How to get number of current running and queued threads from ThreadPoolExecutor?

Question

I need to get number of running threads in a ThreadPoolExecutor, as well as the Queue size.

I have a working implementation as (keep track of each futures in an arraylist and count which is not completed):

java.util.concurrent.ArrayBlockingQueue<Runnable> threadpoolQueue = 
    new java.util.concurrent.ArrayBlockingQueue<Runnable>(10);

ThreadPoolExecutor threadpool = new java.util.concurrent.ThreadPoolExecutor(0, 
    executingThreads, retryInterval, java.util.concurrent.TimeUnit.MILLISECONDS, threadpoolQueue);

ArrayList<Future> threads = new ArrayList<Future>();

threads.add(threadpool.submit(/*Runnable*/));

//Get Sizes
int threadpoolRunningThreads = 0;
for (Future obj : threads) {
    if (!obj.isDone()) {
         threadpoolRunningThreads++;
    }
}
logger.debug("Merging all threads threadpool.size=" + threadpoolRunningThreads 
    + ",threadpool.queue.size="+ threadpoolQueue.size());

This is a very awkward way of tracking threadpool, and I don't see any methods provided in threadpool that allows to get the number for running and queued threads. I wanna do something like:

threadpool.getIncompletedTaskSize();
threadpool.getQueuedTaskSize();

Can I achieve this? or at least something easier than my implementation? I am using Java 1.6.

Answer 1

Maybe ThreadPoolExecutor#getActiveCount() and ThreadPoolExecutor#getQueue()#size() ?