Implementing Inactivity Timeout with ScheduledExecutorService

Question

Our system processes messages delivered from a messaging system. If no message is received after 10 seconds, an error should be raised (inactivity timeout).

I was thinking of using a ScheduledExecutorService (with 1 Thread). Each time a message is received, I cancel the previous timeout task and submit a new one:

ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);
Callable timeoutTask = new Callable() {...};

...

synchronized {
    timeout.cancel();
    timeout = executor.schedule( timeoutTask, 10, TimeUnit.SECONDS);
}

In normal case, we process ~ 1000 / sec. Would this approach scale?

Answer 1

If you share the threadpool and keep the running time of timeoutTask low, it'd be most probably fine. If you'd have one threadpool per ~ 1000 / sec tasks then that would not work.

If you are still worried, you can have a look at HashedWheelTimer from the Netty project (link). This thing is very efficient in scheduling timeouts. Note that you MUST share instance of HashedWheelTimer as well.