SyncFinisher.java

package com.xiaoleilu.hutool.lang;

import java.util.LinkedHashSet;
import java.util.Set;
import java.util.concurrent.CountDownLatch;

import com.xiaoleilu.hutool.exceptions.NotInitedException;

/**
 * 线程同步结束器<br>
 * 在完成一组正在其他线程中执行的操作之前，它允许一个或多个线程一直等待。<br>
 * 不能保证同时开始
 * @author xiaoleilu
 *
 */
public class SyncFinisher{
	private CountDownLatch countDownLatch;
	
	private Set<Worker> workers = new LinkedHashSet<Worker>();
	
	/**
	 * 增加工作线程
	 * @param worker 工作线程
	 */
	synchronized public void addWorker(Worker worker) {
		workers.add(worker);
	}
	
	/**
	 * 开始工作
	 */
	public void start() {
		countDownLatch = new CountDownLatch(workers.size());
		for (Worker worker : workers) {
			worker.start();
		}
	}
	
	/**
	 * 等待所有Worker工作结束，否则阻塞
	 * @throws InterruptedException
	 */
	public void await() throws InterruptedException {
		if(countDownLatch == null) {
			throw new NotInitedException("Please call start() method first!");
		}
		
		countDownLatch.await();
	}
	
	/**
	 * 清空工作线程对象
	 */
	public void clearWorker() {
		workers.clear();
	}
	
	/**
	 * @return 并发数
	 */
	public long count() {
		return countDownLatch.getCount();
	}
	
	/**
	 * 工作者，为一个线程
	 * @author xiaoleilu
	 *
	 */
	public abstract class Worker extends Thread {

		@Override
		public void run() {
			try {
				work();
			} finally {
				countDownLatch.countDown();
			}
		}
		
		public abstract void work();
	}
}