Odtnhj

I have two actors coded as follows.

class Actor1 extends Actor 
 val r : ActorRef = actorOf (Props[Actor2], "master")

 def receive: Receive = 
 case class Mul (a,b) =>
 r ! CalcMul (a,b)

 case class MulReply (ans) =>
 println("Multiply result : " + ans)
 // want to send "ans" value to testObject..
 


class Actor2 extends Actor 

 def receive: Receive = 
 case class CalcMul (a,b) =>
 sender ! MulReply (a*b)
 


object testObject extends App 
 val a = ActorSystem("ActorSystem").actorOf(Props[Actor1], "root")

 a ! CalcMul (5, 15)
 // how to receive "ans" value here?

I am able to receive and print the result in Actor1 but need those values in testObject so I can use them for future operations. Cannot have a receive method in testObject as done to receive a message in Actor1 from Actor2, so cannot send them with tell method.

As you want to receive a response from an actor you can use ask pattern for this purpose.

import akka.actor.Actor, ActorRef, ActorSystem, Props
import akka.pattern._
import akka.util.Timeout

import scala.concurrent.ExecutionContext.Implicits.global
import scala.concurrent.Future
import scala.concurrent.duration.SECONDS


case class CalsMul(a: Int, b: Int)

 class Actor1 extends Actor 
 val r: ActorRef = context.actorOf(Props[Actor2], "master")

 def receive: Receive = 
 case req: CalsMul =>
 println("received message by Actor1")
 r forward req
 
 

 class Actor2 extends Actor 

 def receive: Receive = 
 case request: CalsMul =>
 println("received message by Actor2")
 Future.successful(request.a * request.b) pipeTo sender
 
 

 object testObject extends App 
 implicit val system: ActorSystem = ActorSystem("ActorSystem")
 val a: ActorRef = system.actorOf(Props[Actor1], "root")
 implicit val timeout: Timeout = Timeout(20, SECONDS)

 println(system, "sending message to Actor1")
 val ans: Future[Int] = (a ? CalsMul(5, 15)).mapTo[Int] // as you are returning the multiplication of a*b

 ans.foreach(println)
 

Note: CPU bound operations are not advised to use with actors it can have adverse effect on the performance of your application