So I ve run into an issue that works in Java but I can t figure out how to make it work in Kotlin Specifically I m trying to create an empty instance of an enum set given a type reference Context for this is a custom deserializer to map null to empty set Here s the code that works in java type is a CollectionType ``` Class lt Enum gt enumType = type getContentType getRawClass as Class lt Enum gt EnumSet noneOf enumType ``` However the kotlin version does not like the types if implemented as followed ``` val enumType = type contentType rawClass as Class lt Enum lt gt gt EnumSet noneOf enumType ``` The error kotlin displays on the noneOf call is about Enum lt gt not being a subtype of Enum lt Enum lt gt gt Is there any way to make this work Thanks

So I've run into an issue that works in Java, but I can't figure out how to make it work in Kotlin. Specifically, I'm trying to create an empty instance of an enum set given a type reference. Context for this is a custom deserializer to map null to empty set. Here's the code that works in java (type is a CollectionType)

Class<Enum> enumType = type.getContentType().getRawClass() as Class<Enum>
EnumSet.noneOf(enumType)

However, the kotlin version does not like the types if implemented as followed

val enumType = type.contentType.rawClass as Class<Enum<*>>
EnumSet.noneOf(enumType)

The error kotlin displays on the noneOf call is about Enum<*> not being a subtype of Enum<Enum<*>>. Is there any way to make this work? Thanks!

diesieben07

02/21/2018, 3:42 PM

Casting to

Class<Nothing>

should work.

David R.

02/21/2018, 4:01 PM

Nice. I didn't know about that. It works. Thanks

joelpedraza

02/21/2018, 4:04 PM

Why not just

emptySet<Nothing>()

David R.

02/21/2018, 4:16 PM

That doesn't work because in my case because Jackson throws an argument type mismatch exception since my data class prop is typed as an EnumSet

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