[jboss-user] [JBossCache] - TreeCache: How to write atomic updates?

[kapilanand]

hi all
I am trying to do the following from two or more hosts that are part of a JBossCache group. (I am using JBossCache 1.4)

If exists(FQN, key)
{ 
    lock FQN
    value = get(FQN, key)
    value--
    if (value == 0)
    {
        remove(FQN, key)
     }
     else
     {
         put(FQN, key, value)
     }
     unlock FQN   
}

There is another thread of code that will increment the value. increment and decrement may happen on any of the hosts.

My intention is only to lock the map and i guess that is only achieved by locking the FQN node. Please correct me if i am wrong.

My question is "how to explicitly lock and unlock the nodes?"
Javadoc for TreeCache._lock() has one-liner saying "Should not be called."   I see _releaseAllLocks() and releaseAllLocks().

And is there a mechanism for timing-out the lock. That is what happens if the process/thread that locked the node dies?

thanks

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