crdt.scala

case object Hello
case object Howdy
case object GetCount
case class HelloCount(count: Int)

class HelloActor extends Actor {
  
  var count = 0
  
  def receive = {
    case Hello =>
      count += 1
      sender() ! Howdy
    case GetCount =>
      sender() ! HelloCount(count)
}

val helloActor = system.actorOf(Props[HelloActor])
helloActor ! Hello
for {
  HelloCount(count) <- (helloActor ? GetCount).mapTo[HelloCount]
} yield {
  println(count)
}




class ImpressionCounter extends Actor {
  import akka.cluster.ddata.Replicator._

  val replicator = DistributedData(context.system).replicator
  implicit val cluster = Cluster(context.system)
  val ImpressionsKey = PNCounterMapKey("impressions")

  def receive = {
    case AdViewed(adId) ⇒
      val update = Update(ImpressionsKey, PNCounterMap(), WriteLocal) {
        _.increment(adId, 1)
      }
      replicator ! update

    case GetImpressions(adId) ⇒
      replicator ! Get(ImpressionsKey, ReadAll(3.seconds), Some(GetImpressionsReq(adId, sender()))

    case g @ GetSuccess(ImpressionsKey, Some(GetImpressionsReq(adId, replyTo))) ⇒
      val data = g.get(ImpressionsKey)
      replyTo ! AdImpressions(data.entries(adId))
  }
}