Thanks I will try that out On Wed, Oct 28, 2015 at 4:00 PM, Jordan Zimmerman < [email protected]> wrote:
> Another thing is to use InterProcessSemaphoreMutex instead. It is a > non-reentrant lock and can be unlocked from any thread. > > -JZ > > On Oct 28, 2015, at 2:55 PM, tathagata roy <[email protected]> wrote: > > Thanks Jordan for the response. > > I cannot use the strategy because the thread can hold multiple locks , and > if i do that it will release all the locks. The example i have put in the > question is just a sample i was trying but in the actual project a single > thread holds multiple locks. > > Is there any other way i can do that? > > On Wed, Oct 28, 2015 at 3:43 PM, Jordan Zimmerman < > [email protected]> wrote: > >> Your RevocationListener should interrupt the thread that holds the lock. >> Then, that thread can release the lock. >> >> -Jordan >> >> On Oct 28, 2015, at 2:19 PM, tathagata roy <[email protected]> wrote: >> >> All, >>> >>> I am trying to test the revocable Locking in Apache Curator. I have two >>> threads which tries to acquire a lock. If the first test acquires the lock, >>> the second thread can ask the first thread to release the lock so that the >>> 2nd thread can acquire it >>> >>> RetryPolicy retryPolicy = new ExponentialBackoffRetry( >>> baseSleepTimeMills, maxRetries); >>> >>> CuratorFramework client = CuratorFrameworkFactory.newClient(hosts, >>> retryPolicy); >>> client.start(); >>> >>> final InterProcessMutex lock = new InterProcessMutex(client, >>> lockBasePath); >>> >>> Collection<String> nodes = lock.getParticipantNodes(); >>> >>> lock.makeRevocable(new RevocationListener<InterProcessMutex>(){ >>> >>> @Override >>> public void revocationRequested(InterProcessMutex lock1) { >>> try { >>> if(lock.isAcquiredInThisProcess()){ >>> lock.release(); >>> } >>> >>> } catch (Exception e) { >>> // TODO Auto-generated catch block >>> e.printStackTrace(); >>> } >>> >>> } >>> >>> }); >>> >>> if(nodes!=null && !nodes.isEmpty()){ >>> Revoker.attemptRevoke(client, nodes.iterator().next()); >>> } >>> >>> if (lock.acquire(waitTimeSeconds, TimeUnit.SECONDS)) { >>> try { >>> doSomeWork(lockName); >>> } finally { >>> lock.release(); >>> } >>> } else { >>> System.err.printf("%s timed out after %d seconds waiting to >>> acquire lock on %s\n", >>> lockName, waitTimeSeconds, lockPath); >>> } >>> >>> >>> The problem is, when the 2nd thread calls the attemptRevoke, the >>> callback async method is called on the first process, but since its a call >>> back method that's a third thread, and if that invokes the lock.release it >>> throws an Exception >>> >>> *java.lang.IllegalMonitorStateException: You do not own the lock* >>> >>> That is as per the api >>> >>> *release() Perform one release of the mutex if the calling thread is the >>> same thread that acquired it.* >>> >>> So basically this is never possible because callbacks will always be >>> another thread. Is my understanding right? Is there any other way to >>> achieve this? >>> >>> Thanks for any suggestions >>> >>> -Tatha >>> >>> >> >> >> > >
