How to run a task for a specific amount of time

Question

I'm implementing some sort of chat application and I need some help. This is the simplified code:

//...
Boolean stop = false;

while(!stop) {

    ServerRequest message = (ServerRequest) ois.readObject();
    broadcastMessage((String)message.getData()); //this method sends the client's message to all the other clients on the server

    stop = (System.nanoTime() - start >= handUpTime); // I want to let the client send his messages for no more than handUpTime seconds
} //...

I want to let a client to send his messages to the server for a certain amount of time (handUpTime) and then "block" him, but I don't know how to do this in an "elegant" manner. Of course, my code stumbles upon the ois.readObject() part, as the System waits to receive a message, and continues to run for more than handUpTime seconds. How can I solve this problem? I'm open to other approaches too.

@MortezaJalambadani: Your comment suggests that you don't understand the question — Hovercraft Full Of Eels, Aug 19 '18 at 11:15
@HovercraftFullOfEels : if use Thread.sleep in Sub Thread and use listener when Thread time elapsed can solved his problem. :/ — Morteza Jalambadani, Aug 19 '18 at 11:18
@MortezaJalambadani, I guess you mean to use some kind of `wait()` and `notify()` mechanism. Such an approach should work, but I think Java offers far more "modern" alternatives. — dim, Aug 19 '18 at 11:31
May be you should use `ExecutorService` and `Future`: see [this](https://stackoverflow.com/questions/1164301/how-do-i-call-some-blocking-method-with-a-timeout-in-java) — dim, Aug 19 '18 at 11:42

dim · Answer 1 · 2018-08-19T12:40:05.487

You can try:

ExecutorService executorService = Executors.newSingleThreadExecutor();

Callable<Object> callable = () -> {
    // Perform some blocking computation
    return someObject
};

Future<Object> future = executorService.submit(callable);

Object result = future.get(YOUR_TIMEOUT, TimeUnit.SECONDS);

If the future.get() doesn't return in certain amount of time, it throws a TimeoutException so you should handle the exception. See this post.

How to run a task for a specific amount of time

1 Answers1