Stream example gist

FailingNumberFinder.scala

object FailingNumberFinder {
  def findMagicNumber(numbers: Seq[Int]) : Option[Int] = {
    for(number <- numbers) {
       try {
         return Some(SlowErrorProne.search(number))
       } catch {
         case _ =>
       }
    }
    return None
  }
}

FasterMagicNumberFinder.scala

object FasterMagicNumberFinder {
  def findMagicNumber(numbers: Seq[Int]) = {
    def attemptSearch(number: Int) = {
      try  Some(SlowErrorProne.search(number))
      catch { case _ => None }
    }

    val magicNumbers = Stream(numbers: _*) flatMap (
      attemptSearch(_)
    )
    magicNumbers.headOption
  }
}

SimpleMagicNumberFinder.scala

object SimpleMagicNumberFinder {
  def findMagicNumber(numbers: Seq[Int]) = {
    def attemptSearch(number: Int) = {
      try  Some(SlowErrorProne.search(number))
      catch { case _ => None }
    }

    val magicNumbers = numbers flatMap (
      attemptSearch(_)
    )
    magicNumbers.headOption
  }
}

SlowErrorProne.scala

object SlowErrorProne {
   val MAGIC_NUMBERS = List(3, 42, 666)

  def search(number: Int) = {
    Thread.sleep(500)
    if (MAGIC_NUMBERS contains number) number
    else throw new Exception
  }
}

UglyNumberFinder.scala

object UglyNumberFinder {
  def findMagicNumber(numbers: Seq[Int]) : Option[Int] = {
    def attemptSearch(number: Int) = {
      try  Some(SlowErrorProne.search(number))
      catch { case _ => None }
    }

    for(number <- numbers) {
       val result = attemptSearch(number)

       result match {
         case Some(magic) => return Some(magic)
         case _ =>
       }
    }
    return None
  }
}