Composite Pattern Example

// Copyright(C) 2000 Yoshinori Oota All rights reserved. public class CompositeSample { static public void main(String args[]) { /* [???] aComposite --aLeaf --aLeaf --Composite --aLeaf --aLeaf */ Component aComponent1 = new Composite(); Component aComponent2 = new Leaf(); Component aComponent3 = new Leaf(); aComponent1.AddComponent(aComponent2); aComponent1.AddComponent(aComponent3); Component aComponent4 = new Composite(); Component aComponent5 = new Leaf(); Component aComponent6 = new Leaf(); aComponent4.AddComponent(aComponent5); aComponent4.AddComponent(aComponent6); aComponent1.AddComponent(aComponent4); // Opearation [???] aComponent1.Operation(); } } abstract class Component { abstract public void Operation(); abstract public void AddComponent(Component aComponent); } class Leaf extends Component { public Leaf() { } public void Operation() { System.out.println("**I'm Leaf"); } public void AddComponent(Component aComponent) { } } class Composite extends Component { private Vector _components; //children public Composite() { _components = new Vector(); } public void Operation() { System.out.println("I'm Composite"); Enumeration componentList = _components.elements(); while(componentList.hasMoreElements()) { // forall Component in _components // aComponent.Operation(); Component aComponent = (Component)componentList.nextElement(); aComponent.Operation(); } } public void AddComponent(Component aComponent) { _components.addElement(aComponent); } }