Main.java

package io.vertx.core;

import io.netty.channel.EventLoop;
import io.vertx.core.internal.ContextInternal;
import io.vertx.core.internal.VertxInternal;

public class Main {

  public static void main(String[] args) {

    // From netty/vertx event loop thread

    // Netty
    // Vertx
    // Observability
    // Application

    // Vertx -> Application

    // Dispatch on the correct thread : event-loop / worker / virtual thread

    Runnable application = () -> {
      // Application code
      System.out.println(Thread.currentThread() + " - " + Vertx.currentContext());
    };

    VertxInternal vertx = (VertxInternal) Vertx.vertx();

    ContextInternal context = vertx.createWorkerContext();

    EventLoop eventLoop = context.nettyEventLoop();

    eventLoop.execute(() -> {

      // Emit == execute + dispatch
      // runContextContext == execute + dispatch but always schedule a task

      // Like an IO call

      // We enter vertx

      // Vertx running on event-loop -- message passing -> Vertx running on worker thread - Application on worker
      // Vertx running on worker thread -- message passing -> Vertx running on event loop

      // Observability here
      // tracing

      // Application dispatch
      context.dispatch(application);

      // Message passing
      context.execute(() -> {
        // We are on application thread but no context association yet

        application.run();

        // Application dispatch
        context.dispatch(application);
      });
    });


  }

}