JMX: show workQueue size in ExecutorFilter / thread pool

[Victor <dr...@mail333.com>]

Hello,

I think it may be useful to add some info about working queue to JMX.
Currently, we can see how many threads are working, but can not see 
queue size.

First, I tried to add it to ObjectMBean... without success,
but then I added the following method to ExecutorFilter and it works:

public int getWorkQueueSize() {
     	if (executor instanceof ThreadPoolExecutor) {
     		return ((ThreadPoolExecutor)executor).getQueue().size();
     	}
     	return 0;
     }

If you want it working with OrderedThreadPoolExecutor, you should also 
comment OrderedThreadPoolExecutor.getQueue() method (which throws 
UnsupportedOperationException). But seems that OrderedThreadPoolExecutor 
has its specific implementation and ignores workQueue.

Victor N