class SecurityPricingActor(exchange: Exchange, backOffice: BackOffice) extends Actor {
  def receive = {
    case GetPricingInfo(security: Security) =>
      val originalSender = sender
      val bidAndAskFuture = Future { exchange.getBidAndAsk(security.id) }
      val lastPriceFuture = Future { backOffice.getLastPrice(security.id) }

      val response = for {
        (bid, ask) = bidAndAskFuture
        lastPrice = lastPriceFuture
      } yield SecurityPricing(bid, ask, lastPrice)

      response map (originalSender ! _)
  }
}