相位作为CountdownLatch的替代物

Question

使用Phaser代替CountdownLatch在性能、内存、改进、健壮性等方面有什么好处吗？

例如，myCountDownLatch()的行为与myPhaser()相同：

版本1与CountdownLatch:

public static void myCountDownLatch() {

        CountDownLatch countDownLatch = new CountDownLatch(1);
        Thread t = new Thread(() ->
        {
            try {
                log.info("CountDownLatch: in thread..");
                Thread.sleep(3000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            countDownLatch.countDown();
        });
        t.start();
        try {
            countDownLatch.await();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        log.info("CountDownLatch: out thread..");
    }

带有Phaser的版本2：

public static void myPhaser() {

        Phaser phaser = new Phaser(1);
        Thread t = new Thread(() ->
        {
            try {
                log.info("phaser: in thread..");
                Thread.sleep(3000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            phaser.arriveAndDeregister();
        });
        t.start();
        // 1. benefit: With phaser we dont need to manage the InterruptedException ourselves.
        phaser.arriveAndAwaitAdvance();
        log.info("phaser: out thread..");

    }

或者，在java中是否有更好的CountdownLatch替代品？

Answer 1

来自https://www.infoq.com/news/2008/07/phasers/

在三个不同的SMP平台上实现阶段器的可移植实现所获得的性能结果表明，除了它们的通用性和安全性属性带来的生产力好处之外，它们还可以提供比现有障碍实现更好的性能。

有关更多详细信息，请查看JSR 166