Recipie-Book/app/models/Measure.scala

package models

sealed trait Measure {
  def productPrefix: String
  def name: String = this.productPrefix.split("\\.").last
  //  def primaryUnit: Uni
}

object Measure {
  import play.api.libs.json._

  implicit val measureFormat = new Format[Measure] {
    def writes(m: Measure): JsValue = Json.toJson(m.name.toLowerCase)

    def reads(jsValue: JsValue): JsResult[Measure] =
      jsValue.validate[String] match {
        case s: JsSuccess[String] => s.get match {
          case "mass" => JsSuccess(Mass)
          case "volume" => JsSuccess(Volume)
          case "number" => JsSuccess(Number)
        }
        case e: JsError => e
      }
  }
}

case object Mass extends Measure
// {
//   val primaryUnit = Gram
// }

case object Volume extends Measure
// {
//   val primaryUnit = Liter
// }

case object Number extends Measure
// {
//   val primaryUnit = Count
// }