public class CountDownLatchDemo {
    public static void main(String[] args) throws Exception {

        // TODO 枚举类的使用方式
    }

    private static void closeDoor() throws InterruptedException {
        CountDownLatch countDownLatch = new CountDownLatch(6);
        for(int i = 1; i <= 6; ++i){
            new Thread(() -> {
                System.out.println(Thread.currentThread().getName() + "\\t has leaved.");
                countDownLatch.countDown();
            }, String.valueOf(i)).start();
        }

        countDownLatch.await();
        System.out.println(Thread.currentThread().getName() + "\\t monitor can leave.");
    }
}