How do I initialize an empty EnumSet in kotlin?

May 2, 2022

I’m pretty new to Kotlin and trying to create a sort of bitset enum where ints correspond to state and I can toggle individual states by toggling individual bits. But I’m stuck on where an object can have no state.

https://pl.kotl.in/L_fTBahVN

import java.util.*

fun main() {
    var d = Door(100, EnumSet.noneOf(Status))
}

enum class Status(intValue: Int) {
    OPEN(1),
    CLOSED(1 shl 1),
    CRACKED(1 shl 2),
    BROKEN(1 shl 3)
}

class Door(val id: Int, val status: EnumSet<Status>) {}

This code fails with the error Classifier 'Status' does not have a companion object, and thus must be initialized here

I was reading another question where they said to use Status.class inside the EnumSet.noneOf, but that throws even more errors.

>Solution :

Use

EnumSet.noneOf(Status::class.java)

Status::class is similar to Status.class in Java, but gets a Kotlin kotlin.reflect.KClass instead. To get the Java java.lang.Class that EnumSet.noneOf takes, you access the java property.