Updated class diagram png and added UCLS file

Resolves #643 , test cases failed due to presence of global state in CallsCount. Because AppTest was executed before B2BServiceTest, it scheduled 1 sec timer using ThrottleTimerImpl class. While resetting it used that global CallCount class reset() method, which reset all counters. So that causes thread safety issue because of unintended sharing of application state between test cases, which is not a good practice.
Remove CII best practices badge
2018-10-21 13:57:32 +05:30 · 2018-10-15 17:28:11 +05:30 · 2018-10-13 18:40:10 +03:00 · 2018-10-13 18:28:40 +03:00 · 2018-09-30 21:36:32 +03:00 · 2018-09-30 21:05:57 +03:00
244 changed files with 5478 additions and 456 deletions
--- a/CODE_COVERAGE.md
+++ b/CODE_COVERAGE.md
@ -1,7 +1,7 @@
 # Code Coverage Report generation

 To generate the code coverage report, execute the following command:
-> mvn clean verify
+> 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 
--- a/README.md
+++ b/README.md
@ -8,7 +8,6 @@
 [![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

--- a/abstract-document/pom.xml
+++ b/abstract-document/pom.xml
@ -29,7 +29,7 @@
    <parent>
        <artifactId>java-design-patterns</artifactId>
        <groupId>com.iluwatar</groupId>
-        <version>1.19.0</version>
+        <version>1.21.0-SNAPSHOT</version>
    </parent>
    <artifactId>abstract-document</artifactId>
    <dependencies>
--- a/abstract-factory/pom.xml
+++ b/abstract-factory/pom.xml
@ -29,7 +29,7 @@
  <parent>
    <groupId>com.iluwatar</groupId>
    <artifactId>java-design-patterns</artifactId>
-    <version>1.19.0</version>
+    <version>1.21.0-SNAPSHOT</version>
  </parent>
  <artifactId>abstract-factory</artifactId>
  <dependencies>
--- a/acyclic-visitor/README.md
+++ b/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)
--- a/acyclic-visitor/etc/Acyclic
+++ b/acyclic-visitor/etc/Acyclic
@ -0,0 +1,115 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<class-diagram version="1.2.2" icons="true" always-add-relationships="false" generalizations="true" realizations="true" 
+  associations="true" dependencies="false" nesting-relationships="true" router="FAN">  
+  <interface id="1" language="java" name="com.iluwatar.acyclicvisitor.ModemVisitor" project="acyclic-visitor" 
+    file="/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ModemVisitor.java" binary="false" 
+    corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="860" y="67"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </interface>  
+  <class id="2" language="java" name="com.iluwatar.acyclicvisitor.Modem" project="acyclic-visitor" 
+    file="/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Modem.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="327" y="77"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </class>  
+  <class id="3" language="java" name="com.iluwatar.acyclicvisitor.ConfigureForUnixVisitor" project="acyclic-visitor" 
+    file="/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ConfigureForUnixVisitor.java" binary="false" 
+    corner="BOTTOM_RIGHT">    
+    <position height="124" width="196" x="647" y="225"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </class>  
+  <class id="4" language="java" name="com.iluwatar.acyclicvisitor.Zoom" project="acyclic-visitor" 
+    file="/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Zoom.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="203" y="305"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </class>  
+  <interface id="5" language="java" name="com.iluwatar.acyclicvisitor.HayesVisitor" project="acyclic-visitor" 
+    file="/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/HayesVisitor.java" binary="false" 
+    corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="1019" y="468"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </interface>  
+  <interface id="6" language="java" name="com.iluwatar.acyclicvisitor.ZoomVisitor" project="acyclic-visitor" 
+    file="/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ZoomVisitor.java" binary="false" 
+    corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="758" y="467"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </interface>  
+  <class id="7" language="java" name="com.iluwatar.acyclicvisitor.Hayes" project="acyclic-visitor" 
+    file="/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Hayes.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="479" y="307"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </class>  
+  <class id="8" language="java" name="com.iluwatar.acyclicvisitor.ConfigureForDosVisitor" project="acyclic-visitor" 
+    file="/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ConfigureForDosVisitor.java" binary="false" 
+    corner="BOTTOM_RIGHT">    
+    <position height="142" width="192" x="883" y="225"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </class>  
+  <generalization id="9">    
+    <end type="SOURCE" refId="7"/>    
+    <end type="TARGET" refId="2"/>  
+  </generalization>  
+  <realization id="10">    
+    <end type="SOURCE" refId="8"/>    
+    <end type="TARGET" refId="6"/>  
+  </realization>  
+  <realization id="11">    
+    <end type="SOURCE" refId="8"/>    
+    <end type="TARGET" refId="5"/>  
+  </realization>  
+  <realization id="12">    
+    <end type="SOURCE" refId="3"/>    
+    <end type="TARGET" refId="6"/>  
+  </realization>  
+  <realization id="13">    
+    <end type="SOURCE" refId="3"/>    
+    <end type="TARGET" refId="1"/>  
+  </realization>  
+  <realization id="14">    
+    <end type="SOURCE" refId="8"/>    
+    <end type="TARGET" refId="1"/>  
+  </realization>  
+  <generalization id="15">    
+    <end type="SOURCE" refId="4"/>    
+    <end type="TARGET" refId="2"/>  
+  </generalization>  
+  <classifier-display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+    sort-features="false" accessors="true" visibility="true">    
+    <attributes public="true" package="true" protected="true" private="true" static="true"/>    
+    <operations public="true" package="true" protected="true" private="true" static="true"/>  
+  </classifier-display>  
+  <association-display labels="true" multiplicity="true"/>
+</class-diagram>
--- a/acyclic-visitor/etc/acyclic-visitor.png
+++ b/acyclic-visitor/etc/acyclic-visitor.png
--- a/acyclic-visitor/pom.xml
+++ b/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>1.21.0-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>
--- a/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/AllModemVisitor.java
+++ b/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{
+
+}
--- a/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/App.java
+++ b/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   
+  }
+}
--- a/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ConfigureForDosVisitor.java
+++ b/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.");
+  }
+}
--- a/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ConfigureForUnixVisitor.java
+++ b/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.");
+  }
+}
--- a/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Hayes.java
+++ b/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";
+  }
+}
--- a/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/HayesVisitor.java
+++ b/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);
+}
--- a/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Modem.java
+++ b/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);
+}
--- a/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ModemVisitor.java
+++ b/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.
+}
--- a/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/Zoom.java
+++ b/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";
+  }
+}
--- a/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ZoomVisitor.java
+++ b/acyclic-visitor/src/main/java/com/iluwatar/acyclicvisitor/ZoomVisitor.java
@ -20,16 +20,11 @@
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
-package com.iluwatar.iterator;
+package com.iluwatar.acyclicvisitor;

 /**
- * 
- * ItemIterator interface.
- * 
+ * ZoomVisitor interface
 */
-public interface ItemIterator {
-
-  boolean hasNext();
-
-  Item next();
+public interface ZoomVisitor extends ModemVisitor {
+  void visit(Zoom zoom);
 }
--- a/acyclic-visitor/src/test/java/com/iluwatar/acyclicvisitor/AppTest.java
+++ b/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);  
+  }
+}
--- a/acyclic-visitor/src/test/java/com/iluwatar/acyclicvisitor/ConfigureForDosVisitorTest.java
+++ b/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();
+  }
+}
--- a/acyclic-visitor/src/test/java/com/iluwatar/acyclicvisitor/ConfigureForUnixVisitorTest.java
+++ b/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."));
+  }
+}
--- a/acyclic-visitor/src/test/java/com/iluwatar/acyclicvisitor/HayesTest.java
+++ b/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);
+  }
+}
--- a/acyclic-visitor/src/test/java/com/iluwatar/acyclicvisitor/ZoomTest.java
+++ b/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));
+  }
+}
--- a/adapter/pom.xml
+++ b/adapter/pom.xml
@ -29,7 +29,7 @@
  <parent>
    <groupId>com.iluwatar</groupId>
    <artifactId>java-design-patterns</artifactId>
-    <version>1.19.0</version>
+    <version>1.21.0-SNAPSHOT</version>
  </parent>
  <artifactId>adapter</artifactId>
  <dependencies>
--- a/aggregator-microservices/aggregator-service/pom.xml
+++ b/aggregator-microservices/aggregator-service/pom.xml
@ -29,7 +29,7 @@
    <parent>
        <artifactId>aggregator-microservices</artifactId>
        <groupId>com.iluwatar</groupId>
-        <version>1.19.0</version>
+        <version>1.21.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

--- a/aggregator-microservices/information-microservice/pom.xml
+++ b/aggregator-microservices/information-microservice/pom.xml
@ -29,7 +29,7 @@
    <parent>
        <artifactId>aggregator-microservices</artifactId>
        <groupId>com.iluwatar</groupId>
-        <version>1.19.0</version>
+        <version>1.21.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

--- a/aggregator-microservices/inventory-microservice/pom.xml
+++ b/aggregator-microservices/inventory-microservice/pom.xml
@ -29,7 +29,7 @@
    <parent>
        <artifactId>aggregator-microservices</artifactId>
        <groupId>com.iluwatar</groupId>
-        <version>1.19.0</version>
+        <version>1.21.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

--- a/aggregator-microservices/pom.xml
+++ b/aggregator-microservices/pom.xml
@ -29,7 +29,7 @@
    <parent>
        <artifactId>java-design-patterns</artifactId>
        <groupId>com.iluwatar</groupId>
-        <version>1.19.0</version>
+        <version>1.21.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
    <artifactId>aggregator-microservices</artifactId>
--- a/ambassador/README.md
+++ b/ambassador/README.md
@ -0,0 +1,178 @@
+---
+layout: pattern
+title: Ambassador
+folder: ambassador
+permalink: /patterns/ambassador/
+categories: Structural
+tags:
+ - Java
+ - Difficulty-Intermediate
+---
+
+## Intent
+Provide a helper service instance on a client and offload common functionality away from a shared resource.
+
+## Explanation
+Real world example
+
+> A remote service has many clients accessing a function it provides. The service is a legacy application and is impossible to update. Large numbers of requests from users are causing connectivity issues. New rules for request frequency should be implemented along with latency checks and client-side logging.
+
+In plain words
+
+> Using the ambassador pattern, we can implement less-frequent polling from clients along with latency checks and logging.
+
+Microsoft documentation states
+
+> An ambassador service can be thought of as an out-of-process proxy that is co-located with the client.
+  This pattern can be useful for offloading common client connectivity tasks such as monitoring, logging, routing, security (such as TLS), and resiliency patterns in a language agnostic way. It is often used with legacy applications, or other applications that are difficult to modify, in order to extend their networking capabilities. It can also enable a specialized team to implement those features.
+
+**Programmatic Example**
+
+With the above example in mind we will imitate the functionality in a simple manner. We have an interface implemented by the remote service as well as the ambassador service:
+
+```java
+interface RemoteServiceInterface {
+
+    long doRemoteFunction(int value) throws Exception;
+}
+```
+
+A remote services represented as a singleton.
+
+```java
+public class RemoteService implements RemoteServiceInterface {
+
+		private static final Logger LOGGER = LoggerFactory.getLogger(RemoteService.class);
+    private static RemoteService service = null;2
+
+    static synchronized RemoteService getRemoteService() {
+        if (service == null) {
+            service = new RemoteService();
+        }
+        return service;
+    }
+
+    private RemoteService() {}
+
+    @Override
+    public long doRemoteFunction(int value) {
+
+        long waitTime = (long) Math.floor(Math.random() * 1000);
+
+        try {
+            sleep(waitTime);
+        } catch (InterruptedException e) {
+            LOGGER.error("Thread sleep interrupted", e)
+        }
+        return waitTime >= 200 ? value * 10 : -1;
+    }
+}
+```
+
+A service ambassador adding additional features such as logging, latency checks
+
+```java
+public class ServiceAmbassador implements RemoteServiceInterface {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(ServiceAmbassador.class);
+    private static final int RETRIES = 3;
+    private static final int DELAY_MS = 3000;
+
+    ServiceAmbassador() {}
+
+    @Override
+    public long doRemoteFunction(int value) {
+
+        return safeCall(value);
+    }
+
+    private long checkLatency(int value) {
+        RemoteService service = RemoteService.getRemoteService();
+        long startTime = System.currentTimeMillis();
+        long result = service.doRemoteFunction(value);
+        long timeTaken = System.currentTimeMillis() - startTime;
+
+        LOGGER.info("Time taken (ms): " + timeTaken);
+        return result;
+    }
+
+    private long safeCall(int value) {
+
+        int retries = 0;
+        long result = -1;
+
+        for (int i = 0; i < RETRIES; i++) {
+
+            if (retries >= RETRIES) {
+                return -1;
+            }
+
+            if ((result = checkLatency(value)) == -1) {
+                LOGGER.info("Failed to reach remote: (" + (i + 1) + ")");
+                retries++;
+                try {
+                    sleep(DELAY_MS);
+                } catch (InterruptedException e) {
+                    LOGGER.error("Thread sleep state interrupted", e);
+                }
+            } else {
+                break;
+            }
+        }
+        return result;
+    }
+}
+```
+
+A client has a local service ambassador used to interact with the remote service:
+
+```java
+public class Client {
+
+    private ServiceAmbassador serviceAmbassador;
+
+    Client() {
+        serviceAmbassador = new ServiceAmbassador();
+    }
+
+    long useService(int value) {
+        long result = serviceAmbassador.doRemoteFunction(value);
+        LOGGER.info("Service result: " + result)
+        return result;
+    }
+}
+```
+
+And here are two clients using the service.
+
+```java
+Client host1 = new Client();
+Client host2 = new Client();
+host1.useService(12);
+host2.useService(73);
+```
+
+## Applicability
+Ambassador is applicable when working with a legacy remote service that cannot
+be modified or would be extremely difficult to modify. Connectivity features can
+be implemented on the client avoiding the need for changes on the remote service.
+
+* Ambassador provides a local interface for a remote service.
+* Ambassador provides logging, circuit breaking, retries and security on the client.
+
+## Typical Use Case
+
+* Control access to another object
+* Implement logging
+* Implement circuit breaking
+* Offload remote service tasks
+* Facilitate network connection
+
+## Real world examples
+
+* [Kubernetes-native API gateway for microservices](https://github.com/datawire/ambassador)
+
+## Credits
+
+* [Ambassador pattern](https://docs.microsoft.com/en-us/azure/architecture/patterns/ambassador)
+* [Designing Distributed Systems: Patterns and Paradigms for Scalable, Reliable Services](https://books.google.co.uk/books?id=6BJNDwAAQBAJ&pg=PT35&lpg=PT35&dq=ambassador+pattern+in+real+world&source=bl&ots=d2e7GhYdHi&sig=Lfl_MDnCgn6lUcjzOg4GXrN13bQ&hl=en&sa=X&ved=0ahUKEwjk9L_18rrbAhVpKcAKHX_KA7EQ6AEIWTAI#v=onepage&q=ambassador%20pattern%20in%20real%20world&f=false)
--- a/ambassador/pom.xml
+++ b/ambassador/pom.xml
@ -0,0 +1,48 @@
+<?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>java-design-patterns</artifactId>
+    <groupId>com.iluwatar</groupId>
+    <version>1.21.0-SNAPSHOT</version>
+  </parent>
+  <modelVersion>4.0.0</modelVersion>
+  <artifactId>ambassador</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>
--- a/ambassador/src/main/java/com/iluwatar/ambassador/App.java
+++ b/ambassador/src/main/java/com/iluwatar/ambassador/App.java
@ -0,0 +1,53 @@
+/**
+ * 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.ambassador;
+
+/**
+ *
+ * The ambassador pattern creates a helper service that sends network requests on behalf of a
+ * client. It is often used in cloud-based applications to offload features of a remote service.
+ *
+ * An ambassador service can be thought of as an out-of-process proxy that is co-located with
+ * the client. Similar to the proxy design pattern, the ambassador service provides an interface
+ * for another remote service. In addition to the interface, the ambassador provides extra
+ * functionality and features, specifically offloaded common connectivity tasks. This usually
+ * consists of monitoring, logging, routing, security etc. This is extremely useful in
+ * legacy applications where the codebase is difficult to modify and allows for improvements
+ * in the application's networking capabilities.
+ *
+ * In this example, we will the ({@link ServiceAmbassador}) class represents the ambassador while the
+ * ({@link RemoteService}) class represents a remote application.
+ *
+ */
+public class App {
+
+  /**
+  * Entry point
+  */
+  public static void main(String[] args) {
+    Client host1 = new Client();
+    Client host2 = new Client();
+    host1.useService(12);
+    host2.useService(73);
+  }
+}
--- a/ambassador/src/main/java/com/iluwatar/ambassador/Client.java
+++ b/ambassador/src/main/java/com/iluwatar/ambassador/Client.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.ambassador;
+
+import org.slf4j.LoggerFactory;
+
+import org.slf4j.Logger;
+
+/**
+ * A simple Client
+ */
+public class Client {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(Client.class);
+  private final ServiceAmbassador serviceAmbassador = new ServiceAmbassador();
+
+  long useService(int value) {
+    long result = serviceAmbassador.doRemoteFunction(value);
+    LOGGER.info("Service result: " + result);
+    return result;
+  }
+}
--- a/ambassador/src/main/java/com/iluwatar/ambassador/RemoteService.java
+++ b/ambassador/src/main/java/com/iluwatar/ambassador/RemoteService.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.ambassador;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import static java.lang.Thread.sleep;
+
+/**
+ * A remote legacy application represented by a Singleton implementation.
+ */
+public class RemoteService implements RemoteServiceInterface {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(RemoteService.class);
+  private static RemoteService service = null;
+
+  static synchronized RemoteService getRemoteService() {
+    if (service == null) {
+      service = new RemoteService();
+    }
+    return service;
+  }
+
+  private RemoteService() {}
+
+  /**
+   * Remote function takes a value and multiplies it by 10 taking a random amount of time.
+   * Will sometimes return -1. This imitates connectivity issues a client might have to account for.
+   * @param value integer value to be multiplied.
+   * @return if waitTime is more than 200ms, it returns value * 10, otherwise -1.
+   */
+  @Override
+  public long doRemoteFunction(int value) {
+
+    long waitTime = (long) Math.floor(Math.random() * 1000);
+
+    try {
+      sleep(waitTime);
+    } catch (InterruptedException e) {
+      LOGGER.error("Thread sleep state interrupted", e);
+    }
+    return waitTime >= 200 ? value * 10 : -1;
+  }
+}
--- a/ambassador/src/main/java/com/iluwatar/ambassador/RemoteServiceInterface.java
+++ b/ambassador/src/main/java/com/iluwatar/ambassador/RemoteServiceInterface.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.ambassador;
+
+/**
+ * Interface shared by ({@link RemoteService}) and ({@link ServiceAmbassador}).
+ */
+interface RemoteServiceInterface {
+    
+  long doRemoteFunction(int value) throws Exception;
+}
--- a/ambassador/src/main/java/com/iluwatar/ambassador/ServiceAmbassador.java
+++ b/ambassador/src/main/java/com/iluwatar/ambassador/ServiceAmbassador.java
@ -0,0 +1,84 @@
+/**
+ * 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.ambassador;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import static java.lang.Thread.sleep;
+
+/**
+ *
+ * ServiceAmbassador provides an interface for a ({@link Client}) to access ({@link RemoteService}).
+ * The interface adds logging, latency testing and usage of the service in a safe way that will not
+ * add stress to the remote service when connectivity issues occur.
+ *
+ */
+public class ServiceAmbassador implements RemoteServiceInterface {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(ServiceAmbassador.class);
+  private static final int RETRIES = 3;
+  private static final int DELAY_MS = 3000;
+
+  ServiceAmbassador() {}
+
+  @Override
+  public long doRemoteFunction(int value) {
+    return safeCall(value);
+  }
+
+  private long checkLatency(int value) {
+    long startTime = System.currentTimeMillis();
+    long result = RemoteService.getRemoteService().doRemoteFunction(value);
+    long timeTaken = System.currentTimeMillis() - startTime;
+
+    LOGGER.info("Time taken (ms): " + timeTaken);
+    return result;
+  }
+
+  private long safeCall(int value) {
+
+    int retries = 0;
+    long result = -1;
+
+    for (int i = 0; i < RETRIES; i++) {
+
+      if (retries >= RETRIES) {
+        return -1;
+      }
+
+      if ((result = checkLatency(value)) == -1) {
+        LOGGER.info("Failed to reach remote: (" + (i + 1) + ")");
+        retries++;
+        try {
+          sleep(DELAY_MS);
+        } catch (InterruptedException e) {
+          LOGGER.error("Thread sleep state interrupted", e);
+        }
+      } else {
+        break;
+      }
+    }
+    return result;
+  }
+}
--- a/ambassador/src/test/java/com/iluwatar/ambassador/AppTest.java
+++ b/ambassador/src/test/java/com/iluwatar/ambassador/AppTest.java
@ -0,0 +1,36 @@
+/**
+ * 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.ambassador;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Application test
+ */
+public class AppTest {
+
+  @Test
+  public void test() {
+    App.main(new String[]{});
+  }
+}
--- a/ambassador/src/test/java/com/iluwatar/ambassador/ClientTest.java
+++ b/ambassador/src/test/java/com/iluwatar/ambassador/ClientTest.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.ambassador;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test for {@link Client}
+ */
+public class ClientTest {
+
+  @Test
+  public void test() {
+
+    Client client = new Client();
+    long result = client.useService(10);
+
+    assert result == 100 || result == -1;
+  }
+}
--- a/ambassador/src/test/java/com/iluwatar/ambassador/RemoteServiceTest.java
+++ b/ambassador/src/test/java/com/iluwatar/ambassador/RemoteServiceTest.java
@ -0,0 +1,37 @@
+/**
+ * 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.ambassador;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test for {@link RemoteService}
+ */
+public class RemoteServiceTest {
+
+  @Test
+  public void test() {
+    long result = RemoteService.getRemoteService().doRemoteFunction(10);
+    assert result == 100 || result == -1;
+  }
+}
--- a/ambassador/src/test/java/com/iluwatar/ambassador/ServiceAmbassadorTest.java
+++ b/ambassador/src/test/java/com/iluwatar/ambassador/ServiceAmbassadorTest.java
@ -0,0 +1,37 @@
+/**
+ * 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.ambassador;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Test for {@link ServiceAmbassador}
+ */
+public class ServiceAmbassadorTest {
+
+  @Test
+  public void test() {
+    long result = new ServiceAmbassador().doRemoteFunction(10);
+    assert result == 100 || result == -1;
+  }
+}
--- a/api-gateway/api-gateway-service/pom.xml
+++ b/api-gateway/api-gateway-service/pom.xml
@ -29,7 +29,7 @@
  <parent>
    <artifactId>api-gateway</artifactId>
    <groupId>com.iluwatar</groupId>
-    <version>1.19.0</version>
+    <version>1.21.0-SNAPSHOT</version>
  </parent>
  <modelVersion>4.0.0</modelVersion>
  <artifactId>api-gateway-service</artifactId>
--- a/api-gateway/image-microservice/pom.xml
+++ b/api-gateway/image-microservice/pom.xml
@ -29,7 +29,7 @@
  <parent>
    <artifactId>api-gateway</artifactId>
    <groupId>com.iluwatar</groupId>
-    <version>1.19.0</version>
+    <version>1.21.0-SNAPSHOT</version>
  </parent>

  <modelVersion>4.0.0</modelVersion>
--- a/api-gateway/pom.xml
+++ b/api-gateway/pom.xml
@ -29,7 +29,7 @@
  <parent>
    <artifactId>java-design-patterns</artifactId>
    <groupId>com.iluwatar</groupId>
-    <version>1.19.0</version>
+    <version>1.21.0-SNAPSHOT</version>
  </parent>
  <modelVersion>4.0.0</modelVersion>
  <artifactId>api-gateway</artifactId>
--- a/api-gateway/price-microservice/pom.xml
+++ b/api-gateway/price-microservice/pom.xml
@ -29,7 +29,7 @@
  <parent>
    <artifactId>api-gateway</artifactId>
    <groupId>com.iluwatar</groupId>
-    <version>1.19.0</version>
+    <version>1.21.0-SNAPSHOT</version>
  </parent>

  <modelVersion>4.0.0</modelVersion>
--- a/async-method-invocation/pom.xml
+++ b/async-method-invocation/pom.xml
@ -29,7 +29,7 @@
  <parent>
    <groupId>com.iluwatar</groupId>
    <artifactId>java-design-patterns</artifactId>
-    <version>1.19.0</version>
+    <version>1.21.0-SNAPSHOT</version>
  </parent>
  <artifactId>async-method-invocation</artifactId>
  <dependencies>
--- a/balking/pom.xml
+++ b/balking/pom.xml
@ -29,7 +29,7 @@
  <parent>
    <artifactId>java-design-patterns</artifactId>
    <groupId>com.iluwatar</groupId>
-    <version>1.19.0</version>
+    <version>1.21.0-SNAPSHOT</version>
  </parent>
  <modelVersion>4.0.0</modelVersion>

--- a/bridge/pom.xml
+++ b/bridge/pom.xml
@ -29,7 +29,7 @@
  <parent>
    <groupId>com.iluwatar</groupId>
    <artifactId>java-design-patterns</artifactId>
-    <version>1.19.0</version>
+    <version>1.21.0-SNAPSHOT</version>
  </parent>
  <artifactId>bridge</artifactId>
  <dependencies>
--- a/builder/pom.xml
+++ b/builder/pom.xml
@ -29,7 +29,7 @@
  <parent>
    <groupId>com.iluwatar</groupId>
    <artifactId>java-design-patterns</artifactId>
-    <version>1.19.0</version>
+    <version>1.21.0-SNAPSHOT</version>
  </parent>
  <artifactId>builder</artifactId>
  <dependencies>
--- a/business-delegate/pom.xml
+++ b/business-delegate/pom.xml
@ -30,7 +30,7 @@
 	<parent>
 		<groupId>com.iluwatar</groupId>
 		<artifactId>java-design-patterns</artifactId>
-		<version>1.19.0</version>
+		<version>1.21.0-SNAPSHOT</version>
 	</parent>
 	<artifactId>business-delegate</artifactId>
 	<dependencies>
--- a/caching/pom.xml
+++ b/caching/pom.xml
@ -29,7 +29,7 @@
  <parent>
    <groupId>com.iluwatar</groupId>
    <artifactId>java-design-patterns</artifactId>
-    <version>1.19.0</version>
+    <version>1.21.0-SNAPSHOT</version>
  </parent>
  <artifactId>caching</artifactId>
  <dependencies>
--- a/callback/pom.xml
+++ b/callback/pom.xml
@ -29,7 +29,7 @@
  <parent>
    <groupId>com.iluwatar</groupId>
    <artifactId>java-design-patterns</artifactId>
-    <version>1.19.0</version>
+    <version>1.21.0-SNAPSHOT</version>
  </parent>
  <artifactId>callback</artifactId>
  <dependencies>
--- a/chain/pom.xml
+++ b/chain/pom.xml
@ -29,7 +29,7 @@
  <parent>
    <groupId>com.iluwatar</groupId>
    <artifactId>java-design-patterns</artifactId>
-    <version>1.19.0</version>
+    <version>1.21.0-SNAPSHOT</version>
  </parent>
  <artifactId>chain</artifactId>
  <dependencies>
--- a/collection-pipeline/README.md
+++ b/collection-pipeline/README.md
@ -0,0 +1,30 @@
+---
+layout: pattern
+title: Collection Pipeline
+folder: collection-pipeline
+permalink: /patterns/collection-pipeline/
+categories: Functional
+tags:
+ - Java
+ - Difficulty-Beginner
+ - Functional
+---
+
+## Intent
+Collection Pipeline introduces Function Composition and Collection Pipeline, two functional-style patterns that you can combine to iterate collections in your code. 
+In functional programming, it's common to sequence complex operations through a series of smaller modular functions or operations. The series is called a composition of functions, or a function composition. When a collection of data flows through a function composition, it becomes a collection pipeline. Function Composition and Collection Pipeline are two design patterns frequently used in functional-style programming.
+
+![alt text](./etc/collection-pipeline.png "Collection Pipeline")
+
+## Applicability
+Use the Collection Pipeline pattern when
+
+* When you want to perform a sequence of operations where one operation's collected output is fed into the next
+* When you use a lot of statements in your code
+* When you use a lot of loops in your code
+
+## Credits
+
+* [Function composition and the Collection Pipeline pattern](https://www.ibm.com/developerworks/library/j-java8idioms2/index.html)
+* [Martin Fowler](https://martinfowler.com/articles/collection-pipeline/)
+* [Java8 Streams](https://docs.oracle.com/javase/8/docs/api/java/util/stream/package-summary.html)
--- a/collection-pipeline/etc/collection-pipeline.png
+++ b/collection-pipeline/etc/collection-pipeline.png
--- a/collection-pipeline/etc/collection-pipeline.ucls
+++ b/collection-pipeline/etc/collection-pipeline.ucls
@ -0,0 +1,98 @@
+<?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.collectionpipeline.App" project="collection-pipeline" 
+    file="/collection-pipeline/src/main/java/com/iluwatar/collectionpipeline/App.java" binary="false" 
+    corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="150" y="100"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </class>  
+  <class id="2" language="java" name="com.iluwatar.collectionpipeline.ImperativeProgramming" 
+    project="collection-pipeline" 
+    file="/collection-pipeline/src/main/java/com/iluwatar/collectionpipeline/ImperativeProgramming.java" binary="false" 
+    corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="437" y="109"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </class>  
+  <class id="3" language="java" name="com.iluwatar.collectionpipeline.Car" project="collection-pipeline" 
+    file="/collection-pipeline/src/main/java/com/iluwatar/collectionpipeline/Car.java" binary="false" 
+    corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="724" y="339"/>    
+    <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.collectionpipeline.CarFactory" project="collection-pipeline" 
+    file="/collection-pipeline/src/main/java/com/iluwatar/collectionpipeline/CarFactory.java" binary="false" 
+    corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="899" y="91"/>    
+    <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.collectionpipeline.FunctionalProgramming" 
+    project="collection-pipeline" 
+    file="/collection-pipeline/src/main/java/com/iluwatar/collectionpipeline/FunctionalProgramming.java" binary="false" 
+    corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="1187" y="109"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </class>  
+  <enumeration id="6" language="java" name="com.iluwatar.collectionpipeline.Category" project="collection-pipeline" 
+    file="/collection-pipeline/src/main/java/com/iluwatar/collectionpipeline/Category.java" binary="false" 
+    corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="486" y="339"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="true" 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="7" language="java" name="com.iluwatar.collectionpipeline.Person" project="collection-pipeline" 
+    file="/collection-pipeline/src/main/java/com/iluwatar/collectionpipeline/Person.java" binary="false" 
+    corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="723" y="91"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </class>  
+  <association id="8">    
+    <end type="SOURCE" refId="7" navigable="false">      
+      <attribute id="9" name="cars"/>      
+      <multiplicity id="10" minimum="0" maximum="2147483647"/>    
+    </end>    
+    <end type="TARGET" refId="3" navigable="true"/>    
+    <display labels="true" multiplicity="true"/>  
+  </association>  
+  <association id="11">    
+    <end type="SOURCE" refId="3" navigable="false">      
+      <attribute id="12" name="category"/>      
+      <multiplicity id="13" minimum="0" maximum="1"/>    
+    </end>    
+    <end type="TARGET" refId="6" navigable="true"/>    
+    <display labels="true" multiplicity="true"/>  
+  </association>  
+  <classifier-display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+    sort-features="false" accessors="true" visibility="true">    
+    <attributes public="true" package="true" protected="true" private="true" static="true"/>    
+    <operations public="true" package="true" protected="true" private="true" static="true"/>  
+  </classifier-display>  
+  <association-display labels="true" multiplicity="true"/>
+</class-diagram>
--- a/collection-pipeline/pom.xml
+++ b/collection-pipeline/pom.xml
@ -1,4 +1,5 @@
-====
+<!--
+
    The MIT License
    Copyright (c) 2014 Ilkka Seppälä

@ -19,5 +20,26 @@
    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>1.21.0-SNAPSHOT</version>
+  </parent>
+  <artifactId>collection-pipeline</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>
--- a/collection-pipeline/src/main/java/com/iluwatar/collectionpipeline/App.java
+++ b/collection-pipeline/src/main/java/com/iluwatar/collectionpipeline/App.java
@ -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.
+ */
+package com.iluwatar.collectionpipeline;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * In imperative-style programming, it is common to use for and while loops for
+ * most kinds of data processing. Function composition is a simple technique
+ * that lets you sequence modular functions to create more complex operations.
+ * When you run data through the sequence, you have a collection pipeline.
+ * Together, the Function Composition and Collection Pipeline patterns enable
+ * you to create sophisticated programs where data flow from upstream to
+ * downstream and is passed through a series of transformations.
+ *
+ */
+public class App {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(App.class);
+
+  /**
+   * Program entry point.
+   * 
+   * @param args
+   *            command line args
+   */
+  public static void main(String[] args) {
+
+    List<Car> cars = CarFactory.createCars();
+    
+    List<String> modelsImperative = ImperativeProgramming.getModelsAfter2000(cars);
+    LOGGER.info(modelsImperative.toString());
+
+    List<String> modelsFunctional = FunctionalProgramming.getModelsAfter2000(cars);
+    LOGGER.info(modelsFunctional.toString());
+    
+    Map<Category, List<Car>> groupingByCategoryImperative = ImperativeProgramming.getGroupingOfCarsByCategory(cars);
+    LOGGER.info(groupingByCategoryImperative.toString());
+
+    Map<Category, List<Car>> groupingByCategoryFunctional = FunctionalProgramming.getGroupingOfCarsByCategory(cars);
+    LOGGER.info(groupingByCategoryFunctional.toString());
+    
+    Person john = new Person(cars);
+    
+    List<Car> sedansOwnedImperative = ImperativeProgramming.getSedanCarsOwnedSortedByDate(Arrays.asList(john));
+    LOGGER.info(sedansOwnedImperative.toString());
+
+    List<Car> sedansOwnedFunctional = FunctionalProgramming.getSedanCarsOwnedSortedByDate(Arrays.asList(john));
+    LOGGER.info(sedansOwnedFunctional.toString());
+  }
+}
--- a/collection-pipeline/src/main/java/com/iluwatar/collectionpipeline/Car.java
+++ b/collection-pipeline/src/main/java/com/iluwatar/collectionpipeline/Car.java
@ -0,0 +1,109 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.collectionpipeline;
+
+/**
+ * A Car class that has the properties of make, model, year and category.
+ */
+public class Car {
+  private String make;
+  private String model;
+  private int year;
+  private Category category;
+
+  /**
+   * Constructor to create an instance of car.
+   * @param make the make of the car
+   * @param model the model of the car
+   * @param yearOfMake the year of built of the car
+   * @param category the {@link Category} of the car
+   */
+  public Car(String make, String model, int yearOfMake, Category category) {
+    this.make = make;
+    this.model = model;
+    this.year = yearOfMake;
+    this.category = category;
+  }
+
+  @Override
+  public int hashCode() {
+    final int prime = 31;
+    int result = 1;
+    result = prime * result + ((category == null) ? 0 : category.hashCode());
+    result = prime * result + ((make == null) ? 0 : make.hashCode());
+    result = prime * result + ((model == null) ? 0 : model.hashCode());
+    result = prime * result + year;
+    return result;
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if (this == obj) {
+      return true;
+    }
+    if (obj == null) {
+      return false;
+    }
+    if (getClass() != obj.getClass()) {
+      return false;
+    }
+    Car other = (Car) obj;
+    if (category != other.category) {
+      return false;
+    }
+    if (make == null) {
+      if (other.make != null) {
+        return false;
+      }
+    } else if (!make.equals(other.make)) {
+      return false;
+    }
+    if (model == null) {
+      if (other.model != null) {
+        return false;
+      }
+    } else if (!model.equals(other.model)) {
+      return false;
+    }
+    if (year != other.year) {
+      return false;
+    }
+    return true;
+  }
+
+  public String getMake() {
+    return make;
+  }
+
+  public String getModel() {
+    return model;
+  }
+
+  public int getYear() {
+    return year;
+  }
+  
+  public Category getCategory() {
+    return category;
+  }
+}
--- a/collection-pipeline/src/main/java/com/iluwatar/collectionpipeline/CarFactory.java
+++ b/collection-pipeline/src/main/java/com/iluwatar/collectionpipeline/CarFactory.java
@ -0,0 +1,47 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.collectionpipeline;
+
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * A factory class to create a collection of {@link Car} instances.
+ */
+public class CarFactory {
+  private CarFactory() {
+  }
+
+  /**
+   * Factory method to create a {@link List} of {@link Car} instances.
+   * @return {@link List} of {@link Car}
+   */
+  public static List<Car> createCars() {
+    return Arrays.asList(new Car("Jeep", "Wrangler", 2011, Category.JEEP),
+        new Car("Jeep", "Comanche", 1990, Category.JEEP),
+        new Car("Dodge", "Avenger", 2010, Category.SEDAN),
+        new Car("Buick", "Cascada", 2016, Category.CONVERTIBLE),
+        new Car("Ford", "Focus", 2012, Category.SEDAN),
+        new Car("Chevrolet", "Geo Metro", 1992, Category.CONVERTIBLE));
+  }
+}
--- a/collection-pipeline/src/main/java/com/iluwatar/collectionpipeline/Category.java
+++ b/collection-pipeline/src/main/java/com/iluwatar/collectionpipeline/Category.java
@ -0,0 +1,30 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.collectionpipeline;
+
+/**
+ * Enum for the category of car 
+ */
+public enum Category {
+  JEEP, SEDAN, CONVERTIBLE
+}
--- a/collection-pipeline/src/main/java/com/iluwatar/collectionpipeline/FunctionalProgramming.java
+++ b/collection-pipeline/src/main/java/com/iluwatar/collectionpipeline/FunctionalProgramming.java
@ -0,0 +1,84 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.collectionpipeline;
+
+import java.util.Comparator;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+/**
+ * Iterating and sorting with a collection pipeline
+ * 
+ * <p>In functional programming, it's common to sequence complex operations through
+ * a series of smaller modular functions or operations. The series is called a
+ * composition of functions, or a function composition. When a collection of
+ * data flows through a function composition, it becomes a collection pipeline.
+ * Function Composition and Collection Pipeline are two design patterns
+ * frequently used in functional-style programming.
+ * 
+ * <p>Instead of passing a lambda expression to the map method, we passed the
+ * method reference Car::getModel. Likewise, instead of passing the lambda
+ * expression car -> car.getYear() to the comparing method, we passed the method
+ * reference Car::getYear. Method references are short, concise, and expressive.
+ * It is best to use them wherever possible.
+ * 
+ */
+public class FunctionalProgramming {
+  private FunctionalProgramming() {
+  }
+
+  /**
+   * Method to get models using for collection pipeline.
+   * 
+   * @param cars {@link List} of {@link Car} to be used for filtering
+   * @return {@link List} of {@link String} representing models built after year 2000
+   */
+  public static List<String> getModelsAfter2000(List<Car> cars) {
+    return cars.stream().filter(car -> car.getYear() > 2000)
+      .sorted(Comparator.comparing(Car::getYear))
+      .map(Car::getModel).collect(Collectors.toList());
+  }
+  
+  /**
+   * Method to group cars by category using groupingBy
+   * 
+   * @param cars {@link List} of {@link Car} to be used for grouping
+   * @return {@link Map} with category as key and cars belonging to that category as value
+   */
+  public static Map<Category, List<Car>> getGroupingOfCarsByCategory(List<Car> cars) {
+    return cars.stream().collect(Collectors.groupingBy(Car::getCategory));
+  }
+  
+  /**
+   * Method to get all Sedan cars belonging to a group of persons sorted by year of manufacture 
+   * 
+   * @param persons {@link List} of {@link Person} to be used
+   * @return {@link List} of {@link Car} to belonging to the group
+   */
+  public static List<Car> getSedanCarsOwnedSortedByDate(List<Person> persons) {
+    return persons.stream().map(Person::getCars).flatMap(List::stream)
+      .filter(car -> Category.SEDAN.equals(car.getCategory()))
+      .sorted(Comparator.comparing(Car::getYear)).collect(Collectors.toList());
+  }
+}
--- a/collection-pipeline/src/main/java/com/iluwatar/collectionpipeline/ImperativeProgramming.java
+++ b/collection-pipeline/src/main/java/com/iluwatar/collectionpipeline/ImperativeProgramming.java
@ -0,0 +1,131 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.collectionpipeline;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Imperative-style programming to iterate over the list and get the names of
+ * cars made later than the year 2000. We then sort the models in ascending
+ * order by year.
+ * 
+ * <p>As you can see, there's a lot of looping in this code. First, the
+ * getModelsAfter2000UsingFor method takes a list of cars as its parameter. It
+ * extracts or filters out cars made after the year 2000, putting them into a
+ * new list named carsSortedByYear. Next, it sorts that list in ascending order
+ * by year-of-make. Finally, it loops through the list carsSortedByYear to get
+ * the model names and returns them in a list.
+ * 
+ * <p>This short example demonstrates what I call the effect of statements. While
+ * functions and methods in general can be used as expressions, the {@link Collections}
+ * sort method doesn't return a result. Because it is used as a statement, it
+ * mutates the list given as argument. Both of the for loops also mutate lists
+ * as they iterate. Being statements, that's just how these elements work. As a
+ * result, the code contains unnecessary garbage variables
+ */
+public class ImperativeProgramming {
+  private ImperativeProgramming() {
+  }
+
+  /**
+   * Method to return the car models built after year 2000 using for loops.
+   * @param cars {@link List} of {@link Car} to iterate over
+   * @return {@link List} of {@link String} of car models built after year 2000
+   */
+  public static List<String> getModelsAfter2000(List<Car> cars) {
+    List<Car> carsSortedByYear = new ArrayList<>();
+
+    for (Car car : cars) {
+      if (car.getYear() > 2000) {
+        carsSortedByYear.add(car);
+      }
+    }
+
+    Collections.sort(carsSortedByYear, new Comparator<Car>() {
+      public int compare(Car car1, Car car2) {
+        return new Integer(car1.getYear()).compareTo(car2.getYear());
+      }
+    });
+
+    List<String> models = new ArrayList<>();
+    for (Car car : carsSortedByYear) {
+      models.add(car.getModel());
+    }
+
+    return models;
+  }
+  
+  /**
+   * Method to group cars by category using for loops
+   * 
+   * @param cars {@link List} of {@link Car} to be used for grouping
+   * @return {@link Map} with category as key and cars belonging to that category as value
+   */
+  public static Map<Category, List<Car>> getGroupingOfCarsByCategory(List<Car> cars) {
+    Map<Category, List<Car>> groupingByCategory = new HashMap<>();
+    for (Car car: cars) {
+      if (groupingByCategory.containsKey(car.getCategory())) {
+        groupingByCategory.get(car.getCategory()).add(car);
+      } else {
+        List<Car> categoryCars = new ArrayList<>();
+        categoryCars.add(car);
+        groupingByCategory.put(car.getCategory(), categoryCars);
+      }
+    }
+    return groupingByCategory;
+  }
+  
+  /**
+   * Method to get all Sedan cars belonging to a group of persons sorted by year of manufacture using for loops 
+   * 
+   * @param persons {@link List} of {@link Person} to be used
+   * @return {@link List} of {@link Car} to belonging to the group
+   */
+  public static List<Car> getSedanCarsOwnedSortedByDate(List<Person> persons) {
+    List<Car> cars = new ArrayList<>();
+    for (Person person: persons) {
+      cars.addAll(person.getCars());
+    }
+  
+    List<Car> sedanCars = new ArrayList<>();
+    for (Car car: cars) {
+      if (Category.SEDAN.equals(car.getCategory())) {
+        sedanCars.add(car);
+      }
+    }
+  
+    sedanCars.sort(new Comparator<Car>() {
+      @Override
+      public int compare(Car o1, Car o2) {
+        return o1.getYear() - o2.getYear();
+      }
+    });
+  
+    return sedanCars;
+  }
+}
--- a/collection-pipeline/src/main/java/com/iluwatar/collectionpipeline/Person.java
+++ b/collection-pipeline/src/main/java/com/iluwatar/collectionpipeline/Person.java
@ -0,0 +1,44 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.collectionpipeline;
+
+import java.util.List;
+
+/**
+ * A Person class that has the list of cars that the person owns and use.
+ */
+public class Person {
+  private List<Car> cars;
+
+  /**
+   * Constructor to create an instance of person.
+   * @param cars the list of cars owned
+   */
+  public Person(List<Car> cars) {
+    this.cars = cars;
+  }
+
+  public List<Car> getCars() {
+    return cars;
+  }
+}
--- a/collection-pipeline/src/test/java/com/iluwatar/collectionpipeline/AppTest.java
+++ b/collection-pipeline/src/test/java/com/iluwatar/collectionpipeline/AppTest.java
@ -0,0 +1,79 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.collectionpipeline;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Tests that Collection Pipeline methods work as expected.
+ */
+public class AppTest {
+  
+  private List<Car> cars = CarFactory.createCars();
+  
+  @Test
+  public void testGetModelsAfter2000UsingFor() {
+    List<String> models = ImperativeProgramming.getModelsAfter2000(cars);
+    assertEquals(Arrays.asList("Avenger", "Wrangler", "Focus", "Cascada"), models);
+  }
+  
+  @Test
+  public void testGetModelsAfter2000UsingPipeline() {
+    List<String> models = FunctionalProgramming.getModelsAfter2000(cars);
+    assertEquals(Arrays.asList("Avenger", "Wrangler", "Focus", "Cascada"), models);
+  }
+  
+  @Test
+  public void testGetGroupingOfCarsByCategory() {
+    Map<Category, List<Car>> modelsExpected = new HashMap<>();
+    modelsExpected.put(Category.CONVERTIBLE, Arrays.asList(new Car("Buick", "Cascada", 2016, Category.CONVERTIBLE),
+        new Car("Chevrolet", "Geo Metro", 1992, Category.CONVERTIBLE)));
+    modelsExpected.put(Category.SEDAN, Arrays.asList(new Car("Dodge", "Avenger", 2010, Category.SEDAN),
+        new Car("Ford", "Focus", 2012, Category.SEDAN)));
+    modelsExpected.put(Category.JEEP, Arrays.asList(new Car("Jeep", "Wrangler", 2011, Category.JEEP),
+        new Car("Jeep", "Comanche", 1990, Category.JEEP)));
+    Map<Category, List<Car>> modelsFunctional = FunctionalProgramming.getGroupingOfCarsByCategory(cars);
+    Map<Category, List<Car>> modelsImperative = ImperativeProgramming.getGroupingOfCarsByCategory(cars);
+    System.out.println("Category " + modelsFunctional);
+    assertEquals(modelsExpected, modelsFunctional);
+    assertEquals(modelsExpected, modelsImperative);
+  }
+  
+  @Test
+  public void testGetSedanCarsOwnedSortedByDate() {
+    Person john = new Person(cars);
+    List<Car> modelsExpected = Arrays.asList(new Car("Dodge", "Avenger", 2010, Category.SEDAN), 
+        new Car("Ford", "Focus", 2012, Category.SEDAN));
+    List<Car> modelsFunctional = FunctionalProgramming.getSedanCarsOwnedSortedByDate(Arrays.asList(john));
+    List<Car> modelsImperative = ImperativeProgramming.getSedanCarsOwnedSortedByDate(Arrays.asList(john));
+    assertEquals(modelsExpected, modelsFunctional);
+    assertEquals(modelsExpected, modelsImperative);
+  }
+}
--- a/command/pom.xml
+++ b/command/pom.xml
@ -29,7 +29,7 @@
  <parent>
    <groupId>com.iluwatar</groupId>
    <artifactId>java-design-patterns</artifactId>
-    <version>1.19.0</version>
+    <version>1.21.0-SNAPSHOT</version>
  </parent>
  <artifactId>command</artifactId>
  <dependencies>
--- a/composite/pom.xml
+++ b/composite/pom.xml
@ -29,7 +29,7 @@
  <parent>
    <groupId>com.iluwatar</groupId>
    <artifactId>java-design-patterns</artifactId>
-    <version>1.19.0</version>
+    <version>1.21.0-SNAPSHOT</version>
  </parent>
  <artifactId>composite</artifactId>
  <dependencies>
--- a/converter/etc/converter.png
+++ b/converter/etc/converter.png
--- a/converter/pom.xml
+++ b/converter/pom.xml
@ -29,7 +29,7 @@
    <parent>
        <artifactId>java-design-patterns</artifactId>
        <groupId>com.iluwatar</groupId>
-        <version>1.19.0</version>
+        <version>1.21.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
    <dependencies>
--- a/converter/src/main/java/com/iluwatar/converter/Converter.java
+++ b/converter/src/main/java/com/iluwatar/converter/Converter.java
@ -50,37 +50,37 @@ public class Converter<T, U> {
  }

  /**
-   * @param userDto DTO entity
+   * @param dto DTO entity
   * @return The domain representation - the result of the converting function application on dto entity.
   */
-  public final U convertFromDto(final T userDto) {
-    return fromDto.apply(userDto);
+  public final U convertFromDto(final T dto) {
+    return fromDto.apply(dto);
  }

  /**
-   * @param user domain entity
+   * @param entity domain entity
   * @return The DTO representation - the result of the converting function application on domain entity.
   */
-  public final T convertFromEntity(final U user) {
-    return fromEntity.apply(user);
+  public final T convertFromEntity(final U entity) {
+    return fromEntity.apply(entity);
  }

  /**
-   * @param dtoUsers collection of DTO entities
+   * @param dtos collection of DTO entities
   * @return List of domain representation of provided entities retrieved by
   *        mapping each of them with the conversion function
   */
-  public final List<U> createFromDtos(final Collection<T> dtoUsers) {
-    return dtoUsers.stream().map(this::convertFromDto).collect(Collectors.toList());
+  public final List<U> createFromDtos(final Collection<T> dtos) {
+    return dtos.stream().map(this::convertFromDto).collect(Collectors.toList());
  }

  /**
-   * @param users collection of domain entities
+   * @param entities collection of domain entities
   * @return List of domain representation of provided entities retrieved by
   *        mapping each of them with the conversion function
   */
-  public final List<T> createFromEntities(final Collection<U> users) {
-    return users.stream().map(this::convertFromEntity).collect(Collectors.toList());
+  public final List<T> createFromEntities(final Collection<U> entities) {
+    return entities.stream().map(this::convertFromEntity).collect(Collectors.toList());
  }

 }
--- a/cqrs/pom.xml
+++ b/cqrs/pom.xml
@ -21,7 +21,7 @@
 	<parent>
 		<groupId>com.iluwatar</groupId>
 		<artifactId>java-design-patterns</artifactId>
-		<version>1.19.0</version>
+		<version>1.21.0-SNAPSHOT</version>
 	</parent>
 	<artifactId>cqrs</artifactId>
 	<dependencies>
--- a/dao/pom.xml
+++ b/dao/pom.xml
@ -30,7 +30,7 @@
  <parent>
    <groupId>com.iluwatar</groupId>
    <artifactId>java-design-patterns</artifactId>
-    <version>1.19.0</version>
+    <version>1.21.0-SNAPSHOT</version>
  </parent>
  <artifactId>dao</artifactId>

--- a/data-bus/pom.xml
+++ b/data-bus/pom.xml
@ -33,7 +33,7 @@
    <parent>
        <groupId>com.iluwatar</groupId>
        <artifactId>java-design-patterns</artifactId>
-        <version>1.19.0</version>
+        <version>1.21.0-SNAPSHOT</version>
    </parent>
    <artifactId>data-bus</artifactId>
    <dependencies>
--- a/data-mapper/pom.xml
+++ b/data-mapper/pom.xml
@ -28,7 +28,7 @@
 	<parent>
 		<groupId>com.iluwatar</groupId>
 		<artifactId>java-design-patterns</artifactId>
-		<version>1.19.0</version>
+		<version>1.21.0-SNAPSHOT</version>
 	</parent>
 	<artifactId>data-mapper</artifactId>
 	<dependencies>
--- a/data-transfer-object/pom.xml
+++ b/data-transfer-object/pom.xml
@ -28,7 +28,7 @@
    <parent>
        <groupId>com.iluwatar</groupId>
        <artifactId>java-design-patterns</artifactId>
-        <version>1.19.0</version>
+        <version>1.21.0-SNAPSHOT</version>
    </parent>
    <artifactId>data-transfer-object</artifactId>
    <dependencies>
--- a/decorator/pom.xml
+++ b/decorator/pom.xml
@ -29,7 +29,7 @@
  <parent>
    <groupId>com.iluwatar</groupId>
    <artifactId>java-design-patterns</artifactId>
-    <version>1.19.0</version>
+    <version>1.21.0-SNAPSHOT</version>
  </parent>
  <artifactId>decorator</artifactId>
  <dependencies>
--- a/delegation/pom.xml
+++ b/delegation/pom.xml
@ -30,7 +30,7 @@
    <parent>
        <artifactId>java-design-patterns</artifactId>
        <groupId>com.iluwatar</groupId>
-        <version>1.19.0</version>
+        <version>1.21.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

--- a/dependency-injection/pom.xml
+++ b/dependency-injection/pom.xml
@ -29,7 +29,7 @@
  <parent>
    <groupId>com.iluwatar</groupId>
    <artifactId>java-design-patterns</artifactId>
-    <version>1.19.0</version>
+    <version>1.21.0-SNAPSHOT</version>
  </parent>
  <artifactId>dependency-injection</artifactId>
  <dependencies>
--- a/dirty-flag/README.md
+++ b/dirty-flag/README.md
@ -0,0 +1,26 @@
+---
+layout: pattern
+title: Dirty Flag
+folder: dirty-flag
+permalink: /patterns/dirty-flag/
+categories: Other
+tags:
+ - Java
+ - Difficulty-Beginner
+ - Performance
+---
+
+## Intent
+To avoid expensive re-acquisition of resources. The resources retain their identity, are kept in some
+fast-access storage, and are re-used to avoid having to acquire them again.
+
+![alt text](./etc/dirty-flag.png "Dirty Flag")
+
+## Applicability
+Use the Dirty Flag pattern when
+
+* Repetitious acquisition, initialization, and release of the same resource causes unnecessary performance overhead.
+
+## Credits
+
+* [Design Patterns: Dirty Flag](https://www.takeupcode.com/podcast/89-design-patterns-dirty-flag/)
--- a/dirty-flag/etc/dirty-flag.png
+++ b/dirty-flag/etc/dirty-flag.png
--- a/dirty-flag/etc/dirty-flag.ucls
+++ b/dirty-flag/etc/dirty-flag.ucls
@ -0,0 +1,45 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<class-diagram version="1.2.2" icons="true" automaticImage="PNG" always-add-relationships="false" generalizations="true" 
+  realizations="true" associations="true" dependencies="false" nesting-relationships="true" router="FAN">  
+  <class id="1" language="java" name="com.iluwatar.dirtyflag.App" project="dirty-flag" 
+    file="/dirty-flag/src/main/java/com/iluwatar/dirtyflag/App.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="266" y="188"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </class>  
+  <class id="2" language="java" name="com.iluwatar.dirtyflag.DataFetcher" project="dirty-flag" 
+    file="/dirty-flag/src/main/java/com/iluwatar/dirtyflag/DataFetcher.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="153" width="125" x="66" y="291"/>    
+    <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.dirtyflag.World" project="dirty-flag" 
+    file="/dirty-flag/src/main/java/com/iluwatar/dirtyflag/World.java" binary="false" corner="BOTTOM_RIGHT">    
+    <position height="-1" width="-1" x="379" y="366"/>    
+    <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+      sort-features="false" accessors="true" visibility="true">      
+      <attributes public="true" package="true" protected="true" private="true" static="true"/>      
+      <operations public="true" package="true" protected="true" private="true" static="true"/>    
+    </display>  
+  </class>  
+  <association id="4">    
+    <end type="SOURCE" refId="3" navigable="false">      
+      <attribute id="5" name="df"/>      
+      <multiplicity id="6" minimum="0" maximum="1"/>    
+    </end>    
+    <end type="TARGET" refId="2" navigable="true"/>    
+    <display labels="true" multiplicity="true"/>  
+  </association>  
+  <classifier-display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
+    sort-features="false" accessors="true" visibility="true">    
+    <attributes public="true" package="true" protected="true" private="true" static="true"/>    
+    <operations public="true" package="true" protected="true" private="true" static="true"/>  
+  </classifier-display>  
+  <association-display labels="true" multiplicity="true"/>
+</class-diagram>
--- a/dirty-flag/pom.xml
+++ b/dirty-flag/pom.xml
@ -0,0 +1,54 @@
+<?xml version="1.0"?>
+<!--
+
+    The MIT License
+    Copyright (c) 2014 Ilkka Seppälä
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in
+    all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+    THE SOFTWARE.
+
+-->
+<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>com.iluwatar</groupId>
+    <artifactId>java-design-patterns</artifactId>
+    <version>1.21.0-SNAPSHOT</version>
+  </parent>
+  <groupId>com.iluwatar</groupId>
+  <artifactId>dirty-flag</artifactId>
+  <version>1.21.0-SNAPSHOT</version>
+  <name>dirty-flag</name>
+  <url>http://maven.apache.org</url>
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+  </properties>
+  <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>
--- a/dirty-flag/src/main/java/com/iluwatar/dirtyflag/App.java
+++ b/dirty-flag/src/main/java/com/iluwatar/dirtyflag/App.java
@ -0,0 +1,82 @@
+/**
+ * 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.dirtyflag;
+
+import java.util.List;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+
+/**
+ *
+ * This application demonstrates the <b>Dirty Flag</b> pattern. The dirty flag behavioral pattern allows you to avoid
+ * expensive operations that would just need to be done again anyway. This is a simple pattern that really just explains
+ * how to add a bool value to your class that you can set anytime a property changes. This will let your class know that
+ * any results it may have previously calculated will need to be calculated again when they’re requested. Once the
+ * results are re-calculated, then the bool value can be cleared.
+ * 
+ * There are some points that need to be considered before diving into using this pattern:- there are some things you’ll
+ * need to consider:- (1) Do you need it? This design pattern works well when the results to be calculated are difficult
+ * or resource intensive to compute. You want to save them. You also don’t want to be calculating them several times in
+ * a row when only the last one counts. (2) When do you set the dirty flag? Make sure that you set the dirty flag within
+ * the class itself whenever an important property changes. This property should affect the result of the calculated
+ * result and by changing the property, that makes the last result invalid. (3) When do you clear the dirty flag? It
+ * might seem obvious that the dirty flag should be cleared whenever the result is calculated with up-to-date
+ * information but there are other times when you might want to clear the flag.
+ *
+ * In this example, the {@link DataFetcher} holds the <i>dirty flag</i>. It fetches and re-fetches from <i>world.txt</i>
+ * when needed. {@link World} mainly serves the data to the front-end.
+ */
+public class App {
+  /**
+   * Program execution point
+   */
+  public void run() {
+
+    final ScheduledExecutorService executorService = Executors.newSingleThreadScheduledExecutor();
+    executorService.scheduleAtFixedRate(new Runnable() {
+      @Override
+      public void run() {
+        World world = new World();
+        List<String> countries = world.fetch();
+        System.out.println("Our world currently has the following countries:-");
+        for (String country : countries) {
+          System.out.println("\t" + country);
+        }
+      }
+    }, 0, 15, TimeUnit.SECONDS); // Run at every 15 seconds.
+  }
+
+  /**
+   * Program entry point
+   *
+   * @param args
+   *          command line args
+   */
+  public static void main(String[] args) {
+    App app = new App();
+
+    app.run();
+  }
+
+}
--- a/dirty-flag/src/main/java/com/iluwatar/dirtyflag/DataFetcher.java
+++ b/dirty-flag/src/main/java/com/iluwatar/dirtyflag/DataFetcher.java
@ -0,0 +1,81 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.dirtyflag;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileReader;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * A mock database manager -- Fetches data from a raw file.
+ * 
+ * @author swaisuan
+ *
+ */
+public class DataFetcher {
+
+  private final String filename = "world.txt";
+  private long lastFetched;
+
+  public DataFetcher() {
+    this.lastFetched = -1;
+  }
+
+  private boolean isDirty(long fileLastModified) {
+    if (lastFetched != fileLastModified) {
+      lastFetched = fileLastModified;
+      return true;
+    }
+    return false;
+  }
+
+  /**
+   * Fetches data/content from raw file.
+   * 
+   * @return List of strings
+   */
+  public List<String> fetch() {
+    ClassLoader classLoader = getClass().getClassLoader();
+    File file = new File(classLoader.getResource(filename).getFile());
+
+    if (isDirty(file.lastModified())) {
+      System.out.println(filename + " is dirty! Re-fetching file content...");
+
+      List<String> data = new ArrayList<String>();
+      try (BufferedReader br = new BufferedReader(new FileReader(file))) {
+        String line;
+        while ((line = br.readLine()) != null) {
+          data.add(line);
+        }
+      } catch (IOException e) {
+        e.printStackTrace();
+      }
+      return data;
+    }
+
+    return new ArrayList<String>();
+  }
+}
--- a/dirty-flag/src/main/java/com/iluwatar/dirtyflag/World.java
+++ b/dirty-flag/src/main/java/com/iluwatar/dirtyflag/World.java
@ -0,0 +1,58 @@
+/**
+ * The MIT License
+ * Copyright (c) 2014 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.dirtyflag;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * 
+ * A middle-layer app that calls/passes along data from the back-end.
+ * 
+ * @author swaisuan
+ *
+ */
+public class World {
+
+  private List<String> countries;
+  private DataFetcher df;
+
+  public World() {
+    this.countries = new ArrayList<String>();
+    this.df = new DataFetcher();
+  }
+
+  /**
+   * 
+   * Calls {@link DataFetcher} to fetch data from back-end.
+   * 
+   * @return List of strings
+   */
+  public List<String> fetch() {
+    List<String> data = df.fetch();
+
+    countries = data.isEmpty() ? countries : data;
+
+    return countries;
+  }
+}
--- a/dirty-flag/src/main/resources/world.txt
+++ b/dirty-flag/src/main/resources/world.txt
@ -21,3 +21,6 @@
    THE SOFTWARE.
 ====

+UNITED_KINGDOM
+MALAYSIA
+UNITED_STATES
--- a/dirty-flag/src/test/java/org/dirty/flag/AppTest.java
+++ b/dirty-flag/src/test/java/org/dirty/flag/AppTest.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 org.dirty.flag;
+
+import java.io.IOException;
+
+import org.junit.jupiter.api.Test;
+
+import com.iluwatar.dirtyflag.App;
+
+/**
+ * Tests that Dirty-Flag example runs without errors.
+ */
+public class AppTest {
+  @Test
+  public void test() throws IOException {
+    String[] args = {};
+    App.main(args);
+  }
+}
--- a/dirty-flag/src/test/java/org/dirty/flag/DirtyFlagTest.java
+++ b/dirty-flag/src/test/java/org/dirty/flag/DirtyFlagTest.java
@ -0,0 +1,54 @@
+/**
+ * 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 org.dirty.flag;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+
+import com.iluwatar.dirtyflag.DataFetcher;
+
+/**
+ *
+ * Application test
+ *
+ */
+public class DirtyFlagTest {
+
+  @Test
+  public void testIsDirty() {
+    DataFetcher df = new DataFetcher();
+    List<String> countries = df.fetch();
+    assertTrue(!countries.isEmpty());
+  }
+
+  @Test
+  public void testIsNotDirty() {
+    DataFetcher df = new DataFetcher();
+    df.fetch();
+    List<String> countries = df.fetch();
+    assertTrue(countries.isEmpty());
+  }
+}
--- a/double-checked-locking/pom.xml
+++ b/double-checked-locking/pom.xml
@ -27,7 +27,7 @@
  <parent>
    <groupId>com.iluwatar</groupId>
    <artifactId>java-design-patterns</artifactId>
-    <version>1.19.0</version>
+    <version>1.21.0-SNAPSHOT</version>
  </parent>
  <artifactId>double-checked-locking</artifactId>
  <dependencies>
--- a/double-dispatch/pom.xml
+++ b/double-dispatch/pom.xml
@ -29,7 +29,7 @@
  <parent>
    <groupId>com.iluwatar</groupId>
    <artifactId>java-design-patterns</artifactId>
-    <version>1.19.0</version>
+    <version>1.21.0-SNAPSHOT</version>
  </parent>
  <artifactId>double-dispatch</artifactId>
  <dependencies>
--- a/eip-aggregator/pom.xml
+++ b/eip-aggregator/pom.xml
@ -26,7 +26,7 @@
    <parent>
        <groupId>com.iluwatar</groupId>
        <artifactId>java-design-patterns</artifactId>
-        <version>1.19.0</version>
+        <version>1.21.0-SNAPSHOT</version>
    </parent>

    <dependencies>
--- a/eip-message-channel/.gitignore
+++ b/eip-message-channel/.gitignore
--- a/eip-message-channel/README.md
+++ b/eip-message-channel/README.md
@ -1,8 +1,8 @@
 ---
 layout: pattern
-title: Message Channel
-folder: message-channel
-permalink: /patterns/message-channel/
+title: EIP Message Channel
+folder: eip-message-channel
+permalink: /patterns/eip-message-channel/
 categories: Integration
 tags:
 - Java
--- a/eip-message-channel/etc/message-channel.png
+++ b/eip-message-channel/etc/message-channel.png
--- a/eip-message-channel/etc/message-channel.ucls
+++ b/eip-message-channel/etc/message-channel.ucls
--- a/eip-message-channel/pom.xml
+++ b/eip-message-channel/pom.xml
@ -30,9 +30,9 @@
 	<parent>
 		<groupId>com.iluwatar</groupId>
 		<artifactId>java-design-patterns</artifactId>
-		<version>1.19.0</version>
+		<version>1.21.0-SNAPSHOT</version>
 	</parent>
-	<artifactId>message-channel</artifactId>
+	<artifactId>eip-message-channel</artifactId>
 	<dependencies>
 		<dependency>
 			<groupId>org.apache.camel</groupId>
--- a/eip-message-channel/src/main/java/com/iluwatar/eip/message/channel/App.java
+++ b/eip-message-channel/src/main/java/com/iluwatar/eip/message/channel/App.java
@ -20,7 +20,7 @@
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
-package com.iluwatar.message.channel;
+package com.iluwatar.eip.message.channel;

 import org.apache.camel.CamelContext;
 import org.apache.camel.builder.RouteBuilder;
--- a/eip-message-channel/src/test/java/com/iluwatar/eip/message/channel/AppTest.java
+++ b/eip-message-channel/src/test/java/com/iluwatar/eip/message/channel/AppTest.java
@ -20,7 +20,7 @@
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
-package com.iluwatar.publish.subscribe;
+package com.iluwatar.eip.message.channel;

 import org.junit.jupiter.api.Test;

--- a/eip-publish-subscribe/.gitignore
+++ b/eip-publish-subscribe/.gitignore
--- a/eip-publish-subscribe/README.md
+++ b/eip-publish-subscribe/README.md
@ -1,8 +1,8 @@
 ---
 layout: pattern
-title: Publish Subscribe
-folder: publish-subscribe
-permalink: /patterns/publish-subscribe/
+title: EIP Publish Subscribe
+folder: eip-publish-subscribe
+permalink: /patterns/eip-publish-subscribe/
 categories: Integration
 tags:
 - Java
--- a/eip-publish-subscribe/etc/publish-subscribe.png
+++ b/eip-publish-subscribe/etc/publish-subscribe.png
--- a/eip-publish-subscribe/etc/publish-subscribe.ucls
+++ b/eip-publish-subscribe/etc/publish-subscribe.ucls
--- a/Show More
+++ b/Show More
Author	SHA1	Message	Date
npathai	0ed4747a71	Updated class diagram png and added UCLS file	2018-10-21 13:57:32 +05:30
Narendra Pathai	ced1dfe937	Resolves #643 , test cases failed due to presence of global state in CallsCount. Because AppTest was executed before B2BServiceTest, it scheduled 1 sec timer using ThrottleTimerImpl class. While resetting it used that global CallCount class reset() method, which reset all counters. So that causes thread safety issue because of unintended sharing of application state between test cases, which is not a good practice.	2018-10-15 17:28:11 +05:30
Ilkka Seppälä	db33cc533b	Remove CII best practices badge	2018-10-13 18:40:10 +03:00
Ilkka Seppälä	8433c7b712	Merge pull request #793 from andrievsky/master Fix redundant list alloc in LotteryNumbers	2018-10-13 18:28:40 +03:00
Ilkka Seppälä	ee74fec53c	Fix pattern title	2018-09-30 21:36:32 +03:00
Ilkka Seppälä	7a7e891384	Set version for next development iteration	2018-09-30 21:05:57 +03:00
Ilkka Seppälä	26d6d96f78	Reach milestone 1.20.0	2018-09-30 21:03:48 +03:00
Ilkka Seppälä	3cec7a9ec1	Merge pull request #796 from LyndonArmitage/module-ignore-test-output Delete & Ignore output.txt & error.txt	2018-09-25 22:49:25 +03:00
Ilkka Seppälä	b079aec1fd	Merge pull request #794 from iluwatar/Issue781 #781 Resolved ClasscastException from Acyclic Visitor	2018-09-25 22:45:25 +03:00
Lyndon Armitage	8f53df91b9	Delete & Ignore output.txt & error.txt Both output.txt and error.txt are produced by tests. Each file contained a header that was overridden upon executing said tests causing tracked files to be changed. Added them to a local .gitignore file for this module.	2018-09-24 10:08:02 +01:00
Narendra Pathai	709405d964	Resolved checkstyle issues	2018-09-11 16:11:59 +05:30
Narendra Pathai	f3749a2b9d	Solved the classcast exception and used instanceof instead. Improved javadocs a bit.	2018-09-11 15:58:14 +05:30
Nick Andrievsky	1d12d94bac	Fix redundant list alloc in LotteryNumbers	2018-09-11 11:55:53 +02:00
Narendra Pathai	9e56e5cbc1	Merge pull request #791 from er2/executeAroundLambda Execute Around - use lambda	2018-09-09 00:24:42 +05:30
Narendra Pathai	1698b066f3	Merge pull request #767 from nikhilbarar/collection-pipeline #564: Collection Pipeline pattern	2018-09-09 00:21:45 +05:30
nikhilbarar	4ed039d807	Updated UCLS file and PNG image	2018-09-08 20:38:04 +05:30
Eric Riese	ec6d2a8ebe	execute around lambda	2018-09-07 22:29:51 -04:00
nikhilbarar	98c3f93e82	Review changes in Test Cases	2018-09-04 20:52:11 +05:30
nikhilbarar	26fbbed62e	Typo in Readme	2018-09-01 15:48:36 +05:30
nikhilbarar	0f9089dd62	Typo in Readme	2018-09-01 15:48:07 +05:30
Narendra Pathai	038befea26	Merge pull request #779 from mitchellirvin/bst-iterator #778: Binary Search Tree Iterator	2018-08-30 12:46:13 +05:30
nikhilbarar	9daa3140e4	Category Enum for category of Car	2018-08-29 22:02:17 +05:30
mxi1809	8458e426bc	correcting raw types for the item Iterator.	2018-08-29 07:36:52 -04:00
Mitchell Irvin	e6f84f2f41	modified return type of TreasureChestItemIterator's constructor to be Iterator	2018-08-28 07:46:02 -04:00
Narendra Pathai	74f3799eb4	Merge pull request #788 from diffblue-assistant/finallyclosetotrywithresources Use try-with-resources	2018-08-28 13:17:16 +05:30
nikhilbarar	b23d8430af	Added Missing class	2018-08-26 23:31:03 +05:30
nikhilbarar	cb6b0b3600	Checkstyle Fixes	2018-08-26 23:21:25 +05:30
nikhilbarar	cd44ef3c81	Review Changes	2018-08-26 23:12:33 +05:30
Mitchell Irvin	1c2ddfad54	Refactored App.java to remove duplicate code and elegantly demonstrate each implementation of the Iterator interface. Removed the redundant ItemIterator interface. Added insert() method to TreeNode class to allow for more elegant construction of BSTs.	2018-08-25 18:49:43 -04:00
Diffblue assistant	f36de036f6	Use try-with-resources Replace try statements that close a resource in the finally block with a try-with-resources statement [1]. This commit was created automatically by Diffblue refactorings (https://www.diffblue.com/). [1] https://docs.oracle.com/javase/tutorial/essential/exceptions/tryResourceClose.html	2018-08-23 13:44:55 +01:00
Narendra Pathai	b64262303a	Merge pull request #787 from bordoisila1/checkstyle-minor-updates Fixed minor changes suggested by Checkstyle	2018-08-21 11:20:16 +05:30
Narendra Pathai	9d012772fd	Merge pull request #785 from sgyyz/fix-image-name Fix converter image Display Issue	2018-08-21 11:12:40 +05:30
bordoisila1	e1a2f141c5	Fixed minor changes suggested by Checkstyle	2018-08-20 22:36:58 -04:00
Yongzhi Yang	cce104a271	Fix converter image issue	2018-08-20 21:14:16 +08:00
Ilkka Seppälä	16df157181	Add license headers	2018-08-13 08:13:06 +03:00
Ilkka Seppälä	c34004bea5	Merge pull request #763 from 7agustibm/master First proposal for #586 Hexagonal Architecture primary ports should have interfaces	2018-08-10 22:42:09 +03:00
Mitchell Irvin	3e0cfa5684	#778 Implemented BSTIterator. Included comprehensive unit and integration tests. Refactored file structure to be friendly to future contributors with iterators of more data structures. Added JUnitPlatform to enable running test suite across all iterator implementations. Added README to /binarysearchtree to document what it does and how it works.	2018-08-04 21:59:53 -04:00
nikhilbarar	ce459e8f9f	Merge branch 'master' into collection-pipeline # Conflicts: # pom.xml	2018-08-02 02:43:47 +05:30
nikhilbarar	535431fac1	Merge branch 'master' of https://github.com/iluwatar/java-design-patterns	2018-08-02 02:30:08 +05:30
Ilkka Seppälä	facb9e51a6	Merge pull request #774 from zenuo/master Add an 'Override' annotaion	2018-08-01 16:02:23 +03:00
zenuo	9eb8c30bcb	Add Annotation 'Override' to com.iluwatar.reactor.app.AppClient.TcpLoggingClient.run method.	2018-07-18 17:06:19 +08:00
nikhilbarar	fc87f8b7d3	Merge branch 'master' of https://github.com/iluwatar/java-design-patterns # Conflicts: # pom.xml	2018-07-08 23:09:55 +05:30
Agustí Becerra Milà	b453753790	Fix import not used	2018-07-08 19:38:54 +02:00
Agustí Becerra Milà	d2b900b524	Fix checkstyle & update interface services	2018-07-08 19:25:42 +02:00
nikhilbarar	2c8d1744df	#564 : Collection Pipeline pattern	2018-07-08 21:37:30 +05:30
Ilkka Seppälä	d915b66e70	Merge pull request #755 from okinskas/ambassador Ambassador Pattern #722	2018-07-08 09:55:36 +03:00
nikhilbarar	328f917749	#564 : Collection Pipeline pattern	2018-07-02 00:42:04 +05:30
Agustí Becerra Milà	ae07423470	First proposal	2018-07-01 16:29:07 +02:00
Ovidijus Okinskas	7add7b833c	Merge branch 'master' into ambassador	2018-06-29 14:34:31 +01:00
Narendra Pathai	c7f9266768	Merge pull request #753 from Argyro-Sioziou/master Acyclic Visitor pattern #734	2018-06-28 13:55:32 +05:30
Ovidijus Okinskas	0453bf9063	General cleanup. Simplifying code. Replacing all prints with appropriate Logger.	2018-06-23 13:24:07 +01:00
Argyro-Sioziou	f9bdd58bb7	Merge remote-tracking branch 'upstream/master'	2018-06-14 18:34:27 +03:00
Argyro-Sioziou	57f60c5ebf	Updating javadoc comments	2018-06-14 18:30:46 +03:00
Argyro-Sioziou	51659fe9c5	Updating HayesVisitor and ZoomVisitor	2018-06-14 18:04:30 +03:00
Argyro-Sioziou	04d80f05c8	Adding consequences in README.md	2018-06-14 17:56:14 +03:00
Argyro-Sioziou	6636fb151b	Adding AllModemVisitor interface	2018-06-14 12:40:41 +03:00
Argyro-Sioziou	6a0fa747ad	Fixing typos	2018-06-14 12:18:46 +03:00
Argyro-Sioziou	8b1ed95d6b	Updating ConfigureForDosVisitorTest and ConfigureForUnixVisitorTest classes	2018-06-14 12:14:35 +03:00
Argyro-Sioziou	6167d06dce	Removing test case	2018-06-14 12:02:34 +03:00
Argyro-Sioziou	49feead13f	Removing interfaces' test classes	2018-06-14 11:59:02 +03:00
Argyro-Sioziou	179a02bcdd	Removing default constructors	2018-06-14 11:52:23 +03:00
nikhilbarar	71f61cd40e	#466 , #509 : Added diagrams and Readme files	2018-06-13 23:40:36 +05:30
nikhilbarar	d54e29051f	#466 : Fix Checkstyle Issues	2018-06-13 02:54:09 +05:30
nikhilbarar	4456a440bc	Monitor Object pattern #466	2018-06-13 02:43:25 +05:30
nikhilbarar	c48a1e9193	#509 : Checkstyle Fixes	2018-06-11 01:56:32 +05:30
nikhilbarar	971a74e13a	#509 : Component Object Pattern	2018-06-11 00:38:03 +05:30
Ovidijus Okinskas	868e4561b5	Updating pom dependencies and adding license.	2018-06-05 21:16:16 +01:00
Ovidijus Okinskas	c4dd94a019	Fixing CheckStyle issues in Test classes.	2018-06-05 07:32:29 +01:00
Ovidijus Okinskas	ff579fabcf	Fixing CheckStyle issues.	2018-06-04 22:50:59 +01:00
Ovidijus Okinskas	5393c96247	Adding README.md	2018-06-04 22:32:05 +01:00
Ovidijus Okinskas	bae51f5803	Adding license to test classes.	2018-06-04 21:27:04 +01:00
Ovidijus Okinskas	74190e36bb	Adding tests for each class.	2018-06-04 21:20:04 +01:00
Ovidijus Okinskas	6b10f4bdd1	Adding appropriate comments on classes and full description in App.java. Removing added function in ServiceAmbassador as it's not appropriate for the example.	2018-06-04 20:36:10 +01:00
Ovidijus Okinskas	73925cef2e	Ambassador adds logging, imitates trying to connect to remote service and provides new client-side functionality. Need to clean up code, add tests and add descriptive comments.	2018-06-03 22:20:40 +01:00
Ilkka Seppälä	987994f0fe	Add license headers	2018-06-03 14:15:11 +03:00
Ilkka Seppälä	95df47e418	Disable intermittently failing test	2018-06-03 14:15:00 +03:00
Argyro-Sioziou	afe85e22e7	Enhancing code format	2018-05-29 01:37:53 +03:00
giorgosmav21	4023944240	Adding README.md file	2018-05-27 17:10:20 +03:00
Argyro-Sioziou	17164c282a	Adding class diagram	2018-05-27 17:07:34 +03:00
giorgosmav21	27f58e0925	Adding HayesTest and ZoomTest	2018-05-27 17:04:22 +03:00
giorgosmav21	36a14778dc	Adding App class	2018-05-27 17:02:56 +03:00
Argyro-Sioziou	5e1da6361f	Adding ConfigureForDosVisitor and ConfigureForUnixVisitor	2018-05-27 16:58:38 +03:00
Argyro-Sioziou	97718846d1	Adding HayesVisitor and ZoomVisitor	2018-05-27 16:55:08 +03:00
giorgosmav21	bbdf1cd738	Adding Hayes and Zoom classes	2018-05-27 16:51:26 +03:00
giorgosmav21	323395daaf	Adding ModemVisitorTest	2018-05-27 16:49:05 +03:00
giorgosmav21	75734a6b7d	Adding Modem abstract class	2018-05-27 16:45:43 +03:00
Argyro-Sioziou	3f92b8f84e	Adding ModemTest	2018-05-27 16:37:13 +03:00
Argyro-Sioziou	18a75c0620	Adding ModemVisitor interface	2018-05-27 16:12:31 +03:00
Argyro-Sioziou	9e15abbafc	Adding pom.xml file	2018-05-27 15:49:35 +03:00
Argyro-Sioziou	e9a219f643	Merge branch 'master' of https://github.com/Argyro-Sioziou/java-design-patterns into acyclic-visitor	2018-05-27 15:44:04 +03:00
Argyro-Sioziou	8bf53fe91d	Adding acyclic-visitor module in pom.xml	2018-05-27 15:11:06 +03:00
Ilkka Seppälä	c713dbcbf4	Merge pull request #752 from christophercolumbusdog/master #643 Fix flaky tests for throttling pattern	2018-05-27 10:59:52 +03:00
Christian Cygnus	f3e1cd3a1d	Fix checkstyle	2018-05-25 22:47:23 -05:00
Christian Cygnus	4ab46c7fcb	#643 Fix flaky tests for throttling pattern	2018-05-25 22:26:35 -05:00
Narendra Pathai	d7893c1fc2	Updated incorrect tag Corrected improper tag from Difficulty-Easy to Difficulty-Beginner	2018-05-16 12:36:17 +05:30
Narendra Pathai	eddfe76a84	Merge pull request #717 from waisuan/master Dirty Flag pattern #560	2018-05-16 12:31:20 +05:30
Evan Sia Wai Suan	a386d4266d	Fixed UnitTest	2018-05-12 18:18:44 +01:00
Evan Sia Wai Suan	29edeabaae	Fixes based on code review feedback	2018-05-12 17:47:03 +01:00
Evan Sia Wai Suan	abcc39871b	Merged with upstream	2018-05-12 16:12:23 +01:00
Ilkka Seppälä	4ac6f90c96	Merge pull request #748 from pelmegov/clean-converter-class Parameters in Converter class methods was renamed.	2018-04-29 10:39:51 +03:00
pelmegov	a8d89ca861	Parameters in Converter class methods was renamed. A base class must not contain the concrete entities names or concrete class names	2018-04-28 19:34:57 +03:00
Ilkka Seppälä	998600f09e	Merge pull request #744 from pokemon4e/master Consistent naming for EIP patterns #733	2018-04-12 21:02:08 +03:00
Ilkka Seppälä	1e04b17a2d	Merge pull request #743 from MottoX/cleanup Cleanup unnecessary code	2018-04-12 20:39:45 +03:00
Ilkka Seppälä	187b16c9e0	Merge pull request #740 from mernst/coverage-documentation Correct the command for computing code coverage	2018-04-12 20:37:30 +03:00
Milena Sapunova	3b45f2cad6	Consistent naming for EIP patterns #733	2018-04-12 15:49:52 +03:00
MottoX	65e1cae2de	Cleanup unnecessary code	2018-04-11 16:11:37 +08:00
Michael Ernst	0b7343dd34	Correct the command for computing code coverage	2018-04-09 16:38:09 -07:00
Ilkka Seppälä	379a825182	Merge pull request #714 from dheeraj-mummareddy/master #473 serveless implementation using aws compute engine and serverless fram…	2018-04-08 20:01:42 +03:00
Dheeraj Mummareddy	522fbc035f	delete the incorrect package	2018-04-08 10:56:48 -04:00
Dheeraj Mummareddy	40e5cc628a	minor code review comments and Updating license header	2018-04-08 10:56:10 -04:00
Dheeraj Mummareddy	7a13012855	Merge branch 'master' of github.com:iluwatar/java-design-patterns	2018-04-08 10:38:16 -04:00
Ilkka Seppälä	1c0e0cd88b	Set version for next development iteration	2018-03-31 10:36:05 +03:00
Dheeraj Mummareddy	c3b102e547	fixing the link	2018-03-14 19:22:39 -04:00
Dheeraj Mummareddy	3f9a5a254e	code review comments	2018-03-13 12:03:23 -04:00
Dheeraj Mummareddy	05a9c030c0	Merge branch 'master' of github.com:iluwatar/java-design-patterns	2018-03-12 09:19:55 -04:00
Dheeraj Mummareddy	143213483c	fixing typo	2018-03-05 21:41:24 -05:00
Dheeraj Mummareddy	678fa93838	update readme and thanks to Amazon Web Services & cloud guru	2018-03-05 21:25:08 -05:00
Dheeraj Mummareddy	b2607010b4	update readme and ready for review	2018-03-05 21:23:42 -05:00
Dheeraj Mummareddy	b2dd36f607	adding backend as a service with lambda + api gateway + dynamodb	2018-03-05 20:51:32 -05:00
Dheeraj Mummareddy	af6973884f	merge from upstream and fixing conflicts	2018-03-04 17:46:29 -05:00
Dheeraj Mummareddy	3894a0bb6c	Merge branch 'master' of github.com:iluwatar/java-design-patterns	2018-03-04 17:33:58 -05:00
Dheeraj Mummareddy	49f8434911	Merge branch 'master' of github.com:iluwatar/java-design-patterns	2018-03-04 17:33:27 -05:00
Evan Sia Wai Suan	55bbb88ac9	Merge branch 'master' into master	2018-03-04 23:51:04 +08:00
Sia Wai Suan	ce88fd723e	Merge branch 'master' of https://github.com/waisuan/java-design-patterns	2018-03-04 15:25:55 +00:00
Sia Wai Suan	3333a2839b	Remove unused var	2018-02-20 10:58:49 +00:00
Sia Wai Suan	a60fa76fd9	Add UML diagram	2018-02-20 10:35:06 +00:00
Sia Wai Suan	565f5a4e70	Add README.md	2018-02-20 09:48:44 +00:00
Sia Wai Suan	b73ef6e6c5	Dirty Flag pattern #560	2018-02-19 16:08:45 +00:00
Dheeraj Mummareddy	7a7ba871dc	serveless implementation using aws compute engine and serverless framework	2018-02-08 12:03:00 -05:00
Sia Wai Suan	8953bfc81b	Merge pull request #1 from iluwatar/master Bringing fork up-to-date	2016-08-01 16:55:27 +01:00