package multithreading;

import java.util.concurrent.CountDownLatch;

public class CountDownLatchExample {

public static void main(String[] args) throws InterruptedException {

CountDownLatch latch = new CountDownLatch(4);

Worker first = new Worker(1000, latch, "WORKER-1");

Worker second = new Worker(2000, latch, "WORKER-2");

Worker third = new Worker(3000, latch, "WORKER-3");

Worker fourth = new Worker(4000, latch, "WORKER-4");

first.start();

second.start();

third.start();

fourth.start();

latch.wait(); // The main task waits for four threads

System.out.println(Thread.currentThread().getName() + " has finised");

}

}

class Worker extends Thread {

private int delay;

private CountDownLatch latch;

public Worker(int delay, CountDownLatch latch, String name) {

super(name);

this.delay = delay;

this.latch = latch;

}

@Override

public void run() {

try {

Thread.sleep(delay);

latch.countDown();

System.out.println(Thread.currentThread().getName() + " finished");

} catch (Exception e) {

e.printStackTrace();

}

}

}