actors.scala

package sandbox

import actors.Actor
import org.apache.log4j.Logger

object getter extends Actor {
  val logger = Logger.getLogger("Actor")

  def act() {
    while (true) {
      receive { 
        case msg => 
          logger.info("received message: "+ msg)
          Thread.sleep(1000) // Simulate long-running operation
      } 
    } 
  }
}

object Main {
  def main(args: Array[String]): Unit = {
    getter.start()
    getter ! "hi"  
    getter ! "hi"  
    getter ! "hi"
    Thread.sleep(4000)
  }  
}

/*
18:34:14,539 [Thread-1] INFO  Actor  - received message: hi
18:34:15,542 [Thread-1] INFO  Actor  - received message: hi
18:34:16,543 [Thread-1] INFO  Actor  - received message: hi

I want all three “long-running tasks” to run concurrently (probably in separate Java threads).
*/

/*
I'd like the equivalent of this, actually:
*/

package org.talkingpuffin.util

import java.util.concurrent.{Callable, Executors}

object Parallelizer {
  /**
   * Runs, in the number of threads requested, the function f, giving it each A of args, returning a List[T]
   */
  def run[T,A,F](numThreads: Int, args: List[A], f: (A) => T): List[T] = {
    val pool = Executors.newFixedThreadPool(numThreads)
    (for {
      arg <- args
      future = pool.submit(new Callable[T] {def call = f(arg)})
    } yield future).map(_.get)
  }
}
// -----

    def getLists: List[TwitterLists] = {
      for {
        twitterLists <- Parallelizer.run(20, screenNames, session.twitterSession.getLists)
        if twitterLists.isDefined 
      } yield twitterLists.get
    }