scala enums

scala-enums.scala

import Test.{doWhat, findColorById, findColorById2, findColorByName}
import TrafficLightColorById.{Green, Red, TrafficLightColorById, Yellow}

import scala.util.Try

/*
  Enums (id, name) with default id incremental
 */
object TrafficLightColor extends Enumeration {
  val Red = Value(0, "RED")
  val Yellow = Value(10)
  val Green = Value("GREEN")
}

/*
  Add type alias so type of enum is TrafficLightColorById.TrafficLightColorById
  (need to import all members of TrafficLightColorById._)
 */
object TrafficLightColorById extends Enumeration {
  type TrafficLightColorById = Value
  val Red = Value(0, "dark red")
  val Yellow = Value(22, "egg yellow")
  val Green = Value(333, "green as an alien")
}

object Test {
  println(classOf[TrafficLightColor.Value])

  def findColorByName(color: String) = {
    val enum: Try[TrafficLightColor.Value] = Try(TrafficLightColor.withName(color.toUpperCase()))
    enum.getOrElse("not defined")
  }

  def findColorById(id: Int) = {
    val enum: Try[TrafficLightColorById] = Try(TrafficLightColorById(id))
    enum.getOrElse("not defined")
  }


  def findColorById2(id: Int): Option[TrafficLightColorById] = {
    val enum = Try(TrafficLightColorById(id))
    if (enum.isSuccess) {
      Some(enum.get)
    } else {
      None
    }
  }

  def doWhat(color: TrafficLightColorById): String = {
    color match {
      case Red => "STOP"
      case Yellow => "hurry up"
      case Green => "GO"
      case _ => "undefined"
    }
  }
}

object Client extends App {
  println(findColorByName("Red"))
  println(findColorByName("red"))
  println(findColorByName("Green"))
  println(findColorByName("GREEN"))
  println(findColorByName("Yellow"))
  println(TrafficLightColor(10))

  println(TrafficLightColorById(0))
  println(TrafficLightColorById(22))
  println(TrafficLightColorById(333))
  println(findColorById(444))

  println(doWhat(Red))
  println(doWhat(Green))
  println(doWhat(Yellow))
  println(doWhat(null))
  println(doWhat(findColorById2(123).getOrElse(null)))
  println(doWhat(findColorById2(333).getOrElse(null)))
}