SmallRye Reactive Messaging's Emitter.send doesn't send in Kotlin via AMQP broker with Quarkus

问题

Currently, I am trying to write a 'notification service' based on Maven, Quarkus and SmallRye Reactive Messaging in Kotlin. As a base I have an example in Java which works fine and I was trying to "translate" it into Kotlin.

The way I want it to work is, that I send an HTTP request (e.g. GET http://localhost:8080/search/{word}) and the system sends the 'word' (here a String) to the queue 'queries' of the Artemis AMQP message Broker. Another system subscribes to the message Broker and fetches the 'word' in the queue 'queries' upon HTTP request (e.g. GET http://localhost:8080/receiver).

In Kotlin, however, it doesn't work and my best guess is, that the Emitter, doesn't send the 'word' unlike in Java.

Here the code I am using:

Kotlin

Sending

import io.smallrye.reactive.messaging.annotations.Emitter
import io.smallrye.reactive.messaging.annotations.Stream
import javax.ws.rs.GET
import javax.ws.rs.Path
import javax.ws.rs.PathParam


@Path("/search")
class ExampleService {


    @Stream("queries")
    val queryEmitter: Emitter<String>? = null



    @GET
    @Path("/{word}")
    fun search(@PathParam("word") word: String?): String {

        println("about to send word: " + word!!)

        if (word.isNotEmpty()) {

            var qE=queryEmitter?.send(word)
            println("Emitter return : $qE")
            return word
        }
        return "word was empty"
    }


}

Receiving

import org.eclipse.microprofile.reactive.messaging.Incoming
import javax.ws.rs.GET
import javax.ws.rs.Path
import javax.ws.rs.Produces
import javax.ws.rs.core.MediaType


@Path("/receiver")
class AdsResource {


    var word : String = "nothing happened so far"

    @GET
    @Produces(MediaType.TEXT_PLAIN)
    fun getWords(): String {
        return word
    }


    @Incoming("sink")
    fun consume(message: String) {
        println("got user query: $message")
        word = message
    }
}

And here is the Java version

Sending

import io.smallrye.reactive.messaging.annotations.Emitter;
import io.smallrye.reactive.messaging.annotations.Stream;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;



@Path("/search")
public class SearchEndpoint {

    @Stream("queries")
    Emitter<String> queryEmitter;


    @GET
    @Path("/{word}")
    public String search(@PathParam("word") String word) {

        System.out.println("about to send word: " + word);

        if (!word.isEmpty()) {

            Emitter<String> qE = queryEmitter.send(word);
            System.out.println("Emitter return: " + qE);
            return word;
        }

        return "word was empty" ;
    }

}

Receiving

import org.eclipse.microprofile.reactive.messaging.Incoming;
import javax.ws.rs.GET;
import javax.ws.rs.Path;


@Path("/receiver")
public class AdsResource {

   private String word = "";


   @GET
   public String getAd() {
      System.out.println("got user query: " + word);
      return word;
   }
   @Incoming("sink")
   public void consume(String message) {
      System.out.println("got user query: " + message);
      word = message;
   }


}

Here for the configuration files 'application.properties" for both Kotlin and Java

# Configures the AMQP broker credentials.
amqp-username=quarkus
amqp-password=quarkus

# Configure the AMQP connector to write to the `queries `  address
mp.messaging.outgoing.queries.connector=smallrye-amqp
mp.messaging.outgoing.queries.address=sink
mp.messaging.outgoing.queries.durable=true


# Configure the AMQP connector to read from the `queries ` queue
mp.messaging.incoming.sink.connector=smallrye-amqp
mp.messaging.incoming.sink.durable=true

Some information: