pekko-sample-cluster-java/src/main/java/sample/cluster/simple/App.java

package sample.cluster.simple;

import org.apache.pekko.actor.typed.ActorSystem;
import org.apache.pekko.actor.typed.Behavior;
import org.apache.pekko.actor.typed.javadsl.Behaviors;
import com.typesafe.config.Config;
import com.typesafe.config.ConfigFactory;

import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;

public class App {

  public static void main(String[] args) {
    if (args.length == 0) {
      startup(17356);
      startup(17357);
      startup(0);
    } else
      Arrays.stream(args).map(Integer::parseInt).forEach(App::startup);
  }

  private static Behavior<Void> rootBehavior() {
    return Behaviors.setup(context -> {

      // Create an actor that handles cluster domain events
      context.spawn(ClusterListener.create(), "ClusterListener");

      return Behaviors.empty();
    });
  }

  private static void startup(int port) {
    // Override the configuration of the port
    // Override the configuration of the port
    Map<String, Object> overrides = new HashMap<>();
    overrides.put("pekko.remote.artery.canonical.port", port);

    Config config = ConfigFactory.parseMap(overrides)
        .withFallback(ConfigFactory.load());

    // Create an Apache Pekko system
    ActorSystem<Void> system = ActorSystem.create(rootBehavior(), "ClusterSystem", config);
  }
}