Misunderstanding Akka become/unbecome
akka, scala
Solution
This is how is the flow.
- Msg "foo" sent --> `receive` receives the message. `angry` becomes the receive function. Any next message will be sent to `angry`
- Msg "bar" sent --> `angry` receives message. `happy` becomes the receive function. Any next message will be sent to `happy`
Msg "bar" sent --> `happy` receives message. It replied `I am already happy :-)` message. And then it `unbecomes`. As per api for all the previous calls to `context.become`, the `discardOld` was set as default to true. Now after replacing itself there is nothing left to become the next receiver. It takes the default one i.e. `receive` as the receiver
Msg "foo" sent --> `receive` receives the message. `angry` becomes the receive function. Any next message will be sent to `angry`
Problem
The following code: ``` class HotSwapActor extends Actor { import context._ def angry: PartialFunction[Any, Unit] = { case "foo" => sender ! "I am already angry!" case "bar" => become(happy) } def happy: PartialFunction[Any, Unit] = { case "bar" => sender ! "I am already happy :-)"; unbecome case "foo" => become(angry) } def receive = { case "foo" => become(angry) case "bar" => become(happy) } } class OtherActor extends Actor { val system = ActorSystem() val actor = system.actorOf(Props[HotSwapActor]) def receive = { case "start" => actor ! "foo" actor ! "bar" actor ! "bar" actor ! "foo" case a @ _ => println(a) } } object HotSwapMain extends App { val system = ActorSystem() val actor = system.actorOf(Props[OtherActor]) actor ! "start" } ``` Has the output: I am already happy :-) But souldn't it be I am already happy :-) I am already angry! Or am I missing the semantic of unbecome in unbecome in the bar case of the happy PartialFunction?