Java Concurrent CyclicBarrier

Introduction

CyclicBarrier 很久沒用都忘了, 來複習一下..

Description

簡單說就是很多個 thread 去作事情, 作完之後就 await.

CyclicBarrier 等作完的 thread 達到指定的個數後, await 就結束.

Code

public class CyclicBarrierMain {

    public static void main(String[] params) throws InterruptedException {
        int runner = 5;
        CountDownLatch gameOver = new CountDownLatch(runner);
        CyclicBarrier b = new CyclicBarrier(runner, () -> {
            System.out.println("barrier done");
        });
        IntStream.range(0,runner).forEach(idx -> {
            new Thread() {
                @Override
                public void run() {
                    try {
                        System.out.println("wait " + idx);
                        b.await();
                        System.out.println("count down " + idx);
                        gameOver.countDown();
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
            }.start();
        });
        gameOver.await();
        System.out.println("game over");
    }

}