Extension functions apparently can't be JvmStatic... What can I do to improve the API for Java users...

# getting-started

[Stefan Oltmann]

Extension functions apparently can't be JvmStatic... What can I do to improve the API for Java users here?

https://github.com/Ashampoo/kim/blob/49b7f3abdbc7d5ab58e09255282a80e7e983285b/src/jvmMain/kotlin/com/ashampoo/kim/JvmKimExtensions.kt#L33

Without that available it's not very nice to use:
https://github.com/Ashampoo/kim/blob/examples/examples/kim-java-sample/src/main/java/Main.java

JvmKimExtensionsKt itself is available, but this looks strange and I don't want to showcase that.

What are my alternative options to make a Kim.readMetadata(file) work in Java?

[ephemient]

@file:JvmName

[ephemient]

which is an ABI-incompatible change of course

[Stefan Oltmann]

Thanks, will try that. As long as Kim is not a 1.x release I think I'm free to break sometimes 😄

[Stefan Oltmann]

Oh, that's an JvmKimExtensions.kt:27:5 Unresolved reference: Kim

Because there is already a Kim.kt at https://github.com/Ashampoo/kim/blob/main/src/commonMain/kotlin/com/ashampoo/kim/Kim.kt

[Stefan Oltmann]

That Kim object is the central API to use the lib. in commonMain is takes parameters valid for all platforms and in specific source set it extents

[Stefan Oltmann]

In Kotlin code im import the extension function and it looks like it should.
In Java code it's not so easy

[Stefan Oltmann]

Maybe I need to extract the common logic elsewhere and provide each platform with their very own Kim object, but I hope that there is an easier solution

[hfhbd]

Never used it but you could try JvmMultifileClass: https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.jvm/-jvm-multifile-class/
To merge it with the existing Kim file

[ephemient]

only works if everything is also a top-level file and not an object

[hfhbd]

But you already have an object, so why not add the function to Kim?

[Stefan Oltmann]

Ok, understood. I think I create platform-specific Kim objects.

Thank you 🙂

[ephemient]

I don't think you want to do that. that will make it difficult to use Kim in common sourcesets

[hfhbd]

You can also add a JVM only function by hiding it from Kotlin

[Stefan Oltmann]

How?

[hfhbd]

Deprecated.Hidden

[Stefan Oltmann]

I look that up.

[Stefan Oltmann]

I don't think you want to do that. that will make it difficult to use Kim in common sourcesets

Good point.

[Stefan Oltmann]

@Deprecated(HIDDEN) feels a bit wrong/hacky.
It seems to be intended for libraries that are in the process of Kotlin migration.