线程同步工具类--CyclicBarrier

左手的ㄟ右手 2022-06-16 08:52 165阅读 0赞

CyclicBarrier

表示大家彼此等待，等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

package com.javase.thread;
    
    import java.util.Random;
    import java.util.concurrent.BrokenBarrierException;
    import java.util.concurrent.CyclicBarrier;
    import java.util.concurrent.ExecutorService;
    import java.util.concurrent.Executors;
    import java.util.concurrent.TimeUnit;
    import java.util.concurrent.locks.ReentrantLock;
    /**
     * 
     * @author Alex Zhuang
     *
     */
    public class CyclicBarrierDemo {
    	private static boolean isPrint1=true;
    	private static boolean isPrint2=true;
    	private static ReentrantLock lock = new ReentrantLock();
    	public static void main(String[] args) {
    		final CyclicBarrier barrier = new CyclicBarrier(3);
    		ExecutorService threadPool = Executors.newCachedThreadPool();
    		for(int i=0;i<3;i++){
    			Runnable command =new Runnable(){
    				public void run() {
    					System.out.println(Thread.currentThread().getName()+" is waiting now");
    					try {
    						TimeUnit.MILLISECONDS.sleep(new Random().nextInt(5000));
    					} catch (InterruptedException e1) {
    						e1.printStackTrace();
    					}
    					System.out.println("the number of threads currently waiting at the barrier 1 is : "+barrier.getNumberWaiting());
    					try {
    						barrier.await();
    					} catch (InterruptedException e) {
    						e.printStackTrace();
    					} catch (BrokenBarrierException e) {
    						e.printStackTrace();
    					}
    					lock.lock();
    					try{
    						if(isPrint1){
    							System.out.println("All the 3 threads have arrived at place 1");
    							isPrint1=false;
    						}
    					}finally{
    						lock.unlock();
    					}
    					
    					System.out.println(Thread.currentThread().getName()+" is waiting now");
    					try {
    						TimeUnit.MILLISECONDS.sleep(new Random().nextInt(5000));
    					} catch (InterruptedException e1) {
    						e1.printStackTrace();
    					}
    					System.out.println("the number of threads currently waiting at the barrier 2 is : "+barrier.getNumberWaiting());
    					try {
    						barrier.await();
    					} catch (InterruptedException e) {
    						e.printStackTrace();
    					} catch (BrokenBarrierException e) {
    						e.printStackTrace();
    					}
    					lock.lock();
    					try{
    						if(isPrint2){
    							System.out.println("All the 3 threads have arrived at place 2");
    							isPrint2=false;
    						}
    					}finally{
    						lock.unlock();
    					}
    					
    					
    					
    				}
    			};
    			threadPool.execute(command);
    		}
    		threadPool.shutdown();
    
    	}
    
    }