akka简单示例-2

手动敲了一遍计算pi的示例：http://www.gtan.com/akka_doc/intro/getting-started-first-scala.html

有个笔误，花了半个小时定位。

 1 [Torstani@sparkb5-i ~/akka_example/pi]$ cat src/Pi.scala

 2 package akka.tutorial.first.scala

 3 import akka.actor._

 4 import akka.routing.RoundRobinRouter

 5 import scala.concurrent.duration._

 6 

 7 object Pi extends App{

 8         calculate(nrOfWorkers=4, nrOfElements=1000, nrOfMessages=10000)

 9         sealed trait PiMessage

10         case object Calculate extends PiMessage

11         case class Work(stat:Int, nrOfElements: Int) extends PiMessage

12         case class Result(value: Double) extends PiMessage

13         case class PiApproximation(pi: Double, duration: Duration)

14 

15         class Worker extends Actor{

16                 def calculatePiFor(start: Int, nrOfElements: Int):Double = {

17                         var acc = 0.0

18                         for(i<- start until (start + nrOfElements))

19                                 acc += 4.0 * (1 - (i%2) * 2) / (2 * i + 1)

20                         acc

21                 }

22                 def receive = {

23                         case Work(start, nrOfElements) =>

24                                 //println("worker received "+start + ":"+nrOfElements)

25                                 val res = calculatePiFor(start, nrOfElements)

26                                 sender ! Result(res)

27                                 //println("worker send result: "+res)

28                 }

29         }

30 

31         class Master(nrOfWorkers:Int, nrOfMessages:Int, nrOfElements: Int, listener: ActorRef) extends Actor {

32                 var pi:Double = _

33                 var nrOfResults:Int= _

34                 val start:Long = System.currentTimeMillis

35 

36                 val workerRouter = context.actorOf(

37                         Props[Worker].withRouter(RoundRobinRouter(nrOfWorkers)), name="workerRouter")

38                 def receive = {

39                         case Calculate =>

40                                 //println("master receive Calculate")

41                                 for(i <- 0 until nrOfMessages) 

42                                         workerRouter ! Work(i*nrOfElements, nrOfElements)

43                         case Result(value) =>

44                                 //println("master recieve result: "+value)

45                                 pi += value

46                                 nrOfResults += 1

47                                 if(nrOfResults == nrOfMessages){

48                                         listener ! PiApproximation(pi, duration=(System.currentTimeMillis - start).millis)

49                                         context.stop(self)

50                                 }

51                 }

52         }

53         class Listener extends Actor{

54                 def receive = {

55                         case PiApproximation(pi, duration) =>

56                                 println("\tpi approximation: \t\t%s\n\tCalculation time: \t%s".format(pi, duration))

57                         context.system.shutdown()

58                 }

59         }

60         def calculate(nrOfWorkers:Int, nrOfElements:Int, nrOfMessages:Int) = {

61                 val system = ActorSystem("PiSystem")

62                 val listener = system.actorOf(Props[Listener], name="listener")

63                 val master = system.actorOf(Props(new Master(nrOfWorkers, nrOfMessages, nrOfElements, listener)), name="master")

64                 master ! Calculate

65         }

66 }

 1 [Torstan@sparkb5-i ~/akka_example/pi]$ cat Makefile 

 2 SRC_DIR := src

 3 SRC := $(shell find ${SRC_DIR} -name "*.scala")

 4 DIR=remote

 5 

 6 TARGET := HelloRemote.jar

 7 

 8 SCALAC := scalac 

 9 SCFLAGS := /usr/local/scala-2.10.4/lib/akka-actors.jar  

10 

11 .PHONY: all clean

12 

13 all: ${TARGET}

14 

15 ${TARGET}: ${SRC}

16         ${SCALAC} -cp ${SCFLAGS} $^

17 

18 clean:

19         ${RM} -r ${TARGET} ${DIR}

1 [Torstan@sparkb5-i ~/akka_example/pi]$ cat run.sh 

2 #!/bin/bash

3 

4 AKKA_LIB_PATH="/usr/local/akka-2.1.4/lib/akka/"

5 

6 java -cp \

7  .:/usr/local/scala-2.10.4/lib/scala-library.jar:/usr/local/scala-2.10.4/lib/akka-actors.jar:/usr/local/scala-2.10.4/lib/typesafe-config.jar:${AKKA_LIB_PATH}/akka-remote_2.10-2.1.4.jar:${AKKA_LIB_PATH}/protobuf-java-2.4.1.jar:${AKKA_LIB_PATH}/netty-3.5.8.Final.jar \

8 akka.tutorial.first.scala.Pi

执行结果：

[Torstan@sparkb5-i ~/akka_example/pi]$ ./run.sh
pi approximation: 3.1415925535897866
Calculation time: 383 milliseconds