Java interop about enumeratum HOT 2 CLOSED

Hey there,

Thanks for asking this question ! I'm not super experienced w/ calling Scala stuff from Java, but gave it a try and the following seems to work:

I think it's just a matter of syntax? Accessing nested singleton Scala objects from Java should be something like Outer$Inner$.MODULE$, assuming object Outer { object Inner }

// Given
import enumeratum._

sealed trait MyEnum extends EnumEntry

case object MyEnum extends Enum[MyEnum] {

  val values = findValues

  case object First  extends MyEnum
  case object Second extends MyEnum
  case object Third  extends MyEnum

}

The folllowing Java seems to compile fine:

class ExampleUse {
    public static void go() {
        System.out.println(MyEnum$First$.MODULE$);
    }
}

Scala: 2.12.4
Enumeratum: 1.5.12

from enumeratum.

In my case the difference is that MyEnum is inside another object.
Finally I was able to resolve it by introducing "factory methods":

object Transfer {

  sealed trait Type extends EnumEntry

  // the methods are for Java interop
  object Type extends Enum[Type] {
    val values: immutable.IndexedSeq[Type] = findValues

    case object DEPOSIT extends Type
    def deposit(): DEPOSIT.type = DEPOSIT

    case object WITHDRAWAL extends Type
    def withdrawal(): WITHDRAWAL.type = WITHDRAWAL
  }
}

and in the Java code I call them with Transfer.Type$.MODULE$.withdrawal()

Hope this helps someone else!

Thank you!

from enumeratum.