PayloadArgumentResolver does not insist on configured Validator anymore

Issue: SPR-12567
(cherry picked from commit ed0e2f4)

Author: jhoeller

spring-messaging/src/main/java/org/springframework/messaging/handler/annotation/support/PayloadArgumentResolver.java

@@ -5,7 +5,7 @@
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
- * http://www.apache.org/licenses/LICENSE-2.0
+ *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
@@ -16,13 +16,15 @@
 
 package org.springframework.messaging.handler.annotation.support;
 
+import java.lang.annotation.Annotation;
+
 import org.springframework.core.MethodParameter;
 import org.springframework.core.annotation.AnnotationUtils;
 import org.springframework.messaging.Message;
 import org.springframework.messaging.converter.MessageConversionException;
+import org.springframework.messaging.converter.MessageConverter;
 import org.springframework.messaging.handler.annotation.Payload;
 import org.springframework.messaging.handler.invocation.HandlerMethodArgumentResolver;
-import org.springframework.messaging.converter.MessageConverter;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.ObjectUtils;
@@ -33,15 +35,13 @@
 import org.springframework.validation.SmartValidator;
 import org.springframework.validation.Validator;
 
-import java.lang.annotation.Annotation;
-
 /**
  * A resolver to extract and convert the payload of a message using a
  * {@link MessageConverter}. It also validates the payload using a
  * {@link Validator} if the argument is annotated with a Validation annotation.
  *
- * <p>This {@link HandlerMethodArgumentResolver} should be ordered last as it supports all
- * types and does not require the {@link Payload} annotation.
+ * <p>This {@link HandlerMethodArgumentResolver} should be ordered last as it
+ * supports all types and does not require the {@link Payload} annotation.
  *
  * @author Rossen Stoyanchev
  * @author Brian Clozel
@@ -55,9 +55,24 @@ public class PayloadArgumentResolver implements HandlerMethodArgumentResolver {
 	private final Validator validator;
 
 
+	/**
+	 * Create a new {@code PayloadArgumentResolver} with the given
+	 * {@link MessageConverter}.
+	 * @param messageConverter the MessageConverter to use (required)
+	 * @since 4.0.9
+	 */
+	public PayloadArgumentResolver(MessageConverter messageConverter) {
+		this(messageConverter, null);
+	}
+
+	/**
+	 * Create a new {@code PayloadArgumentResolver} with the given
+	 * {@link MessageConverter} and {@link Validator}.
+	 * @param messageConverter the MessageConverter to use (required)
+	 * @param validator the Validator to use (optional)
+	 */
 	public PayloadArgumentResolver(MessageConverter messageConverter, Validator validator) {
-		Assert.notNull(messageConverter, "converter must not be null");
-		Assert.notNull(validator, "validator must not be null");
+		Assert.notNull(messageConverter, "MessageConverter must not be null");
 		this.converter = messageConverter;
 		this.validator = validator;
 	}
@@ -70,14 +85,14 @@ public boolean supportsParameter(MethodParameter parameter) {
 
 	@Override
 	public Object resolveArgument(MethodParameter param, Message<?> message) throws Exception {
-		Payload annot = param.getParameterAnnotation(Payload.class);
-		if ((annot != null) && StringUtils.hasText(annot.value())) {
+		Payload ann = param.getParameterAnnotation(Payload.class);
+		if (ann != null && StringUtils.hasText(ann.value())) {
 			throw new IllegalStateException("@Payload SpEL expressions not supported by this resolver");
 		}
 
 		Object payload = message.getPayload();
 		if (isEmptyPayload(payload)) {
-			if (annot == null || annot.required()) {
+			if (ann == null || ann.required()) {
 				String paramName = getParameterName(param);
 				BindingResult bindingResult = new BeanPropertyBindingResult(payload, paramName);
 				bindingResult.addError(new ObjectError(paramName, "@Payload param is required"));
@@ -106,7 +121,7 @@ public Object resolveArgument(MethodParameter param, Message<?> message) throws
 
 	private String getParameterName(MethodParameter param) {
 		String paramName = param.getParameterName();
-		return (paramName == null ? "Arg " + param.getParameterIndex() : paramName);
+		return (paramName != null ? paramName : "Arg " + param.getParameterIndex());
 	}
 
 	/**
@@ -132,26 +147,21 @@ protected void validate(Message<?> message, MethodParameter parameter, Object ta
 		if (this.validator == null) {
 			return;
 		}
-
-		for (Annotation annot : parameter.getParameterAnnotations()) {
-			if (annot.annotationType().getSimpleName().startsWith("Valid")) {
+		for (Annotation ann : parameter.getParameterAnnotations()) {
+			if (ann.annotationType().getSimpleName().startsWith("Valid")) {
+				Object hints = AnnotationUtils.getValue(ann);
+				Object[] validationHints = (hints instanceof Object[] ? (Object[]) hints : new Object[] {hints});
 				BeanPropertyBindingResult bindingResult =
 						new BeanPropertyBindingResult(target, getParameterName(parameter));
-
-				Object hints = AnnotationUtils.getValue(annot);
-				Object[] validationHints = (hints instanceof Object[] ? (Object[]) hints : new Object[] {hints});
-
 				if (!ObjectUtils.isEmpty(validationHints) && this.validator instanceof SmartValidator) {
 					((SmartValidator) this.validator).validate(target, bindingResult, validationHints);
 				}
 				else {
 					this.validator.validate(target, bindingResult);
 				}
-
 				if (bindingResult.hasErrors()) {
 					throw new MethodArgumentNotValidException(message, parameter, bindingResult);
 				}
-
 				break;
 			}
 		}

spring-messaging/src/main/java/org/springframework/messaging/simp/annotation/support/SimpAnnotationMethodMessageHandler.java

@@ -5,7 +5,7 @@
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
- * http://www.apache.org/licenses/LICENSE-2.0
+ *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
@@ -64,7 +64,6 @@
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.PathMatcher;
-import org.springframework.validation.Errors;
 import org.springframework.validation.Validator;
 
 /**
@@ -181,7 +180,7 @@ public PathMatcher getPathMatcher() {
 	 * The configured Validator instance
 	 */
 	public Validator getValidator() {
-		return validator;
+		return this.validator;
 	}
 
 	/**
@@ -253,8 +252,7 @@ protected List<HandlerMethodArgumentResolver> initArgumentResolvers() {
 		resolvers.add(new MessageMethodArgumentResolver());
 
 		resolvers.addAll(getCustomArgumentResolvers());
-		resolvers.add(new PayloadArgumentResolver(this.messageConverter,
-				(this.validator != null ? this.validator : new NoOpValidator())));
+		resolvers.add(new PayloadArgumentResolver(this.messageConverter, this.validator));
 
 		return resolvers;
 	}
@@ -284,25 +282,23 @@ protected boolean isHandler(Class<?> beanType) {
 
 	@Override
 	protected SimpMessageMappingInfo getMappingForMethod(Method method, Class<?> handlerType) {
-		MessageMapping typeAnnot = AnnotationUtils.findAnnotation(handlerType, MessageMapping.class);
+		MessageMapping typeAnnotation = AnnotationUtils.findAnnotation(handlerType, MessageMapping.class);
 		MessageMapping messageAnnot = AnnotationUtils.findAnnotation(method, MessageMapping.class);
 		if (messageAnnot != null) {
 			SimpMessageMappingInfo result = createMessageMappingCondition(messageAnnot);
-			if (typeAnnot != null) {
-				result = createMessageMappingCondition(typeAnnot).combine(result);
+			if (typeAnnotation != null) {
+				result = createMessageMappingCondition(typeAnnotation).combine(result);
 			}
 			return result;
 		}
-
-		SubscribeMapping subsribeAnnot = AnnotationUtils.findAnnotation(method, SubscribeMapping.class);
-		if (subsribeAnnot != null) {
-			SimpMessageMappingInfo result = createSubscribeCondition(subsribeAnnot);
-			if (typeAnnot != null) {
-				result = createMessageMappingCondition(typeAnnot).combine(result);
+		SubscribeMapping subsribeAnnotation = AnnotationUtils.findAnnotation(method, SubscribeMapping.class);
+		if (subsribeAnnotation != null) {
+			SimpMessageMappingInfo result = createSubscribeCondition(subsribeAnnotation);
+			if (typeAnnotation != null) {
+				result = createMessageMappingCondition(typeAnnotation).combine(result);
 			}
 			return result;
 		}
-
 		return null;
 	}
 
@@ -368,17 +364,4 @@ protected AbstractExceptionHandlerMethodResolver createExceptionHandlerMethodRes
 		return new AnnotationExceptionHandlerMethodResolver(beanType);
 	}
 
-
-	private static final class NoOpValidator implements Validator {
-
-		@Override
-		public boolean supports(Class<?> clazz) {
-			return false;
-		}
-
-		@Override
-		public void validate(Object target, Errors errors) {
-		}
-	}
-
 }