java Callable FutureTask Excecuter：如何监听已完成的任务 [英] java Callable FutureTask Excecuter: How to listen to finished task

问题描述

我对执行者服务很陌生。喜欢自己做所有事情，但我认为是时候相信这些服务了。

我想交出 Executer a 可运行。执行者将它包装在 FutureTask 中并将其交还给我。现在我调用 done（）方法调查。但是我希望在 done（）方法返回true时收到通知。

有一个 get（）阻塞直到 Runnable 完成的方法，但是我需要为每个作业添加一个额外的线程，只是为了看看它什么时候结束。

我可以给我的执行者一些额外的 Callable 以获得有关完成任务的通知吗？ / p>

这里有什么方法？我可以在 run 方法的末尾添加一些代码，但是 done（）可能仍然是false。 。

解决方案

如果您可以对使用java.util.concurrent.ThreadPoolExecutor做出具体假设，那么您可以使用它的钩子方法; afterExecute（）和beforeExecute（）。

http://download.oracle.com/javase/6/docs/api/java/util/concurrent/ThreadPoolExecutor.html

它们不如ListenableFuture那么优雅，但它可能是一个适当的解决方案，前提是您只需要一种类型的侦听器给定的执行器实例。

I'm quite new to executer services. Liked doing everything myself, but I think it's time to trust these services.

I want to hand by Executer a Runnable. The executer wraps that in a FutureTask and hands it back to me. Now I call poll the done() method. But I would like to be notified when then done() method would return true.

There is a get() method that blocks until the Runnable has finished, but then I would need a extra thread for every job, just to see when it's finished.

Can I hand my executer some extra Callable to get notified about the task finishing?

What's the way to go here? I could add some code to the end of the run method, but then done() might still be false...

解决方案

If you can make a specific assumption of using a java.util.concurrent.ThreadPoolExecutor, then you can use its hook methods; afterExecute() and beforeExecute().

http://download.oracle.com/javase/6/docs/api/java/util/concurrent/ThreadPoolExecutor.html

They are not as elegant as the ListenableFuture, but it might be an adequate solution provided you need only one type of a "listener" for a given executor instance.

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