jobcoordinator.scala

来自「resetful样式的ws样例,一种面向资源的webservices服务」· SCALA 代码 · 共 67 行

import scala.actors.Actor
import scala.actors.Actor._
import scala.actors.OutputChannel
import scala.collection.mutable.Stack

package com.sun.jersey.samples.mandel {

class JobCoordinator(n: int) {
    trait Job {
        def execute: unit
    }

    private case object FinishedProducing

    private case object Completed

    private def worker = actor {
        loop { react { 
            case j: Job => 
                j.execute
                sender ! Completed
            case Completed => exit
        } }
    }

    val coordinator = actor {
        var finisher: OutputChannel[Any] = null
        val workers = new Stack[OutputChannel[Any]]
        val jobs = new Stack[Job]

        for (i <- 0 to n - 1) workers += worker

        loop { react {
            case j: Job => 
                if (!workers.isEmpty) (workers pop) ! j
                else jobs += j
            case FinishedProducing =>
                finisher = sender
            case Completed =>
                if (!jobs.isEmpty) sender ! (jobs pop)
                else workers += sender

                if (workers.size == n && finisher != null) { 
                    workers foreach (x => x ! Completed)
                    finisher ! Completed
                    exit 
                }
        }}
    }

    def job (j: => unit) : unit = {
        coordinator ! new Job { def execute = j }
    }

    def ! (j : Job) : unit = {
        coordinator ! j
    }

    def waitForCompletion: unit = {
        coordinator !? FinishedProducing match {
            case Completed =>
        }
    }
}

} // package