Scala FlowDesign

FlowDesign.scala

import scala.collection.mutable.MutableList

class A {
  val onResult: MutableList[Function1[Int, Unit]] = MutableList.empty

  def process(x: Int) = {
    onResult.foreach(f => f(x))
  }

}

class B {
  def notifyResult(x: Int) = println("Result: " + x) 
}

object FlowFesign {
  def main(args: Array[String]): Unit = {
    val a = new A
    val b = new B

    a.onResult += b.notifyResult

    a.process(10)
  }
}