Skip to content

concat + concurrency + multiple subscribers #552

Closed
@samuelgruetter

Description

@samuelgruetter

This C# snippet

var o = Observable.Concat(
    Observable.Interval(TimeSpan.FromMilliseconds(500)).Take(2),
    Observable.Interval(TimeSpan.FromMilliseconds(500)).Take(2)
);
o.Subscribe(x => Console.WriteLine("a: " + x), t => Console.WriteLine(t), () => Console.WriteLine("a: done"));
o.Subscribe(x => Console.WriteLine("b: " + x), t => Console.WriteLine(t), () => Console.WriteLine("b: done"));
Console.WriteLine("all subscribed");
Thread.Sleep(5000);

outputs, as expected, this:

all subscribed
b: 0
a: 0
b: 1
a: 1
a: 0
b: 0
a: 1
a: done
b: 1
b: done

The same translated to Java:

Action1<Long> printNext(final String who) {
    return new Action1<Long>() {
        public void call(Long o) {
            System.out.println(who + o);
        }
    };
}
Action1<Throwable> printErr(final String who) {
    return new Action1<Throwable>() {
        public void call(Throwable o) {
            System.out.println(who + o);
        }
    };
}
Action0 printComplete(final String who) {
    return new Action0() {
        public void call() {
            System.out.println(who + "done");
        }
    };
}
@Test public void testConcat2() throws Exception {
    Observable<Long> o = Observable.concat(
        Observable.interval(500, TimeUnit.MILLISECONDS).take(2),
        Observable.interval(500, TimeUnit.MILLISECONDS).take(2)
    );        
    o.subscribe(printNext("a: "), printErr("a: "), printComplete("a: "));
    o.subscribe(printNext("b: "), printErr("b: "), printComplete("b: "));
    System.out.println("all subscribed");
    Thread.sleep(5000);
}

only outputs this:

all subscribed
a: 0
a: 1
a: 0
a: 1
a: done

If I replace the Observable.interval by an Observable.from, the problem disappears, so I think the problem only shows up if we have concat + concurrency + multiple subscribers.

Metadata

Metadata

Assignees

No one assigned

    Labels

    No labels
    No labels

    Type

    No type

    Projects

    No projects

    Milestone

    No milestone

    Relationships

    None yet

    Development

    No branches or pull requests

    Issue actions