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

This example Akka source code file (ActorLifeCycleSpec.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, akka, atomicinteger, become, concurrent, duration, eventfilter, kill, ok, oneforonestrategy, props, string, test, testing, throwable, time

The ActorLifeCycleSpec.scala Akka example source code

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

package akka.actor

import language.postfixOps

import org.scalatest.BeforeAndAfterEach
import org.scalatest.Matchers

import akka.actor.Actor._
import akka.testkit._
import scala.concurrent.duration._
import java.util.concurrent.atomic._
import scala.concurrent.Await
import akka.pattern.ask
import java.util.UUID.{ randomUUID ⇒ newUuid }

object ActorLifeCycleSpec {

  class LifeCycleTestActor(testActor: ActorRef, id: String, generationProvider: AtomicInteger) extends Actor {
    def report(msg: Any) = testActor ! message(msg)
    def message(msg: Any): Tuple3[Any, String, Int] = (msg, id, currentGen)
    val currentGen = generationProvider.getAndIncrement()
    override def preStart() { report("preStart") }
    override def postStop() { report("postStop") }
    def receive = { case "status" ⇒ sender() ! message("OK") }
  }

}

@org.junit.runner.RunWith(classOf[org.scalatest.junit.JUnitRunner])
class ActorLifeCycleSpec extends AkkaSpec("akka.actor.serialize-messages=off") with BeforeAndAfterEach with ImplicitSender with DefaultTimeout {
  import ActorLifeCycleSpec._

  "An Actor" must {

    "invoke preRestart, preStart, postRestart when using OneForOneStrategy" in {
      filterException[ActorKilledException] {
        val id = newUuid.toString
        val supervisor = system.actorOf(Props(classOf[Supervisor], OneForOneStrategy(maxNrOfRetries = 3)(List(classOf[Exception]))))
        val gen = new AtomicInteger(0)
        val restarterProps = Props(new LifeCycleTestActor(testActor, id, gen) {
          override def preRestart(reason: Throwable, message: Option[Any]) { report("preRestart") }
          override def postRestart(reason: Throwable) { report("postRestart") }
        }).withDeploy(Deploy.local)
        val restarter = Await.result((supervisor ? restarterProps).mapTo[ActorRef], timeout.duration)

        expectMsg(("preStart", id, 0))
        restarter ! Kill
        expectMsg(("preRestart", id, 0))
        expectMsg(("postRestart", id, 1))
        restarter ! "status"
        expectMsg(("OK", id, 1))
        restarter ! Kill
        expectMsg(("preRestart", id, 1))
        expectMsg(("postRestart", id, 2))
        restarter ! "status"
        expectMsg(("OK", id, 2))
        restarter ! Kill
        expectMsg(("preRestart", id, 2))
        expectMsg(("postRestart", id, 3))
        restarter ! "status"
        expectMsg(("OK", id, 3))
        restarter ! Kill
        expectMsg(("postStop", id, 3))
        expectNoMsg(1 seconds)
        system.stop(supervisor)
      }
    }

    "default for preRestart and postRestart is to call postStop and preStart respectively" in {
      filterException[ActorKilledException] {
        val id = newUuid().toString
        val supervisor = system.actorOf(Props(classOf[Supervisor], OneForOneStrategy(maxNrOfRetries = 3)(List(classOf[Exception]))))
        val gen = new AtomicInteger(0)
        val restarterProps = Props(classOf[LifeCycleTestActor], testActor, id, gen)
        val restarter = Await.result((supervisor ? restarterProps).mapTo[ActorRef], timeout.duration)

        expectMsg(("preStart", id, 0))
        restarter ! Kill
        expectMsg(("postStop", id, 0))
        expectMsg(("preStart", id, 1))
        restarter ! "status"
        expectMsg(("OK", id, 1))
        restarter ! Kill
        expectMsg(("postStop", id, 1))
        expectMsg(("preStart", id, 2))
        restarter ! "status"
        expectMsg(("OK", id, 2))
        restarter ! Kill
        expectMsg(("postStop", id, 2))
        expectMsg(("preStart", id, 3))
        restarter ! "status"
        expectMsg(("OK", id, 3))
        restarter ! Kill
        expectMsg(("postStop", id, 3))
        expectNoMsg(1 seconds)
        system.stop(supervisor)
      }
    }

    "not invoke preRestart and postRestart when never restarted using OneForOneStrategy" in {
      val id = newUuid().toString
      val supervisor = system.actorOf(Props(classOf[Supervisor],
        OneForOneStrategy(maxNrOfRetries = 3)(List(classOf[Exception]))))
      val gen = new AtomicInteger(0)
      val props = Props(classOf[LifeCycleTestActor], testActor, id, gen)
      val a = Await.result((supervisor ? props).mapTo[ActorRef], timeout.duration)
      expectMsg(("preStart", id, 0))
      a ! "status"
      expectMsg(("OK", id, 0))
      system.stop(a)
      expectMsg(("postStop", id, 0))
      expectNoMsg(1 seconds)
      system.stop(supervisor)
    }

    "log failues in postStop" in {
      val a = system.actorOf(Props(new Actor {
        def receive = Actor.emptyBehavior
        override def postStop { throw new Exception("hurrah") }
      }))
      EventFilter[Exception]("hurrah", occurrences = 1) intercept {
        a ! PoisonPill
      }
    }

    "clear the behavior stack upon restart" in {
      final case class Become(recv: ActorContext ⇒ Receive)
      val a = system.actorOf(Props(new Actor {
        def receive = {
          case Become(beh) ⇒ { context.become(beh(context), discardOld = false); sender() ! "ok" }
          case x           ⇒ sender() ! 42
        }
      }))
      a ! "hello"
      expectMsg(42)
      a ! Become(ctx ⇒ {
        case "fail" ⇒ throw new RuntimeException("buh")
        case x      ⇒ ctx.sender() ! 43
      })
      expectMsg("ok")
      a ! "hello"
      expectMsg(43)
      EventFilter[RuntimeException]("buh", occurrences = 1) intercept {
        a ! "fail"
      }
      a ! "hello"
      expectMsg(42)
    }
  }

}