package com.lyq.jsoup.MyQueue;
/**
* Created by mike on 2016/12/19.
*/
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
/**
* 示例:CountDownLatch的使用舉例
* 構造方法參數指定了計數的次數
* countDown方法,當前線程調用此方法,則計數減一
* await方法,調用此方法會一直阻塞當前線程,直到計時器的值爲0
*/
public class TestCountDownLatch {
private static final int N = 5;
public static void main(String[] args) throws InterruptedException {
CountDownLatch startSignal = new CountDownLatch(1);//控制每一個線程是否開始
CountDownLatch doneSignal = new CountDownLatch(N);
for (int i = 1; i <= N; i++) {
new Thread(new Worker(doneSignal, startSignal), "t" + i).start();//所有線程啓動,都處於等待狀態
}
System.out.println("begin------------");
startSignal.countDown();//2:所有線程都執行
doneSignal.await();//3:等待所有的線程執行完畢
System.out.println("Ok");
}
static class Worker implements Runnable {
private final CountDownLatch doneSignal;
private final CountDownLatch startSignal;
Worker(CountDownLatch doneSignal,
CountDownLatch startSignal) {
this.startSignal = startSignal;
this.doneSignal = doneSignal;
}
public void run() {
try {
startSignal.await(); //1:等待開始執行信號的發佈
System.out.println("thread name:" + Thread.currentThread().getName());
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
doneSignal.countDown();//4:每個線程一行完成,都會減一,知道doneSignal.count = 0
}
}
}
}
CountDownLatch 自己的一點理解
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