CountDownLatch的使用

   概念:CountDownLatch是java.util.concurrent包中一个类,CountDownLatch只要提供的机制是多个(具体数量等于初始化CountDownLatch时count的值)线程都达到了预期状态或者完成了预期工作时触发事件,其他线程可以等待这个事件来触发自己后续的工作。等待的线程可以是多个,即CountDownLatch可以唤醒多个等待的线程。到达自己预期状态的线程会调用CountDownLatch的countDown方法,而等待的线程会调用CountDownLatch的await方法。 

   我们平时如果想要去玩lol,首先是不是应该打开电脑,然后登陆lol,然后才可以玩呢,本文以玩游戏为例,简单介绍下CountDownLatch的使用

@Slf4j
public class CountDownLatchDemo {

    static class TurnOnTheComputer implements Runnable {
        private CountDownLatch latch;

        public TurnOnTheComputer(CountDownLatch countDownLatch) {
            this.latch = countDownLatch;
        }

        @Override
        public void run() {
            log.info("打开电脑...");
            latch.countDown();
        }
    }

    static class LoginLOL implements Runnable {
        private CountDownLatch latch;

        public LoginLOL(CountDownLatch countDownLatch) {
            this.latch = countDownLatch;
        }

        @Override
        public void run() {
            log.info("登录LOL...");
            latch.countDown();
        }
    }

    public static void main(String[] args) throws InterruptedException {
        CountDownLatch countDownLatch = new CountDownLatch(2);
        new Thread(new TurnOnTheComputer(countDownLatch)).start();
        new Thread(new LoginLOL(countDownLatch)).start();
        countDownLatch.await();
        log.info("开始游戏 ...");
    }

}

 

结果如下: 

 

       CountDownLatch: 一个线程(或者多个), 等待另外N个线程完成某个事情之后才能执行。
  CyclicBrrier: N个线程相互等待,任何一个线程完成之前,所有的线程都必须等待。

 

posted @ 2019-08-30 15:16  梦飞翔up  阅读(179)  评论(0编辑  收藏  举报