Type for holding Java objects

[kud1ing]

Currently there are JvmClass, JvmObject and JvmStrings to bring some compile time type safety into Rust regarding different JVM classes. Unfortunately there is some code duplication.

Come up with an optimal way to hold Java objects in a Rust type that reflect the most specific Java class.

Aspects:

• jobject is just a type alias to *mut _jobject
  • jclass, jstring etc. are just type aliases to jobject
• in the constructor of the wrapper
  • do not accept JVM null pointers
  • do not accept JVM objects of the wrong type
  • IsInstanceOf() compares a jobject with a jclass.

Options:

• Macros? See https://github.com/rawrasaur/rust-jdbc/blob/5ad63b8f06ce1ded4e5c731cbae26c69d6c4b457/src/lib.rs
  • Rust nightly not necessary anymore?
• Tuple Struct?
  • does it help to reduce code duplication?
• Generic type in conjunction with an enum?

[treyzania]

You could probably write some macros to make this more ergonomic. I'm not sure how possible it would be but perhaps you could design a procedural macro that just takes Java code and generate structs/impls to mirror it.

[kud1ing]

Indeed rawrasaur/rust-jdbc uses some macros: https://github.com/rawrasaur/rust-jdbc/blob/5ad63b8f06ce1ded4e5c731cbae26c69d6c4b457/src/lib.rs

[kud1ing]

Yeah, that worked quite well actually: https://github.com/kud1ing/rucaja/commit/4d776df9aae45e257ed80d61132251d406dd905d