2011-11-11 19:57:27 +01:00
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// /**
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// * Copyright (C) 2009-2011 Typesafe Inc. <http://www.typesafe.com>
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// */
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// //#imports
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// package akka.tutorial.first.scala
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// import akka.actor.{ Actor, ActorSystem, PoisonPill }
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// import akka.routing.Routing.Broadcast
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// import akka.routing.{ RoutedProps, Routing }
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// import java.util.concurrent.CountDownLatch
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// //#imports
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// //#app
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// object Pi extends App {
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// val app = ActorSystem()
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// calculate(nrOfWorkers = 4, nrOfElements = 10000, nrOfMessages = 10000)
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// //#actors-and-messages
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// // ====================
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// // ===== Messages =====
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// // ====================
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// //#messages
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// sealed trait PiMessage
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// case object Calculate extends PiMessage
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// case class Work(start: Int, nrOfElements: Int) extends PiMessage
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// case class Result(value: Double) extends PiMessage
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// //#messages
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// // ==================
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// // ===== Worker =====
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// // ==================
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// //#worker
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// class Worker extends Actor {
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// // define the work
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// //#calculatePiFor
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// def calculatePiFor(start: Int, nrOfElements: Int): Double = {
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// var acc = 0.0
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// for (i ← start until (start + nrOfElements))
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// acc += 4.0 * (1 - (i % 2) * 2) / (2 * i + 1)
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// acc
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// }
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// //#calculatePiFor
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// def receive = {
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// case Work(start, nrOfElements) ⇒ sender ! Result(calculatePiFor(start, nrOfElements)) // perform the work
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// }
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// }
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// //#worker
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// // ==================
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// // ===== Master =====
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// // ==================
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// //#master
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// class Master(nrOfWorkers: Int, nrOfMessages: Int, nrOfElements: Int, latch: CountDownLatch) extends Actor {
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// var pi: Double = _
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// var nrOfResults: Int = _
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// var start: Long = _
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// //#create-workers
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// // create the workers
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// val workers = Vector.fill(nrOfWorkers)(app.actorOf[Worker])
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// // wrap them with a load-balancing router
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// val router = app.actorOf(RoutedProps().withRoundRobinRouter.withLocalConnections(workers), "pi")
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// //#create-workers
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// //#master-receive
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// // message handler
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// def receive = {
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// //#handle-messages
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// case Calculate ⇒
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// // schedule work
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// for (i ← 0 until nrOfMessages) router ! Work(i * nrOfElements, nrOfElements)
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// // send a PoisonPill to all workers telling them to shut down themselves
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// router ! Broadcast(PoisonPill)
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// // send a PoisonPill to the router, telling him to shut himself down
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// router ! PoisonPill
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// case Result(value) ⇒
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// // handle result from the worker
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// pi += value
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// nrOfResults += 1
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// if (nrOfResults == nrOfMessages) self.stop()
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// //#handle-messages
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// }
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// //#master-receive
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// override def preStart() {
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// start = System.currentTimeMillis
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// }
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// override def postStop() {
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// // tell the world that the calculation is complete
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// println(
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// "\n\tPi estimate: \t\t%s\n\tCalculation time: \t%s millis"
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// .format(pi, (System.currentTimeMillis - start)))
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// latch.countDown()
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// }
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// }
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// //#master
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// //#actors-and-messages
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// // ==================
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// // ===== Run it =====
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// // ==================
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// def calculate(nrOfWorkers: Int, nrOfElements: Int, nrOfMessages: Int) {
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// // this latch is only plumbing to know when the calculation is completed
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// val latch = new CountDownLatch(1)
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// // create the master
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// val master = app.actorOf(new Master(nrOfWorkers, nrOfMessages, nrOfElements, latch))
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// // start the calculation
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// master ! Calculate
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// // wait for master to shut down
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// latch.await()
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// }
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// }
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// //#app
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