Polishing in HTTP interface argument resolvers

Author: rstoyanchev

framework-docs/modules/ROOT/pages/integration/rest-clients.adoc

@@ -978,11 +978,13 @@ method parameters:
   `MultiValueMap<String, ?>` with multiple cookies, a `Collection<?>` of values, or an
   individual value. Type conversion is supported for non-String values.
 
-The parameters can't be null unless they are set as not required through the annotation,
-annotated with `@Nullable` or they are `Optional`.
-
 |===
 
+Method parameters cannot be `null` unless the `required` attribute (where available on a
+parameter annotation) is set to `false`, or the parameter is marked optional as determined by
+{spring-framework-api}/core/MethodParameter.html#isOptional()[`MethodParameter#isOptional`].
+
+
 
 [[rest-http-interface-return-values]]
 === Return Values

framework-docs/modules/ROOT/pages/rsocket.adoc

@@ -1115,8 +1115,9 @@ method parameters:
 | `@Payload`
 | Set the input payload(s) for the request. This can be a concrete value, or any producer
   of values that can be adapted to a Reactive Streams `Publisher` via
-  `ReactiveAdapterRegistry`. The payload can't be null unless it's set as not required
-through the annotation, annotated with `@Nullable` or it is `Optional`.
+  `ReactiveAdapterRegistry`. A payload must be provided unless the `required` attribute
+  is set to `false`, or the parameter is marked optional as determined by
+  {spring-framework-api}/core/MethodParameter.html#isOptional()[`MethodParameter#isOptional`].
 
 | `Object`, if followed by `MimeType`
 | The value for a metadata entry in the input payload. This can be any `Object` as long

spring-messaging/src/main/java/org/springframework/messaging/rsocket/service/PayloadArgumentResolver.java

@@ -56,27 +56,27 @@ public boolean resolve(
 		}
 
 		if (argument == null) {
-			boolean required = (annot == null || annot.required()) && !parameter.isOptional();
-			Assert.isTrue(!required, () -> "Missing payload");
+			boolean isOptional = ((annot != null && !annot.required()) || parameter.isOptional());
+			Assert.isTrue(isOptional, () -> "Missing payload");
 			return true;
 		}
 
-		ReactiveAdapter reactiveAdapter = this.reactiveAdapterRegistry
-				.getAdapter(parameter.getParameterType());
-		if (reactiveAdapter == null) {
+		ReactiveAdapter adapter = this.reactiveAdapterRegistry.getAdapter(parameter.getParameterType());
+		if (adapter == null) {
 			requestValues.setPayloadValue(argument);
 		}
 		else {
 			MethodParameter nestedParameter = parameter.nested();
 
 			String message = "Async type for @Payload should produce value(s)";
 			Assert.isTrue(nestedParameter.getNestedParameterType() != Void.class, message);
-			Assert.isTrue(!reactiveAdapter.isNoValue(), message);
+			Assert.isTrue(!adapter.isNoValue(), message);
 
 			requestValues.setPayload(
-					reactiveAdapter.toPublisher(argument),
+					adapter.toPublisher(argument),
 					ParameterizedTypeReference.forType(nestedParameter.getNestedGenericParameterType()));
 		}
+
 		return true;
 	}
 }

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

@@ -63,6 +63,7 @@ public boolean resolve(
 		if (logger.isTraceEnabled()) {
 			logger.trace("Resolved HTTP method to: " + httpMethod.name());
 		}
+
 		return true;
 	}
 

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

@@ -81,8 +81,7 @@ public boolean resolve(
 		}
 
 		if (this.reactiveAdapterRegistry != null) {
-			ReactiveAdapter adapter = this.reactiveAdapterRegistry
-					.getAdapter(parameter.getParameterType());
+			ReactiveAdapter adapter = this.reactiveAdapterRegistry.getAdapter(parameter.getParameterType());
 			if (adapter != null) {
 				MethodParameter nestedParameter = parameter.nested();
 
@@ -102,6 +101,7 @@ public boolean resolve(
 				return true;
 			}
 		}
+
 		// Not a reactive type
 		requestValues.setBodyValue(argument);
 		return true;