Scala Actors vs Akka Actors

Question

I'm learning about Actors using Scala. I found this great implementation of The Santa Claus Problem here. However, this is using Scala Actors instead of Akka Actors. There is a particular part that I don't understand how to do with Akka Actors, starting at line 80:

/*(line 80)*/object Secretary extends Actor{

  def act = loop(Group[Elf](3), Group[Reindeer](9))

  private def addToGroup[T <% Helper](helper: T, group: Group[T]) = {
    val updatedGroup = group.copy(helpers = helper :: group.helpers)
    if(updatedGroup.hasSpace) updatedGroup else {
      Santa ! updatedGroup
      group.copy(helpers = List[T]())
    }
  }

  // How to implement this using 'receive' with akka
  private def loop(elves: Group[Elf], reindeers: Group[Reindeer]):Unit = {
    react {
      case Idle(reindeer: Reindeer) => loop(elves, addToGroup(reindeer, reindeers))
      case Idle(elf: Elf) => loop(addToGroup(elf, elves), reindeers)
    }
  }

}

I'm using this guide to migrate it to Akka Actors, and I understand that the act method should be replaced with receive. But I don't understand how to do the same loop using receive. An explanation or a sample code would be helpful

Answer 1

You could use context.become like this:

def receive = loop(Group[Elf](3), Group[Reindeer](9))

private def loop(elves: Group[Elf], reindeers: Group[Reindeer]): Receive = {
  case Idle(reindeer: Reindeer) => context become loop(elves, addToGroup(reindeer, reindeers))
  case Idle(elf: Elf) => context become loop(addToGroup(elf, elves), reindeers)
}