sample_of_ConsumerSingleObserver.java

public final class ConsumerSingleObserver<T>
    extends AtomicReference<Disposable>
    implements SingleObserver<T>, 
               Disposable, 
               LambdaConsumerIntrospection {

    // ...

    @Override
    public void onSubscribe(Disposable d) {
        DisposableHelper.setOnce(this, d);
    }

    @Override
    public void onSuccess(T value) {
        lazySet(DisposableHelper.DISPOSED);
        try {
            onSuccess.accept(value);
        } catch (Throwable ex) {
            // ...
        }
    }

    @Override
    public void dispose() {
        DisposableHelper.dispose(this);
    }

    // ...
}