EnumExample.scala

  sealed abstract class LoyaltyDomain(val id: String) {
    def name = {
      this match {
        case LoyaltyDomain.ANDROID => "Android"
        case LoyaltyDomain.IOS => "iOS"
        case LoyaltyDomain.AMAZON => "Amazon"
        case LoyaltyDomain.WINPHONE => "Windows Phone"
        case LoyaltyDomain.WINSTORE => "Windows Store"

        // ???
        case LoyaltyDomain.UNDETERMINED => "Undetermined"
        case LoyaltyDomain.ALL => "All"
      }
    }
    override def toString = this.id
  }
  object LoyaltyDomain {
    case object ANDROID extends LoyaltyDomain("com.google.play")
    case object IOS extends LoyaltyDomain("com.apple.itunes")
    case object AMAZON extends LoyaltyDomain("com.amazon.apps")
    case object WINPHONE extends LoyaltyDomain("com.windowsphone")
    case object WINSTORE extends LoyaltyDomain("com.windowsstore")

    // This exists so we can iterate over the possible values (e.g. for the admin UI). I can't think of a
    // non-reflective way to automate this, so I think we'll have to maintain this list along with the objects above.
    val list: List[LoyaltyDomain] = List(
      ANDROID,
      IOS,
      AMAZON,
      WINPHONE,
      WINSTORE
      // TODO: undetermined/all?
    )

    // ???
    case object UNDETERMINED extends LoyaltyDomain("undetermined")
    case object ALL extends LoyaltyDomain("all")
  }


  // ----------------------------------------------------------------------------


  // Normal usage will look like this:
  def handleDomain(domain: LoyaltyDomain) = {
    domain match {
      case LoyaltyDomain.IOS =>
        // ...
      case LoyaltyDomain.ANDROID =>
        // ...
      case _ =>
        // We'll get warnings about non-exhaustive matches if we go with a sealed class/case objects.
    }
  }
  handleDomain(LoyaltyDomain.ANDROID)

  // For admin UI, etc:
  val niceNames = LoyaltyDomain.list.map { domain =>
    domain.name -> domain.id
  }