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

This example Akka source code file (LoggingDocTest.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

actor, actorref, actorsystem, akka, event, mysystem, object, override, received, starting, test, testing, testkit, untypedactor, warning

The LoggingDocTest.java Akka example source code

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

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

//#imports

//#imports-listener
import akka.event.Logging.InitializeLogger;
import akka.event.Logging.Error;
import akka.event.Logging.Warning;
import akka.event.Logging.Info;
import akka.event.Logging.Debug;

//#imports-listener

import org.junit.Test;
import akka.testkit.JavaTestKit;
import scala.Option;

//#imports-mdc
import akka.event.Logging;
import akka.event.DiagnosticLoggingAdapter;
import java.util.HashMap;
import java.util.Map;
//#imports-mdc

//#imports-deadletter
import akka.actor.Props;
import akka.actor.ActorRef;
import akka.actor.ActorSystem;
import akka.actor.UntypedActor;
import akka.actor.DeadLetter;
//#imports-deadletter

public class LoggingDocTest {
  
  @Test
  public void useLoggingActor() {
    ActorSystem system = ActorSystem.create("MySystem");
    ActorRef myActor = system.actorOf(Props.create(MyActor.class, this));
    myActor.tell("test", ActorRef.noSender());
    JavaTestKit.shutdownActorSystem(system);
  }

  @Test
  public void useLoggingActorWithMDC() {
    ActorSystem system = ActorSystem.create("MyDiagnosticSystem");
    ActorRef mdcActor = system.actorOf(Props.create(MdcActor.class, this));
    mdcActor.tell("some request", ActorRef.noSender());
    JavaTestKit.shutdownActorSystem(system);
  }

  @Test
  public void subscribeToDeadLetters() {
    //#deadletters
    final ActorSystem system = ActorSystem.create("DeadLetters");
    final ActorRef actor = system.actorOf(Props.create(DeadLetterActor.class));
    system.eventStream().subscribe(actor, DeadLetter.class);
    //#deadletters
    JavaTestKit.shutdownActorSystem(system);
  }
  
  @Test
  public void demonstrateMultipleArgs() {
    final ActorSystem system = ActorSystem.create("multiArg");
    //#array
    final Object[] args = new Object[] { "The", "brown", "fox", "jumps", 42 };
    system.log().debug("five parameters: {}, {}, {}, {}, {}", args);
    //#array
    JavaTestKit.shutdownActorSystem(system);
  }

  //#my-actor
  class MyActor extends UntypedActor {
    LoggingAdapter log = Logging.getLogger(getContext().system(), this);

    @Override
    public void preStart() {
      log.debug("Starting");
    }

    @Override
    public void preRestart(Throwable reason, Option<Object> message) {
      log.error(reason, "Restarting due to [{}] when processing [{}]",
        reason.getMessage(), message.isDefined() ? message.get() : "");
    }

    public void onReceive(Object message) {
      if (message.equals("test")) {
        log.info("Received test");
      } else {
        log.warning("Received unknown message: {}", message);
      }
    }
  }

  //#my-actor

  //#mdc-actor
  class MdcActor extends UntypedActor {

      final DiagnosticLoggingAdapter log = Logging.getLogger(this);

      public void onReceive(Object message) {

          Map<String, Object> mdc;
          mdc = new HashMap<String, Object>();
          mdc.put("requestId", 1234);
          mdc.put("visitorId", 5678);
          log.setMDC(mdc);

          log.info("Starting new request");

          log.clearMDC();
      }
  }

  //#mdc-actor

  //#my-event-listener
  class MyEventListener extends UntypedActor {
    public void onReceive(Object message) {
      if (message instanceof InitializeLogger) {
        getSender().tell(Logging.loggerInitialized(), getSelf());
      } else if (message instanceof Error) {
        // ...
      } else if (message instanceof Warning) {
        // ...
      } else if (message instanceof Info) {
        // ...
      } else if (message instanceof Debug) {
        // ...
      }
    }
  }
  //#my-event-listener

  static
  //#deadletter-actor
  public class DeadLetterActor extends UntypedActor {
    public void onReceive(Object message) {
      if (message instanceof DeadLetter) {
        System.out.println(message);
      }
    }
  }
  //#deadletter-actor
}