Higher-level api for defining java functions in a more "rusty" manner about jni-rs HOT 5 OPEN

Definitely want to see this. Something like:

#[jni("com.example.Foo")]
pub fn init(filename: &str) -> Result<(), Error> { ... }

#[jni("com.example.Bar")]
pub fn close_it(env: JNIEnv, filename: JString) -> Result<(), Error> { ... }

Becomes something like

#[no_mangle]
pub extern "system" fn Java_com_example_Bar_closeIt(env: JNIEnv, _: JClass, filename: JString) {
  // [...]
} 

1. Name maker. Pass in java path and the name becomes java-y.
2. Auto-conversion between Rust and Java types. Java types can still be expressed if you want to do it yourself.
3. catch_unwind
4. Handle Results and throw on error

from jni-rs.

After playing around with some JNI bindings of my own and encountering similar pain points, I've just published jni_fn which accomplishes at least the first item from @mehcode's comment:

1. Name maker. Pass in java path and the name becomes java-y.

That seemed like the most well-defined problem to knock off the list, and was also my biggest confusion when starting out (where did this long auto-generated name come from and why do I need to care about it?).

I'm happy to explore incorporating the jni_fn macro into jni if there's interest!

I'm also open to adding in the other 3 items from that list, but I'd appreciate more design discussion; ideally examples of code before and after expansion. I've only just started investigating JNI and I'm sure I don't have a good mental model of the "edge cases" of JNI usage yet.

from jni-rs.

After playing around with some JNI bindings of my own and encountering similar pain points, I've just published jni_fn which accomplishes at least the first item from @mehcode's comment:

1. Name maker. Pass in java path and the name becomes java-y.

...

I'm happy to explore incorporating the jni_fn macro into jni if there's interest!

@antonok-edm That looks super useful! Will try it in our project soon. Thanks for sharing 🙏

from jni-rs.

After having used a functionality pretty muchg exactly as @mehcode describes in Pyo3, this would be a great productivity boost. However it wouldn't be too difficult to simply create a proc_macro crate on top of jni to do this.

from jni-rs.

Agreed. Having to mix java's exceptions and rust's Result enum, I'm confident the syntax proposed would look and feel so much better.

from jni-rs.