java等待来自线程的事件

Question

我有一个具有主线程的应用程序。在 A 点，我创建了一个执行某些操作的子线程。同时，主应用程序线程不应停止。

在B点，子线程到达中间解。现在它需要来自主应用程序线程的输入。我怎样才能实现这个目标？

我不能使用wait()/notify()，因为主应用程序线程不应该等待(即ui事件仍然应该被处理)。我设想这样的事情(简化/伪验证):

主线程:

public void foo(){
    child = new Thread();
    child.start();
    ...
    return;
}

...


public void receiveEventFromChildProcess(){
    bar();
}

child

Public void start(){
    run();
}

Public void run(){
    bla();
    //Intermediate solution reached
    notifyMainApplicationThread();
}

这可行吗？我承认我可能根本没有正确地处理这个问题。不过还是感谢您的帮助:)

Answer 1

我认为您可以使用CountDownLatch来实现您的用例。我在这里提供一个例子。

public class Main {

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

            CountDownLatch countDownLatch = new CountDownLatch(1);
            Thread worker = new Thread(new Worker(countDownLatch));
            worker.start();
            // do some work in mian
            // now the point reached and you want wait main therad for notification from child therad
            countDownLatch.await(); //main will wait at this ponit still the child thread did not call countDownLatch.countDown();

        }

    }

    class Worker implements Runnable {

        CountDownLatch countDownLatch;

        Worker(CountDownLatch countDownLatch) {
            this.countDownLatch = countDownLatch;
        }

        @Override
        public void run() {
            // bla();
            countDownLatch.countDown(); // it will notify the main thread to resume its work
            // notifyMainApplicationThread();
        }
    }