added decorator sample

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

@@ -0,0 +1,18 @@
+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

@@ -0,0 +1,23 @@
+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

@@ -0,0 +1,13 @@
+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!");
+	}
+	
+}