从在ScheduledExecutorService中运行的任务本身停止周期性任务 [英] Stop a periodic task from within the task itself running in a ScheduledExecutorService

问题描述

在ScheduledExecutorService中运行时，有没有很好的方法来阻止任务从任务本身重复？

Is there a nice way to stop the repetition of task from within the task itself when running in a ScheduledExecutorService?

我有以下任务： / p>

Lets say, I have the following task:

Future<?> f = scheduledExecutor.scheduleAtFixedRate(new Runnable() {
    int count = 0;
    public void run() {
       System.out.println(count++);
       if (count == 10) {
           // ??? cancel self
       }
    }
}, 1, 1, TimeUnit.SECONDS);

从外部，很容易通过f.cancel（）取消，在指定地点重复？ （通过AtomicReference传递未来是不安全的，因为当scheduleAtFixedRate返回f late并且变量被设置为late时，有一个潜在的窗口，并且任务本身可能已经运行，在引用中看到一个null。）

From outside, it is easy to cancel via f.cancel(), but how can I stop the repetition at the specified place? (Passing the Future through an AtomicReference is not safe, because there is a potential window when the scheduleAtFixedRate returns f late and the variable is set late too, and the task itself might already run, seeing a null in the reference.)

推荐答案

当重复任务抛出异常或错误时，它被放置在未来，任务不会再次重复。您可以抛出一个您选择的RuntimeException或错误。

When a repeating task throws an Exception or Error, it is placed in the Future and the task is not repeated again. You can throw a RuntimeException or Error of your choice.

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