Polish method parameter handling

spring-webflux/src/main/java/org/springframework/web/reactive/result/AbstractHandlerResultHandler.java

@@ -25,10 +25,12 @@ import java.util.Set;
 import java.util.function.Supplier;
 
 import org.springframework.core.Ordered;
+import org.springframework.core.ReactiveAdapter;
 import org.springframework.core.ReactiveAdapterRegistry;
 import org.springframework.http.MediaType;
 import org.springframework.util.Assert;
 import org.springframework.web.reactive.HandlerMapping;
+import org.springframework.web.reactive.HandlerResult;
 import org.springframework.web.reactive.accept.RequestedContentTypeResolver;
 import org.springframework.web.server.ServerWebExchange;
 
@@ -72,6 +74,14 @@ public abstract class AbstractHandlerResultHandler implements Ordered {
 		return this.adapterRegistry;
 	}
 
+	/**
+	 * Shortcut to get a ReactiveAdapter for the top-level return value type.
+	 */
+	protected ReactiveAdapter getAdapter(HandlerResult result) {
+		Class<?> returnType = result.getReturnType().getRawClass();
+		return getAdapterRegistry().getAdapter(returnType, result.getReturnValue());
+	}
+
 	/**
 	 * Return the configured {@link RequestedContentTypeResolver}.
 	 */

spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/AbstractMessageReaderArgumentResolver.java

@@ -113,11 +113,7 @@ public abstract class AbstractMessageReaderArgumentResolver {
 
 		ResolvableType bodyType = ResolvableType.forMethodParameter(bodyParameter);
 		ReactiveAdapter adapter = getAdapterRegistry().getAdapter(bodyType.resolve());
-
-		ResolvableType elementType = ResolvableType.forMethodParameter(bodyParameter);
-		if (adapter != null) {
-			elementType = elementType.getGeneric(0);
-		}
+		ResolvableType elementType = (adapter != null ? bodyType.getGeneric(0) : bodyType);
 
 		ServerHttpRequest request = exchange.getRequest();
 		ServerHttpResponse response = exchange.getResponse();
@@ -139,8 +135,8 @@ public abstract class AbstractMessageReaderArgumentResolver {
 					else {
 						flux = reader.read(elementType, request, readHints);
 					}
-					flux = flux.onErrorResumeWith(ex -> Flux.error(wrapReadError(ex, bodyParameter)));
-					if (checkRequired(adapter, isBodyRequired)) {
+					flux = flux.onErrorResumeWith(ex -> Flux.error(getReadError(bodyParameter, ex)));
+					if (isBodyRequired || !adapter.supportsEmpty()) {
 						flux = flux.switchIfEmpty(Flux.error(getRequiredBodyError(bodyParameter)));
 					}
 					Object[] hints = extractValidationHints(bodyParameter);
@@ -159,8 +155,8 @@ public abstract class AbstractMessageReaderArgumentResolver {
 					else {
 						mono = reader.readMono(elementType, request, readHints);
 					}
-					mono = mono.otherwise(ex -> Mono.error(wrapReadError(ex, bodyParameter)));
-					if (checkRequired(adapter, isBodyRequired)) {
+					mono = mono.otherwise(ex -> Mono.error(getReadError(bodyParameter, ex)));
+					if (isBodyRequired || (adapter != null && !adapter.supportsEmpty())) {
 						mono = mono.otherwiseIfEmpty(Mono.error(getRequiredBodyError(bodyParameter)));
 					}
 					Object[] hints = extractValidationHints(bodyParameter);
@@ -181,15 +177,11 @@ public abstract class AbstractMessageReaderArgumentResolver {
 		return Mono.error(new UnsupportedMediaTypeStatusException(mediaType, this.supportedMediaTypes));
 	}
 
-	protected ServerWebInputException wrapReadError(Throwable ex, MethodParameter parameter) {
+	private ServerWebInputException getReadError(MethodParameter parameter, Throwable ex) {
 		return new ServerWebInputException("Failed to read HTTP message", parameter, ex);
 	}
 
-	protected boolean checkRequired(ReactiveAdapter adapter, boolean isBodyRequired) {
-		return adapter != null && !adapter.supportsEmpty() || isBodyRequired;
-	}
-
-	protected ServerWebInputException getRequiredBodyError(MethodParameter parameter) {
+	private ServerWebInputException getRequiredBodyError(MethodParameter parameter) {
 		return new ServerWebInputException("Required request body is missing: " +
 				parameter.getMethod().toGenericString());
 	}
@@ -199,7 +191,7 @@ public abstract class AbstractMessageReaderArgumentResolver {
 	 * a (possibly empty) Object[] with validation hints. A return value of
 	 * {@code null} indicates that validation is not required.
 	 */
-	protected Object[] extractValidationHints(MethodParameter parameter) {
+	private Object[] extractValidationHints(MethodParameter parameter) {
 		Annotation[] annotations = parameter.getParameterAnnotations();
 		for (Annotation ann : annotations) {
 			Validated validAnnot = AnnotationUtils.getAnnotation(ann, Validated.class);
@@ -211,8 +203,8 @@ public abstract class AbstractMessageReaderArgumentResolver {
 		return null;
 	}
 
-	protected void validate(Object target, Object[] validationHints,
-			MethodParameter param, BindingContext binding, ServerWebExchange exchange) {
+	private void validate(Object target, Object[] validationHints, MethodParameter param,
+			BindingContext binding, ServerWebExchange exchange) {
 
 		String name = Conventions.getVariableNameForParameter(param);
 		WebExchangeDataBinder binder = binding.createDataBinder(exchange, target, name);

spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/AbstractMessageWriterResultHandler.java

@@ -93,21 +93,19 @@ public abstract class AbstractMessageWriterResultHandler extends AbstractHandler
 	@SuppressWarnings("unchecked")
 	protected Mono<Void> writeBody(Object body, MethodParameter bodyParameter, ServerWebExchange exchange) {
 
-		ResolvableType valueType = ResolvableType.forMethodParameter(bodyParameter);
-		Class<?> valueClass = valueType.resolve();
-		ReactiveAdapter adapter = getAdapterRegistry().getAdapter(valueClass, body);
+		ResolvableType bodyType = ResolvableType.forMethodParameter(bodyParameter);
+		Class<?> bodyClass = bodyType.resolve();
+		ReactiveAdapter adapter = getAdapterRegistry().getAdapter(bodyClass, body);
 
 		Publisher<?> publisher;
 		ResolvableType elementType;
 		if (adapter != null) {
 			publisher = adapter.toPublisher(body);
-			elementType = adapter.isNoValue() ?
-					ResolvableType.forClass(Void.class) : valueType.getGeneric(0);
+			elementType = adapter.isNoValue() ? ResolvableType.forClass(Void.class) : bodyType.getGeneric(0);
 		}
 		else {
 			publisher = Mono.justOrEmpty(body);
-			elementType = (valueClass == null && body != null ?
-					ResolvableType.forInstance(body) : valueType);
+			elementType = (bodyClass == null && body != null ? ResolvableType.forInstance(body) : bodyType);
 		}
 
 		if (void.class == elementType.getRawClass() || Void.class == elementType.getRawClass()) {
@@ -122,7 +120,7 @@ public abstract class AbstractMessageWriterResultHandler extends AbstractHandler
 				if (messageWriter.canWrite(elementType, bestMediaType)) {
 					return (messageWriter instanceof ServerHttpMessageWriter ?
 							((ServerHttpMessageWriter<?>) messageWriter).write((Publisher) publisher,
-									valueType, elementType, bestMediaType, request, response, Collections.emptyMap()) :
+									bodyType, elementType, bestMediaType, request, response, Collections.emptyMap()) :
 							messageWriter.write((Publisher) publisher, elementType,
 									bestMediaType, response, Collections.emptyMap()));
 				}

spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/HttpEntityArgumentResolver.java

@@ -22,9 +22,7 @@ import reactor.core.publisher.Mono;
 
 import org.springframework.core.MethodParameter;
 import org.springframework.core.ReactiveAdapterRegistry;
-import org.springframework.core.ResolvableType;
 import org.springframework.http.HttpEntity;
-import org.springframework.http.HttpHeaders;
 import org.springframework.http.RequestEntity;
 import org.springframework.http.codec.HttpMessageReader;
 import org.springframework.http.server.reactive.ServerHttpRequest;
@@ -69,29 +67,20 @@ public class HttpEntityArgumentResolver extends AbstractMessageReaderArgumentRes
 	}
 
 	@Override
-	public Mono<Object> resolveArgument(MethodParameter param, BindingContext bindingContext,
+	public Mono<Object> resolveArgument(MethodParameter parameter, BindingContext bindingContext,
 			ServerWebExchange exchange) {
 
-		ResolvableType entityType = ResolvableType.forMethodParameter(param);
-		MethodParameter bodyParameter = new MethodParameter(param);
-		bodyParameter.increaseNestingLevel();
+		Class<?> entityType = parameter.getParameterType();
 
-		return readBody(bodyParameter, false, bindingContext, exchange)
-				.map(body -> createHttpEntity(body, entityType, exchange))
-				.defaultIfEmpty(createHttpEntity(null, entityType, exchange));
+		return readBody(parameter.nested(), false, bindingContext, exchange)
+				.map(body -> createEntity(body, entityType, exchange.getRequest()))
+				.defaultIfEmpty(createEntity(null, entityType, exchange.getRequest()));
 	}
 
-	private Object createHttpEntity(Object body, ResolvableType entityType,
-			ServerWebExchange exchange) {
-
-		ServerHttpRequest request = exchange.getRequest();
-		HttpHeaders headers = request.getHeaders();
-		if (RequestEntity.class == entityType.getRawClass()) {
-			return new RequestEntity<>(body, headers, request.getMethod(), request.getURI());
-		}
-		else {
-			return new HttpEntity<>(body, headers);
-		}
+	private Object createEntity(Object body, Class<?> entityType, ServerHttpRequest request) {
+		return RequestEntity.class.equals(entityType) ?
+				new RequestEntity<>(body, request.getHeaders(), request.getMethod(), request.getURI()) :
+				new HttpEntity<>(body, request.getHeaders());
 	}
 
 }

spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/ModelAttributeMethodArgumentResolver.java

@@ -28,6 +28,7 @@ import org.springframework.core.ReactiveAdapter;
 import org.springframework.core.ReactiveAdapterRegistry;
 import org.springframework.core.ResolvableType;
 import org.springframework.core.annotation.AnnotationUtils;
+import org.springframework.ui.Model;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.StringUtils;
@@ -122,9 +123,10 @@ public class ModelAttributeMethodArgumentResolver implements HandlerMethodArgume
 
 		ResolvableType type = ResolvableType.forMethodParameter(parameter);
 		ReactiveAdapter adapter = getAdapterRegistry().getAdapter(type.resolve());
-		Class<?> valueType = (adapter != null ? type.resolveGeneric(0) : parameter.getParameterType());
+		ResolvableType valueType = (adapter != null ? type.getGeneric(0) : type);
+
 		String name = getAttributeName(valueType, parameter);
-		Mono<?> valueMono = getAttributeMono(name, valueType, parameter, context, exchange);
+		Mono<?> valueMono = getAttributeMono(name, valueType, context.getModel());
 
 		Map<String, Object> model = context.getModel().asMap();
 		MonoProcessor<BindingResult> bindingResultMono = MonoProcessor.create();
@@ -146,10 +148,10 @@ public class ModelAttributeMethodArgumentResolver implements HandlerMethodArgume
 						if (adapter != null) {
 							return adapter.fromPublisher(errors.hasErrors() ?
 									Mono.error(new WebExchangeBindException(parameter, errors)) :
-									Mono.just(value));
+									valueMono);
 						}
 						else {
-							if (errors.hasErrors() && checkErrorsArgument(parameter)) {
+							if (errors.hasErrors() && !hasErrorsArgument(parameter)) {
 								throw new WebExchangeBindException(parameter, errors);
 							}
 							return value;
@@ -158,46 +160,37 @@ public class ModelAttributeMethodArgumentResolver implements HandlerMethodArgume
 		});
 	}
 
-	private String getAttributeName(Class<?> valueType, MethodParameter parameter) {
+	private String getAttributeName(ResolvableType valueType, MethodParameter parameter) {
 		ModelAttribute annot = parameter.getParameterAnnotation(ModelAttribute.class);
 		if (annot != null && StringUtils.hasText(annot.value())) {
 			return annot.value();
 		}
 		// TODO: Conventions does not deal with async wrappers
-		return ClassUtils.getShortNameAsProperty(valueType);
+		return ClassUtils.getShortNameAsProperty(valueType.getRawClass());
 	}
 
-	private Mono<?> getAttributeMono(String attributeName, Class<?> attributeType,
-			MethodParameter param, BindingContext context, ServerWebExchange exchange) {
-
-		Object attribute = context.getModel().asMap().get(attributeName);
+	private Mono<?> getAttributeMono(String attributeName, ResolvableType attributeType, Model model) {
+		Object attribute = model.asMap().get(attributeName);
 		if (attribute == null) {
-			attribute = createAttribute(attributeName, attributeType, param, context, exchange);
+			attribute = BeanUtils.instantiateClass(attributeType.getRawClass());
 		}
-		if (attribute != null) {
-			ReactiveAdapter adapterFrom = getAdapterRegistry().getAdapter(null, attribute);
-			if (adapterFrom != null) {
-				Assert.isTrue(!adapterFrom.isMultiValue(), "Data binding supports single-value async types.");
-				return Mono.from(adapterFrom.toPublisher(attribute));
-			}
+		ReactiveAdapter adapterFrom = getAdapterRegistry().getAdapter(null, attribute);
+		if (adapterFrom != null) {
+			Assert.isTrue(!adapterFrom.isMultiValue(), "Data binding supports single-value async types.");
+			return Mono.from(adapterFrom.toPublisher(attribute));
+		}
+		else {
+			return Mono.justOrEmpty(attribute);
 		}
-		return Mono.justOrEmpty(attribute);
-	}
-
-
-	protected Object createAttribute(String attributeName, Class<?> attributeType,
-			MethodParameter parameter, BindingContext context, ServerWebExchange exchange) {
-
-		return BeanUtils.instantiateClass(attributeType);
 	}
 
-	protected boolean checkErrorsArgument(MethodParameter methodParam) {
+	private boolean hasErrorsArgument(MethodParameter methodParam) {
 		int i = methodParam.getParameterIndex();
 		Class<?>[] paramTypes = methodParam.getMethod().getParameterTypes();
-		return paramTypes.length <= (i + 1) || !Errors.class.isAssignableFrom(paramTypes[i + 1]);
+		return paramTypes.length > i && Errors.class.isAssignableFrom(paramTypes[i + 1]);
 	}
 
-	protected void validateIfApplicable(WebExchangeDataBinder binder, MethodParameter parameter) {
+	private void validateIfApplicable(WebExchangeDataBinder binder, MethodParameter parameter) {
 		Annotation[] annotations = parameter.getParameterAnnotations();
 		for (Annotation ann : annotations) {
 			Validated validAnnot = AnnotationUtils.getAnnotation(ann, Validated.class);

spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/PathVariableMapMethodArgumentResolver.java

@@ -43,9 +43,10 @@ public class PathVariableMapMethodArgumentResolver implements SyncHandlerMethodA
 
 	@Override
 	public boolean supportsParameter(MethodParameter parameter) {
-		PathVariable ann = parameter.getParameterAnnotation(PathVariable.class);
-		return (ann != null && (Map.class.isAssignableFrom(parameter.getParameterType()))
-				&& !StringUtils.hasText(ann.value()));
+		PathVariable annotation = parameter.getParameterAnnotation(PathVariable.class);
+		return (annotation != null &&
+				Map.class.isAssignableFrom(parameter.getParameterType()) &&
+				!StringUtils.hasText(annotation.value()));
 	}
 
 	@Override

spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/RequestBodyArgumentResolver.java

@@ -74,8 +74,8 @@ public class RequestBodyArgumentResolver extends AbstractMessageReaderArgumentRe
 	public Mono<Object> resolveArgument(MethodParameter param, BindingContext bindingContext,
 			ServerWebExchange exchange) {
 
-		boolean isRequired = param.getParameterAnnotation(RequestBody.class).required();
-		return readBody(param, isRequired, bindingContext, exchange);
+		RequestBody annotation = param.getParameterAnnotation(RequestBody.class);
+		return readBody(param, annotation.required(), bindingContext, exchange);
 	}
 
 }

spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/ResponseBodyResultHandler.java

@@ -55,31 +55,26 @@ public class ResponseBodyResultHandler extends AbstractMessageWriterResultHandle
 
 
 	/**
-	 * Constructor with {@link HttpMessageWriter}s and a
-	 * {@code RequestedContentTypeResolver}.
-	 *
-	 * @param messageWriters writers for serializing to the response body stream
-	 * @param contentTypeResolver for resolving the requested content type
+	 * Basic constructor with a default {@link ReactiveAdapterRegistry}.
+	 * @param writers writers for serializing to the response body
+	 * @param resolver to determine the requested content type
 	 */
-	public ResponseBodyResultHandler(List<HttpMessageWriter<?>> messageWriters,
-			RequestedContentTypeResolver contentTypeResolver) {
+	public ResponseBodyResultHandler(List<HttpMessageWriter<?>> writers,
+			RequestedContentTypeResolver resolver) {
 
-		this(messageWriters, contentTypeResolver, new ReactiveAdapterRegistry());
+		this(writers, resolver, new ReactiveAdapterRegistry());
 	}
 
 	/**
-	 * Constructor with an additional {@link ReactiveAdapterRegistry}.
-	 *
-	 * @param messageWriters writers for serializing to the response body stream
-	 * @param contentTypeResolver for resolving the requested content type
-	 * @param adapterRegistry for adapting other reactive types (e.g. rx.Observable,
-	 * rx.Single, etc.) to Flux or Mono
+	 * Constructor with an {@link ReactiveAdapterRegistry} instance.
+	 * @param writers writers for serializing to the response body
+	 * @param resolver to determine the requested content type
+	 * @param registry for adaptation to reactive types
 	 */
-	public ResponseBodyResultHandler(List<HttpMessageWriter<?>> messageWriters,
-			RequestedContentTypeResolver contentTypeResolver,
-			ReactiveAdapterRegistry adapterRegistry) {
+	public ResponseBodyResultHandler(List<HttpMessageWriter<?>> writers,
+			RequestedContentTypeResolver resolver, ReactiveAdapterRegistry registry) {
 
-		super(messageWriters, contentTypeResolver, adapterRegistry);
+		super(writers, resolver, registry);
 		setOrder(100);
 	}
 
@@ -87,32 +82,11 @@ public class ResponseBodyResultHandler extends AbstractMessageWriterResultHandle
 	@Override
 	public boolean supports(HandlerResult result) {
 		MethodParameter parameter = result.getReturnTypeSource();
-		return hasResponseBodyAnnotation(parameter) && !isHttpEntityType(result);
-	}
-
-	private boolean hasResponseBodyAnnotation(MethodParameter parameter) {
 		Class<?> containingClass = parameter.getContainingClass();
 		return (AnnotationUtils.findAnnotation(containingClass, ResponseBody.class) != null ||
 				parameter.getMethodAnnotation(ResponseBody.class) != null);
 	}
 
-	private boolean isHttpEntityType(HandlerResult result) {
-		Class<?> rawClass = result.getReturnType().getRawClass();
-		if (HttpEntity.class.isAssignableFrom(rawClass)) {
-			return true;
-		}
-		else {
-			ReactiveAdapter adapter = getAdapterRegistry().getAdapter(rawClass, result.getReturnValue());
-			if (adapter != null && !adapter.isNoValue()) {
-				ResolvableType genericType = result.getReturnType().getGeneric(0);
-				if (HttpEntity.class.isAssignableFrom(genericType.getRawClass())) {
-					return true;
-				}
-			}
-		}
-		return false;
-	}
-
 	@Override
 	public Mono<Void> handleResult(ServerWebExchange exchange, HandlerResult result) {
 		Object body = result.getReturnValue().orElse(null);

spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/ResponseEntityResultHandler.java

@@ -18,7 +18,6 @@ package org.springframework.web.reactive.result.method.annotation;
 import java.time.Instant;
 import java.util.Arrays;
 import java.util.List;
-import java.util.Optional;
 
 import reactor.core.publisher.Mono;
 
@@ -54,78 +53,61 @@ public class ResponseEntityResultHandler extends AbstractMessageWriterResultHand
 
 
 	/**
-	 * Constructor with {@link HttpMessageWriter}s and a
-	 * {@code RequestedContentTypeResolver}.
-	 *
-	 * @param messageWriters writers for serializing to the response body stream
-	 * @param contentTypeResolver for resolving the requested content type
+	 * Basic constructor with a default {@link ReactiveAdapterRegistry}.
+	 * @param writers writers for serializing to the response body
+	 * @param resolver to determine the requested content type
 	 */
-	public ResponseEntityResultHandler(List<HttpMessageWriter<?>> messageWriters,
-			RequestedContentTypeResolver contentTypeResolver) {
+	public ResponseEntityResultHandler(List<HttpMessageWriter<?>> writers,
+			RequestedContentTypeResolver resolver) {
 
-		this(messageWriters, contentTypeResolver, new ReactiveAdapterRegistry());
+		this(writers, resolver, new ReactiveAdapterRegistry());
 	}
 
 	/**
-	 * Constructor with an additional {@link ReactiveAdapterRegistry}.
-	 *
-	 * @param messageWriters writers for serializing to the response body stream
-	 * @param contentTypeResolver for resolving the requested content type
-	 * @param adapterRegistry for adapting other reactive types (e.g. rx.Observable,
-	 * rx.Single, etc.) to Flux or Mono
+	 * Constructor with an {@link ReactiveAdapterRegistry} instance.
+	 * @param writers writers for serializing to the response body
+	 * @param resolver to determine the requested content type
+	 * @param registry for adaptation to reactive types
 	 */
-	public ResponseEntityResultHandler(List<HttpMessageWriter<?>> messageWriters,
-			RequestedContentTypeResolver contentTypeResolver,
-			ReactiveAdapterRegistry adapterRegistry) {
+	public ResponseEntityResultHandler(List<HttpMessageWriter<?>> writers,
+			RequestedContentTypeResolver resolver, ReactiveAdapterRegistry registry) {
 
-		super(messageWriters, contentTypeResolver, adapterRegistry);
+		super(writers, resolver, registry);
 		setOrder(0);
 	}
 
 
 	@Override
 	public boolean supports(HandlerResult result) {
-		Class<?> returnType = result.getReturnType().getRawClass();
-		if (isSupportedType(returnType)) {
+		if (isSupportedType(result.getReturnType())) {
 			return true;
 		}
-		else {
-			ReactiveAdapter adapter = getAdapterRegistry().getAdapter(returnType, result.getReturnValue());
-			if (adapter != null && !adapter.isMultiValue() && !adapter.isNoValue()) {
-				ResolvableType genericType = result.getReturnType().getGeneric(0);
-				return isSupportedType(genericType.getRawClass());
-			}
-		}
-		return false;
+		ReactiveAdapter adapter = getAdapter(result);
+		return adapter != null && !adapter.isNoValue() &&
+				isSupportedType(result.getReturnType().getGeneric(0));
 	}
 
-	private boolean isSupportedType(Class<?> clazz) {
+	private boolean isSupportedType(ResolvableType type) {
+		Class<?> clazz = type.getRawClass();
 		return (HttpEntity.class.isAssignableFrom(clazz) && !RequestEntity.class.isAssignableFrom(clazz));
 	}
 
 
 	@Override
 	public Mono<Void> handleResult(ServerWebExchange exchange, HandlerResult result) {
-		ResolvableType returnType = result.getReturnType();
-		MethodParameter bodyType;
 
 		Mono<?> returnValueMono;
-		Optional<Object> optionalValue = result.getReturnValue();
-
-		Class<?> rawClass = returnType.getRawClass();
-		ReactiveAdapter adapter = getAdapterRegistry().getAdapter(rawClass, optionalValue);
+		MethodParameter bodyParameter;
+		ReactiveAdapter adapter = getAdapter(result);
 
 		if (adapter != null) {
 			Assert.isTrue(!adapter.isMultiValue(), "Only a single ResponseEntity supported");
-			returnValueMono = Mono.from(adapter.toPublisher(optionalValue));
-			bodyType = new MethodParameter(result.getReturnTypeSource());
-			bodyType.increaseNestingLevel();
-			bodyType.increaseNestingLevel();
+			returnValueMono = Mono.from(adapter.toPublisher(result.getReturnValue()));
+			bodyParameter = result.getReturnTypeSource().nested().nested();
 		}
 		else {
-			returnValueMono = Mono.justOrEmpty(optionalValue);
-			bodyType = new MethodParameter(result.getReturnTypeSource());
-			bodyType.increaseNestingLevel();
+			returnValueMono = Mono.justOrEmpty(result.getReturnValue());
+			bodyParameter = result.getReturnTypeSource().nested();
 		}
 
 		return returnValueMono.then(returnValue -> {
@@ -156,7 +138,7 @@ public class ResponseEntityResultHandler extends AbstractMessageWriterResultHand
 				return exchange.getResponse().setComplete();
 			}
 
-			return writeBody(httpEntity.getBody(), bodyType, exchange);
+			return writeBody(httpEntity.getBody(), bodyParameter, exchange);
 		});
 	}
 

spring-webflux/src/main/java/org/springframework/web/reactive/result/view/ViewResolutionResultHandler.java

@@ -22,7 +22,6 @@ import java.util.Collections;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
-import java.util.Optional;
 import java.util.stream.Collectors;
 
 import reactor.core.publisher.Flux;
@@ -94,29 +93,27 @@ public class ViewResolutionResultHandler extends AbstractHandlerResultHandler
 
 
 	/**
-	 * Constructor with {@link ViewResolver}s and a {@link RequestedContentTypeResolver}.
-	 * @param resolvers the resolver to use
-	 * @param contentTypeResolver for resolving the requested content type
+	 * Basic constructor with a default {@link ReactiveAdapterRegistry}.
+	 * @param viewResolvers the resolver to use
+	 * @param contentTypeResolver to determine the requested content type
 	 */
-	public ViewResolutionResultHandler(List<ViewResolver> resolvers,
+	public ViewResolutionResultHandler(List<ViewResolver> viewResolvers,
 			RequestedContentTypeResolver contentTypeResolver) {
 
-		this(resolvers, contentTypeResolver, new ReactiveAdapterRegistry());
+		this(viewResolvers, contentTypeResolver, new ReactiveAdapterRegistry());
 	}
 
 	/**
-	 * Constructor with {@code ViewResolver}s tand a {@code ConversionService}.
-	 * @param resolvers the resolver to use
-	 * @param contentTypeResolver for resolving the requested content type
-	 * @param adapterRegistry for adapting from other reactive types (e.g.
-	 * rx.Single) to Mono
+	 * Constructor with an {@link ReactiveAdapterRegistry} instance.
+	 * @param viewResolvers the view resolver to use
+	 * @param contentTypeResolver to determine the requested content type
+	 * @param registry for adaptation to reactive types
 	 */
-	public ViewResolutionResultHandler(List<ViewResolver> resolvers,
-			RequestedContentTypeResolver contentTypeResolver,
-			ReactiveAdapterRegistry adapterRegistry) {
+	public ViewResolutionResultHandler(List<ViewResolver> viewResolvers,
+			RequestedContentTypeResolver contentTypeResolver, ReactiveAdapterRegistry registry) {
 
-		super(contentTypeResolver, adapterRegistry);
-		this.viewResolvers.addAll(resolvers);
+		super(contentTypeResolver, registry);
+		this.viewResolvers.addAll(viewResolvers);
 		AnnotationAwareOrderComparator.sort(this.viewResolvers);
 	}
 
@@ -148,113 +145,97 @@ public class ViewResolutionResultHandler extends AbstractHandlerResultHandler
 
 	@Override
 	public boolean supports(HandlerResult result) {
-		Class<?> clazz = result.getReturnType().getRawClass();
-		if (hasModelAttributeAnnotation(result)) {
+		if (hasModelAnnotation(result.getReturnTypeSource())) {
 			return true;
 		}
-		Optional<Object> optional = result.getReturnValue();
-		ReactiveAdapter adapter = getAdapterRegistry().getAdapter(clazz, optional);
+		Class<?> type = result.getReturnType().getRawClass();
+		ReactiveAdapter adapter = getAdapter(result);
 		if (adapter != null) {
 			if (adapter.isNoValue()) {
 				return true;
 			}
-			else {
-				clazz = result.getReturnType().getGeneric(0).getRawClass();
-				return isSupportedType(clazz);
-			}
-		}
-		else if (isSupportedType(clazz)) {
-			return true;
+			type = result.getReturnType().getGeneric(0).getRawClass();
 		}
-		return false;
+		return (CharSequence.class.isAssignableFrom(type) || View.class.isAssignableFrom(type) ||
+				Model.class.isAssignableFrom(type) || Map.class.isAssignableFrom(type) ||
+				!BeanUtils.isSimpleProperty(type));
 	}
 
-	private boolean hasModelAttributeAnnotation(HandlerResult result) {
-		MethodParameter returnType = result.getReturnTypeSource();
-		return returnType.hasMethodAnnotation(ModelAttribute.class);
-	}
-
-	private boolean isSupportedType(Class<?> clazz) {
-		return (CharSequence.class.isAssignableFrom(clazz) || View.class.isAssignableFrom(clazz) ||
-				Model.class.isAssignableFrom(clazz) || Map.class.isAssignableFrom(clazz) ||
-				!BeanUtils.isSimpleProperty(clazz));
+	private boolean hasModelAnnotation(MethodParameter parameter) {
+		return parameter.hasMethodAnnotation(ModelAttribute.class);
 	}
 
 	@Override
 	@SuppressWarnings("unchecked")
 	public Mono<Void> handleResult(ServerWebExchange exchange, HandlerResult result) {
 
-		Mono<Object> returnValueMono;
-		ResolvableType elementType;
-		ResolvableType parameterType = result.getReturnType();
-
-		Optional<Object> optional = result.getReturnValue();
-		ReactiveAdapter adapter = getAdapterRegistry().getAdapter(parameterType.getRawClass(), optional);
+		Mono<Object> valueMono;
+		ResolvableType valueType;
+		ReactiveAdapter adapter = getAdapter(result);
 
 		if (adapter != null) {
 			Assert.isTrue(!adapter.isMultiValue(), "Only single-value async return type supported.");
-			returnValueMono = optional
-					.map(value -> Mono.from(adapter.toPublisher(value)))
-					.orElse(Mono.empty());
-			elementType = !adapter.isNoValue() ?
-					parameterType.getGeneric(0) : ResolvableType.forClass(Void.class);
+			valueMono = result.getReturnValue()
+					.map(value -> Mono.from(adapter.toPublisher(value))).orElse(Mono.empty());
+			valueType = adapter.isNoValue() ?
+					ResolvableType.forClass(Void.class) : result.getReturnType().getGeneric(0);
 		}
 		else {
-			returnValueMono = Mono.justOrEmpty(result.getReturnValue());
-			elementType = parameterType;
+			valueMono = Mono.justOrEmpty(result.getReturnValue());
+			valueType = result.getReturnType();
 		}
 
-		return returnValueMono
+		return valueMono
 				.otherwiseIfEmpty(exchange.isNotModified() ? Mono.empty() : NO_VALUE_MONO)
 				.then(returnValue -> {
 
 					Mono<List<View>> viewsMono;
 					Model model = result.getModel();
+					MethodParameter parameter = result.getReturnTypeSource();
 
 					Locale acceptLocale = exchange.getRequest().getHeaders().getAcceptLanguageAsLocale();
 					Locale locale = acceptLocale != null ? acceptLocale : Locale.getDefault();
 
-					Class<?> clazz = elementType.getRawClass();
+					Class<?> clazz = valueType.getRawClass();
 					if (clazz == null) {
 						clazz = returnValue.getClass();
 					}
 
 					if (returnValue == NO_VALUE || Void.class.equals(clazz) || void.class.equals(clazz)) {
-						viewsMono = resolveViews(getDefaultViewName(result, exchange), locale);
+						viewsMono = resolveViews(getDefaultViewName(exchange), locale);
 					}
 					else if (Model.class.isAssignableFrom(clazz)) {
 						model.addAllAttributes(((Model) returnValue).asMap());
-						viewsMono = resolveViews(getDefaultViewName(result, exchange), locale);
+						viewsMono = resolveViews(getDefaultViewName(exchange), locale);
 					}
 					else if (Map.class.isAssignableFrom(clazz)) {
 						model.addAllAttributes((Map<String, ?>) returnValue);
-						viewsMono = resolveViews(getDefaultViewName(result, exchange), locale);
+						viewsMono = resolveViews(getDefaultViewName(exchange), locale);
 					}
 					else if (View.class.isAssignableFrom(clazz)) {
 						viewsMono = Mono.just(Collections.singletonList((View) returnValue));
 					}
-					else if (CharSequence.class.isAssignableFrom(clazz) && !hasModelAttributeAnnotation(result)) {
+					else if (CharSequence.class.isAssignableFrom(clazz) && !hasModelAnnotation(parameter)) {
 						viewsMono = resolveViews(returnValue.toString(), locale);
 					}
 					else {
-						String name = getNameForReturnValue(clazz, result.getReturnTypeSource());
+						String name = getNameForReturnValue(clazz, parameter);
 						model.addAttribute(name, returnValue);
-						viewsMono = resolveViews(getDefaultViewName(result, exchange), locale);
+						viewsMono = resolveViews(getDefaultViewName(exchange), locale);
 					}
 
 					return resolveAsyncAttributes(model.asMap())
-							.doOnSuccess(aVoid -> addBindingResult(result, exchange))
+							.doOnSuccess(aVoid -> addBindingResult(result.getBindingContext(), exchange))
 							.then(viewsMono)
 							.then(views -> render(views, model.asMap(), exchange));
 				});
 	}
 
 	/**
-	 * Select a default view name when a controller leaves the view unspecified.
-	 * The default implementation strips the leading and trailing slash from the
-	 * as well as any extension and uses that as the view name.
+	 * Select a default view name when a controller did not specify it.
+	 * Use the request path the leading and trailing slash stripped.
 	 */
-	protected String getDefaultViewName(HandlerResult result, ServerWebExchange exchange) {
+	private String getDefaultViewName(ServerWebExchange exchange) {
 		String path = this.pathHelper.getLookupPathForRequest(exchange);
 		if (path.startsWith("/")) {
 			path = path.substring(1);
@@ -332,8 +313,7 @@ public class ViewResolutionResultHandler extends AbstractHandlerResultHandler
 				.then();
 	}
 
-	private void addBindingResult(HandlerResult result, ServerWebExchange exchange) {
-		BindingContext context = result.getBindingContext();
+	private void addBindingResult(BindingContext context, ServerWebExchange exchange) {
 		Map<String, Object> model = context.getModel().asMap();
 		model.keySet().stream()
 				.filter(name -> isBindingCandidate(name, model.get(name)))

spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/HttpEntityArgumentResolverTests.java

@@ -43,6 +43,7 @@ import org.springframework.http.codec.DecoderHttpMessageReader;
 import org.springframework.http.codec.HttpMessageReader;
 import org.springframework.mock.http.server.reactive.test.MockServerHttpRequest;
 import org.springframework.mock.http.server.reactive.test.MockServerHttpResponse;
+import org.springframework.util.ObjectUtils;
 import org.springframework.web.reactive.BindingContext;
 import org.springframework.web.method.ResolvableMethod;
 import org.springframework.web.server.ServerWebExchange;
@@ -83,23 +84,26 @@ public class HttpEntityArgumentResolverTests {
 
 	@Test
 	public void supports() throws Exception {
-		testSupports(httpEntityType(String.class));
-		testSupports(httpEntityType(forClassWithGenerics(Mono.class, String.class)));
-		testSupports(httpEntityType(forClassWithGenerics(Single.class, String.class)));
-		testSupports(httpEntityType(forClassWithGenerics(io.reactivex.Single.class, String.class)));
-		testSupports(httpEntityType(forClassWithGenerics(Maybe.class, String.class)));
-		testSupports(httpEntityType(forClassWithGenerics(CompletableFuture.class, String.class)));
-		testSupports(httpEntityType(forClassWithGenerics(Flux.class, String.class)));
-		testSupports(httpEntityType(forClassWithGenerics(Observable.class, String.class)));
-		testSupports(httpEntityType(forClassWithGenerics(io.reactivex.Observable.class, String.class)));
-		testSupports(httpEntityType(forClassWithGenerics(Flowable.class, String.class)));
-		testSupports(forClassWithGenerics(RequestEntity.class, String.class));
+		testSupports(this.testMethod.arg(httpEntityType(String.class)));
+		testSupports(this.testMethod.arg(httpEntityType(Mono.class, String.class)));
+		testSupports(this.testMethod.arg(httpEntityType(Single.class, String.class)));
+		testSupports(this.testMethod.arg(httpEntityType(io.reactivex.Single.class, String.class)));
+		testSupports(this.testMethod.arg(httpEntityType(Maybe.class, String.class)));
+		testSupports(this.testMethod.arg(httpEntityType(CompletableFuture.class, String.class)));
+		testSupports(this.testMethod.arg(httpEntityType(Flux.class, String.class)));
+		testSupports(this.testMethod.arg(httpEntityType(Observable.class, String.class)));
+		testSupports(this.testMethod.arg(httpEntityType(io.reactivex.Observable.class, String.class)));
+		testSupports(this.testMethod.arg(httpEntityType(Flowable.class, String.class)));
+		testSupports(this.testMethod.arg(forClassWithGenerics(RequestEntity.class, String.class)));
+	}
+
+	private void testSupports(MethodParameter parameter) {
+		assertTrue(this.resolver.supportsParameter(parameter));
 	}
 
 	@Test
 	public void doesNotSupport() throws Exception {
-		ResolvableType type = ResolvableType.forClassWithGenerics(Mono.class, String.class);
-		assertFalse(this.resolver.supportsParameter(this.testMethod.arg(type)));
+		assertFalse(this.resolver.supportsParameter(this.testMethod.arg(Mono.class, String.class)));
 		assertFalse(this.resolver.supportsParameter(this.testMethod.arg(String.class)));
 	}
 
@@ -113,7 +117,7 @@ public class HttpEntityArgumentResolverTests {
 
 	@Test
 	public void emptyBodyWithMono() throws Exception {
-		ResolvableType type = httpEntityType(forClassWithGenerics(Mono.class, String.class));
+		ResolvableType type = httpEntityType(Mono.class, String.class);
 		HttpEntity<Mono<String>> entity = resolveValueWithEmptyBody(type);
 
 		StepVerifier.create(entity.getBody()).expectNextCount(0).expectComplete().verify();
@@ -121,7 +125,7 @@ public class HttpEntityArgumentResolverTests {
 
 	@Test
 	public void emptyBodyWithFlux() throws Exception {
-		ResolvableType type = httpEntityType(forClassWithGenerics(Flux.class, String.class));
+		ResolvableType type = httpEntityType(Flux.class, String.class);
 		HttpEntity<Flux<String>> entity = resolveValueWithEmptyBody(type);
 
 		StepVerifier.create(entity.getBody()).expectNextCount(0).expectComplete().verify();
@@ -129,7 +133,7 @@ public class HttpEntityArgumentResolverTests {
 
 	@Test
 	public void emptyBodyWithSingle() throws Exception {
-		ResolvableType type = httpEntityType(forClassWithGenerics(Single.class, String.class));
+		ResolvableType type = httpEntityType(Single.class, String.class);
 		HttpEntity<Single<String>> entity = resolveValueWithEmptyBody(type);
 
 		StepVerifier.create(RxReactiveStreams.toPublisher(entity.getBody()))
@@ -140,7 +144,7 @@ public class HttpEntityArgumentResolverTests {
 
 	@Test
 	public void emptyBodyWithRxJava2Single() throws Exception {
-		ResolvableType type = httpEntityType(forClassWithGenerics(io.reactivex.Single.class, String.class));
+		ResolvableType type = httpEntityType(io.reactivex.Single.class, String.class);
 		HttpEntity<io.reactivex.Single<String>> entity = resolveValueWithEmptyBody(type);
 
 		StepVerifier.create(entity.getBody().toFlowable())
@@ -151,7 +155,7 @@ public class HttpEntityArgumentResolverTests {
 
 	@Test
 	public void emptyBodyWithRxJava2Maybe() throws Exception {
-		ResolvableType type = httpEntityType(forClassWithGenerics(Maybe.class, String.class));
+		ResolvableType type = httpEntityType(Maybe.class, String.class);
 		HttpEntity<Maybe<String>> entity = resolveValueWithEmptyBody(type);
 
 		StepVerifier.create(entity.getBody().toFlowable())
@@ -162,7 +166,7 @@ public class HttpEntityArgumentResolverTests {
 
 	@Test
 	public void emptyBodyWithObservable() throws Exception {
-		ResolvableType type = httpEntityType(forClassWithGenerics(Observable.class, String.class));
+		ResolvableType type = httpEntityType(Observable.class, String.class);
 		HttpEntity<Observable<String>> entity = resolveValueWithEmptyBody(type);
 
 		StepVerifier.create(RxReactiveStreams.toPublisher(entity.getBody()))
@@ -173,7 +177,7 @@ public class HttpEntityArgumentResolverTests {
 
 	@Test
 	public void emptyBodyWithRxJava2Observable() throws Exception {
-		ResolvableType type = httpEntityType(forClassWithGenerics(io.reactivex.Observable.class, String.class));
+		ResolvableType type = httpEntityType(io.reactivex.Observable.class, String.class);
 		HttpEntity<io.reactivex.Observable<String>> entity = resolveValueWithEmptyBody(type);
 
 		StepVerifier.create(entity.getBody().toFlowable(BackpressureStrategy.BUFFER))
@@ -184,7 +188,7 @@ public class HttpEntityArgumentResolverTests {
 
 	@Test
 	public void emptyBodyWithFlowable() throws Exception {
-		ResolvableType type = httpEntityType(forClassWithGenerics(Flowable.class, String.class));
+		ResolvableType type = httpEntityType(Flowable.class, String.class);
 		HttpEntity<Flowable<String>> entity = resolveValueWithEmptyBody(type);
 
 		StepVerifier.create(entity.getBody())
@@ -195,7 +199,7 @@ public class HttpEntityArgumentResolverTests {
 
 	@Test
 	public void emptyBodyWithCompletableFuture() throws Exception {
-		ResolvableType type = httpEntityType(forClassWithGenerics(CompletableFuture.class, String.class));
+		ResolvableType type = httpEntityType(CompletableFuture.class, String.class);
 		HttpEntity<CompletableFuture<String>> entity = resolveValueWithEmptyBody(type);
 
 		entity.getBody().whenComplete((body, ex) -> {
@@ -217,7 +221,7 @@ public class HttpEntityArgumentResolverTests {
 	@Test
 	public void httpEntityWithMonoBody() throws Exception {
 		String body = "line1";
-		ResolvableType type = httpEntityType(forClassWithGenerics(Mono.class, String.class));
+		ResolvableType type = httpEntityType(Mono.class, String.class);
 		HttpEntity<Mono<String>> httpEntity = resolveValue(type, body);
 
 		assertEquals(this.request.getHeaders(), httpEntity.getHeaders());
@@ -227,7 +231,7 @@ public class HttpEntityArgumentResolverTests {
 	@Test
 	public void httpEntityWithSingleBody() throws Exception {
 		String body = "line1";
-		ResolvableType type = httpEntityType(forClassWithGenerics(Single.class, String.class));
+		ResolvableType type = httpEntityType(Single.class, String.class);
 		HttpEntity<Single<String>> httpEntity = resolveValue(type, body);
 
 		assertEquals(this.request.getHeaders(), httpEntity.getHeaders());
@@ -237,7 +241,7 @@ public class HttpEntityArgumentResolverTests {
 	@Test
 	public void httpEntityWithRxJava2SingleBody() throws Exception {
 		String body = "line1";
-		ResolvableType type = httpEntityType(forClassWithGenerics(io.reactivex.Single.class, String.class));
+		ResolvableType type = httpEntityType(io.reactivex.Single.class, String.class);
 		HttpEntity<io.reactivex.Single<String>> httpEntity = resolveValue(type, body);
 
 		assertEquals(this.request.getHeaders(), httpEntity.getHeaders());
@@ -247,7 +251,7 @@ public class HttpEntityArgumentResolverTests {
 	@Test
 	public void httpEntityWithRxJava2MaybeBody() throws Exception {
 		String body = "line1";
-		ResolvableType type = httpEntityType(forClassWithGenerics(Maybe.class, String.class));
+		ResolvableType type = httpEntityType(Maybe.class, String.class);
 		HttpEntity<Maybe<String>> httpEntity = resolveValue(type, body);
 
 		assertEquals(this.request.getHeaders(), httpEntity.getHeaders());
@@ -257,7 +261,7 @@ public class HttpEntityArgumentResolverTests {
 	@Test
 	public void httpEntityWithCompletableFutureBody() throws Exception {
 		String body = "line1";
-		ResolvableType type = httpEntityType(forClassWithGenerics(CompletableFuture.class, String.class));
+		ResolvableType type = httpEntityType(CompletableFuture.class, String.class);
 		HttpEntity<CompletableFuture<String>> httpEntity = resolveValue(type, body);
 
 		assertEquals(this.request.getHeaders(), httpEntity.getHeaders());
@@ -267,7 +271,7 @@ public class HttpEntityArgumentResolverTests {
 	@Test
 	public void httpEntityWithFluxBody() throws Exception {
 		String body = "line1\nline2\nline3\n";
-		ResolvableType type = httpEntityType(forClassWithGenerics(Flux.class, String.class));
+		ResolvableType type = httpEntityType(Flux.class, String.class);
 		HttpEntity<Flux<String>> httpEntity = resolveValue(type, body);
 
 		assertEquals(this.request.getHeaders(), httpEntity.getHeaders());
@@ -292,18 +296,13 @@ public class HttpEntityArgumentResolverTests {
 	}
 
 
-	private ResolvableType httpEntityType(Class<?> bodyType) {
-		return httpEntityType(ResolvableType.forClass(bodyType));
+	private ResolvableType httpEntityType(Class<?> bodyType, Class<?>... generics) {
+		return ResolvableType.forClassWithGenerics(HttpEntity.class,
+				ObjectUtils.isEmpty(generics) ?
+						ResolvableType.forClass(bodyType) :
+						ResolvableType.forClassWithGenerics(bodyType, generics));
 	}
 
-	private ResolvableType httpEntityType(ResolvableType type) {
-		return forClassWithGenerics(HttpEntity.class, type);
-	}
-
-	private void testSupports(ResolvableType type) {
-		MethodParameter parameter = this.testMethod.arg(type);
-		assertTrue(this.resolver.supportsParameter(parameter));
-	}
 
 	@SuppressWarnings("unchecked")
 	private <T> T resolveValue(ResolvableType type, String body) {

spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/ResponseBodyResultHandlerTests.java

@@ -16,6 +16,7 @@
 
 package org.springframework.web.reactive.result.method.annotation;
 
+import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -27,7 +28,6 @@ import rx.Single;
 
 import org.springframework.core.codec.ByteBufferEncoder;
 import org.springframework.core.codec.CharSequenceEncoder;
-import org.springframework.http.ResponseEntity;
 import org.springframework.http.codec.EncoderHttpMessageWriter;
 import org.springframework.http.codec.HttpMessageWriter;
 import org.springframework.http.codec.ResourceHttpMessageWriter;
@@ -41,7 +41,10 @@ import org.springframework.web.reactive.HandlerResult;
 import org.springframework.web.reactive.accept.RequestedContentTypeResolver;
 import org.springframework.web.reactive.accept.RequestedContentTypeResolverBuilder;
 
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.springframework.web.method.ResolvableMethod.on;
 
 /**
  * Unit tests for {@link ResponseBodyResultHandler}.When adding a test also
@@ -75,22 +78,42 @@ public class ResponseBodyResultHandlerTests {
 	@Test
 	public void supports() throws NoSuchMethodException {
 		Object controller = new TestController();
-		testSupports(controller, "handleToString", true);
-		testSupports(controller, "doWork", false);
-
-		controller = new TestRestController();
-		testSupports(controller, "handleToString", true);
-		testSupports(controller, "handleToMonoString", true);
-		testSupports(controller, "handleToSingleString", true);
-		testSupports(controller, "handleToCompletable", true);
-		testSupports(controller, "handleToResponseEntity", false);
-		testSupports(controller, "handleToMonoResponseEntity", false);
+		Method method;
+
+		method = on(TestController.class).annotPresent(ResponseBody.class).resolveMethod();
+		testSupports(controller, method);
+
+		method = on(TestController.class).annotNotPresent(ResponseBody.class).resolveMethod();
+		HandlerResult handlerResult = getHandlerResult(controller, method);
+		assertFalse(this.resultHandler.supports(handlerResult));
+	}
+
+	@Test
+	public void supportsRestController() throws NoSuchMethodException {
+		Object controller = new TestRestController();
+		Method method;
+
+		method = on(TestRestController.class).returning(String.class).resolveMethod();
+		testSupports(controller, method);
+
+		method = on(TestRestController.class).returning(Mono.class, String.class).resolveMethod();
+		testSupports(controller, method);
+
+		method = on(TestRestController.class).returning(Single.class, String.class).resolveMethod();
+		testSupports(controller, method);
+
+		method = on(TestRestController.class).returning(Completable.class).resolveMethod();
+		testSupports(controller, method);
 	}
 
-	private void testSupports(Object controller, String method, boolean result) throws NoSuchMethodException {
-		HandlerMethod hm = handlerMethod(controller, method);
-		HandlerResult handlerResult = new HandlerResult(hm, null, hm.getReturnType());
-		assertEquals(result, this.resultHandler.supports(handlerResult));
+	private void testSupports(Object controller, Method method) {
+		HandlerResult handlerResult = getHandlerResult(controller, method);
+		assertTrue(this.resultHandler.supports(handlerResult));
+	}
+
+	private HandlerResult getHandlerResult(Object controller, Method method) {
+		HandlerMethod handlerMethod = new HandlerMethod(controller, method);
+		return new HandlerResult(handlerMethod, null, handlerMethod.getReturnType());
 	}
 
 	@Test
@@ -99,10 +122,6 @@ public class ResponseBodyResultHandlerTests {
 	}
 
 
-	private HandlerMethod handlerMethod(Object controller, String method) throws NoSuchMethodException {
-		return new HandlerMethod(controller, controller.getClass().getMethod(method));
-	}
-
 
 	@RestController
 	@SuppressWarnings("unused")
@@ -125,14 +144,6 @@ public class ResponseBodyResultHandlerTests {
 		public Completable handleToCompletable() {
 			return null;
 		}
-
-		public ResponseEntity<String> handleToResponseEntity() {
-			return null;
-		}
-
-		public Mono<ResponseEntity<String>> handleToMonoResponseEntity() {
-			return null;
-		}
 	}