In Scala you might meet many different implementations of enums:

• build-in scala.Enumeration,
• sum-type based sealed hierarchies,
• enumeratum as the previous one on steroids,
• Java's `enum` type which use static methods and has no companion object.
• filters for select, update and delete queries

You are in control of what implementation you pick, but you have no control over what other people use. So if you had to use APIs using many different implementations how would you handle common code?

With a type class.

Add to your sbt (2.11 and 2.12 supported):

libraryDependencies += "io.scalaland" %% "enumz" % "1.0.0"

or, if you use Scala.js

libraryDependencies += "io.scalaland" %%% "enumz" % "1.0.0"

From now on you can define enums whatever you want and use one common interface for all of them.

public enum TestJavaEnum {
    A, B, C
}

object TestEnumeration extends Enumeration {
  type TestEnumeration = Value
  val A, B, C = Value
}

sealed trait TestSumType extends Product with Serializable
object TestSumType {
  case object A extends TestSumType
  case object B extends TestSumType
  case object C extends TestSumType
}

import enumeratum.{Enum => EnumeratumEnum, _}

sealed trait TestEnumeratum extends EnumEntry
object TestEnumeratum extends EnumeratumEnum[TestEnumeratum] {
  val values = findValues
  case object A extends TestEnumeratum
  case object B extends TestEnumeratum
  case object C extends TestEnumeratum
}

import io.scalaland.enumz.Enum

Enum[TestJavaEnum].values
Enum[TestEnumeration.TestEnumeration].values
Enum[TestSumType].values
Enum[TestEnumeratum].values

You can also test it with ammonite like:

import $ivy.`io.scalaland::enumz:0.1.2`, io.scalaland.enumz.Enum

{
sealed trait TestSumType extends Product with Serializable
object TestSumType {
  case object A extends TestSumType
  case object B extends TestSumType
  case object C extends TestSumType
}
}

Enum[TestSumType].values

Enum[TestSumType].values // Vector(TestSumType.A, TestSumType.B, TestSumType.C)
Enum[TestSumType].indices // Map(TestSumType.A -> 0, TestSumType.B -> 1, TestSumType.C -> 2)

Enum[TestSumType].getName(TestSumType.A) // "A"
Enum[TestSumType].getIndex(TestSumType.A) // 0

Enum[TestSumType].withIndexOption(0) // Some(TestSumType.A)
Enum[TestSumType].withIndexOption(-1) // None

Enum[TestSumType].withIndex(0) // TestSumType.A
Enum[TestSumType].withIndex(-1) // throws!

Enum[TestSumType].withNameOption("A") // Some(TestSumType.A)
Enum[TestSumType].withNameOption("") // None

Enum[TestSumType].withName("A") // TestSumType.A
Enum[TestSumType].withName("") // throws!

Enum[TestSumType].withNameInsensitiveOption("a") // Some(TestSumType.A)
Enum[TestSumType].withNameInsensitiveOption("") // None

Enum[TestSumType].withNameInsensitive("a") // TestSumType.A
Enum[TestSumType].withNameInsensitive("") // throws!

Enum[TestSumType].`A` // TestSumType.A