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("	pi approximation: 		%s
	Calculation time: 	%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