Akka/Scala example source code file (DispatcherDocTest.java)

This example Akka source code file (DispatcherDocTest.java) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Akka and Scala source code examples by using tags.

All credit for the original source code belongs to akka.io; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Akka tags/keywords

actorref, akka, concurrent, dispatch, dispatcherdoctest, event, exception, javatestkit, mycontrolmessage, object, override, suppresswarnings, test, testing, testkit, untypedactor

The DispatcherDocTest.java Akka example source code

/**
 * Copyright (C) 2009-2014 Typesafe Inc. <http://www.typesafe.com>
 */
package docs.dispatcher;

import akka.dispatch.ControlMessage;
import akka.dispatch.RequiresMessageQueue;
import akka.testkit.AkkaSpec;
import com.typesafe.config.ConfigFactory;
import docs.actor.MyBoundedUntypedActor;
import docs.actor.MyUntypedActor;
import org.junit.ClassRule;
import org.junit.Test;
import scala.concurrent.ExecutionContext;

//#imports
import akka.actor.*;
//#imports

//#imports-prio
import akka.event.Logging;
import akka.event.LoggingAdapter;

//#imports-prio

//#imports-prio-mailbox
import akka.dispatch.PriorityGenerator;
import akka.dispatch.UnboundedPriorityMailbox;
import akka.testkit.AkkaJUnitActorSystemResource;
import akka.testkit.JavaTestKit;
import com.typesafe.config.Config;

//#imports-prio-mailbox

//#imports-required-mailbox

//#imports-required-mailbox

public class DispatcherDocTest {

  @ClassRule
  public static AkkaJUnitActorSystemResource actorSystemResource =
    new AkkaJUnitActorSystemResource("DispatcherDocTest", ConfigFactory.parseString(
      DispatcherDocSpec.javaConfig()).withFallback(ConfigFactory.parseString(
      DispatcherDocSpec.config())).withFallback(AkkaSpec.testConf()));

  private final ActorSystem system = actorSystemResource.getSystem();

  @SuppressWarnings("unused")
  @Test
  public void defineDispatcherInConfig() {
    //#defining-dispatcher-in-config
    ActorRef myActor =
      system.actorOf(Props.create(MyUntypedActor.class),
        "myactor");
    //#defining-dispatcher-in-config
  }

  @SuppressWarnings("unused")
  @Test
  public void defineDispatcherInCode() {
    //#defining-dispatcher-in-code
    ActorRef myActor =
      system.actorOf(Props.create(MyUntypedActor.class).withDispatcher("my-dispatcher"),
        "myactor3");
    //#defining-dispatcher-in-code
  }

  @SuppressWarnings("unused")
  @Test
  public void definePinnedDispatcher() {
    //#defining-pinned-dispatcher
    ActorRef myActor = system.actorOf(Props.create(MyUntypedActor.class)
        .withDispatcher("my-pinned-dispatcher"));
    //#defining-pinned-dispatcher
  }
  
  @SuppressWarnings("unused")
  public void compileLookup() {
    //#lookup
    // this is scala.concurrent.ExecutionContext
    // for use with Futures, Scheduler, etc.
    final ExecutionContext ex = system.dispatchers().lookup("my-dispatcher");
    //#lookup
  }

  @SuppressWarnings("unused")
  @Test
  public void defineMailboxInConfig() {
    //#defining-mailbox-in-config
    ActorRef myActor =
      system.actorOf(Props.create(MyUntypedActor.class),
        "priomailboxactor");
    //#defining-mailbox-in-config
  }

  @SuppressWarnings("unused")
  @Test
  public void defineMailboxInCode() {
    //#defining-mailbox-in-code
    ActorRef myActor =
      system.actorOf(Props.create(MyUntypedActor.class)
        .withMailbox("prio-mailbox"));
    //#defining-mailbox-in-code
  }

  @SuppressWarnings("unused")
  @Test
  public void usingARequiredMailbox() {
    ActorRef myActor =
      system.actorOf(Props.create(MyBoundedUntypedActor.class));
  }

  @Test
  public void priorityDispatcher() throws Exception {
    JavaTestKit probe = new JavaTestKit(system);
    //#prio-dispatcher

    class Demo extends UntypedActor {
      LoggingAdapter log = Logging.getLogger(getContext().system(), this);
      {
        for (Object msg : new Object[] { "lowpriority", "lowpriority",
            "highpriority", "pigdog", "pigdog2", "pigdog3", "highpriority",
            PoisonPill.getInstance() }) {
          getSelf().tell(msg, getSelf());
        }
      }

      public void onReceive(Object message) {
        log.info(message.toString());
      }
    }

    // We create a new Actor that just prints out what it processes
    ActorRef myActor = system.actorOf(Props.create(Demo.class, this)
        .withDispatcher("prio-dispatcher"));

    /*
    Logs:
      'highpriority
      'highpriority
      'pigdog
      'pigdog2
      'pigdog3
      'lowpriority
      'lowpriority
    */
    //#prio-dispatcher

    probe.watch(myActor);
    probe.expectMsgClass(Terminated.class);
  }

  @Test
  public void controlAwareDispatcher() throws Exception {
    JavaTestKit probe = new JavaTestKit(system);
    //#control-aware-dispatcher

    class Demo extends UntypedActor {
      LoggingAdapter log = Logging.getLogger(getContext().system(), this);
      {
        for (Object msg : new Object[] { "foo", "bar", new MyControlMessage(),
                PoisonPill.getInstance() }) {
          getSelf().tell(msg, getSelf());
        }
      }

      public void onReceive(Object message) {
        log.info(message.toString());
      }
    }

    // We create a new Actor that just prints out what it processes
    ActorRef myActor = system.actorOf(Props.create(Demo.class, this)
            .withDispatcher("control-aware-dispatcher"));

    /*
    Logs:
      'MyControlMessage
      'foo
      'bar
    */
    //#control-aware-dispatcher

    probe.watch(myActor);
    probe.expectMsgClass(Terminated.class);
  }

  static
  //#prio-mailbox
  public class MyPrioMailbox extends UnboundedPriorityMailbox {
    // needed for reflective instantiation
    public MyPrioMailbox(ActorSystem.Settings settings, Config config) {
      // Create a new PriorityGenerator, lower prio means more important
      super(new PriorityGenerator() {
        @Override
        public int gen(Object message) {
          if (message.equals("highpriority"))
            return 0; // 'highpriority messages should be treated first if possible
          else if (message.equals("lowpriority"))
            return 2; // 'lowpriority messages should be treated last if possible
          else if (message.equals(PoisonPill.getInstance()))
            return 3; // PoisonPill when no other left
          else
            return 1; // By default they go between high and low prio
        }
      });
    }
  }
  //#prio-mailbox

  static
  //#control-aware-mailbox-messages
  public class MyControlMessage implements ControlMessage {}
  //#control-aware-mailbox-messages

  @Test
  public void requiredMailboxDispatcher() throws Exception {
    ActorRef myActor = system.actorOf(Props.create(MyUntypedActor.class)
      .withDispatcher("custom-dispatcher"));
  }

  static
  //#require-mailbox-on-actor
  public class MySpecialActor extends UntypedActor implements
    RequiresMessageQueue<MyUnboundedJMessageQueueSemantics> {
    //#require-mailbox-on-actor
    @Override
    public void onReceive(Object message) throws Exception {
      unhandled(message);
    }
    //#require-mailbox-on-actor
    // ...
  }
  //#require-mailbox-on-actor

  @Test
  public void requiredMailboxActor() throws Exception {
    ActorRef myActor = system.actorOf(Props.create(MySpecialActor.class));
  }

}