暂停用户输入Java上的线程池

Question

I have a threadpool which runs with a while loop in my main class

   executor = Executors.newFixedThreadPool(numThreads);
   for (int i = 0; i < numThreads; i++) {
        Runnable crawl = new crawlThread(this);
        executor.execute(crawl);
    }
    executor.shutdown();

    try {
        while (!executor.isTerminated()) {
                Thread.sleep(1000);
                this.liveStatus();

                if (System.in.available() != 0) {

                    System.out.println("What would you like to do? (0 = quit, 1 = pause, 2 = resume)");

                    Scanner runinput = new Scanner(System.in);
                    Integer answer = runinput.nextInt();
                    if (answer == 0)
                    {
                        System.out.println("Quitting...");
                        break;
                    } else if (answer == 1)
                    {
                        this.forcePause = true;
                        System.out.println("Pausing...");
                    } else if (answer == 2)
                    {
                        this.forcePause = false;
                        System.out.println("Resuming...");
                    }
                    runinput.close();
                }

        }
    } catch (Exception e) {
        e.printStackTrace();
    }

Although I'm not sure how to go about actually pausing my runnables when I get the user input. I had tried checking the forcePause status of this code from thread / runnable class file, and if it is set to pause to skip its execution instructions although it was not working. Is there any proper way to go about pausing and resuming my threads based on my user input.

Thanks

Answer 1

You code is fine, you should just abstract it out a bit more so you can catch exceptions.

Example:

class MyThread extends Thread {

    private volatile boolean running = true; // Run unless told to pause

    ...

    @Override
    public void run()
    {
        for(int i=0 ; ; i++)
        {

            // This is a crude implementation of pausing the thread
            while (!running)
                // Work

            area.setText(i+"");
    }

    public void pauseThread() throws InterruptedException
    {
        running = false;
    }

    public void resumeThread()
    {
        running = true;
    }

}