Interrupting running Future

Question

My code runs on Java 5.
The callables I submit to a given ExecutorService are pure-computational, meaning: no calls to "low-level blocking methods".
I'd like these computations to be cancellable in a ASAP fashion: that means I'll sometimes call cancel(true) of the Future instance.
If I understand correctly, this will set the interruption status of the thread executing the given Future to true. Now my question is: how can my code distinguish between
a) an interruption request triggered by a cancel(true) on the Future
b) an interruption request triggered by a shutdownNow of the pool
I would like quick cancellation (through interruption), but quick and correct shutdown of the pool is important as well (meaning: I'll likely use shutdownNow() in some circumstances).
Reading stuff like the following make me kind of nervous:
http://forum.java.sun.com/thread.jspa?threadID=775640&start=20&tstart=0
I hope some of the fixes are sheduled for a backport to Java 5?

Answer 1

My original question could have been more clear:
"Should I always propagate the interruption status from the Callable/Runnable to the executor?"
Looking some more at the TPE source, I guess the answer is:
"Not when running on Java 5.0, until the relevant fixes from 6.0 are backported"
So:
1) In my computational loop I inspect isInterrupted()
2) Upon interruption, I exit the loop
3) Before returning from run(), I clear the interruption status
If the current thread interruption status was set because of pool shutdown, the current worker thread will exit anyway (since getTask() will return null)
Message was edited by:
Pakka-Pakka