added decorator sample

decorator/pom.xml

+<?xml version="1.0"?>
+<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>com.iluwatar</groupId>
+    <artifactId>java-design-patterns</artifactId>
+    <version>1.0-SNAPSHOT</version>
+  </parent>
+  <groupId>com.iluwatar</groupId>
+  <artifactId>decorator</artifactId>
+  <version>1.0-SNAPSHOT</version>
+  <name>decorator</name>
+  <url>http://maven.apache.org</url>
+  <dependencies>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <version>3.8.1</version>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+</project>

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

+package com.iluwatar;
+
+public class App 
+{
+    public static void main( String[] args )
+    {
+    	
+    	System.out.println("A simple looking troll approaches.");
+    	Troll troll = new Troll();
+    	troll.attack();
+    	troll.fleeBattle();
+    	
+    	System.out.println("\nA smart looking troll surprises you.");
+    	Troll smart = new SmartTroll(new Troll());
+    	smart.attack();
+    	smart.fleeBattle();
+    }
+}

decorator/src/main/java/com/iluwatar/SmartTroll.java

+package com.iluwatar;
+
+public class SmartTroll extends Troll {
+
+	private Troll decorated;
+
+	public SmartTroll(Troll decorated) {
+		this.decorated = decorated;
+	}
+	
+	@Override
+	public void attack() {
+		System.out.println("The troll throws a rock at you!");
+		decorated.attack();
+	}
+
+	@Override
+	public void fleeBattle() {
+		System.out.println("The troll calls for help!");
+		decorated.fleeBattle();
+	}
+	
+}

decorator/src/main/java/com/iluwatar/Troll.java

+package com.iluwatar;
+
+public class Troll {
+
+	public void attack() {
+		System.out.println("The troll swings at you with a club!");
+	}
+	
+	public void fleeBattle() {
+		System.out.println("The troll shrieks in horror and runs away!");
+	}
+	
+}

pom.xml

@@ -26,5 +26,6 @@
     <module>adapter</module>
     <module>bridge</module>
     <module>composite</module>
+    <module>decorator</module>
   </modules>
 </project>
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