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From: Robert Klemme <shortcutter@googlemail.com>
Newsgroups: comp.lang.java.programmer
Subject: Re: polling IRQs in a thread's code
Date: Mon, 25 Mar 2013 23:15:54 +0100
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On 25.03.2013 00:14, markspace wrote:
> On 3/24/2013 3:45 PM, Stefan Ram wrote:
>>
>>    Is this the usual way to proceed? Or can I simplifiy this somehow?
>
> Yes and no.  First, I wish you would not use IRQ as your method name.
> Interrupt ReQuest is a hardware thing, and we don't have access to those
> from within the Java API.
>
> Second, I'd use interrupt().  It's the usual way of asking that a thread
> stop.  Many routines in the Java API already check for the interrupt
> flag for you, which releaves you of some of the burden for testing.
> Likewise, wait() and similar fuctions also test for interrupts even when
> the thread isn't running, something you would be hard pressed to do.

That can also be viewed as a downside: you loose control over when the 
process may be interrupted.  If you only want to allow for interruption 
at certain steps in the process then interrupt() might actually be unusable.

> Third, your code could be structured a little better.

Another structure could be:

private final List<Task> tasks = ...
private volatile boolean run;

public void run() {
   run = true;

   for (final Task t : tasks) {
     t.execute();

     if (!run) {
       cleanup();
       return;
     }
   }
}

or even

public void run() {
   run = true;

   for (final Task t : tasks) {
     if (run) {
       t.execute();
     }
     else {
       t.ignore();
     }
   }
}

> P. S. Get Java Concurrency In Practice.  It's just about required for
> working with concurrency in Java.

+1

Kind regards

	robert


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