用观查者模式传递线程状态

场景，某action把任务分配给N个线程，当线程完成后通知action，action返回。 Java代码

 

package com.koubei.Observable;   
  
import java.util.Observable;   
import java.util.Observer;   
  
public class Action implements Observer{   
  
    private int count;   
       
    public String execute() throws InterruptedException{   
           
        new Thread(new MadeCardThread(10,this)).start();   
        new Thread(new MadeCardThread(10,this)).start();   
        new Thread(new MadeCardThread(10,this)).start();   
        new Thread(new MadeCardThread(10,this)).start();   
           
        while(count != 40){   
            Thread.sleep(1000);   
        }   
        System.out.println("========= end =========");   
        return "success";   
    }   
  
       
    public void update(Observable o, Object arg) {   
        // TODO Auto-generated method stub   
        if(arg instanceof Integer){   
            count = count + (Integer)arg;   
        }   
    }   
       
    public static void main(String[] args) throws InterruptedException {   
        (new Action()).execute();   
    }   
}   
  
class MadeCardThread extends Observable implements Runnable {   
  
    private int count;   
       
       
    public MadeCardThread(int count,Observer observer){   
        this.addObserver(observer);   
        this.count = count;   
    }   
       
    public void run() {   
        // TODO Auto-generated method stub   
        for(int i=0; i<count; i++){   
            System.out.println(Thread.currentThread().getId() + " : " + i);   
        }   
        this.setChanged();   
        this.notifyObservers(count);   
    }   
       
}