CODEWITHSUNDEEP
javascheduled-tasksjava-threads
Nikolai Neverov
Nikolai Neverov

Reputation: 25

ScheduledExecutorService end after a timeout

Good day! I have scheduler and I need to check how much time does it works. How can I do that? I need to return an error from someFunction() when scheduler works more than 5 minutes 

ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);

public int someFunction() {
    ScheduledFuture<Integer> future = 
        scheduler.schedule(new ScheduledPrinter(), 10, TimeUnit.SECONDS);
    if (scheduler.isShutdown()) {
        return future.get();
    }
}
private class ScheduledPrinter implements Callable<Integer> {
    public Integer call() throws Exception {
        // do something
        if (!serverResponse.getErrorData().equals("QueueIsNotReady")) {
            scheduler.shutdown();
            return getResponse();
        } 
        return null;
    }
}

Upvotes: 0

Views: 4576

Answers (1)

hoaz
hoaz

Reputation: 10161

You can use following options:

  1. scheduler.awaitTermination(5, TimeUnit.MINUTES)

    ScheduledFuture<Integer> future = 
        scheduler.schedule(new ScheduledPrinter(), 10, TimeUnit.SECONDS);
if (!scheduler.awaitTermination(5, TimeUnit.MINUTES)) {
    throw new Exception("task did not complete");
}

  2. future.get(5, TimeUnit.MINUTES). This method allows you to reuse scheduler for other tasks:

    ScheduledFuture<Integer> future =
        scheduler.schedule(new ScheduledPrinter(), 10, TimeUnit.SECONDS);
future.get(5, TimeUnit.MINUTES)); // this will throw TimeoutException after 5 minutes

  3. Schedule another task to run in 5 minutes that will check first task status. This method can be used for asynchronous handling of timeout. someFunction will return immediately in this case:

    ScheduledFuture<Integer> future =
        scheduler.schedule(new ScheduledPrinter(), 10, TimeUnit.SECONDS);
scheduler.schedule(() -> {
    if (!future.isDone()) {
        future.cancel(true);  // cancel task if it runs more than 5 minutes
    }
}, 5, TimeUnit.MINUTES);

Upvotes: 6

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