CyclicBarrier

  类似旅游的一个场景

   表示大家彼此等待，大家集合好后才开始出发，分散活动后又在指定地点集合碰面，
这就好比整个公司的人员利用周末时间集体郊游一样，先各自从家出发到公司集合后，再同时
出发到公园游玩，在指定地点集合后再同时开始就餐，...。

package com.ronbay.thread.timer;

import java.util.concurrent.CyclicBarrier;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class CyclicBarrierTest {

	public static void main(String[] args) {
		ExecutorService service = Executors.newCachedThreadPool();
		final CyclicBarrier cb = new CyclicBarrier(3); 

		for (int i = 0; i < 3; i++) {
			final Runnable runnable = new Runnable(){
				@Override
				public void run() {
					try {
						Thread.sleep((long)Math.random()*10000);
						System.out.println("线程" + Thread.currentThread().getName() + ",即将到达集合地点1，当前已有" +
						(cb.getNumberWaiting() + 1) + "个已经到达，" + (cb.getNumberWaiting() == 2?"都到齐了,继续走啊":"正在等候") );
						cb.await();
						
						Thread.sleep((long)Math.random()*10000);
						System.out.println("线程" + Thread.currentThread().getName() + "即将到达集合地点2，当前已有" +  
						(cb.getNumberWaiting() + 1) + "个已经到达，" + (cb.getNumberWaiting() == 2?"都到齐了,继续走啊":"正在等候"));
						cb.await();
						
						Thread.sleep((long)Math.random()*10000);
						System.out.println("线程" + Thread.currentThread().getName() + "即将到达集合地点3，当前已有" + 
						(cb.getNumberWaiting() + 1) + "个已经到达，" + (cb.getNumberWaiting() == 2?"都到齐了,继续走啊":"正在等候"));
						cb.await();
					} catch (Exception e) {
						e.printStackTrace();
					}
				}
				
			};
			service.execute(runnable);
		}
		service.shutdown();
	}

}