Beers.java

    Router router = Router.router(vertx);
    router
      .get("/beer")
      .handler(BodyHandler.create())
      .handler(beersHandlers::handleGetBeers);
    router
      .post("/beer")
      .handler(BodyHandler.create())
      .handler(beersHandlers::handlePostBeer);


  public void handleGetBeers(RoutingContext rc) {
    beersCircuitBreaker
      .execute(
        () -> beersServiceClient
          .rxGetBeersList()
          .flatMap(res -> res.statusCode() != 200 ? Single.error(new HttpStatusException(500, "Beers service error")) : Single.just(res))
      )
      .onErrorResumeNext(t -> Single.error(new HttpStatusException(503, "Beers service not available", t)))
      .flatMapObservable(httpResponse -> Observable.fromIterable(httpResponse.bodyAsJsonArray()))
      .map(o -> new io.slinkydeveloper.brewery.beers.client.models.Beer((JsonObject) o))
      .flatMapSingle(this::solveStyleAndBuildApiBeer)
      .collectInto(new JsonArray(), (j, apiBeer) -> j.add(apiBeer.toJson()))
      .subscribe(
        result ->
          rc
            .response()
            .setStatusCode(200)
            .putHeader("content-type", "application/json")
            .end(result.encode()),
        rc::fail
      );
  }

  public void handlePostBeer(RoutingContext rc) {
    JsonObject body = rc.getBodyAsJson();
    ((body.containsKey("style")) ? addBeerAndStyle(body) : addBeer(body))
      .subscribe(
        result ->
          rc
            .response()
            .setStatusCode(200)
            .putHeader("content-type", "application/json")
            .end(result.toJson().encode()),
        rc::fail
      );
  }