Question

I use an ArrayBlockingQueue in my code. Clients will wait until an element becomes available:

myBlockingQueue.take();

How can I “shutdown” my service in case no elements are present in the queue and the take() is waiting indefinitely for an element to become available? This method throws an InterruptedException. My question is, how can I “evoke” an Interrupted Exception so that take() will quit? (I also tought about notify(), but it seems I doesn’t help here..)

I know I could insert an special “EOF/QUIT” marker Element but is this really the only solution?

UPDATE (regarding the comment, that points to another question with two solutions):

one mentioned above using a “Poisoning Pill Object” and the second one is Thread.interrupt():

The myBlockingQueue.take() is used NOT in a Thread (extending Thread) but rather implements Runnable. It seems a Runnable does not provide the .interrupt() method?

How could I interrupt the Runnable?

Answer 1

You can implement the Runnable like this. (It assumes you have started the Runnable before you attempt to interrupt it)

class MyRunnable implements Runnable {
    private Thread thisThread;
    public void run() {
       thisThread = Thread.currentThread();
       try {
          // do some work
       } catch(Throwable t) {
          t.printStackTrace(); // or log the error.
       } 
    }
    public void interrupt() {
       thisThread.interrupt();
    }
}