My goal is more than supporting idiomatic Kotlin on the JVM, but to be able to develop with CBL in a pure Kotlin KMM shared module, such that the code can be compiled to both Android/JVM and iOS/Native. The reason for wrapping the API is so that the compiler can utilize either the underlying Java or Objective-C SDK, depending on the compilation target. The Kotlin API is mostly replicated from the Java API, with only a few minor differences (like property accessors instead of getters/setters in some cases). I’m also including the KTX extension functions in the API as well.
The code utilizes the Kotlin expect/actual mechanism to create platform-specific wrapper implementations around the CBL SDKs. In some cases for the Java API this can be achieved with a simple typealias, if the underlying code matches the Kotlin API 1:1. But in other cases (like if there are static functions that need to become companion object functions or other KMM nuances) then the Java code must be wrapped similar to the ObjC. The ObjC wrapper also converts types to align properly with the underlying SDK.
My goal with the KMM wrapper API is to mirror as much of CBL’s original API as possible. There are a handful of API methods I haven’t been able to implement for one reason or another because there is no pure Kotlin unifying API to utilize, mostly I/O and Executor related functions. I mentioned some of these here a while back.
I’ve achieved good success having done this originally for v2.8.6. I’m now working on updating the API to v3.0.0. I’d like to look at open sourcing my code once it’s ready. It’d be great to partner more closely with you in this effort.