Component：节点的抽象类

public abstract class Component {

public abstract void Operation();

public abstract void Add(Component c);

public abstract void Remove(Component c);

public abstract Component GetChild(int i);

}

Composite：组合体，如树一般，可包含叶子节点或子树

import java.util.ArrayList;

import java.util.List;

public class Composite extends Component {

// Composite由多个Component组成(聚合关系)

private List list = new ArrayList();

public void Operation() {

for (Component c : list) {

// 遍历所有子节点，并执行子节点的方法

c.Operation();

}

}

public void Add(Component c) {

list.add(c);

}

@Override

public void Remove(Component c) {

// TODO Auto-generated method stub

}

@Override

public Component GetChild(int i) {

// TODO Auto-generated method stub

return null;

}

}

Leaf：叶子节点

public class Leaf extends Component {

public void Operation() {

System.out.println("this is leaf");

}

@Override

public void Add(Component c) {

// TODO Auto-generated method stub

}

@Override

public void Remove(Component c) {

// TODO Auto-generated method stub

}

@Override

public Component GetChild(int i) {

// TODO Auto-generated method stub

return null;

}

}

Client：客户端，构造一个组合体，并遍历该组合体的所有叶子节点，如下图所示：

这个类很重要，这个类是否写正确，以及运行结果是否正确意味着对设计模式是否真正理解

public class Client {

public static void main(String[] args) {

Leaf leaf1 = new Leaf();// 叶子节点

Leaf leaf2 = new Leaf();

Leaf leaf3 = new Leaf();

Composite c = new Composite();// 子树节点,包含两个叶子节点

c.Add(leaf2);

c.Add(leaf3);

Composite composite = new Composite();// 树

composite.Add(c);

composite.Add(leaf1);

composite.Operation();// 遍历所有节点

}

}