return value from AdvancedCache.lock

[millerm120]

The AdvancedCache.lock methods return a boolean which according to the JavaDoc is true if lock acquired and false if it is not acquired.

* @return true if the lock acquisition attempt was successful for <i>all</i> keys; false otherwise.

All of the sample code I have seen looks like this:

   tx.begin()

   cache.lock(K)    // acquire cluster wide lock on K

   cache.put(K,V5)  // guaranteed to succeed

   tx.commit()      // releases locks

and does not check the return value of the lock call.

Is it possible for the call to lock to return false or will it always either return true or throw an exception?

Thanks in advance,

Mark

[galder.zamarreno]

Hmm, is this a question for JBoss Cache or Infinispan?

[millerm120]

You are right, I moved it to the Infinispan discussion.

[galder.zamarreno]

This is something we need to sort out, or document better. As shown in https://github.com/infinispan/infinispan/blob/master/core/src/test/java/org/infinispan/lock/APITest.java#L72, an unchecked org.infinispan.util.concurrent.TimeoutException can be thrown by lock() method.

It could happen though that it returns false too as shown in https://github.com/infinispan/infinispan/blob/master/core/src/test/java/org/infinispan/lock/APITest.java#L95, but it looks to me that this is limited to when FAIL_SILENT flag is used.

[millerm120]

Thanks, that makes sense.  You are right that it should be documented better.  At a minimum the JavaDoc for the lock methods should mention that they block waiting for the lock.  Ideally the @return should discuss that the false return is only possible if the FAIL_SILENTLY flag is used.

Thanks for the quick reply.