CyclicBarrier介绍

package com.karl.concurrent.utils;

import java.util.concurrent.BrokenBarrierException;
import java.util.concurrent.CyclicBarrier;

/**
* Created by karl.
*/
public class CyclicBarrierTest {
public static class Task implements Runnable{
private CyclicBarrier barrier;

public Task(CyclicBarrier barrier){
this.barrier = barrier;
}

@Override
public void run() {
System.out.println(Thread.currentThread().getName()+" is waiting the barrier.");
try {
barrier.await();
} catch (InterruptedException e) {
e.printStackTrace();
} catch (BrokenBarrierException e) {
e.printStackTrace();
}
System.out.println(Thread.currentThread().getName()+" cross the barrier");

}

}

public static void main(String[] args) {
//也可以只有第一个参数，表示参与者数目，即当3个参数与者到达barrier，则跨过barrier
//第二个参数是一个线程，这个表示指定数目的线程到到达barrier后，将回执行这个线程。
CyclicBarrier cb = new CyclicBarrier(3, new Runnable() {
@Override
public void run() {
System.out.println("all parties are arrived at barrier,lets play");
}
}) ;
Thread t1 = new Thread(new Task(cb), "Thread 1");
Thread t2 = new Thread(new Task(cb), "Thread 2");
Thread t3 = new Thread(new Task(cb), "Thread 3");
Thread t4 = new Thread(new Task(cb), "Thread 4");
Thread t5 = new Thread(new Task(cb), "Thread 5");
Thread t6 = new Thread(new Task(cb), "Thread 6");
t1.start();
t2.start();
t3.start();
t4.start();
t5.start();
t6.start();
cb.reset();  //重新设置barrier
}
}

Thread 1 is waiting the barrier.
Thread 2 is waiting the barrier.
Thread 3 is waiting the barrier.
all parties are arrived at barrier,lets play
Thread 3 cross the barrier
Thread 1 cross the barrier
Thread 2 cross the barrier
Thread 4 is waiting the barrier.
Thread 5 is waiting the barrier.
Thread 6 is waiting the barrier.
all parties are arrived at barrier,lets play
Thread 6 cross the barrier
Thread 4 cross the barrier
Thread 5 cross the barrier

Process finished with exit code 0