Hi folks, question about annotation processing. Anyone knows how to read the annotations of the prop...

# announcements

[Ademir Queiroga]

Hi folks, question about annotation processing. Anyone knows how to read the annotations of the properties in a interface when processing the interface class?

@Model
interface Config {
    @Prop(name = "renamedConfigField")
    val configField: String
}

When processing the Config interface I would like to be able to iterate over it’s properties (which I’m already doing) but I’m not being able to read the fields annotations (e.g. read the @Prop annotation on the configField)

[Ademir Queiroga]

I’m working with KotlinPoet by the way

[Ademir Queiroga]

Ultimately what I want to achieve is to generate a class like this:

class ConfigModel(val renamedConfigField: String)

[Tyler Hodgkins]

Have you looked into #C013BA8EQSE? It’s a library/framework that facilitates Kotlin-specific annotation processing (and you can use KotlinPoet, though there isn’t an official binding from KSP to KotlinPoet like there is to kotlin.reflection).

[Tyler Hodgkins]

KSP’s libraries allow you to retrieve lots of information about Kotlin source declarations.

I’ve used it to build exactly what you describe - an annotation processor capable of deriving a class (with a constructor) from an annotated interface.

[Ademir Queiroga]

Hmm I didn’t. I’ll look into it. Thanks man!

[Tyler Hodgkins]

https://github.com/ty1824/dialector/blob/master/dialector-kt-processor/src/main/kotlin/dev/dialector/processor/DialectorSymbolProcessor.kt

I’m sorry in advance - this isn’t polished by any means 😄

[Ademir Queiroga]

Cool stuff!

[Ademir Queiroga]

Rewriting the processor I had with the #C013BA8EQSE. Much easier… I still didn’t reach the file generation part yet but looks promising.

[Ademir Queiroga]

Also, did you figure out a way to log? I’m having to write into a file as a logging tool

[Tyler Hodgkins]

I'll be honest, I haven't used/looked for a Kotlin logging library, probably should get around to that at some point 😅

[Tyler Hodgkins]

Just use file gen to write a Kotlin source file containing the problems found? 😂

[Ademir Queiroga]

println neither the logger passed in the init() prints in the std out

[Ademir Queiroga]

Yeah that’s what I am doing ahhaha. But seriously the main logic I had is basically done. MUCH MUCH easier it’s like magic

[Ademir Queiroga]

it just works

[Tyler Hodgkins]

Hmm, it would print to the compiler's output stream, which may be truncated/hidden in a file somewhere

[Tyler Hodgkins]

The folks in #C013BA8EQSE may have some better suggestions though!

[Tyler Hodgkins]

The maintainers of the project are pretty active :)

[Ademir Queiroga]

Really appreciate your help man! thanks a lot!!

[Tyler Hodgkins]

My pleasure, glad you found KSP useful :D It's a great tool!