JAvaマルチスレッドCountDownLatchの使い方

CountDownLatchは、他のスレッドで実行されている操作のセットを完了する前に、1つ以上のスレッドを待機させる同期支援クラスです.
主な方法
 public CountDownLatch(int count);
 public void countDown();
 public void await() throws InterruptedException  
コンストラクションメソッドパラメータはカウントの回数を指定します
countDownメソッド、現在のスレッドがこのメソッドを呼び出すと、カウントが1減少します.
awaintメソッドは、タイマの値が0になるまで現在のスレッドをブロックします.
 
例

public class CountDownLatchDemo {
	final static SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    public static void main(String[] args) throws InterruptedException {
    	CountDownLatch latch=new CountDownLatch(2);//       
    	Worker worker1=new Worker("zhang san", 5000, latch);
    	Worker worker2=new Worker("li si", 8000, latch);
    	worker1.start();//
    	worker2.start();//
    	latch.await();//          
        System.out.println("all work done at "+sdf.format(new Date()));
	}
    
    
    static class Worker extends Thread{
    	String workerName; 
    	int workTime;
    	CountDownLatch latch;
    	public Worker(String workerName ,int workTime ,CountDownLatch latch){
    		 this.workerName=workerName;
    		 this.workTime=workTime;
    		 this.latch=latch;
    	}
    	public void run(){
    		System.out.println("Worker "+workerName+" do work begin at "+sdf.format(new Date()));
    		doWork();//   
    		System.out.println("Worker "+workerName+" do work complete at "+sdf.format(new Date()));
    		latch.countDown();//      ，     

    	}
    	
    	private void doWork(){
    		try {
				Thread.sleep(workTime);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
    	}
    }
    
     
}

 
出力:
Worker zhang san do work begin at 2011-04-14 11:05:11Worker li si do work begin at 2011-04-14 11:05:11Worker zhang san do work complete at 2011-04-14 11:05:16Worker li si do work complete at 2011-04-14 11:05:19all work done at 2011-04-14 11:05:19