incompatible types: Single<HttpServer> cannot be converted to Completable

Question

I am trying to use RxJava2 in Vert.x within a verticle:

import io.reactivex.Completable;
import io.vertx.core.Promise;

public class MainVerticle extends io.vertx.reactivex.core.AbstractVerticle {


  @Override
  public Completable rxStart() {
    return vertx.createHttpServer().requestHandler(req -> {
      req.response()
        .putHeader("content-type", "text/plain")
        .end("Hello from Vert.x!");
    })
      .rxListen(8080);

  }
}

The compile complains:

 error: incompatible types: Single<HttpServer> cannot be converted to Completable
      .rxListen(8080);
               ^
1 error

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':compileJava'.
> Compilation failed; see the compiler error output for details.

I do not know, which method I should call.

Answer 1

Single<HttpServer> rxListen(int port,String host)

returns an instance of Single not Completable from the question is not clear what you're trying to do but if you want to listen on a port you need to do something like this

public class MyVerticle extends AbstractVerticle {

 private HttpServer server;

 public void start(Future<Void> startFuture) {
   server = vertx.createHttpServer().requestHandler(req -> {
     req.response()
       .putHeader("content-type", "text/plain")
       .end("Hello from Vert.x!");
     });

   // Now bind the server:
   server.listen(8080, res -> {
     if (res.succeeded()) {
       startFuture.complete();
     } else {
       startFuture.fail(res.cause());
     }
   });
 }
}

if you want to work with Completable you need to subscribe to the server and call the method rxClose

 Completable single = server.rxClose();

    // Subscribe to bind the server
    single.
      subscribe(
        () -> {
          // Server is closed
        },
        failure -> {
          // Server closed but encoutered issue
        }
      );