Using ThreadPoolExecutor, wish to obtain thread for known runnable object

Question

My problem is this:
I use a ThreadPoolExecutor with default ThreadFactory to create a pair of threads; one operates a live particle simulation, the other mouse interactions with the particles.
I would like to be able to stop one particle simulation (which is a class extending Runnable) and replace it with another. The problem is that I call myRunnableSimulator.stop(), but then I am unable to join() its thread before creating the new particle simulator, because the ThreadPoolExecutor uses a ThreadFactory. And since I have 2 threads running, Thread.currentThread() isn't much use.
ThreadedPoolExecutor.awaitTermination(long duration, TimeUnit unit) doesn't help me either, since it waits for all tasks to terminate. I could set the timeout to some duration that feels safe for the thread I want to die to do so, but it's a bit of a fudge.
Any advice would be much appreciated.

Answer 1

If the tasks you submit to an executor have termination dependencies then you need to explicitly code them into the task based on its state, not the state of the thread executing the task.
Thread.join() is a lazy way to asking "has my task finished execution". And it tells you nothing about the success or failure of that execution. myTask.isDone() is what you need - whether isDone comes from a Future or from your own task implementation.