Akka/Scala example source code file (Main.scala)

This example Akka source code file (Main.scala) 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, actorlogging, actorref, actorsystem, akka, array, main, nonfatal, terminated, terminator, unit, utilities

The Main.scala Akka example source code

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

package akka

import akka.actor.ActorSystem
import akka.actor.ExtendedActorSystem
import akka.actor.Actor
import akka.actor.Terminated
import akka.actor.ActorLogging
import akka.actor.Props
import akka.actor.ActorRef
import scala.util.control.NonFatal

/**
 * Main class to start an [[akka.actor.ActorSystem]] with one
 * top level application supervisor actor. It will shutdown
 * the actor system when the top level actor is terminated.
 */
object Main {

  /**
   * @param args one argument: the class of the application supervisor actor
   */
  def main(args: Array[String]): Unit = {
    if (args.length != 1) {
      println("you need to provide exactly one argument: the class of the application supervisor actor")
    } else {
      val system = ActorSystem("Main")
      try {
        val appClass = system.asInstanceOf[ExtendedActorSystem].dynamicAccess.getClassFor[Actor](args(0)).get
        val app = system.actorOf(Props(appClass), "app")
        val terminator = system.actorOf(Props(classOf[Terminator], app), "app-terminator")
      } catch {
        case NonFatal(e) ⇒ system.shutdown(); throw e
      }
    }
  }

  class Terminator(app: ActorRef) extends Actor with ActorLogging {
    context watch app
    def receive = {
      case Terminated(_) ⇒
        log.info("application supervisor has terminated, shutting down")
        context.system.shutdown()
    }
  }

}