Kotlin Easy-JNI

[cretz]

Now that we know it's quite trivial to use Kotlin with JNI, how about making the interaction easier? For example, in Kotlin Native:

package somepkg

@ExposeJNI
class Foo {
    fun bar() = "baz"
}

That will create a bridge method of Java_somepkg_Foo_bar and methods for create and finalize. Generate, in Kotlin:

class Foo {
    private val ptr: Long
    init { ptr = createNative() }

    external fun bar(): String

    protected external override fun finalize()

    companion object {
        private fun createNative(): Long
    }
}

• Obviously can only expose primitives, strings, other native objects, and arrays of those last three
• JNI bridge methods do the conversion
• Native method created to create the object, and finalize is a native
• While native classes may be marked open (e.g. @ExposeJNI(open = true)), they themselves extend from nothing even if they do in the native side
• Public and protected methods and properties can be exposed