AnnotatedMethodArgumentResolver class final

Resolves parameters of handler methods annotated with request parameter annotations in JetLeaf's web request handling system.

An AnnotatedMethodArgumentResolver is responsible for:

• Inspecting method parameters at runtime.
• Detecting annotations that are either RequestParameter or annotated with RequestParameter.
• Locating a corresponding Resolver (via ResolvedBy) to extract values from the ServerHttpRequest.

This resolver allows developers to define custom parameter resolution strategies using annotations on method parameters, enabling a clean separation between controller logic and request parsing.

Resolution Workflow

1. Annotation Discovery: Collects all direct annotations on a parameter.
2. Type Matching: Checks if an annotation is a RequestParameter or is meta-annotated with RequestParameter.
3. Resolver Extraction: Looks for a ResolvedBy annotation on the annotation class to retrieve the resolver instance.
4. Value Resolution: Uses the resolver to extract the argument value from the incoming request.
5. Returns null if no suitable resolver is found.

Example

class UserController {
  void getUser(
    @RequestParam('id') String id,
    @RequestParam('verbose') bool verbose
  ) {}
}

final resolver = AnnotatedMethodArgumentResolver();
final param = HandlerMethod(UserController.getUser).getParameter('id');
final value = await resolver.resolveArgument(param, request, response, handler);

Design Notes

• This class is stateless and can be reused across multiple requests.
• Supports annotation-driven parameter resolution via RequestParameter and ResolvedBy.
• Reflection failures while inspecting annotation metadata are silently ignored, ensuring robust request handling.
• Designed for internal use in the JetLeaf request dispatch pipeline.