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

This example Akka source code file (SettingsExtensionDocTest.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, actorsystem, akka, circuit_breaker_timeout, concurrent, connection, db_uri, duration, settings, settingsimpl, settingsprovider, string, test, time

The SettingsExtensionDocTest.java Akka example source code

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

//#imports
import akka.actor.Extension;
import akka.actor.AbstractExtensionId;
import akka.actor.ExtensionIdProvider;
import akka.actor.ActorSystem;
import akka.actor.ExtendedActorSystem;
import scala.concurrent.duration.Duration;
import com.typesafe.config.Config;
import java.util.concurrent.TimeUnit;

//#imports

import akka.actor.UntypedActor;
import org.junit.Test;

public class SettingsExtensionDocTest {

  static
  //#extension
  public class SettingsImpl implements Extension {

    public final String DB_URI;
    public final Duration CIRCUIT_BREAKER_TIMEOUT;

    public SettingsImpl(Config config) {
      DB_URI = config.getString("myapp.db.uri");
      CIRCUIT_BREAKER_TIMEOUT =
        Duration.create(config.getDuration("myapp.circuit-breaker.timeout", 
          TimeUnit.MILLISECONDS), TimeUnit.MILLISECONDS);
    }

  }

  //#extension

  static
  //#extensionid
  public class Settings extends AbstractExtensionId<SettingsImpl>
    implements ExtensionIdProvider {
    public final static Settings SettingsProvider = new Settings();

    private Settings() {}

    public Settings lookup() {
      return Settings.SettingsProvider;
    }

    public SettingsImpl createExtension(ExtendedActorSystem system) {
      return new SettingsImpl(system.settings().config());
    }
  }

  //#extensionid

  static
  //#extension-usage-actor
  public class MyActor extends UntypedActor {
    // typically you would use static import of the Settings.SettingsProvider field
    final SettingsImpl settings =
      Settings.SettingsProvider.get(getContext().system());
    Connection connection =
      connect(settings.DB_URI, settings.CIRCUIT_BREAKER_TIMEOUT);

  //#extension-usage-actor

    public Connection connect(String dbUri, Duration circuitBreakerTimeout) {
      return new Connection();
    }

    public void onReceive(Object msg) {
    }
  //#extension-usage-actor
  }
  //#extension-usage-actor

  public static class Connection {
  }

  @Test
  public void demonstrateHowToCreateAndUseAnAkkaExtensionInJava() {
    final ActorSystem system = null;
    try {
      //#extension-usage
      // typically you would use static import of the Settings.SettingsProvider field
      String dbUri = Settings.SettingsProvider.get(system).DB_URI;
      //#extension-usage
    } catch (Exception e) {
      //do nothing
    }
  }

}