111 lines
3.1 KiB
Scala
111 lines
3.1 KiB
Scala
/**
|
|
* Copyright (C) 2009-2011 Typesafe Inc. <http://www.typesafe.com>
|
|
*/
|
|
package akka.tutorial.first.scala
|
|
|
|
import java.util.concurrent.CountDownLatch
|
|
import akka.actor._
|
|
import akka.routing._
|
|
import com.typesafe.config.{ ConfigFactory, Config }
|
|
|
|
object Pi extends App {
|
|
|
|
// Initiate the calculation
|
|
calculate(nrOfWorkers = 4, nrOfElements = 10000, nrOfMessages = 10000)
|
|
|
|
// ====================
|
|
// ===== Messages =====
|
|
// ====================
|
|
sealed trait PiMessage
|
|
|
|
case object Calculate extends PiMessage
|
|
|
|
case class Work(start: Int, nrOfElements: Int) extends PiMessage
|
|
|
|
case class Result(value: Double) extends PiMessage
|
|
|
|
// ==================
|
|
// ===== Worker =====
|
|
// ==================
|
|
class Worker extends Actor {
|
|
|
|
// define the work
|
|
def calculatePiFor(start: Int, nrOfElements: Int): Double = {
|
|
var acc = 0.0
|
|
for (i ← start until (start + nrOfElements))
|
|
acc += 4.0 * (1 - (i % 2) * 2) / (2 * i + 1)
|
|
acc
|
|
}
|
|
|
|
def receive = {
|
|
case Work(start, nrOfElements) ⇒
|
|
sender ! Result(calculatePiFor(start, nrOfElements)) // perform the work
|
|
}
|
|
}
|
|
|
|
// ==================
|
|
// ===== Master =====
|
|
// ==================
|
|
class Master(nrOfWorkers: Int, nrOfMessages: Int, nrOfElements: Int, latch: CountDownLatch)
|
|
extends Actor {
|
|
|
|
var pi: Double = _
|
|
var nrOfResults: Int = _
|
|
var start: Long = _
|
|
|
|
// create the workers
|
|
val workers = Vector.fill(nrOfWorkers)(context.actorOf[Worker])
|
|
|
|
// create a round robin router for the workers
|
|
val router = context.actorOf(Props(new Worker).withRouting(RoundRobinRouter(nrOfInstances = 5)), "pi")
|
|
//val router = context.actorOf(Props(new Worker).withRouting(RoundRobinRouter(nrOfInstances = 3, targets = Seq(workers.head, workers.tail.head))), "pi")
|
|
|
|
// message handler
|
|
def receive = {
|
|
case Calculate ⇒
|
|
// schedule work
|
|
for (i ← 0 until nrOfMessages) router ! Work(i * nrOfElements, nrOfElements)
|
|
case Result(value) ⇒
|
|
// handle result from the worker
|
|
pi += value
|
|
nrOfResults += 1
|
|
|
|
// Stop this actor and all its supervised children
|
|
if (nrOfResults == nrOfMessages) self.stop()
|
|
}
|
|
|
|
override def preStart() {
|
|
start = System.currentTimeMillis
|
|
}
|
|
|
|
override def postStop() {
|
|
// tell the world that the calculation is complete
|
|
println(
|
|
"\n\tPi estimate: \t\t%s\n\tCalculation time: \t%s millis"
|
|
.format(pi, (System.currentTimeMillis - start)))
|
|
latch.countDown()
|
|
}
|
|
}
|
|
|
|
// ==================
|
|
// ===== Run it =====
|
|
// ==================
|
|
def calculate(nrOfWorkers: Int, nrOfElements: Int, nrOfMessages: Int) {
|
|
val system = ActorSystem("PiSystem", ConfigFactory.load("akka.conf"))
|
|
|
|
// this latch is only plumbing to know when the calculation is completed
|
|
val latch = new CountDownLatch(1)
|
|
|
|
// create the master
|
|
val master = system.actorOf(Props(new Master(nrOfWorkers, nrOfMessages, nrOfElements, latch)), "master")
|
|
|
|
// start the calculation
|
|
master ! Calculate
|
|
|
|
// wait for master to shut down
|
|
latch.await()
|
|
|
|
// Shut down the system
|
|
system.stop()
|
|
}
|
|
}
|