同步工具类-闭锁

背景：多个线程，同时启动（像比赛一样，从起跑线开跑）

思想：那就搞一个起跑线或者门之类的，线程准备好了，开门，大家跑吧

/**
  * @author yisea  
  * @Description: 同步工具类：闭锁
 */
public class TestHarness implements Runnable{

    public long timeTasks(int nThreads, final Runnable task) throws InterruptedException{
        final CountDownLatch startGate = new CountDownLatch();
        final CountDownLatch endGate = new CountDownLatch(nThreads);

        for(int i = ; i < nThreads; i++){
            Thread t = new Thread(){
                public void run(){
                    try {
                        startGate.await();// 我ready了，其他线程兄弟快点，等着呢
                        try {
                            task.run(); // go go go
                        } finally {
                            endGate.countDown(); // 结束门-1（我结束了哈，你们记得打卡~）
                        }
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }

                }
            };
            t.start();
        }

        long start = System.nanoTime();
        startGate.countDown();// 启动门-1 开启
        endGate.await(); // 结束门，主线程等待所有线程都结束，方可开门让你走
        long end = System.nanoTime();
        return end - start; // 并发时间差

    }

    @Override
    public void run() {
    System.out.println("Go！！" + System.currentTimeMillis());

    }

    public static void main(String[] args) {
        TestHarness mainTask = new TestHarness();
        try {
            Long fu = mainTask.timeTasks(, mainTask);
            System.out.println(fu);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

}
           

注：参考《Java Concurency in Practice》