Expose return-value-handlers in mvc namespace

Mirroring the MvcConfigurer#addCustomReturnValueHandlers callback which
allows for providing a list of HandlerMethodReturnValueHandler types

git-svn-id: https://src.springframework.org/svn/spring-framework/trunk@4271 50f2f4bb-b051-0410-bef5-90022cba6387

org.springframework.web.servlet/src/main/java/org/springframework/web/servlet/config/AnnotationDrivenBeanDefinitionParser.java

@@ -124,6 +124,7 @@ class AnnotationDrivenBeanDefinitionParser implements BeanDefinitionParser {
 
 		ManagedList<?> messageConverters = getMessageConverters(element, source, parserContext);
 		ManagedList<?> argumentResolvers = getArgumentResolvers(element, source, parserContext);
+		ManagedList<?> returnValueHandlers = getReturnValueHandlers(element, source, parserContext);
 
 		RootBeanDefinition methodAdapterDef = new RootBeanDefinition(RequestMappingHandlerAdapter.class);
 		methodAdapterDef.setSource(source);
@@ -133,6 +134,9 @@ class AnnotationDrivenBeanDefinitionParser implements BeanDefinitionParser {
 		if (argumentResolvers != null) {
 			methodAdapterDef.getPropertyValues().add("customArgumentResolvers", argumentResolvers);
 		}
+		if (returnValueHandlers != null) {
+			methodAdapterDef.getPropertyValues().add("customReturnValueHandlers", returnValueHandlers);
+		}
 		String methodAdapterName = parserContext.getReaderContext().registerWithGeneratedName(methodAdapterDef);
 
 		RootBeanDefinition csInterceptorDef = new RootBeanDefinition(ConversionServiceExposingInterceptor.class);
@@ -228,6 +232,14 @@ class AnnotationDrivenBeanDefinitionParser implements BeanDefinitionParser {
 		return null;
 	}
 
+	private ManagedList<?> getReturnValueHandlers(Element element, Object source, ParserContext parserContext) {
+		Element handlersElement = DomUtils.getChildElementByTagName(element, "return-value-handlers");
+		if (handlersElement != null) {
+			return extractBeanSubElements(handlersElement, parserContext);
+		}
+		return null;
+	}
+
 	private ManagedList<?> getMessageConverters(Element element, Object source, ParserContext parserContext) {
 		Element convertersElement = DomUtils.getChildElementByTagName(element, "message-converters");
 		ManagedList<? super Object> messageConverters = new ManagedList<Object>();

org.springframework.web.servlet/src/main/resources/org/springframework/web/servlet/config/spring-mvc-3.1.xsd

@@ -60,7 +60,27 @@
 							<xsd:element ref="beans:bean" minOccurs="1" maxOccurs="unbounded">
 								<xsd:annotation>
 									<xsd:documentation><![CDATA[
-	The HttpMessageConverter bean definition.
+	The HandlerMethodArgumentResolver or WebArgumentResolver bean definition.
+									]]></xsd:documentation>
+								</xsd:annotation>
+							</xsd:element>
+						</xsd:sequence>
+					</xsd:complexType>
+				</xsd:element>			
+				<xsd:element name="return-value-handlers" minOccurs="0">
+					<xsd:annotation>
+						<xsd:documentation><![CDATA[
+	Configures one or more HandlerMethodReturnValueHandler types to use for handling the return value from handler methods.
+	Using this configuration element is optional.
+	Using it does not override the built-in support for handling return values.
+						]]></xsd:documentation>
+					</xsd:annotation>
+					<xsd:complexType>
+						<xsd:sequence>
+							<xsd:element ref="beans:bean" minOccurs="1" maxOccurs="unbounded">
+								<xsd:annotation>
+									<xsd:documentation><![CDATA[
+	The HandlerMethodReturnValueHandler bean definition.
 									]]></xsd:documentation>
 								</xsd:annotation>
 							</xsd:element>

org.springframework.web.servlet/src/test/java/org/springframework/web/servlet/config/AnnotationDrivenBeanDefinitionParserTests.java

@@ -37,6 +37,7 @@ import org.springframework.web.bind.support.WebDataBinderFactory;
 import org.springframework.web.context.request.NativeWebRequest;
 import org.springframework.web.context.support.GenericWebApplicationContext;
 import org.springframework.web.method.support.HandlerMethodArgumentResolver;
+import org.springframework.web.method.support.HandlerMethodReturnValueHandler;
 import org.springframework.web.method.support.ModelAndViewContainer;
 import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter;
 import org.springframework.web.servlet.mvc.method.annotation.ExceptionHandlerExceptionResolver;
@@ -96,6 +97,20 @@ public class AnnotationDrivenBeanDefinitionParserTests {
 		assertTrue(resolvers.get(1) instanceof TestHandlerMethodArgumentResolver);
 	}
 
+	@SuppressWarnings("unchecked")
+	@Test
+	public void testReturnValueHandlers() {
+		loadBeanDefinitions("mvc-config-return-value-handlers.xml");
+		RequestMappingHandlerAdapter adapter = appContext.getBean(RequestMappingHandlerAdapter.class);
+		assertNotNull(adapter);
+		Object value = new DirectFieldAccessor(adapter).getPropertyValue("customReturnValueHandlers");
+		assertNotNull(value);
+		assertTrue(value instanceof List);
+		List<HandlerMethodReturnValueHandler> handlers = (List<HandlerMethodReturnValueHandler>) value;
+		assertEquals(1, handlers.size());
+		assertEquals(TestHandlerMethodReturnValueHandler.class, handlers.get(0).getClass());
+	}
+
 	private void loadBeanDefinitions(String fileName) {
 		XmlBeanDefinitionReader reader = new XmlBeanDefinitionReader(appContext);
 		reader.loadBeanDefinitions(new ClassPathResource(fileName,
@@ -141,6 +156,19 @@ class TestHandlerMethodArgumentResolver implements HandlerMethodArgumentResolver
 	}
 }
 
+class TestHandlerMethodReturnValueHandler implements HandlerMethodReturnValueHandler {
+
+	public boolean supportsReturnType(MethodParameter returnType) {
+		return false;
+	}
+
+	public void handleReturnValue(Object returnValue,
+			MethodParameter returnType, ModelAndViewContainer mavContainer,
+			NativeWebRequest webRequest) throws Exception {
+	}
+	
+}
+
 class TestMessageCodesResolver implements MessageCodesResolver {
 
 	public String[] resolveMessageCodes(String errorCode, String objectName) {

org.springframework.web.servlet/src/test/resources/org/springframework/web/servlet/config/mvc-config-return-value-handlers.xml

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<beans xmlns="http://www.springframework.org/schema/beans"
+    xmlns:mvc="http://www.springframework.org/schema/mvc"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
+		http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd">
+
+	<mvc:annotation-driven>
+		<mvc:return-value-handlers>
+			<bean class="org.springframework.web.servlet.config.TestHandlerMethodReturnValueHandler"/>
+		</mvc:return-value-handlers>
+	</mvc:annotation-driven>
+
+</beans>