Question

The following awaits forever, I think. How do I specify a timeout?

await(new Job<Long>() {
    @Override
    public Long doJobWithResult() throws Exception {
        ...
    }
}.now());

Answer 1

Implementing a timeout which kills a thread is actually a pretty difficult thing to do generically since you’d need to use Thread.stop() or something else horrid like that which might not clean up when it dies. The nicer way to do it is have the timeout set a flag in your long job that makes it stop processing and return sooner. Or alternatively, you let the long job continue and just render a response on the timeout.

Here is a testcase that does what you want:

https://github.com/playframework/play/blob/1.3.x/samples-and-tests/just-test-cases/app/controllers/WithContinuations.java#L73

public static void waitWithTimeout() {
        Promise<String> task1 = new jobs.DoSomething(100).now();
        Promise<String> task2 = new jobs.DoSomething(2000).now();
        Either<List<String>,Timeout> r = await(Promise.waitEither(Promise.waitAll(task1, task2), Timeout(300)));

        for(Timeout t : r._2) {

            StringBuilder result = new StringBuilder();

            if(task1.isDone()) {
                result.append(" + Task1 -> " + task1.getOrNull());
            }

            if(task2.isDone()) {
                result.append(" + Task2 -> " + task2.getOrNull());
            }

            renderText("Timeout! Partial result is " + result);
        }

        renderText("Fail!");
    }