Best way to convert an Enumeration<String> to Array<String> in Kotlin?

Issue

Incidentally, I have an Enumeration<String> in Kotlin. It contains toList(), but I need to convert it to an Array<String>.

What is the best way to do this in Kotlin?

Solution

Lists can be converted to arrays via the .toTypeArray function:

val myEnumeration: Enumeration<String> = ...
val array = myEnumeration.toList().toTypedArray() // array is Array<String>

A simple extension function as a shortcut is also trivial:

inline fun <reified T> java.util.Enumeration<T>.toTypedArray(): Array<T> = toList().toTypedArray()

The reason toTypedArray() doesn't work directly on an Enumeration is that it needs a Collection<T> to be able to efficiently instantiate the new array, but going through toList() first is still efficient enough for most scenarios.

Answered By - Bill