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

This example Akka source code file (NumberProcessorSpec.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

akka, concurrent, deliver, getnumber, int, numberprocessorspec, persistence, persistent, persistentchannelsettings, setnumber, string, subtract, test, testing, testprobe, time

The NumberProcessorSpec.scala Akka example source code

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

import scala.language.postfixOps

import com.typesafe.config._

import scala.concurrent.duration._

import akka.actor._
import akka.persistence._

import akka.testkit._

object NumberProcessorSpec {
  case class SetNumber(number: Int)
  case class Add(number: Int)
  case class Subtract(number: Int)
  case object DecrementAndGet
  case object GetNumber

  class NumberProcessorWithPersistentChannel(name: String) extends NamedProcessor(name) {
    var num = 0

    val channel = context.actorOf(PersistentChannel.props(channelId = "stable_id",
      PersistentChannelSettings(redeliverInterval = 30 seconds, redeliverMax = 15)),
      name = "myPersistentChannel")

    def receive = {
      case Persistent(SetNumber(number), _) ⇒ num = number
      case Persistent(Add(number), _)       ⇒ num = num + number
      case Persistent(Subtract(number), _)  ⇒ num = num - number
      case GetNumber                        ⇒ channel ! Deliver(Persistent(num), sender().path)
      case p @ Persistent(DecrementAndGet, _) ⇒
        num = num - 1
        channel ! Deliver(p.withPayload(num), sender().path)
    }
  }
}

/*
 * This test found the problem described in ticket #3933
 */
class NumberProcessorSpec extends AkkaSpec(PersistenceSpec.config("leveldb", "NumberProcessorSpec"))
  with PersistenceSpec {
  import NumberProcessorSpec._

  "A processor using a persistent channel" must {

    "resurrect with the correct state, not replaying confirmed messages to clients" in {
      val deliveredProbe = TestProbe()
      system.eventStream.subscribe(deliveredProbe.testActor, classOf[DeliveredByPersistentChannel])

      val probe = TestProbe()

      val processor = namedProcessor[NumberProcessorWithPersistentChannel]
      processor.tell(GetNumber, probe.testActor)

      val zero = probe.expectMsgType[ConfirmablePersistent]
      zero.confirm()
      zero.payload should equal(0)

      deliveredProbe.expectMsgType[DeliveredByPersistentChannel]

      processor.tell(Persistent(DecrementAndGet), probe.testActor)

      val decrementFrom0 = probe.expectMsgType[ConfirmablePersistent]
      decrementFrom0.confirm()
      decrementFrom0.payload should equal(-1)

      deliveredProbe.expectMsgType[DeliveredByPersistentChannel]

      watch(processor)
      system.stop(processor)
      expectMsgType[Terminated]

      val processorResurrected = namedProcessor[NumberProcessorWithPersistentChannel]
      processorResurrected.tell(Persistent(DecrementAndGet), probe.testActor)

      val decrementFromMinus1 = probe.expectMsgType[ConfirmablePersistent]
      decrementFromMinus1.confirm()
      decrementFromMinus1.payload should equal(-2)

      deliveredProbe.expectMsgType[DeliveredByPersistentChannel]
    }
  }
}