https://sonarcloud.io -Dsonar.login=$SONAR_TOKEN
+- bash update-ghpages.sh
+
+# use latest java version available instead of travis default
+addons:
+  apt:
+    packages:
+      - oracle-java8-installer
+
+notifications:
+  email:
+    - iluwatar@gmail.com
+  webhooks:
+    urls:
+      - https://webhooks.gitter.im/e/3319623945358a093a6f
+    on_success: change  # options: [always|never|change] default: always
+    on_failure: always  # options: [always|never|change] default: always
+    on_start: never     # options: [always|never|change] default: always
+
+sudo: required

CODE_COVERAGE.md

@@ -0,0 +1,13 @@
+# Code Coverage Report generation
+
+To generate the code coverage report, execute the following command:
+> mvn clean verify jacoco:report
+
+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

PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,15 @@
+
+Pull request title
+
+- Clearly and concisely describes what it does
+- Refer to the issue that it solves, if available
+
+
+Pull request description
+
+- Describes the main changes that come with the pull request
+- Any relevant additional information is provided
+
+
+
+> For detailed contributing instructions see https://github.com/iluwatar/java-design-patterns/wiki/01.-How-to-contribute

README.md

@@ -2,12 +2,13 @@
      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)
+[![Quality Gate](https://sonarcloud.io/api/project_badges/measure?project=com.iluwatar%3Ajava-design-patterns&metric=alert_status)](https://sonarcloud.io/dashboard/index/com.iluwatar%3Ajava-design-patterns)
+[![CII Best Practices](https://bestpractices.coreinfrastructure.org/projects/1503/badge)](https://bestpractices.coreinfrastructure.org/projects/1503)
 
 # Introduction
 
@@ -23,10 +24,16 @@ 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.
 
-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 +41,7 @@ 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 +1,29 @@
+---
+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.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.ucls

@@ -0,0 +1,142 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<class-diagram version="1.2.2" icons="true" always-add-relationships="false" generalizations="true" realizations="true" 
+  associations="true" dependencies="false" nesting-relationships="true" router="FAN">  
+  <class id="1" language="java" name="com.iluwatar.abstractdocument.AbstractDocument" project="abstract-document" 
+    file="/abstract-document/src/main/java/com/iluwatar/abstractdocument/AbstractDocument.java" binary="false" 
+    corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="659" y="286"/>    
+    <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.abstractdocument.Document" project="abstract-document" 
+    file="/abstract-document/src/main/java/com/iluwatar/abstractdocument/Document.java" binary="false" 
+    corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="562" y="27"/>    
+    <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.abstractdocument.domain.Car" project="abstract-document" 
+    file="/abstract-document/src/main/java/com/iluwatar/abstractdocument/domain/Car.java" binary="false" 
+    corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="348" y="737"/>    
+    <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="abstract-document" 
+    file="/abstract-document/src/main/java/com/iluwatar/abstractdocument/domain/Part.java" binary="false" 
+    corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="760" y="746"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </class>  
+  <interface id="5" language="java" name="com.iluwatar.abstractdocument.domain.HasModel" project="abstract-document" 
+    file="/abstract-document/src/main/java/com/iluwatar/abstractdocument/domain/HasModel.java" binary="false" 
+    corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="355" y="297"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </interface>  
+  <interface id="6" language="java" name="com.iluwatar.abstractdocument.domain.HasParts" project="abstract-document" 
+    file="/abstract-document/src/main/java/com/iluwatar/abstractdocument/domain/HasParts.java" binary="false" 
+    corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="109" y="297"/>    
+    <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="7" language="java" name="com.iluwatar.abstractdocument.domain.HasPrice" project="abstract-document" 
+    file="/abstract-document/src/main/java/com/iluwatar/abstractdocument/domain/HasPrice.java" binary="false" 
+    corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="1008" y="283"/>    
+    <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="8" language="java" name="com.iluwatar.abstractdocument.domain.HasType" project="abstract-document" 
+    file="/abstract-document/src/main/java/com/iluwatar/abstractdocument/domain/HasType.java" binary="false" 
+    corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="1257" y="277"/>    
+    <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>  
+  <realization id="9">    
+    <end type="SOURCE" refId="4"/>    
+    <end type="TARGET" refId="8"/>  
+  </realization>  
+  <realization id="10">    
+    <end type="SOURCE" refId="3"/>    
+    <end type="TARGET" refId="7"/>  
+  </realization>  
+  <generalization id="11">    
+    <end type="SOURCE" refId="6"/>    
+    <end type="TARGET" refId="2"/>  
+  </generalization>  
+  <realization id="12">    
+    <end type="SOURCE" refId="4"/>    
+    <end type="TARGET" refId="5"/>  
+  </realization>  
+  <realization id="13">    
+    <end type="SOURCE" refId="4"/>    
+    <end type="TARGET" refId="7"/>  
+  </realization>  
+  <generalization id="14">    
+    <end type="SOURCE" refId="3"/>    
+    <end type="TARGET" refId="1"/>  
+  </generalization>  
+  <realization id="15">    
+    <end type="SOURCE" refId="3"/>    
+    <end type="TARGET" refId="6"/>  
+  </realization>  
+  <generalization id="16">    
+    <end type="SOURCE" refId="8"/>    
+    <end type="TARGET" refId="2"/>  
+  </generalization>  
+  <generalization id="17">    
+    <end type="SOURCE" refId="7"/>    
+    <end type="TARGET" refId="2"/>  
+  </generalization>  
+  <realization id="18">    
+    <end type="SOURCE" refId="3"/>    
+    <end type="TARGET" refId="5"/>  
+  </realization>  
+  <generalization id="19">    
+    <end type="SOURCE" refId="4"/>    
+    <end type="TARGET" refId="1"/>  
+  </generalization>  
+  <generalization id="20">    
+    <end type="SOURCE" refId="5"/>    
+    <end type="TARGET" refId="2"/>  
+  </generalization>  
+  <realization id="21">    
+    <end type="SOURCE" refId="1"/>    
+    <end type="TARGET" refId="2"/>  
+  </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 +1,47 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+    The MIT License
+    Copyright (c) 2014-2016 Ilkka Seppälä
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in
+    all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+    THE SOFTWARE.
+
+-->
+<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>1.20.0-SNAPSHOT</version>
+    </parent>
+    <artifactId>abstract-document</artifactId>
+    <dependencies>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-api</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-engine</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) 2014-2016 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 +1,91 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 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 org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+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 {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(App.class);
+
+  /**
+   * Executes the App
+   */
+  public App() {
+    LOGGER.info("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);
+
+    LOGGER.info("Here is our car:");
+    LOGGER.info("-> model: {}", car.getModel().get());
+    LOGGER.info("-> price: {}", car.getPrice().get());
+    LOGGER.info("-> parts: ");
+    car.getParts().forEach(p -> LOGGER.info("\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) 2014-2016 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) 2014-2016 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) 2014-2016 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) 2014-2016 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) 2014-2016 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) 2014-2016 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) 2014-2016 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) 2014-2016 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.jupiter.api.Test;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Stream;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.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) 2014-2016 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.jupiter.api.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) 2014-2016 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.jupiter.api.Test;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.junit.jupiter.api.Assertions.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

@@ -0,0 +1,199 @@
+---
+layout: pattern
+title: Abstract Factory
+folder: abstract-factory
+permalink: /patterns/abstract-factory/
+categories: Creational
+tags:
+ - Java
+ - Gang Of Four
+ - Difficulty-Intermediate
+---
+
+## Also known as
+Kit
+
+## Intent
+Provide an interface for creating families of related or dependent
+objects without specifying their concrete classes.
+
+## Explanation
+Real world example
+
+> To create a kingdom we need objects with common theme. Elven kingdom needs an Elven king, Elven castle and Elven army whereas Orcish kingdom needs an Orcish king, Orcish castle and Orcish army. There is a dependency between the objects in the kingdom.
+
+In plain words
+
+> A factory of factories; a factory that groups the individual but related/dependent factories together without specifying their concrete classes.
+
+Wikipedia says
+
+> The abstract factory pattern provides a way to encapsulate a group of individual factories that have a common theme without specifying their concrete classes
+
+**Programmatic Example**
+
+Translating the kingdom example above. First of all we have some interfaces and implementation for the objects in the kingdom
+
+```java
+public interface Castle {
+  String getDescription();
+}
+public interface King {
+  String getDescription();
+}
+public interface Army {
+  String getDescription();
+}
+
+// Elven implementations ->
+public class ElfCastle implements Castle {
+  static final String DESCRIPTION = "This is the Elven castle!";
+  @Override
+  public String getDescription() {
+    return DESCRIPTION;
+  }
+}
+public class ElfKing implements King {
+  static final String DESCRIPTION = "This is the Elven king!";
+  @Override
+  public String getDescription() {
+    return DESCRIPTION;
+  }
+}
+public class ElfArmy implements Army {
+  static final String DESCRIPTION = "This is the Elven Army!";
+  @Override
+  public String getDescription() {
+    return DESCRIPTION;
+  }
+}
+
+// Orcish implementations similarly...
+
+```
+
+Then we have the abstraction and implementations for the kingdom factory
+
+```java
+public interface KingdomFactory {
+  Castle createCastle();
+  King createKing();
+  Army createArmy();
+}
+
+public class ElfKingdomFactory implements KingdomFactory {
+  public Castle createCastle() {
+    return new ElfCastle();
+  }
+  public King createKing() {
+    return new ElfKing();
+  }
+  public Army createArmy() {
+    return new ElfArmy();
+  }
+}
+
+public class OrcKingdomFactory implements KingdomFactory {
+  public Castle createCastle() {
+    return new OrcCastle();
+  }
+  public King createKing() {
+    return new OrcKing();
+  }
+  public Army createArmy() {
+    return new OrcArmy();
+  }
+}
+```
+
+Now we have our abstract factory that lets us make family of related objects i.e. Elven kingdom factory creates Elven castle, king and army etc.
+
+```java
+KingdomFactory factory = new ElfKingdomFactory();
+Castle castle = factory.createCastle();
+King king = factory.createKing();
+Army army = factory.createArmy();
+
+castle.getDescription();  // Output: This is the Elven castle!
+king.getDescription(); // Output: This is the Elven king!
+army.getDescription(); // Output: This is the Elven Army!
+```
+
+Now, we can design a factory for our different kingdom factories. In this example, we created FactoryMaker, responsible for returning an instance of either ElfKingdomFactory or OrcKingdomFactory.  
+The client can use FactoryMaker to create the desired concrete factory which, in turn, will produce different concrete objects (Army, King, Castle).  
+In this example, we also used an enum to parameterize which type of kingdom factory the client will ask for.
+
+```java
+public static class FactoryMaker {
+
+  public enum KingdomType {
+    ELF, ORC
+  }
+
+  public static KingdomFactory makeFactory(KingdomType type) {
+    switch (type) {
+      case ELF:
+        return new ElfKingdomFactory();
+      case ORC:
+        return new OrcKingdomFactory();
+      default:
+        throw new IllegalArgumentException("KingdomType not supported.");
+    }
+  }
+}
+
+public static void main(String[] args) {
+  App app = new App();
+
+  LOGGER.info("Elf Kingdom");
+  app.createKingdom(FactoryMaker.makeFactory(KingdomType.ELF));
+  LOGGER.info(app.getArmy().getDescription());
+  LOGGER.info(app.getCastle().getDescription());
+  LOGGER.info(app.getKing().getDescription());
+
+  LOGGER.info("Orc Kingdom");
+  app.createKingdom(FactoryMaker.makeFactory(KingdomType.ORC));
+  -- similar use of the orc factory
+}
+```
+
+
+## Applicability
+Use the Abstract Factory pattern when
+
+* a system should be independent of how its products are created, composed and represented
+* a system should be configured with one of multiple families of products
+* a family of related product objects is designed to be used together, and you need to enforce this constraint
+* you want to provide a class library of products, and you want to reveal just their interfaces, not their implementations
+* the lifetime of the dependency is conceptually shorter than the lifetime of the consumer.
+*	you need a run-time value to construct a particular dependency
+*	you want to decide which product to call from a family at runtime.
+*	you need to supply one or more parameters only known at run-time before you can resolve a dependency.
+
+## Use Cases:	
+
+*	Selecting to call the appropriate implementation of FileSystemAcmeService or DatabaseAcmeService or NetworkAcmeService at runtime.
+*	Unit test case writing becomes much easier
+
+## Consequences:
+
+*	Dependency injection in java hides the service class dependencies that can lead to runtime errors that would have been caught at compile time.
+
+
+## Tutorial
+* [Abstract Factory Pattern Tutorial](https://www.journaldev.com/1418/abstract-factory-design-pattern-in-java) 
+
+## Presentations
+
+* [Abstract Factory Pattern](etc/presentation.html) 
+
+
+## Real world examples
+
+* [javax.xml.parsers.DocumentBuilderFactory](http://docs.oracle.com/javase/8/docs/api/javax/xml/parsers/DocumentBuilderFactory.html)
+* [javax.xml.transform.TransformerFactory](http://docs.oracle.com/javase/8/docs/api/javax/xml/transform/TransformerFactory.html#newInstance--)
+* [javax.xml.xpath.XPathFactory](http://docs.oracle.com/javase/8/docs/api/javax/xml/xpath/XPathFactory.html#newInstance--)
+
+## Credits
+
+* [Design Patterns: Elements of Reusable Object-Oriented Software](http://www.amazon.com/Design-Patterns-Elements-Reusable-Object-Oriented/dp/0201633612)

abstract-factory/etc/abstract-factory.ucls

@@ -1,159 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<class-diagram version="1.1.8" icons="true" automaticImage="PNG" always-add-relationships="false" generalizations="true" 
-  realizations="true" associations="true" dependencies="false" nesting-relationships="true">  
-  <interface id="1" language="java" name="com.iluwatar.abstractfactory.Army" project="abstract-factory" 
-    file="/abstract-factory/src/main/java/com/iluwatar/abstractfactory/Army.java" binary="false" corner="BOTTOM_RIGHT">    
-    <position height="70" width="161" x="1407" y="300"/>    
-    <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.abstractfactory.KingdomFactory" project="abstract-factory" 
-    file="/abstract-factory/src/main/java/com/iluwatar/abstractfactory/KingdomFactory.java" binary="false" 
-    corner="BOTTOM_RIGHT">    
-    <position height="124" width="161" x="1001" y="300"/>    
-    <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.abstractfactory.ElfCastle" project="abstract-factory" 
-    file="/abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfCastle.java" binary="false" 
-    corner="BOTTOM_RIGHT">    
-    <position height="106" width="161" x="96" y="118"/>    
-    <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.abstractfactory.ElfKingdomFactory" project="abstract-factory" 
-    file="/abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfKingdomFactory.java" binary="false" 
-    corner="BOTTOM_RIGHT">    
-    <position height="142" width="161" x="900" y="118"/>    
-    <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.abstractfactory.ElfKing" project="abstract-factory" 
-    file="/abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfKing.java" binary="false" 
-    corner="BOTTOM_RIGHT">    
-    <position height="106" width="161" x="498" y="118"/>    
-    <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.abstractfactory.King" project="abstract-factory" 
-    file="/abstract-factory/src/main/java/com/iluwatar/abstractfactory/King.java" binary="false" corner="BOTTOM_RIGHT">    
-    <position height="70" width="161" x="599" y="300"/>    
-    <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.abstractfactory.OrcCastle" project="abstract-factory" 
-    file="/abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcCastle.java" binary="false" 
-    corner="BOTTOM_RIGHT">    
-    <position height="106" width="161" x="297" y="118"/>    
-    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
-      sort-features="false" accessors="true" visibility="true">      
-      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
-      <operations public="true" package="true" protected="true" private="true" static="true"/>    
-    </display>  
-  </class>  
-  <class id="8" language="java" name="com.iluwatar.abstractfactory.OrcKing" project="abstract-factory" 
-    file="/abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcKing.java" binary="false" 
-    corner="BOTTOM_RIGHT">    
-    <position height="106" width="161" x="699" y="118"/>    
-    <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="9" language="java" name="com.iluwatar.abstractfactory.ElfArmy" project="abstract-factory" 
-    file="/abstract-factory/src/main/java/com/iluwatar/abstractfactory/ElfArmy.java" binary="false" 
-    corner="BOTTOM_RIGHT">    
-    <position height="106" width="161" x="1306" y="118"/>    
-    <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="10" language="java" name="com.iluwatar.abstractfactory.OrcArmy" project="abstract-factory" 
-    file="/abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcArmy.java" binary="false" 
-    corner="BOTTOM_RIGHT">    
-    <position height="106" width="161" x="1507" y="118"/>    
-    <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="11" language="java" name="com.iluwatar.abstractfactory.Castle" project="abstract-factory" 
-    file="/abstract-factory/src/main/java/com/iluwatar/abstractfactory/Castle.java" binary="false" corner="BOTTOM_RIGHT">    
-    <position height="70" width="161" x="197" y="300"/>    
-    <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="12" language="java" name="com.iluwatar.abstractfactory.OrcKingdomFactory" project="abstract-factory" 
-    file="/abstract-factory/src/main/java/com/iluwatar/abstractfactory/OrcKingdomFactory.java" binary="false" 
-    corner="BOTTOM_RIGHT">    
-    <position height="142" width="165" x="1101" y="118"/>    
-    <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="13">    
-    <end type="SOURCE" refId="4"/>    
-    <end type="TARGET" refId="2"/>  
-  </realization>  
-  <realization id="14">    
-    <end type="SOURCE" refId="7"/>    
-    <end type="TARGET" refId="11"/>  
-  </realization>  
-  <realization id="15">    
-    <end type="SOURCE" refId="8"/>    
-    <end type="TARGET" refId="6"/>  
-  </realization>  
-  <realization id="16">    
-    <end type="SOURCE" refId="3"/>    
-    <end type="TARGET" refId="11"/>  
-  </realization>  
-  <realization id="17">    
-    <end type="SOURCE" refId="10"/>    
-    <end type="TARGET" refId="1"/>  
-  </realization>  
-  <realization id="18">    
-    <end type="SOURCE" refId="12"/>    
-    <end type="TARGET" refId="2"/>  
-  </realization>  
-  <realization id="19">    
-    <end type="SOURCE" refId="5"/>    
-    <end type="TARGET" refId="6"/>  
-  </realization>  
-  <realization id="20">    
-    <end type="SOURCE" refId="9"/>    
-    <end type="TARGET" refId="1"/>  
-  </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-factory/etc/presentation.html

@@ -0,0 +1,190 @@
+<!--
+
+    The MIT License
+    Copyright (c) 2017 Rodolfo Forte
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in
+    all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+    THE SOFTWARE.
+
+-->
+<!DOCTYPE html>
+<html>
+  <head>
+    <title>Design Patterns - Abstract Factory Presentation</title>
+    <meta charset="utf-8">
+    <style>
+      @import url(https://fonts.googleapis.com/css?family=Yanone+Kaffeesatz);
+      @import url(https://fonts.googleapis.com/css?family=Droid+Serif:400,700,400italic);
+      @import url(https://fonts.googleapis.com/css?family=Ubuntu+Mono:400,700,400italic);
+
+      body { font-family: 'Droid Serif'; }
+      h1, h2, h3 {
+        font-family: 'Yanone Kaffeesatz';
+        font-weight: normal;
+      }
+      .remark-code, .remark-inline-code { font-family: 'Ubuntu Mono'; }
+	  
+	  blockquote {
+		border-left: 0.3em solid rgba(0,0,0,0.5);
+		padding: 0 15px;
+		font-style: italic;
+	  }
+	  
+	  img {
+		max-width:100%;
+	  }
+    </style>
+  </head>
+  <body>
+    <textarea id="source">
+
+class: center, middle
+
+# Abstract Factory
+
+---
+
+# Also known as
+
+* Kit
+
+---
+
+# Intent
+
+* Provide an interface for creating families of related or dependent objects without specifying their concrete classes
+
+---
+
+# Explanation
+
+* [Wikipedia](https://en.wikipedia.org/wiki/Abstract_factory_pattern) says:
+  > "The abstract factory pattern provides a way to encapsulate a group of individual factories that have a common theme without specifying their concrete classes"
+
+<br />
+
+* In plain words:
+  * A factory that groups individual but related/dependent factories together without specifying their concrete classes;
+  * A factory of factories; 
+
+---
+
+# Example
+
+* In a factory that creates kingdoms, we need objects with common theme:
+
+  * Elven kingdom needs an Elven king, Elven castle and Elven army;
+  
+  * Orcish kingdom needs an Orcish king, Orcish castle and Orcish army;
+
+<br />
+  
+* There is a dependency between the objects in the kingdom;
+
+---
+
+# Diagram
+
+* Based on the kingdom example, the diagram below showcases the different concrete factories and their concrete products:
+
+.center[![Diagram](diagram1.png)]
+
+
+---
+
+# Diagram
+
+* The class diagram below showcases the factory of factories;
+
+* At runtime, we can define which Kingdom type is needed and pass it as a parameter to define which concrete KingdomFactory to instantiate;
+
+* The concrete factory returned will then be able to produce the related objects of the specified type;
+  
+.center[![Diagram](diagram2.png)]
+
+---
+
+# Applicability
+
+Use the Abstract Factory pattern when:
+
+* A system should be independent of how its products are created, composed and represented;
+
+* A system should be configured with one of multiple families of products;
+
+* A family of related product objects is designed to be used together, and you need to enforce this constraint;
+
+* You want to provide a class library of products, and you want to reveal just their interfaces, not their implementations;
+
+---
+
+# Applicability
+
+Use the Abstract Factory pattern when:
+
+* The lifetime of the dependency is conceptually shorter than the lifetime of the consumer;
+
+* You need a run-time value to construct a particular dependency;
+
+* You want to decide which product to call from a family at runtime;
+
+* You need to supply one or more parameters only known at run-time before you can resolve a dependency;
+
+---
+
+#Use Cases
+
+* Selecting to call the appropriate implementation of FileSystemAcmeService or DatabaseAcmeService or NetworkAcmeService at runtime;
+* Unit test case writing becomes much easier;
+
+---
+
+# Consequences
+
+* Dependency injection in java hides the service class dependencies that can lead to runtime errors that would have been caught at compile time
+
+---
+
+# Real world examples
+
+[javax.xml.parsers.DocumentBuilderFactory](http://docs.oracle.com/javase/8/docs/api/javax/xml/parsers/DocumentBuilderFactory.html)
+
+[javax.xml.transform.TransformerFactory](http://docs.oracle.com/javase/8/docs/api/javax/xml/transform/TransformerFactory.html#newInstance--)
+
+[javax.xml.xpath.XPathFactory](http://docs.oracle.com/javase/8/docs/api/javax/xml/xpath/XPathFactory.html#newInstance--)
+
+---
+
+# Credits
+
+* [Design Patterns: Elements of Reusable Object-Oriented Software](http://www.amazon.com/Design-Patterns-Elements-Reusable-Object-Oriented/dp/0201633612)
+
+---
+
+# Tutorials
+
+* Source code http://java-design-patterns.com/patterns/abstract-factory/
+
+    </textarea>
+    <script src="https://gnab.github.io/remark/downloads/remark-latest.min.js">
+    </script>
+    <script>
+      var slideshow = remark.create();
+    </script>
+  </body>
+</html>

abstract-factory/index.md

@@ -1,24 +0,0 @@
----
-layout: pattern
-title: Abstract Factory
-folder: abstract-factory
-permalink: /patterns/abstract-factory/
-categories: Creational
-tags: Java
----
-
-**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
-
-* 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:**
-
-* [javax.xml.parsers.DocumentBuilderFactory](http://docs.oracle.com/javase/8/docs/api/javax/xml/parsers/DocumentBuilderFactory.html)

abstract-factory/pom.xml

@@ -1,17 +1,46 @@
 <?xml version="1.0"?>
+<!--
+
+    The MIT License
+    Copyright (c) 2014-2016 Ilkka Seppälä
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in
+    all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+    THE SOFTWARE.
+
+-->
 <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>
+    <version>1.20.0-SNAPSHOT</version>
   </parent>
   <artifactId>abstract-factory</artifactId>
   <dependencies>
     <dependency>
-      <groupId>junit</groupId>
-      <artifactId>junit</artifactId>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-api</artifactId>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-engine</artifactId>
       <scope>test</scope>
     </dependency>
   </dependencies>

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

@@ -1,73 +1,147 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
 package com.iluwatar.abstractfactory;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.iluwatar.abstractfactory.App.FactoryMaker.KingdomType;
 
 /**
  * 
- * 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 static final Logger LOGGER = LoggerFactory.getLogger(App.class);
 
-	/**
-	 * 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;
-	}
-}
+  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;
+  }
+
+  /**
+   * The factory of kingdom factories.
+   */
+  public static class FactoryMaker {
+
+    /**
+     * Enumeration for the different types of Kingdoms.
+     */
+    public enum KingdomType {
+      ELF, ORC
+    }
+
+    /**
+     * The factory method to create KingdomFactory concrete objects.
+     */
+    public static KingdomFactory makeFactory(KingdomType type) {
+      switch (type) {
+        case ELF:
+          return new ElfKingdomFactory();
+        case ORC:
+          return new OrcKingdomFactory();
+        default:
+          throw new IllegalArgumentException("KingdomType not supported.");
+      }
+    }
+  }
+
+  /**
+   * Program entry point.
+   * 
+   * @param args
+   *          command line args
+   */
+  public static void main(String[] args) {
+
+    App app = new App();
+
+    LOGGER.info("Elf Kingdom");
+    app.createKingdom(FactoryMaker.makeFactory(KingdomType.ELF));
+    LOGGER.info(app.getArmy().getDescription());
+    LOGGER.info(app.getCastle().getDescription());
+    LOGGER.info(app.getKing().getDescription());
+
+    LOGGER.info("Orc Kingdom");
+    app.createKingdom(FactoryMaker.makeFactory(KingdomType.ORC));
+    LOGGER.info(app.getArmy().getDescription());
+    LOGGER.info(app.getCastle().getDescription());
+    LOGGER.info(app.getKing().getDescription());
+  }
+}

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

@@ -1,3 +1,25 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
 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) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
 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) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
 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) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
 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) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
 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) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
 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) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
 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) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
 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) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
 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) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
 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) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
 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) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
 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 +1,106 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.abstractfactory;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import com.iluwatar.abstractfactory.App.FactoryMaker;
+import com.iluwatar.abstractfactory.App.FactoryMaker.KingdomType;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test for abstract factory
+ */
+public class AbstractFactoryTest {
+
+  private App app = new App();
+  private KingdomFactory elfFactory;
+  private KingdomFactory orcFactory;
+
+  @BeforeEach
+  public void setUp() {
+    elfFactory = FactoryMaker.makeFactory(KingdomType.ELF);
+    orcFactory = FactoryMaker.makeFactory(KingdomType.ORC);
+  }
+
+  @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) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
 package com.iluwatar.abstractfactory;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
 
-import org.junit.Before;
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
+import java.io.IOException;
+
+/**
+ * Tests that Abstract Factory example runs without errors.
+ */
 public class AppTest {
-
-	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());
-	}
+  @Test
+  public void test() throws IOException {
+    String[] args = {};
+    App.main(args);
+  }
 }

acyclic-visitor/README.md

@@ -0,0 +1,39 @@
+---
+layout: pattern
+title: Acyclic Visitor
+folder: acyclic-visitor
+permalink: /patterns/acyclic-visitor/
+categories: Behavioral
+tags:
+ - Java
+ - Difficulty-Intermediate
+---
+
+![alt text](./etc/acyclic-visitor.png "Acyclic Visitor")
+
+## Intent
+Allow new functions to be added to existing class hierarchies without affecting those hierarchies, and without creating the troublesome dependency cycles that are inherent to the GOF VISITOR Pattern.
+
+## Applicability
+This pattern can be used:
+* When you need to add a new function to an existing hierarchy without the need to alter or affect that hierarchy.
+* When there are functions that operate upon a hierarchy, but which do not belong in the hierarchy itself. e.g. the ConfigureForDOS / ConfigureForUnix / ConfigureForX issue.
+* When you need to perform very different operations on an object depending upon its type.
+* When the visited class hierarchy will be frequently extended with new derivatives of the Element class.
+* When the recompilation, relinking, retesting or redistribution of the derivatives of Element is very expensive.
+
+## Consequences
+The good:
+* No dependency cycles between class hierarchies.
+* No need to recompile all the visitors if a new one is added.
+* Does not cause compilation failure in existing visitors if class hierarchy has a new member.
+
+The bad:
+* Violates the principle of least surprise or Liskov's Substitution principle by showing that it can accept all visitors but actually only being interested in particular visitors.
+* Parallel hierarchy of visitors has to be created for all members in visitable class hierarchy.
+
+## Related patterns
+* [Visitor Pattern](../visitor/README.md)
+
+## Credits
+* [Acyclic Visitor](http://condor.depaul.edu/dmumaugh/OOT/Design-Principles/acv.pdf)

acyclic-visitor/etc/Acyclic Visitor.ucls

@@ -1,113 +1,111 @@
 <?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.factory.method.OrcBlacksmith" project="factory-method" 
-    file="/factory-method/src/main/java/com/iluwatar/factory/method/OrcBlacksmith.java" binary="false" 
+<class-diagram version="1.2.2" icons="true" always-add-relationships="false" generalizations="true" realizations="true" 
+  associations="true" dependencies="false" nesting-relationships="true" router="FAN">  
+  <interface id="1" language="java" name="com.iluwatar.acyclicvisitor.ModemVisitor" project="acyclic-visitor" 
+    file="/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ModemVisitor.java" binary="false" 
     corner="BOTTOM_RIGHT">    
-    <position height="106" width="280" x="-46" y="239"/>    
-    <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.factory.method.Blacksmith" project="factory-method" 
-    file="/factory-method/src/main/java/com/iluwatar/factory/method/Blacksmith.java" binary="false" 
-    corner="BOTTOM_RIGHT">    
-    <position height="88" width="280" x="114" y="385"/>    
+    <position height="-1" width="-1" x="860" y="67"/>    
     <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
       sort-features="false" accessors="true" visibility="true">      
       <attributes public="true" package="true" protected="true" private="true" static="true"/>      
       <operations public="true" package="true" protected="true" private="true" static="true"/>    
     </display>  
   </interface>  
-  <enumeration id="3" language="java" name="com.iluwatar.factory.method.WeaponType" project="factory-method" 
-    file="/factory-method/src/main/java/com/iluwatar/factory/method/WeaponType.java" binary="false" 
+  <class id="2" language="java" name="com.iluwatar.acyclicvisitor.Modem" project="acyclic-visitor" 
+    file="/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Modem.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="327" y="77"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </class>  
+  <class id="3" language="java" name="com.iluwatar.acyclicvisitor.ConfigureForUnixVisitor" project="acyclic-visitor" 
+    file="/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ConfigureForUnixVisitor.java" binary="false" 
     corner="BOTTOM_RIGHT">    
-    <position height="196" width="210" x="793" y="385"/>    
-    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
-      sort-features="false" accessors="true" visibility="true">      
-      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
-      <operations public="true" package="true" protected="true" private="true" static="true"/>    
-    </display>  
-  </enumeration>  
-  <class id="4" language="java" name="com.iluwatar.factory.method.OrcWeapon" project="factory-method" 
-    file="/factory-method/src/main/java/com/iluwatar/factory/method/OrcWeapon.java" binary="false" corner="BOTTOM_RIGHT">    
-    <position height="106" width="178" x="806" y="239"/>    
+    <position height="124" width="196" x="647" y="225"/>    
     <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
       sort-features="false" accessors="true" visibility="true">      
       <attributes public="true" package="true" protected="true" private="true" static="true"/>      
       <operations public="true" package="true" protected="true" private="true" static="true"/>    
     </display>  
   </class>  
-  <class id="5" language="java" name="com.iluwatar.factory.method.ElfWeapon" project="factory-method" 
-    file="/factory-method/src/main/java/com/iluwatar/factory/method/ElfWeapon.java" binary="false" corner="BOTTOM_RIGHT">    
-    <position height="106" width="172" x="594" y="239"/>    
+  <class id="4" language="java" name="com.iluwatar.acyclicvisitor.Zoom" project="acyclic-visitor" 
+    file="/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Zoom.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="203" y="305"/>    
     <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
       sort-features="false" accessors="true" visibility="true">      
       <attributes public="true" package="true" protected="true" private="true" static="true"/>      
       <operations public="true" package="true" protected="true" private="true" static="true"/>    
     </display>  
   </class>  
-  <interface id="6" language="java" name="com.iluwatar.factory.method.Weapon" project="factory-method" 
-    file="/factory-method/src/main/java/com/iluwatar/factory/method/Weapon.java" binary="false" corner="BOTTOM_RIGHT">    
-    <position height="70" width="159" x="594" y="385"/>    
+  <interface id="5" language="java" name="com.iluwatar.acyclicvisitor.HayesVisitor" project="acyclic-visitor" 
+    file="/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/HayesVisitor.java" binary="false" 
+    corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="1019" y="468"/>    
     <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
       sort-features="false" accessors="true" visibility="true">      
       <attributes public="true" package="true" protected="true" private="true" static="true"/>      
       <operations public="true" package="true" protected="true" private="true" static="true"/>    
     </display>  
   </interface>  
-  <class id="7" language="java" name="com.iluwatar.factory.method.ElfBlacksmith" project="factory-method" 
-    file="/factory-method/src/main/java/com/iluwatar/factory/method/ElfBlacksmith.java" binary="false" 
+  <interface id="6" language="java" name="com.iluwatar.acyclicvisitor.ZoomVisitor" project="acyclic-visitor" 
+    file="/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ZoomVisitor.java" binary="false" 
     corner="BOTTOM_RIGHT">    
-    <position height="106" width="280" x="274" y="239"/>    
+    <position height="-1" width="-1" x="758" y="467"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </interface>  
+  <class id="7" language="java" name="com.iluwatar.acyclicvisitor.Hayes" project="acyclic-visitor" 
+    file="/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Hayes.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="479" y="307"/>    
     <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
       sort-features="false" accessors="true" visibility="true">      
       <attributes public="true" package="true" protected="true" private="true" static="true"/>      
       <operations public="true" package="true" protected="true" private="true" static="true"/>    
     </display>  
   </class>  
-  <realization id="8">    
-    <end type="SOURCE" refId="4"/>    
-    <end type="TARGET" refId="6"/>  
-  </realization>  
-  <realization id="9">    
+  <class id="8" language="java" name="com.iluwatar.acyclicvisitor.ConfigureForDosVisitor" project="acyclic-visitor" 
+    file="/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ConfigureForDosVisitor.java" binary="false" 
+    corner="BOTTOM_RIGHT">    
+    <position height="142" width="192" x="883" y="225"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </class>  
+  <generalization id="9">    
     <end type="SOURCE" refId="7"/>    
     <end type="TARGET" refId="2"/>  
-  </realization>  
+  </generalization>  
   <realization id="10">    
-    <end type="SOURCE" refId="5"/>    
+    <end type="SOURCE" refId="8"/>    
     <end type="TARGET" refId="6"/>  
   </realization>  
-  <association id="11">    
-    <end type="SOURCE" refId="4" navigable="false">      
-      <attribute id="12" name="weaponType">        
-        <position height="0" width="0" x="0" y="0"/>      
-      </attribute>      
-      <multiplicity id="13" minimum="0" maximum="1">        
-        <position height="0" width="0" x="0" y="0"/>      
-      </multiplicity>    
-    </end>    
-    <end type="TARGET" refId="3" navigable="true"/>    
-    <display labels="true" multiplicity="true"/>  
-  </association>  
-  <realization id="14">    
-    <end type="SOURCE" refId="1"/>    
-    <end type="TARGET" refId="2"/>  
+  <realization id="11">    
+    <end type="SOURCE" refId="8"/>    
+    <end type="TARGET" refId="5"/>  
   </realization>  
-  <association id="15">    
-    <end type="SOURCE" refId="5" navigable="false">      
-      <attribute id="16" name="weaponType">        
-        <position height="0" width="0" x="0" y="0"/>      
-      </attribute>      
-      <multiplicity id="17" minimum="0" maximum="1">        
-        <position height="0" width="0" x="0" y="0"/>      
-      </multiplicity>    
-    </end>    
-    <end type="TARGET" refId="3" navigable="true"/>    
-    <display labels="true" multiplicity="true"/>  
-  </association>  
+  <realization id="12">    
+    <end type="SOURCE" refId="3"/>    
+    <end type="TARGET" refId="6"/>  
+  </realization>  
+  <realization id="13">    
+    <end type="SOURCE" refId="3"/>    
+    <end type="TARGET" refId="1"/>  
+  </realization>  
+  <realization id="14">    
+    <end type="SOURCE" refId="8"/>    
+    <end type="TARGET" refId="1"/>  
+  </realization>  
+  <generalization id="15">    
+    <end type="SOURCE" refId="4"/>    
+    <end type="TARGET" refId="2"/>  
+  </generalization>  
   <classifier-display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
     sort-features="false" accessors="true" visibility="true">    
     <attributes public="true" package="true" protected="true" private="true" static="true"/>    

acyclic-visitor/pom.xml

@@ -0,0 +1,76 @@
+<!--
+
+    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>
+		<groupId>com.iluwatar</groupId>
+		<artifactId>java-design-patterns</artifactId>
+		<version>1.20.0-SNAPSHOT</version>
+	</parent>
+	
+	<artifactId>acyclic-visitor</artifactId>
+
+	<properties>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+		<maven.compiler.source>1.8</maven.compiler.source>
+		<maven.compiler.target>1.8</maven.compiler.target>
+	</properties>
+
+	<dependencies>
+		<!-- https://mvnrepository.com/artifact/org.assertj/assertj-core -->
+		<dependency>
+			<groupId>org.assertj</groupId>
+			<artifactId>assertj-core</artifactId>
+			<version>3.9.1</version>
+			<scope>test</scope>
+		</dependency>
+		<!-- https://mvnrepository.com/artifact/uk.org.lidalia/slf4j-test -->
+		<dependency>
+			<groupId>uk.org.lidalia</groupId>
+			<artifactId>slf4j-test</artifactId>
+			<version>1.0.0</version>
+			<scope>test</scope>
+		</dependency>
+		<dependency>
+      		<groupId>org.junit.jupiter</groupId>
+      		<artifactId>junit-jupiter-api</artifactId>
+      		<scope>test</scope>
+    	</dependency>
+    	<dependency>
+      		<groupId>org.junit.jupiter</groupId>
+      		<artifactId>junit-jupiter-engine</artifactId>
+      		<scope>test</scope>
+    	</dependency>
+		<dependency>
+			<groupId>org.mockito</groupId>
+			<artifactId>mockito-all</artifactId>
+			<version>1.9.5</version>
+			<scope>test</scope>
+		</dependency>
+	</dependencies>
+</project>

acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/AllModemVisitor.java

@@ -0,0 +1,31 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.acyclicvisitor;
+
+/**
+ * All ModemVisitor interface extends all visitor interfaces. This interface
+ * provides ease of use when a visitor needs to visit all modem types.
+ */
+public interface AllModemVisitor extends ZoomVisitor, HayesVisitor{
+
+}

acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/App.java

@@ -0,0 +1,55 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.acyclicvisitor;
+
+/**
+ * The Acyclic Visitor pattern allows new functions to be added to existing class 
+ * hierarchies without affecting those hierarchies, and without creating the dependency 
+ * cycles that are inherent to the GoF Visitor pattern, by making the Visitor base class 
+ * degenerate
+ * <p>
+ * In this example the visitor base class is {@link ModemVisitor}. The base class of the 
+ * visited hierarchy is {@link Modem} and has two children {@link Hayes} and {@link Zoom} 
+ * each one having its own visitor interface {@link HayesVisitor} and {@link ZoomVisitor} 
+ * respectively. {@link ConfigureForUnixVisitor} and {@link ConfigureForDosVisitor} 
+ * implement each derivative's visit method only if it is required 
+ */
+public class App {
+  
+  /**
+   * Program's entry point
+   */
+  
+  public static void main(String[] args) {  
+    ConfigureForUnixVisitor conUnix = new ConfigureForUnixVisitor();
+    ConfigureForDosVisitor conDos = new ConfigureForDosVisitor();
+    
+    Zoom zoom = new Zoom();
+    Hayes hayes = new Hayes();
+    
+    hayes.accept(conDos); // Hayes modem with Unix configurator
+    zoom.accept(conDos); // Zoom modem with Dos configurator
+    hayes.accept(conUnix); // Hayes modem with Unix configurator
+    zoom.accept(conUnix); // Zoom modem with Unix configurator   
+  }
+}

acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ConfigureForDosVisitor.java

@@ -0,0 +1,43 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.acyclicvisitor;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * ConfigureForDosVisitor class implements both zoom's and  hayes' visit method 
+ * for Dos manufacturer
+ */
+public class ConfigureForDosVisitor implements AllModemVisitor {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(ConfigureForDosVisitor.class);
+
+  public void visit(Hayes hayes) {
+    LOGGER.info(hayes + " used with Dos configurator.");
+  }
+
+  public void visit(Zoom zoom) {
+    LOGGER.info(zoom + " used with Dos configurator.");
+  }
+}

acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ConfigureForUnixVisitor.java

@@ -0,0 +1,40 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.acyclicvisitor;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * ConfigureForUnixVisitor class implements zoom's visit method for Unix 
+ * manufacturer, unlike traditional visitor pattern, this class may selectively implement
+ * visit for other modems.
+ */
+public class ConfigureForUnixVisitor implements ZoomVisitor {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(ConfigureForUnixVisitor.class);
+
+  public void visit(Zoom zoom) {
+    LOGGER.info(zoom + " used with Unix configurator.");
+  }
+}

acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Hayes.java

@@ -0,0 +1,56 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.acyclicvisitor;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Hayes class implements its accept method
+ */
+public class Hayes extends Modem {
+  
+  private static final Logger LOGGER = LoggerFactory.getLogger(ConfigureForDosVisitor.class);
+
+  /**
+   * Accepts all visitors but honors only HayesVisitor
+   */
+  @Override
+  public void accept(ModemVisitor modemVisitor) {
+    if (modemVisitor instanceof HayesVisitor) {
+      ((HayesVisitor) modemVisitor).visit(this);
+    } else {
+      LOGGER.info("Only HayesVisitor is allowed to visit Hayes modem");
+    }
+
+  }
+  
+  /**
+   * Hayes' modem's toString
+   * method
+   */
+  @Override
+  public String toString() {
+    return "Hayes modem";
+  }
+}

acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/HayesVisitor.java

@@ -0,0 +1,30 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.acyclicvisitor;
+
+/**
+ * HayesVisitor interface
+ */
+public interface HayesVisitor extends ModemVisitor {
+  void visit(Hayes hayes);
+}

acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Modem.java

@@ -0,0 +1,30 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.acyclicvisitor;
+
+/**
+ * Modem abstract class
+ */
+public abstract class Modem {
+  public abstract void accept(ModemVisitor modemVisitor);
+}

acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ModemVisitor.java

@@ -0,0 +1,32 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.acyclicvisitor;
+
+/**
+ * ModemVisitor interface does not contain any visit methods so that it does not
+ * depend on the visited hierarchy. Each derivative's visit method is declared in 
+ * its own visitor interface
+ */
+public interface ModemVisitor {
+  // Visitor is a degenerate base class for all visitors.
+}

acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Zoom.java

@@ -0,0 +1,55 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.acyclicvisitor;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Zoom class implements its accept method
+ */
+public class Zoom extends Modem {
+  
+  private static final Logger LOGGER = LoggerFactory.getLogger(ConfigureForDosVisitor.class);
+
+  /**
+   * Accepts all visitors but honors only ZoomVisitor
+   */
+  @Override
+  public void accept(ModemVisitor modemVisitor) {
+    if (modemVisitor instanceof  ZoomVisitor) {
+      ((ZoomVisitor) modemVisitor).visit(this);
+    } else {
+      LOGGER.info("Only ZoomVisitor is allowed to visit Zoom modem");
+    }
+  }
+  
+  /**
+   * Zoom modem's toString
+   * method
+   */
+  @Override
+  public String toString() {
+    return "Zoom modem";
+  }
+}

acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ZoomVisitor.java

@@ -0,0 +1,30 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.acyclicvisitor;
+
+/**
+ * ZoomVisitor interface
+ */
+public interface ZoomVisitor extends ModemVisitor {
+  void visit(Zoom zoom);
+}

acyclic-visitor/src/test/java/com/iluwatar/acyclicvisitor/AppTest.java

@@ -0,0 +1,39 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.acyclicvisitor;
+
+import org.junit.jupiter.api.Test;
+
+import com.iluwatar.acyclicvisitor.App;
+
+/**
+ * Tests that the Acyclic Visitor example runs without errors.
+ */
+public class AppTest {
+  
+  @Test
+  public void test() {
+    String[] args = {};
+    App.main(args);  
+  }
+}

acyclic-visitor/src/test/java/com/iluwatar/acyclicvisitor/ConfigureForDosVisitorTest.java

@@ -0,0 +1,75 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.acyclicvisitor;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.groups.Tuple.tuple;
+import static org.mockito.Mockito.mock;
+import static uk.org.lidalia.slf4jext.Level.INFO;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Test;
+
+import com.iluwatar.acyclicvisitor.ConfigureForDosVisitor;
+import com.iluwatar.acyclicvisitor.Hayes;
+import com.iluwatar.acyclicvisitor.HayesVisitor;
+import com.iluwatar.acyclicvisitor.Zoom;
+import com.iluwatar.acyclicvisitor.ZoomVisitor;
+
+import uk.org.lidalia.slf4jtest.TestLogger;
+import uk.org.lidalia.slf4jtest.TestLoggerFactory;
+
+/**
+ * ConfigureForDosVisitor test class
+ */
+public class ConfigureForDosVisitorTest {
+
+  TestLogger logger = TestLoggerFactory.getTestLogger(ConfigureForDosVisitor.class);
+  
+  @Test
+  public void testVisitForZoom() {    
+    ConfigureForDosVisitor conDos = new ConfigureForDosVisitor();
+    Zoom zoom = new Zoom();
+    
+    conDos.visit(zoom);
+    
+    assertThat(logger.getLoggingEvents()).extracting("level", "message").contains(
+        tuple(INFO, zoom + " used with Dos configurator."));
+  }
+  
+  @Test
+  public void testVisitForHayes() {
+    ConfigureForDosVisitor conDos = new ConfigureForDosVisitor();
+    Hayes hayes = new Hayes();
+    
+    conDos.visit(hayes);
+    
+    assertThat(logger.getLoggingEvents()).extracting("level", "message").contains(
+        tuple(INFO, hayes + " used with Dos configurator."));
+  }
+  
+  @AfterEach
+  public void clearLoggers() {
+    TestLoggerFactory.clear();
+  }
+}

acyclic-visitor/src/test/java/com/iluwatar/acyclicvisitor/ConfigureForUnixVisitorTest.java

@@ -0,0 +1,65 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.acyclicvisitor;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.groups.Tuple.tuple;
+import static uk.org.lidalia.slf4jext.Level.INFO;
+import static org.mockito.Mockito.mock;
+
+import uk.org.lidalia.slf4jtest.TestLogger;
+import uk.org.lidalia.slf4jtest.TestLoggerFactory;
+import org.junit.jupiter.api.Test;
+
+import com.iluwatar.acyclicvisitor.ConfigureForUnixVisitor;
+import com.iluwatar.acyclicvisitor.Hayes;
+import com.iluwatar.acyclicvisitor.HayesVisitor;
+import com.iluwatar.acyclicvisitor.Zoom;
+import com.iluwatar.acyclicvisitor.ZoomVisitor;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Assertions;
+
+/**
+ * ConfigureForUnixVisitor test class
+ */
+public class ConfigureForUnixVisitorTest {
+  
+  TestLogger logger = TestLoggerFactory.getTestLogger(ConfigureForUnixVisitor.class);
+  
+  @AfterEach
+  public void clearLoggers() {
+    TestLoggerFactory.clear();
+  }
+  
+  @Test
+  public void testVisitForZoom() {
+    ConfigureForUnixVisitor conUnix = new ConfigureForUnixVisitor();
+    Zoom zoom = new Zoom();
+    
+    conUnix.visit(zoom);
+    
+    assertThat(logger.getLoggingEvents()).extracting("level", "message").contains(
+        tuple(INFO, zoom + " used with Unix configurator."));
+  }
+}

acyclic-visitor/src/test/java/com/iluwatar/acyclicvisitor/HayesTest.java

@@ -0,0 +1,60 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.acyclicvisitor;
+
+import static org.mockito.Matchers.eq;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.verifyZeroInteractions;
+
+import org.junit.jupiter.api.Test;
+
+import com.iluwatar.acyclicvisitor.ConfigureForDosVisitor;
+import com.iluwatar.acyclicvisitor.ConfigureForUnixVisitor;
+import com.iluwatar.acyclicvisitor.Hayes;
+import com.iluwatar.acyclicvisitor.HayesVisitor;
+
+/**
+ * Hayes test class
+ */
+public class HayesTest {
+
+  @Test
+  public void testAcceptForDos() {  
+    Hayes hayes = new Hayes();
+    ConfigureForDosVisitor mockVisitor = mock(ConfigureForDosVisitor.class);
+    
+    hayes.accept(mockVisitor);
+    verify((HayesVisitor)mockVisitor).visit(eq(hayes));
+  }
+  
+  @Test
+  public void testAcceptForUnix() {    
+    Hayes hayes = new Hayes();
+    ConfigureForUnixVisitor mockVisitor = mock(ConfigureForUnixVisitor.class);
+    
+    hayes.accept(mockVisitor);
+    
+    verifyZeroInteractions(mockVisitor);
+  }
+}

acyclic-visitor/src/test/java/com/iluwatar/acyclicvisitor/ZoomTest.java

@@ -0,0 +1,59 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.acyclicvisitor;
+
+
+import static org.mockito.Matchers.eq;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.mock;
+
+import org.junit.jupiter.api.Test;
+
+import com.iluwatar.acyclicvisitor.ConfigureForDosVisitor;
+import com.iluwatar.acyclicvisitor.ConfigureForUnixVisitor;
+import com.iluwatar.acyclicvisitor.Zoom;
+import com.iluwatar.acyclicvisitor.ZoomVisitor;
+
+/**
+ * Zoom test class
+ */
+public class ZoomTest {
+  
+  @Test
+  public void testAcceptForDos() {  
+    Zoom zoom = new Zoom();
+    ConfigureForDosVisitor mockVisitor = mock(ConfigureForDosVisitor.class);
+    
+    zoom.accept(mockVisitor);
+    verify((ZoomVisitor)mockVisitor).visit(eq(zoom));
+  }
+  
+  @Test
+  public void testAcceptForUnix() {
+    Zoom zoom = new Zoom();
+    ConfigureForUnixVisitor mockVisitor = mock(ConfigureForUnixVisitor.class);
+    
+    zoom.accept(mockVisitor);
+    verify((ZoomVisitor)mockVisitor).visit(eq(zoom));
+  }
+}

adapter/README.md

@@ -0,0 +1,133 @@
+---
+layout: pattern
+title: Adapter
+folder: adapter
+permalink: /patterns/adapter/
+categories: Structural
+tags:
+ - Java
+ - Gang Of Four
+ - Difficulty-Beginner
+---
+
+## 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.
+
+## Explanation
+
+Real world example
+
+> Consider that you have some pictures in your memory card and you need to transfer them to your computer. In order to transfer them you need some kind of adapter that is compatible with your computer ports so that you can attach memory card to your computer. In this case card reader is an adapter.
+> Another example would be the famous power adapter; a three legged plug can't be connected to a two pronged outlet, it needs to use a power adapter that makes it compatible with the two pronged outlet.
+> Yet another example would be a translator translating words spoken by one person to another
+
+In plain words
+
+> Adapter pattern lets you wrap an otherwise incompatible object in an adapter to make it compatible with another class.
+
+Wikipedia says
+
+> In software engineering, the adapter pattern is a software design pattern that allows the interface of an existing class to be used as another interface. It is often used to make existing classes work with others without modifying their source code.
+
+**Programmatic Example**
+
+Consider a captain that can only use rowing boats and cannot sail at all.
+
+First we have interfaces `RowingBoat` and `FishingBoat`
+
+```java
+public interface RowingBoat {
+  void row();
+}
+
+public class FishingBoat {
+  private static final Logger LOGGER = LoggerFactory.getLogger(FishingBoat.class);
+  public void sail() {
+    LOGGER.info("The fishing boat is sailing");
+  }
+}
+```
+
+And captain expects an implementation of `RowingBoat` interface to be able to move
+
+```java
+public class Captain implements RowingBoat {
+
+  private RowingBoat rowingBoat;
+
+  public Captain(RowingBoat rowingBoat) {
+    this.rowingBoat = rowingBoat;
+  }
+
+  @Override
+  public void row() {
+    rowingBoat.row();
+  }
+}
+```
+
+Now let's say the pirates are coming and our captain needs to escape but there is only fishing boat available. We need to create an adapter that allows the captain to operate the fishing boat with his rowing boat skills.
+
+```java
+public class FishingBoatAdapter implements RowingBoat {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(FishingBoatAdapter.class);
+
+  private FishingBoat boat;
+
+  public FishingBoatAdapter() {
+    boat = new FishingBoat();
+  }
+
+  @Override
+  public void row() {
+    boat.sail();
+  }
+}
+```
+
+And now the `Captain` can use the `FishingBoat` to escape the pirates.
+
+```java
+Captain captain = new Captain(new FishingBoatAdapter());
+captain.row();
+```
+
+## 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.
+* most of the applications using third party libraries use adapters as a middle layer between the application and the 3rd party library to decouple the application from the library. If another library has to be used only an adapter for the new library is required without having to change the application code.
+
+## Consequences:
+Class and object adapters have different trade-offs. A class adapter
+
+*	adapts Adaptee to Target by committing to a concrete Adaptee class. As a consequence, a class adapter won’t work when we want to adapt a class and all its subclasses.
+*	let’s Adapter override some of Adaptee’s behavior, since Adapter is a subclass of Adaptee.
+*	introduces only one object, and no additional pointer indirection is needed to get to the adaptee.
+
+An object adapter	
+
+*	let’s a single Adapter work with many Adaptees—that is, the Adaptee itself and all of its subclasses (if any). The Adapter can also add functionality to all Adaptees at once.
+*	makes it harder to override Adaptee behavior. It will require subclassing Adaptee and making Adapter refer to the subclass rather than the Adaptee itself.
+
+
+## Real world examples
+
+* [java.util.Arrays#asList()](http://docs.oracle.com/javase/8/docs/api/java/util/Arrays.html#asList%28T...%29)
+* [java.util.Collections#list()](https://docs.oracle.com/javase/8/docs/api/java/util/Collections.html#list-java.util.Enumeration-)
+* [java.util.Collections#enumeration()](https://docs.oracle.com/javase/8/docs/api/java/util/Collections.html#enumeration-java.util.Collection-)
+* [javax.xml.bind.annotation.adapters.XMLAdapter](http://docs.oracle.com/javase/8/docs/api/javax/xml/bind/annotation/adapters/XmlAdapter.html#marshal-BoundType-)
+
+
+## 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/index.md

@@ -1,24 +0,0 @@
----
-layout: pattern
-title: Adapter
-folder: adapter
-permalink: /patterns/adapter/
-categories: Structural
-tags: Java
----
-
-**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")
-
-**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:**
-
-* [java.util.Arrays#asList()](http://docs.oracle.com/javase/8/docs/api/java/util/Arrays.html#asList%28T...%29)

adapter/pom.xml

@@ -1,17 +1,51 @@
 <?xml version="1.0"?>
+<!--
+
+    The MIT License
+    Copyright (c) 2014-2016 Ilkka Seppälä
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in
+    all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+    THE SOFTWARE.
+
+-->
 <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>
+    <version>1.20.0-SNAPSHOT</version>
   </parent>
   <artifactId>adapter</artifactId>
   <dependencies>
     <dependency>
-      <groupId>junit</groupId>
-      <artifactId>junit</artifactId>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-api</artifactId>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-engine</artifactId>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.mockito</groupId>
+      <artifactId>mockito-core</artifactId>
       <scope>test</scope>
     </dependency>
   </dependencies>

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

@@ -1,25 +1,60 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
 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 FishingBoatAdapter}) converts the interface of the adaptee class (
+ * {@link FishingBoat}) into a suitable one expected by the client ( {@link RowingBoat} ).
+ *
+ * <p>
+ * The story of this implementation is this. <br>
+ * Pirates are coming! we need a {@link RowingBoat} to flee! 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 rowing boat which he can operate. The spec is in {@link RowingBoat}. 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) {
+    // The captain can only operate rowing boats but with adapter he is able to use fishing boats as well
+    Captain captain = new Captain(new FishingBoatAdapter());
+    captain.row();
+  }
 }

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

@@ -0,0 +1,47 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.adapter;
+
+/**
+ * The Captain uses {@link RowingBoat} to sail. <br>
+ * This is the client in the pattern.
+ */
+public class Captain {
+
+  private RowingBoat rowingBoat;
+
+  public Captain() {}
+
+  public Captain(RowingBoat rowingBoat) {
+    this.rowingBoat = rowingBoat;
+  }
+
+  public void setRowingBoat(RowingBoat rowingBoat) {
+    this.rowingBoat = rowingBoat;
+  }
+
+  public void row() {
+    rowingBoat.row();
+  }
+
+}

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 +1,42 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.adapter;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ *
+ * Device class (adaptee in the pattern). We want to reuse this class.
+ * Fishing boat moves by sailing.
+ *
+ */
+public class FishingBoat {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(FishingBoat.class);
+
+  public void sail() {
+    LOGGER.info("The fishing boat is sailing");
+  }
+
+}

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

@@ -0,0 +1,43 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.adapter;
+
+/**
+ *
+ * Adapter class. Adapts the interface of the device ({@link FishingBoat}) into {@link RowingBoat}
+ * interface expected by the client ({@link Captain}).
+ *
+ */
+public class FishingBoatAdapter implements RowingBoat {
+
+  private FishingBoat boat;
+
+  public FishingBoatAdapter() {
+    boat = new FishingBoat();
+  }
+
+  @Override
+  public void row() {
+    boat.sail();
+  }
+}

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/main/java/com/iluwatar/adapter/RowingBoat.java

@@ -0,0 +1,34 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.adapter;
+
+/**
+ * The interface expected by the client.<br>
+ * A rowing boat is rowed to move.
+ *
+ */
+public interface RowingBoat {
+
+  void row();
+
+}

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

@@ -0,0 +1,78 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.adapter;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.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 FISHING_BEAN = "fisher";
+
+  private static final String ROWING_BEAN = "captain";
+
+  /**
+   * This method runs before the test execution and sets the bean objects in the beans Map.
+   */
+  @BeforeEach
+  public void setup() {
+    beans = new HashMap<>();
+
+    FishingBoatAdapter fishingBoatAdapter = spy(new FishingBoatAdapter());
+    beans.put(FISHING_BEAN, fishingBoatAdapter);
+
+    Captain captain = new Captain();
+    captain.setRowingBoat((FishingBoatAdapter) beans.get(FISHING_BEAN));
+    beans.put(ROWING_BEAN, captain);
+  }
+
+  /**
+   * This test asserts that when we use the row() method on a captain bean(client), it is
+   * internally calling sail method on the fishing boat object. The Adapter ({@link FishingBoatAdapter}
+   * ) converts the interface of the target class ( {@link FishingBoat}) into a suitable one
+   * expected by the client ({@link Captain} ).
+   */
+  @Test
+  public void testAdapter() {
+    Captain captain = (Captain) beans.get(ROWING_BEAN);
+
+    // when captain moves
+    captain.row();
+
+    // the captain internally calls the battleship object to move
+    RowingBoat adapter = (RowingBoat) beans.get(FISHING_BEAN);
+    verify(adapter).row();
+  }
+}

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

@@ -1,19 +1,38 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
 package com.iluwatar.adapter;
 
-import org.junit.Test;
+import org.junit.jupiter.api.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 +1,93 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+    The MIT License
+    Copyright (c) 2014-2016 Ilkka Seppälä
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in
+    all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+    THE SOFTWARE.
+
+-->
+<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>1.20.0-SNAPSHOT</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>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-api</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-engine</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) 2014-2016 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 +1,42 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 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;
+
+/**
+ * Spring Boot EntryPoint Class
+ */
+@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) 2014-2016 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) 2014-2016 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 +1,57 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 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.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Component;
+
+import java.io.IOException;
+
+/**
+ * An adapter to communicate with information micro-service.
+ */
+@Component
+public class ProductInformationClientImpl implements ProductInformationClient {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(ProductInformationClientImpl.class);
+
+  @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) {
+      LOGGER.error("Exception caught.", e);
+    }
+    return response;
+  }
+}

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

@@ -0,0 +1,31 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 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 +1,57 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 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.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Component;
+
+import java.io.IOException;
+
+/**
+ * An adapter to communicate with inventory micro-service.
+ */
+@Component
+public class ProductInventoryClientImpl implements ProductInventoryClient {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(ProductInventoryClientImpl.class);
+
+  @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) {
+      LOGGER.error("Exception caught.", e);
+    }
+    return Integer.parseInt(response);
+  }
+}

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

@@ -0,0 +1,24 @@
+#
+# The MIT License
+# Copyright (c) 2014-2016 Ilkka Seppälä
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+#
+
+server.port=50004

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

@@ -0,0 +1,70 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 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.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.Mockito.when;
+
+/**
+ * Test Aggregation of domain objects
+ */
+public class AggregatorTest {
+
+  @InjectMocks
+  private Aggregator aggregator;
+
+  @Mock
+  private ProductInformationClient informationClient;
+
+  @Mock
+  private ProductInventoryClient inventoryClient;
+
+  @BeforeEach
+  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 +1,84 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+    The MIT License
+    Copyright (c) 2014-2016 Ilkka Seppälä
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in
+    all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+    THE SOFTWARE.
+
+-->
+<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>1.20.0-SNAPSHOT</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>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-api</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-engine</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) 2014-2016 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 +1,44 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 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;
+
+/**
+ * Controller providing endpoints to retrieve information about products
+ */
+@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) 2014-2016 Ilkka Seppälä
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+#
+
+server.port=51515

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

@@ -0,0 +1,43 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014-2016 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.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+/**
+ * Test for Information Rest Controller
+ */
+public class InformationControllerTest {
+
+  @Test
+  public void shouldGetProductTitle() {
+    InformationController infoController = new InformationController();
+
+    String title = infoController.getProductTitle();
+
+    assertEquals("The Product Title.", title);
+  }
+
+}

aggregator-microservices/inventory-microservice/pom.xml

@@ -0,0 +1,84 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+
+    The MIT License
+    Copyright (c) 2014-2016 Ilkka Seppälä
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in
+    all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+    THE SOFTWARE.
+
+-->
+<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>1.20.0-SNAPSHOT</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>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-api</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-engine</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>