Boolean extractor

boolean_extractor.scala

  /**
    * A Boolean extractor
    * Unapply method doesn't have to reside in companion object of the class for which it is applicable
    */
  object premiumCandidate{
     def unapply(user: FreeUser): Boolean = user.upgradeProbability > 0.75
   }

  def initiateSpamProgram(freeUser: FreeUser) = () //do something useful here

  user match {
    case freeUser @ premiumCandidate() => initiateSpamProgram(freeUser)
  }