一旦我认为它已经完成，如何在ScheduledThreadPoolExecutor中停止任务 [英] How to stop a task in ScheduledThreadPoolExecutor once I think it's completed

问题描述

我有一个ScheduledThreadPoolExecutor，我用它来安排以固定速率运行的任务。我希望任务以指定的延迟运行最多10次，直到它成功。在那之后，我不希望重试任务。所以基本上我需要停止运行计划任务，当我希望它被停止时，但不关闭ScheduledThreadPoolExecutor。知道我该怎么做吗？

I have a ScheduledThreadPoolExecutor with which I schedule a task to run at a fixed rate. I want the task to be running with a specified delay for a maximum of say 10 times until it "succeeds". After that, I will not want the task to be retried. So basically I'll need to stop running the scheduled task when I want it to be stopped, but without shutting down the ScheduledThreadPoolExecutor. Any idea how I'd do that?

这里有一些伪代码 -

Here's some pseudocode -

public class ScheduledThreadPoolExecutorTest
{
  public static ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(15);  // no multiple instances, just one to serve all requests

  class MyTask implements Runnable
  {
    private int MAX_ATTEMPTS = 10;
    public void run()
    {
      if(++attempt <= MAX_ATTEMPTS)
      {
        doX();
        if(doXSucceeded)
        {
          //stop retrying the task anymore
        }
      }
      else
      { 
        //couldn't succeed in MAX attempts, don't bother retrying anymore!
      }
    }
  }

  public void main(String[] args)
  {
    executor.scheduleAtFixedRate(new ScheduledThreadPoolExecutorTest().new MyTask(), 0, 5, TimeUnit.SECONDS);
  }
}

推荐答案

运行此测试，打印 1 2 3 4 5 并停止

run this test, it prints 1 2 3 4 5 and stops

public class ScheduledThreadPoolExecutorTest {
    static ScheduledThreadPoolExecutor executor = new ScheduledThreadPoolExecutor(15); // no
    static ScheduledFuture<?> t;

    static class MyTask implements Runnable {
        private int attempt = 1;

        public void run() {
            System.out.print(attempt + " ");
            if (++attempt > 5) {
                t.cancel(false);
            }
        }
    }

    public static void main(String[] args) {
        t = executor.scheduleAtFixedRate(new MyTask(), 0, 1, TimeUnit.SECONDS);
    }
}

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