import java.util.concurrent.CountDownLatch;

public class CountDown {

	private static CountDownLatch connectedSignal = new CountDownLatch(50);

	static class MyThread implements Runnable {

		public void run() {

			for (int i = 0; i < 25; ++i) { sale(); }

		}

		public synchronized void sale() {

			if (connectedSignal.getCount() > 0) {

				Thread current = Thread.currentThread();

				connectedSignal.countDown();

				System.out.println("Thread id" + current.getId() + "value = "

						+ connectedSignal.getCount());

			}

		}

	}

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

		MyThread my = new MyThread();

		Thread t1 = new Thread(my, "test1");

		Thread t2 = new Thread(my, "test2");

        t1.start();

        t2.start();

        connectedSignal.await(); // 等待结束

        System.out.println(connectedSignal.getCount());

	}

}