Expose HttpExchange metadata to argument resolvers

See gh-33220

spring-web/src/main/java/org/springframework/web/service/invoker/AbstractNamedValueArgumentResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -77,7 +77,7 @@ public abstract class AbstractNamedValueArgumentResolver implements HttpServiceA
 	public boolean resolve(
 			@Nullable Object argument, MethodParameter parameter, HttpRequestValues.Builder requestValues) {
 
-		NamedValueInfo info = getNamedValueInfo(parameter);
+		NamedValueInfo info = getNamedValueInfo(parameter, requestValues);
 		if (info == null) {
 			return false;
 		}
@@ -102,10 +102,10 @@ public abstract class AbstractNamedValueArgumentResolver implements HttpServiceA
 	}
 
 	@Nullable
-	private NamedValueInfo getNamedValueInfo(MethodParameter parameter) {
+	private NamedValueInfo getNamedValueInfo(MethodParameter parameter, HttpRequestValues.Metadata requestValues) {
 		NamedValueInfo info = this.namedValueInfoCache.get(parameter);
 		if (info == null) {
-			info = createNamedValueInfo(parameter);
+			info = createNamedValueInfo(parameter, requestValues);
 			if (info == null) {
 				return null;
 			}
@@ -122,6 +122,18 @@ public abstract class AbstractNamedValueArgumentResolver implements HttpServiceA
 	@Nullable
 	protected abstract NamedValueInfo createNamedValueInfo(MethodParameter parameter);
 
+	/**
+	 * Variant of {@link #createNamedValueInfo(MethodParameter)} that also provides
+	 * access to the static values set from {@code @HttpExchange} attributes.
+	 * @since 6.2
+	 */
+	@Nullable
+	protected NamedValueInfo createNamedValueInfo(
+			MethodParameter parameter, HttpRequestValues.Metadata requestValues) {
+
+		return createNamedValueInfo(parameter);
+	}
+
 	private NamedValueInfo updateNamedValueInfo(MethodParameter parameter, NamedValueInfo info) {
 		String name = info.name;
 		if (info.name.isEmpty()) {

spring-web/src/main/java/org/springframework/web/service/invoker/HttpRequestValues.java

@@ -183,10 +183,42 @@ public class HttpRequestValues {
 	}
 
 
+	/**
+	 * Expose static metadata from {@code @HttpExchange} annotation attributes.
+	 * @since 6.2
+	 */
+	public interface Metadata {
+
+		/**
+		 * Return the HTTP method, if known.
+		 */
+		@Nullable
+		HttpMethod getHttpMethod();
+
+		/**
+		 * Return the URI template, if set already.
+		 */
+		@Nullable
+		String getUriTemplate();
+
+		/**
+		 * Return the content type, if set already.
+		 */
+		@Nullable
+		MediaType getContentType();
+
+		/**
+		 * Return the acceptable media types, if set already.
+		 */
+		@Nullable
+		List<MediaType> getAcceptMediaTypes();
+	}
+
+
 	/**
 	 * Builder for {@link HttpRequestValues}.
 	 */
-	public static class Builder {
+	public static class Builder implements Metadata {
 
 		@Nullable
 		private HttpMethod httpMethod;
@@ -357,6 +389,34 @@ public class HttpRequestValues {
 			this.bodyValue = bodyValue;
 		}
 
+
+		// Implementation of {@link Metadata} methods
+
+		@Override
+		@Nullable
+		public HttpMethod getHttpMethod() {
+			return this.httpMethod;
+		}
+
+		@Override
+		@Nullable
+		public String getUriTemplate() {
+			return this.uriTemplate;
+		}
+
+		@Override
+		@Nullable
+		public MediaType getContentType() {
+			return (this.headers != null ? this.headers.getContentType() : null);
+		}
+
+		@Override
+		@Nullable
+		public List<MediaType> getAcceptMediaTypes() {
+			return (this.headers != null ? this.headers.getAccept() : null);
+		}
+
+
 		/**
 		 * Build the {@link HttpRequestValues} instance.
 		 */