Akka/Scala example source code file (FactorialFrontend.scala)

This example Akka source code file (FactorialFrontend.scala) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Akka and Scala source code examples by using tags.

All credit for the original source code belongs to akka.io; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Akka tags/keywords

actor, actorsystem, akka, bigint, boolean, cluster, concurrent, duration, factorialfrontend, int, receivetimeout, route, time, timeout, unit

The FactorialFrontend.scala Akka example source code

package sample.cluster.factorial

import scala.concurrent.duration._
import com.typesafe.config.ConfigFactory
import akka.actor.Actor
import akka.actor.ActorLogging
import akka.actor.ActorSystem
import akka.actor.Props
import akka.cluster.Cluster
import akka.routing.FromConfig
import akka.actor.ReceiveTimeout

//#frontend
class FactorialFrontend(upToN: Int, repeat: Boolean) extends Actor with ActorLogging {

  val backend = context.actorOf(FromConfig.props(),
    name = "factorialBackendRouter")

  override def preStart(): Unit = {
    sendJobs()
    if (repeat) {
      context.setReceiveTimeout(10.seconds)
    }
  }

  def receive = {
    case (n: Int, factorial: BigInt) =>
      if (n == upToN) {
        log.debug("{}! = {}", n, factorial)
        if (repeat) sendJobs()
        else context.stop(self)
      }
    case ReceiveTimeout =>
      log.info("Timeout")
      sendJobs()
  }

  def sendJobs(): Unit = {
    log.info("Starting batch of factorials up to [{}]", upToN)
    1 to upToN foreach { backend ! _ }
  }
}
//#frontend

object FactorialFrontend {
  def main(args: Array[String]): Unit = {
    val upToN = 200

    val config = ConfigFactory.parseString("akka.cluster.roles = [frontend]").
      withFallback(ConfigFactory.load("factorial"))

    val system = ActorSystem("ClusterSystem", config)
    system.log.info("Factorials will start when 2 backend members in the cluster.")
    //#registerOnUp
    Cluster(system) registerOnMemberUp {
      system.actorOf(Props(classOf[FactorialFrontend], upToN, true),
        name = "factorialFrontend")
    }
    //#registerOnUp
  }
}