设计模式09-组合模式

1. 概念

         有时候又叫做部分-整体模式    存在整体和部分的时候  希望客户端忽略整体和部分的区别 

2. 案例 

/**********************************************************************
 * <pre>
 * FILE : Demo01.java
 * CLASS : Demo01
 *
 * AUTHOR : Liaokailin
 *
 * FUNCTION : TODO
 *
 *
 *======================================================================
 * CHANGE HISTORY LOG
 *----------------------------------------------------------------------
 * MOD. NO.|   DATE   |   NAME  | REASON  | CHANGE REQ.
 *----------------------------------------------------------------------
 *             |2014-3-5|Liaokailin| Created |
 * DESCRIPTION:
 * </pre>
 ***********************************************************************/
package org.demo.composite;

import java.util.ArrayList;
import java.util.Iterator;

/**
 * 存在整体和部分的时候  希望客户端忽略整体和部分的区别
 * Function : 
 * @author : Liaokailin
 * CreateDate : 2014-3-5
 * version : 1.0
 */
public class Demo01 {
    @SuppressWarnings("unchecked")
    public static void main(String args[]){
        Node root = new Node("root") ;
        root.add(new Leaf("-leaf1")) ;
        Node c2 = new Node("-Node1") ;
        c2.add(new Leaf("--leaf2")) ;
        c2.add(new Leaf("--leaf3")) ;
        root.add(c2) ;
        c2 = new Node("-Node2");
        c2.add(new Leaf("--Leaf4"));
        c2.add(new Leaf("--Leaf5"));
        root.add(c2);
        root.operation() ;
    }
}


interface Component{
    void operation() ;
}


class Leaf implements Component{
    private String name  ;
    public Leaf(String name ){this.name = name ;}
    public String toString(){ return this.name ;}
    @Override
    public void operation() {
        System.out.println(this) ;
    }
}

class Node extends ArrayList implements Component{
    private String name ;
    public Node(String name){this.name = name ;}
    public String toString(){return this.name ;}
    @Override
    public void operation() {
        System.out.println(this) ;
        for(Iterator it = iterator() ;it.hasNext();){  // iterator() :获取集合中的元素
            ((Component)(it.next())).operation() ;
        }
    }
    
}

允许的结果： 

   

root
-leaf1
-Node1
--leaf2
--leaf3
-Node2
--Leaf4
--Leaf5