added composite sample

composite/src/main/java/com/iluwatar/LetterComposite.java

@@ -0,0 +1,29 @@
+package com.iluwatar;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public abstract class LetterComposite {
+
+	private List<LetterComposite> children = new ArrayList<LetterComposite>();
+
+	public void add(LetterComposite letter) {
+		children.add(letter);
+	}
+	
+	public int count() {
+		return children.size();
+	}
+	
+	protected abstract void printThisBefore();
+
+	protected abstract void printThisAfter();
+	
+	public void print() {
+		printThisBefore();
+		for (LetterComposite letter: children) {
+			letter.print();
+		}
+		printThisAfter();
+	}
+}