package com.concurrent;
import java.util.concurrent.CountDownLatch; import java.util.concurrent.TimeUnit;
public class CountDownLatchTest {
class Worker implements Runnable{ private CountDownLatch buyLatch;
private CountDownLatch cookLatch;
public Worker(CountDownLatch buyLatch, CountDownLatch cookLatch) { super(); this.buyLatch = buyLatch; this.cookLatch = cookLatch; }
@Override public void run() { // TODO Auto-generated method stub System.out.println("Thread " + Thread.currentThread().getName() + " is buying"); buyLatch.countDown(); try { TimeUnit.MILLISECONDS.sleep(100); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } System.out.println("Thread " + Thread.currentThread().getName() + " is cooking"); cookLatch.countDown(); } } public static void main(String[] args){ CountDownLatch buylatch = new CountDownLatch(10); CountDownLatch cooklatch = new CountDownLatch(10); CountDownLatchTest test = new CountDownLatchTest(); for(int i = 0 ; i < 10; i++){ new Thread(test.new Worker(buylatch, cooklatch)).start(); } try { buylatch.await(); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } System.out.println("Buying is done"); try { cooklatch.await(); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } System.out.println("Cooking is done"); } }
Note:
When using a CyclicBarrier, the assumption is that you specify the number of waiting threads that trigger the barrier. If you specify 5, you must have at least 5 threads to call await().
When using a CountDownLatch, you specify the number of calls to countDown() that will result in all waiting threads being released. This means that you can use a CountDownLatch with only a single thread.
