Java并发组件二之CyclicBarriar

CyclicBarriar

相关文章：

1. CountDownLatch
2. CyclicBarriar--循环屏障
3. Semaphore--信号量

使用场景：

多个线程相互等待，直到都满足条件之后，才能执行后续的操作。CyclicBarrier描述的是各个线程之间相互等待的关系。

使用场景：

1. 正常实例化：CyclicBarrier sCyclicBarrier=new CyclicBarrier(3);
2. 带runnable的实例化，打破屏障时，优先执行Runnable：CyclicBarrier sCyclicBarrier=new CyclicBarrier(3，new Runnable(){//todo});
3. await线程：sCyclicBarrier.await();
4. 当wait线程数量为，count值时。唤醒所有等待线程。

代码示例：

1.正常实例化:

/**
 * 作者:jtl
 * 日期:Created in 2019/7/29 17:32
 * 描述:CyclicBarrier示例
 * 更改:
 */

class CyclicBarrierExample1 {
    private static int count=20;
    private static CyclicBarrier sCyclicBarrier=new CyclicBarrier(5);
    public static void main(String[] args) throws Exception{
        ExecutorService executorService= Executors.newCachedThreadPool();

        for (int i=0;i<count;i++){
            int threadNum=i;
            Thread.sleep(1000);
            executorService.execute(()->{
                try {
                    Thread.currentThread().setName("executorService:"+threadNum);
                    test(threadNum);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                    System.out.println("InterruptedException:"+e.getMessage());
                } catch (BrokenBarrierException e) {
                    e.printStackTrace();
                    System.out.println("BrokenBarrierException:"+e.getMessage());
                }
            });
        }

        //关闭线程池
        executorService.shutdown();
    }

    private static void test(int threadNum) throws InterruptedException, BrokenBarrierException {
        System.out.println("wait:"+threadNum+" ThreadName: "+Thread.currentThread().getName());
        sCyclicBarrier.await();
        System.out.println("continue:"+threadNum+" ThreadName: "+Thread.currentThread().getName());
    }
}

2. 带runnable的实例化:

/**
 * 作者:jtl
 * 日期:Created in 2019/7/30 19:40
 * 描述: 带Runnable的CyclicBarrier示例
 * 更改:
 */

class CyclicBarrierExample2 {
    private static int count=20;
    private static CyclicBarrier sCyclicBarrier=new CyclicBarrier(5, () ->
            System.out.println("Runnable is running")
    );

    public static void main(String[] args) throws Exception{
        ExecutorService executorService= Executors.newCachedThreadPool();

        for (int i=0;i<count;i++){
            int threadNum=i;
            Thread.sleep(1000);
            executorService.execute(()->{
                try {
                    Thread.currentThread().setName("executorService:"+threadNum);
                    test(threadNum);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                    System.out.println("InterruptedException:"+e.getMessage());
                } catch (BrokenBarrierException e) {
                    e.printStackTrace();
                    System.out.println("BrokenBarrierException:"+e.getMessage());
                }
            });
        }

        //关闭线程池
        executorService.shutdown();
    }

    private static void test(int threadNum) throws InterruptedException, BrokenBarrierException {
        System.out.println("wait:"+threadNum+" ThreadName: "+Thread.currentThread().getName());
        sCyclicBarrier.await();
        System.out.println("continue:"+threadNum+" ThreadName: "+Thread.currentThread().getName());
    }
}