多个线程的同步(所有任务都完成之后再向下执行)--转

package countdownlatch;

import java.util.concurrent.CountDownLatch;

/**
 *
 *<p>Test</p>
 *<p>Description:</P>
 *<p>Company:</p>
 *<p>Department:CAS</p>
 *@Author: Tommy Zhou
 *@Since: 1.0
 *@Version:Date:2011-4-26
 *
 **/

public class CountDownLatchSample {
    
    public static void main(String[] args) {
        String[] strs = getResult();
        for (int i = 0; i < strs.length; i++) {
            System.out.println(strs[i]);
        }
        
    }
    
    public static String[] getResult(){
        String[] strs = new String[3];
        CountDownLatch countDownLatch = new CountDownLatch(3);
        Work1 work1 = new Work1(countDownLatch,strs[0]);
        Work2 work2 = new Work2(countDownLatch,strs[1]);
        Work3 work3 = new Work3(countDownLatch,strs[2]);
        work1.start();
        work2.start();
        work3.start();
        try {
            countDownLatch.await();
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        strs[0] = work1.str1;
        strs[1] = work2.str2;
        strs[2] = work3.str3;
        return strs;
    }
}

class Work1 extends Thread{
    public String str1;
    public CountDownLatch latch1;
    public Work1(CountDownLatch latch1,String str1){
        this.latch1 = latch1;
        this.str1 = str1;
    }
    
    
    public void run(){
        str1="work1";
        latch1.countDown();
    }
}

class Work2 extends Thread{
    public String str2;
    public CountDownLatch latch2;
    public Work2(CountDownLatch latch2,String str2){
        this.latch2 = latch2;
        this.str2 = str2;
    }
    
    
    public void run(){
        try {
            Thread.sleep(3000);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        str2="work2";
        latch2.countDown();
    }
}

class Work3 extends Thread{
    public String str3;
    public CountDownLatch latch3;
    public Work3(CountDownLatch latch3,String str3){
        this.latch3 = latch3;
        this.str3 = str3;
    }
    
    
    public void run(){
        try {
            Thread.sleep(3000);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        str3="work3";
        latch3.countDown();
    }
}