foiled_by_actors.scala

import scala.actors._
import Actor._

object Bank{
        
  val accounts = Map("from" -> new Account("from", 500), "to" -> new Account("to", 500) )

  def transfer(fromNo: String, toNo: String, amount: Int): Unit = {
    val (from, to) = (accounts(fromNo), accounts(toNo))
    val balance = (from !? Balance).asInstanceOf[Int]
    if(balance > amount){
      to ! Credit(amount)
      from ! Debit(amount)
    }
  }

}

case class Credit(amount: Int)
case class Debit(amount: Int)
case object Balance

class Account(val accountNo: String, beginningBalance: Int) extends Actor{
  private var _balance = beginningBalance

  def act = {
    loop{
      receive{
        case Credit(amount) => _balance = _balance + amount
        case Debit(amount) => _balance = _balance - amount
        case Balance => reply(_balance)
      }
    }
  }
}