Populating an Abstract Trait's Requirements with Futures

FutureTest.scala

import scala.concurrent._
import scala.util.{ Success, Failure }
import ExecutionContext.Implicits.global
import scala.concurrent.duration._

trait Calculator {
  def hardToCalculate1: Int
  def hardToCalculate2: Int
  def hardToCalculate3: Int

  def result1 = hardToCalculate1 + hardToCalculate2
  def result2 = hardToCalculate2 + hardToCalculate3
  def result3 = hardToCalculate1 + hardToCalculate3
}

object FutureTest extends App {
  def f1 = future {
    println("calculating 1")
    1
  }
  def f2 = future {
    println("calculating 2")
    2
  }
  def f3 = future {
    println("calculating 3")
    3
  }

  // first try:
  val myCalc = for {
    m1 <- f1
    m2 <- f2
    m3 <- f3
  } yield new Calculator {
    def hardToCalculate1 = m1
    def hardToCalculate2 = m2
    def hardToCalculate3 = m3
  }
  myCalc onComplete {
    case Success(calc) => println("Result: " + calc.result1)
  }

  // second try:
  val calculator = new Calculator {
    lazy val hardToCalculate1 = Await.result(f1, 10 seconds)
    lazy val hardToCalculate2 = Await.result(f2, 10 seconds)
    lazy val hardToCalculate3 = Await.result(f3, 10 seconds)
  }
  println("result: " + calculator.result1)
}