How do I reflectively instantiate an enum given an...

# reflect

[pniederw]

How do I reflectively instantiate an enum given an enum class of type java.lang.Class<*>? Can't find a way to make the type checker happy.

[Marc Knaup]

So what's the code?

[pniederw]

Couldn't figure out how to call java.lang.Enum.valueOf() from Kotlin (given a java.lang.Class<*>), but java.lang.Class.getEnumConstants() did the trick.

[jdiaz]

You can just reference the java.lang: return java.lang.Enum.valueOf(typeStructure.type as Class<T>, value.asString())

[pniederw]

Huh? Referencing java.lang.Enum isn't the problem; convincing the type checker to pass a java.lang.Class<*> to java.lang.Enum.valueOf is (give it a try).

[jdiaz]

That's why the cast. It's just I'm using that same line of code in my project

[pniederw]

I don't understand. To begin with, I don't have a type parameter T. All I have is an instance of java.lang.Class<*> that I know is an enum type.

[pniederw]

I tried such things as java.lang.Enum.valueOf(clazz as Class<Enum<*>>, "foo") but couldn't get past the type checker.

[Marc Knaup]

Why do you want to use Enum.valueOf() in the first place? It's not supposed to be used if you don't know the concrete type.
There are ways around that but using Class.getEnumConstants() should be sufficient.

[diesieben07]

For the record, the key here is the Nothing type:
Enum.valueOf(cls as Class<Nothing>, "foo")

[pniederw]

@diesieben07 thanks, good to know!

[pniederw]

@Marc Knaup I was just looking for a solution and had not yet found getEnumConstants().

[udalov]

Related: https://youtrack.jetbrains.com/issue/KT-5191