Java回调实现

/** 
* Created by IntelliJ IDEA. 
* User: leizhimin 
* Date: 2008-7-31 13:18:33 
* 事件接口 
*/ 
public  interface Event { 
     /** 
     * 返回发生事件信息 
     * 
     * @return 事件信息 
     */ 
     public String happendEvent(); 
}

/** 
* Created by IntelliJ IDEA. 
* User: leizhimin 
* Date: 2008-7-31 13:18:14 
* 事件A 
*/ 
public  class EventA  implements Event { 
     /** 
     * 返回发生事件信息 
     * 
     * @return 事件信息 
     */ 
     public String happendEvent() { 
         return  "发生了事件 EventA！"; 
    } 
}

/** 
* Created by IntelliJ IDEA. 
* User: leizhimin 
* Date: 2008-7-31 13:18:21 
* 事件B 
*/ 
public  class EventB  implements Event{ 
     /** 
     * 返回发生事件信息 
     * @return 事件信息 
     */ 
     public String happendEvent() { 
         return  "发生了事件 EventB！"; 
    } 
}

/** 
* Created by IntelliJ IDEA. 
* User: leizhimin 
* Date: 2008-7-31 13:20:48 
* 工人 
*/ 
public  class Worker { 
     private Event event;     //事件 
     private String name;     //工人姓名 
     private Boss boss;       //工人所属的老板 

     public Worker(String name, Boss boss) { 
         this.name = name; 
         this.boss = boss; 
    } 

     /** 
     * 干活 
     */ 
     public  void doWork() { 
        System.out.println(name +  " is doing working..."); 
         //工人挺辛苦，干着枯燥乏味的重复工作，哈哈 
         for ( int i = 0; i < 2000000; i++) { 
             int x = i / 234 + 234; 
        } 
        System.out.println(name +  " was finished work."); 
         //向老板说明发生的情况 
        boss.getWorkerEvent( this, event); 
    } 

     public Event getEvent() { 
         return event; 
    } 

     public  void setEvent(Event event) { 
         this.event = event; 
    } 

     public String getName() { 
         return name; 
    } 

     public  void setName(String name) { 
         this.name = name; 
    } 
}

/** 
* Created by IntelliJ IDEA. 
* User: leizhimin 
* Date: 2008-7-31 13:26:22 
* 老板 
*/ 
public  class Boss { 
     private String name; 

     public Boss(String name) { 
         this.name = name; 
    } 

     /** 
     * 老板接收工人的事件 
     * @param worker 工人 
     * @param event  事件 
     */ 
     public  void getWorkerEvent(Worker worker, Event event) { 
        System.out.println( "老板接收到事件信息： "+worker.getName() +  ": " + event.happendEvent()); 
    } 
}

/** 
* Created by IntelliJ IDEA. 
* User: leizhimin 
* Date: 2008-7-31 13:35:38 
* 测试类 
*/ 
public  class Test { 
     public  static  void main(String args[]){ 
         //初始化老板和工人 
        Boss boss =  new Boss( "老板"); 
        Worker worker1=  new Worker( "张三",boss); 
        Worker worker2=  new Worker( "李四",boss); 

         //捏造两个事件 
        Event event1 =  new EventA(); 
        Event event2 =  new EventB(); 

         //事件是工人发出的 
        worker1.setEvent(event1); 
        worker2.setEvent(event2); 

         //工人干活，干完了通知老板干的情况如何 
        worker1.doWork(); 
        worker2.doWork(); 

    } 
}

张三 is doing working... 
张三 was finished work. 
老板接收到事件信息： 张三: 发生了事件 EventA！ 
李四 is doing working... 
李四 was finished work. 
老板接收到事件信息： 李四: 发生了事件 EventB！ 

Process finished with exit code 0