@MustBeDocumented
@Target(AnnotationTarget.CLASS)
@Retention(AnnotationRetention.RUNTIME)
annotation class MyAnnotation

abstract class MyFactory<in t: Any> {
   ...
   abstract fun genericMethod(model: T): Int
   ...
}

class MyFactoryImplementation<MyAnnotationType> {
   ...
   override fun genericMethod(model: MyAnnotation): Int {
      return when (model) {
         is UsesAnnotation -> 1
         else -> 0
   }
   ...
}

@MyAnnotation
class UsesAnnotation