What should I use instead of the deprecated `Vertex#rxExecuteBlocking`, starting with Vert.x 4.5?

Question

Starting with Vert.x 4.5.0, Vertx#rxExecuteBlocking (and the signatures of executeBlocking that return a Maybe) are deprecated.

How should I go from a Vert.x Future (with Vertx#executeBlocking) to an RxJava Maybe (or an Observable)?

Answer 1

This isn't the answer I'm looking for, but is an answer nonetheless

I imagine that there must somewhere be a function that turns a Future to a Maybe or even an Observable straight away. That's what I'm looking for!

---

The option I figured out

Here's an option, although I'm not sure it is the most appropriate one:

Where you would get a Vert.x Future from some computation-intensive activity (such as Thread#sleep ) from a method defined as follows:

private static final Vertx VERTX = Vertx.vertx();

private static Future<String> compute() {
  return VERTX.executeBlocking(() -> {
    Thread.sleep(1000);
    return "Done.";
  });
}

You could get a Maybe like so:

final Maybe<String> maybe = MaybeHelper
  .toMaybe(handler -> compute().onComplete(handler));

---

As an additional note, I'd like to point out that the Maybe-to-Observable conversion seems to be trivially resolved using Maybe#toObservable, thus allowing the following way to obtain an Observable out of Vertx#executeBlocking:

final Observable<String> observable = MaybeHelper
  .toMaybe(handler -> compute().onComplete(handler))
  .toObservable();

---

Here's a small helper class that may assist you in converting a Vert.x Future to an RxJava Observable (which I think should exist in the vertx-rx-java3 package but I can't locate):

import io.reactivex.rxjava3.core.Observable;
import io.vertx.core.Future;
import io.vertx.rxjava3.MaybeHelper;

public class Observables {

  public static <T> Observable<T> from(final Future<T> future) {
    return MaybeHelper.<T>toMaybe(future::onComplete).toObservable();
  }

}

Answer 2

This is a bug that will be fixed in Vert.x 4.5.1