サンプルコード in "プログラミング言語のパラダイムシフトーScalaから見る関数型と並列性時代の幕開けー http://www.slideshare.net/TanUkkii/functional-and-concurencyinscala"

gistfile1.scala

import akka.actor._
import akka.routing.{SmallestMailboxPool}
import akka.testkit.{TestKit, ImplicitSender}
import com.typesafe.config.ConfigFactory
import jp.trifort.ifu.StopSystemAfterAll
import org.scalatest.{MustMatchers, WordSpecLike}
import scala.concurrent.{Await, Future}
import akka.util.Timeout
import scala.concurrent.duration._

class CountAActor extends Actor {
  var totalA = 0
  def receive: Receive = {
    case "How many?" => sender ! totalA
    case text: String => totalA += text.toUpperCase().count(_ == 'A')
  }
}

object CountAActor {
  def props = Props(new CountAActor)
}

trait RouterCreator {
  def createRouter = SmallestMailboxPool(100).props(CountAActor.props)
}

class CountARouter extends Actor with RouterCreator {
  val countARouter = context.actorOf(createRouter)
  def receive: Receive = {
    case hm@"How many?" => {
      import akka.routing.Broadcast
      val reducer = context.actorOf(Reducer.props(sender(), 100))
      countARouter.tell(Broadcast(hm), reducer)
    }
    case msg => countARouter forward msg
  }
}

object CountARouter {
  def props = Props(new CountARouter)
}

class Reducer(sendTo: ActorRef, maxCount: Int) extends Actor {
  var total = 0; var count = 0
  def receive: Receive = {
    case sum: Int => {
      total += sum; count += 1
      if (count == maxCount) {
        sendTo ! total
        self ! PoisonPill
      }
    }
  }
}

object Reducer {
  def props(sendTo: ActorRef, maxCount: Int) = Props(new Reducer(sendTo, maxCount))
}


class CrashActor extends Actor with ActorLogging {
  def receive: Receive = {
    case "Crash!!!" => throw new Exception("crashed!")
  }

  override def preStart() {
    log.info("preStart")
  }

  override def preRestart(reason: Throwable, message: Option[Any]) = {
    log.info("preRestart")
    super.preRestart(reason, message)
  }

  override def postRestart(reason: Throwable) {
    log.info("postRestart")
    super.postRestart(reason)
  }

  override def postStop() {
    log.info("postStop")
  }
}

object CrashActor {
  def props = Props(new CrashActor)
}

class Supervisor extends Actor {
  val crashActor = context.actorOf(CrashActor.props)

  def receive: Receive = {
    case msg => crashActor forward msg
  }
}

object Supervisor {
  def props = Props(new Supervisor)
}

class SampleTest extends TestKit(ActorSystem("SampleSystem", ConfigFactory.empty()))
with WordSpecLike with MustMatchers with ImplicitSender with StopSystemAfterAll {

  "Future" must {
    import scala.concurrent.ExecutionContext.Implicits.global
    "map and flatMap" in {
      val futureMessage = Future {
        Thread.sleep(1000); 1
      }.flatMap(value => Future {
        Thread.sleep(1000); value + 1
      }).map(s => s"This is a value of future after $s seconds")
      Await.result(futureMessage, 5 seconds) must be("This is a value of future after 2 seconds")
    }
    "for comprehension" in {
      val futureMessage = for {
        s1 <- Future {
          Thread.sleep(1000); 1
        }
        s2 <- Future {
          Thread.sleep(1000); s1 + 1
        }
      } yield s"This is a value of future after $s2 seconds"
      Await.result(futureMessage, 5 seconds) must be("This is a value of future after 2 seconds")
    }
  }

  "parallel collection" must {
    "behave same as standard one" in {
      val list = (0 to 9999).toList
      list.map(_ + 1).filter(_ % 2 == 0).fold(0)(_ + _) must be
      list.par.map(_ + 1).filter(_ % 2 == 0).fold(0)(_ + _)
    }
  }

  "CountAActor" must {
    "count A and a" in {
      val countAActor = system.actorOf(CountAActor.props, "countAActor")
      countAActor ! "na" * 16
      countAActor ! "BATMAN!"
      countAActor ! "How many?"
      expectMsg(18)
    }

    "count A and a in parallel" in {
      implicit val dispatcher =  system.dispatcher
      implicit val timeout = Timeout(5 seconds)
      import akka.pattern.ask
      val countAActor1 = system.actorOf(CountAActor.props, "countAActor1")
      val countAActor2 = system.actorOf(CountAActor.props, "countAActor2")
      countAActor1 ! "na" * 16
      countAActor2 ! "BATMAN!"
      val futures = Seq(countAActor1, countAActor2).map(_ ? "How many?").map(_.mapTo[Int])
      val result = Future.sequence(futures).map(_.reduce(_ + _))
      Await.result(result, 5 seconds) must be(18)
    }
  }

  "Router" must {
    "route messages" in {
      val router = system.actorOf(CountARouter.props, "CountARouter")
      Stream.fill(10000)("BATMAN!").foreach(router ! _)
      router ! "How many?"
      expectMsg(10000 * 2)
    }
  }

  "Supervisor" must {
    "crush CrashActor" in {
      val supervisor = system.actorOf(Supervisor.props, "supervisor")
      supervisor ! "Crash!!!"
      Thread.sleep(1000)
    }
  }
}