Jeroen,
Yes - I get what you are saying. Volatile is OK for one way communication;
the interrupting thread does not need to know the state of the interrupted
thread.
Thanks - AJ
On 11 May 2013 08:49, Jeroen Frijters <jer...@sumatra.nl> wrote:
> Charles Oliver Nutter wrote:
> > You need CAS because one form of the interrupt check clears it and
> > another does not. So the get + check + set of interrupt status needs to
> > be atomic, or another thread could jump in and change it during that
> > process.
>
> I believe Thread.interrupted() and Thread.isInterrupted() can both be
> implemented without a lock or CAS.
>
> Here are correct implementations:
>
> private volatile boolean interruptPending;
>
> public boolean isInterrupted() {
> return interruptPending;
> }
>
> public static boolean interrupted() {
> Thread current = currentThread();
> if (!current.interruptPending) {
> return false;
> }
> current.interruptPending = false;
> return true;
> }
>
> Any interrupts that happen before we clear the flag are duplicates that we
> can ignore and any that happen after are new ones that will be returned by
> a subsequent call. The key insight is that the interruptPending flag can be
> set by any thread, but it can only be cleared by the thread it applies to.
>
> Regards,
> Jeroen
>
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