JavaでEnumをよく使うがScala版はよくわからなかったのでメモ

/*
 * 指定した曜日コードからcodeとnameをタプル形式で取得する
 */
object EnumWeek extends App {
  (1 to 5).toList.foreach(a => println( Week.code(a) ) )
}

結果は、英語と日本語で曜日が取れた。

(monday,月曜日)
(tuesday,火曜日)
(wednesday,水曜日)
(thursday,木曜日)
(friday,金曜日)

Enumは以下リンクのサイト参考。

trait EnumLike {
  type Value
  def value: Value
}
trait Enum[T] extends EnumLike {
  type Value = T
}
trait EnumCompanion[A <: EnumLike] {
  def values: Seq[A]
  def valueOf(value: A#Value): Option[A] = values.find(_.value == value)
}
abstract sealed class WeekType[T](val value: Int) extends Enum[Int]{
  def code: T 
  def name: T 
}
object Week extends EnumCompanion[WeekType[String]]{
  case object MONDAY extends WeekType[String](1){
    override def code = "monday"
    override def name = "月曜日"}
  case object TUESDAY extends WeekType[String](2){
    override def code = "tuesday"
    override def name = "火曜日" }
  case object WEDNESDAY extends WeekType[String](3){
    override def code = "wednesday"
    override def name = "水曜日" }
  case object THURSDAY extends WeekType[String](4){
    override def code = "thursday"
    override def name = "木曜日" }
  case object FRIDAY extends WeekType[String](5){
    override def code = "friday"
    override def name = "金曜日" }
  lazy val values = Seq(MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY)
  def code(cd:Int): (String, String) = {
    (valueOf(cd).map(_.code).getOrElse(""), valueOf(cd).map(_.name).getOrElse(""))
  }
}

参考：
https://gist.github.com/gakuzzzz/4ad53153e28b3a6e0aa6