An abstract Observer that allows asynchronous cancellation by implementing Disposable.

All pre-implemented final methods are thread-safe.

Use the public dispose() method to dispose the sequence from within an onNext implementation.

Like all other consumers, DisposableObserver can be subscribed only once. Any subsequent attempt to subscribe it to a new source will yield an IllegalStateException with message "It is not allowed to subscribe with a(n) <class name> multiple times.".

Implementation of onStart(), onNext(Object), onError(Throwable) and onComplete() are not allowed to throw any unchecked exceptions. If for some reason this can't be avoided, use io.reactivex.rxjava3.core.Observable#safeSubscribe(io.reactivex.rxjava3.core.Observer) instead of the standard subscribe() method.

Example

Disposable d =
    Observable.range(1, 5)
    .subscribeWith(new DisposableObserver<Integer>() {
        @Override public void onStart() {
            System.out.println("Start!");
        }
        @Override public void onNext(Integer t) {
            if (t == 3) {
                dispose();
            }
            System.out.println(t);
        }
        @Override public void onError(Throwable t) {
            t.printStackTrace();
        }
        @Override public void onComplete() {
            System.out.println("Done!");
        }
    });
// ...
d.dispose();