How to implement synchronous method timeouts in Java?

Question

I have an synchronous execution path which needs to either complete or timeout within a given time frame.

Let's say I have a class with a main() method in which I invoke method A(), which in-turn calls B(), and that in-turn calls C(), of the same or different classes, all synchronous, and without using an external resource like database , webservice, or file system (so not blocking IO, it's more like a CPU or memory intensive computation).

How do I code for its timeout in Java? I have looked at TimerTask but that is more of making the flow async and for scheduling tasks. Any other suggestions?

Answer 1

You should use ExecutorService to do that

ExecutorService executor = Executors.newSingleThreadExecutor();
Future<String> future = executor.submit(new Callable() {

    public String call() throws Exception {
        //do operations you want
        return "OK";
    }
});
try {
    System.out.println(future.get(2, TimeUnit.SECONDS)); //timeout is in 2 seconds
} catch (TimeoutException e) {
    System.err.println("Timeout");
}
executor.shutdownNow();