Problems with multiple trait mixins and Actors - scala

Question

trait A extends Actor {
private val s = Set[Int]()
override def act() {
loop {
react {
// case code that modifies s
}
}
}
}
trait B extends Actor {
private val t = Set[String]()
override def act() {
loop {
react {
// case code that modifies t
}
}
}
}
val c = new C with A with B //...?
What I really want is some sort of auto-combining of B.act() and C.act(), but with trait mix-ins, only B.act() will be called. Is there an easy way to accomplish this?
EDIT: Here is a half-solution I've found. I say 'half' because the original traits no longer extend Actor, and C with A with B needs to be defined as a class as opposed to dynamic mixing-in. Maybe I should call it a 'quarter-solution'?

Answer 1

Maybe you could make a trait that forwards the message on to a list of other Actors, so that you don't have to modify A or B:
trait C extends Actor {
private val acts: Seq[Actor] = Seq(new A{}, new B{})
override def act() {
acts foreach (_.start)
loop {
react { case x => acts foreach { _ ! x } }
}
}
}
You could of course leave acts abstract or override it with a different set when you instantiate this.

Answer 2

Extending the Actor class:
import actors.Actor
class MixableActor extends Actor {
protected var acts = List[PartialFunction[Any, Unit]]()
final override def act() {
loop {
react {
acts.reduce((a, b) => a orElse b)
}
}
}
final def receive(act: PartialFunction[Any, Unit]) {
acts = act :: acts
}
}
Sample Code:
abstract class Node extends MixableActor {
...
}
trait User extends MixableActor {
val files = scala.collection.mutable.Set[Data]()
}
trait Provider extends User {
receive({
case ("provide", file: Data) =>
provide(file)
}: PartialFunction[Any, Unit])
}
trait Consumer extends User {
receive({
case ("consume", file: Data) =>
consume(file)
}: PartialFunction[Any, Unit])
}
Sample Usage:
val provider = new Node with Provider
val consumer = new Node with Consumer
val provider_and_consumer = new Node with Provider with Consumer