JarCastingenumz
One enum type class to rule them all.
In Scala you might meet many different implementations of enums:
- build-in
scala.Enumeration, - sum-type based sealed hierarchies,
enumeratumas the previous one on steroids,- Java's
enumtype which use static methods and has no companion object.
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.
Usage
Add to your sbt (2.11, 2.12 and 2.13 supported)
libraryDependencies += "io.scalaland" %% "enumz" % enumzVersion // see Maven badge
or, if you use Scala.js
libraryDependencies += "io.scalaland" %%% "enumz" % enumzVersion // see Maven badge
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:1.0.0`, 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
Methods
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
