How do I get parameters from constructors Java Element object from Annotation Processor process. using Kotlin Data Class

Question

Currently I'm trying this way:

element.enclosedElements.filter { it.kind == ElementKind.FIELD }.filter {
            it.modifiers.contains(Modifier.FINAL) &&
                    !it.modifiers.contains(Modifier.STATIC)
        }

but the problem with this way is that it is also returned member fields that are not in the constructor.

data class Post(
    val id: Int,
    val title: String,
    val content: String?,
    val a: Char,
    val b: Char?,
    val author_id: Int?,
    val is_public: Boolean,
    val is_updated: Boolean?,
) {
    private val myCustomField = true // I don't need this field when processing this class in annotation processor.
}

Note: I've tried this library: https://github.com/Takhion/kotlin-metadata but this library doesn't support the latest version of Kotlin.

Thanks.

Answer 1

Assuming there is only one public constructor (will throw exceptionIllegalArgumentException if more than one constructor exists):

(element.enclosedElements.single { 
    it.kind == ElementKind.CONSTRUCTOR && it.modifiers.contains(Modifier.PUBLIC) 
} as ExecutableElement).parameters

Getting all public constructors.

val publicConstructors = element.enclosedElements.filter {
    it.kind == ElementKind.CONSTRUCTOR && it.modifiers.contains(Modifier.PUBLIC)
}.map { it as ExecutableElement }