The org.jboss.aspects.concurrent Semaphore aspect does what I had in mind.

I would also like a way to share the Semaphore instances (used internally by the Semaphore aspect) between multiple components. For example, I might want immutable application components to share a named Semaphore that has 64 permits and mutable components to share a named Semaphore that has 8 permits.

Sound like a good enhancement?

I looked at the existing semaphore support and I think my needs are already covered.

I should be able to have a SemaphoreAspect or SemaphoreMethodAspect instance throttle several different components in the application by changing the "scope".

Sound right?

Scott

Yes, I meant the scope when you declare the aspect.

Yes, a group or "named semaphore" attribute would be ideal.

I'm thinking that we need a way to configure the "named semaphore" but I'm not sure what that should look like. The configuration would specify the number of Semaphore permits and the name.

Would this work? Have a SemaphoreAspectFactory instance for each named semaphore definition and create the semaphoreAspect from the factory.

Something like:

<aspect name="ThrottleReadMostlyAspect" factory="org.jboss.aspects.concurrent.SemaphoreAspectFactory" scope="PER_JVM">
<attribute name="permits">48</attribute>
</aspect>

I'm tempted to have a standalone module manage the named semaphores (perhaps called SemaphoreManager). The SemaphoreManager api methods could be used for reconfiguration (JMX aspect could expose them in the JMX console.)

The api should allow:

* List all named semaphores (show name, total permit count + current available permits)
* Increase number of permits for a named semaphore
* Decrease number of permits for a named semaphore


I'm still trying to understand how all of this AOP stuff works together. I see that the SemaphoreAspect is loosely coupled with the underlying semaphore instance via the SemaphoredObject class. Should we have a SemaphoreFactory class that can return a SemaphoredObject implementation that is based on a named semaphore? I suppose that the SemaphoreFactory could also return a SemaphoredObject based on an anonymous semaphore as well.

The SemaphoreFactory factory would depend on the SemaphoreManager for resolving the semaphore instances.

Make any sense?

On a different node, I can build trunk with "mvn install" command. I would like to run the testsuite but "mvn test" doesn't seem to do much. How can I run the unit tests?

Scott