Add order attribute to MVC ViewResolver config

The ViewResolverComposite that contains the ViewResolver's registered
throug the MVC Java config and namespace can now be assigned an
explicit order.

Author: rstoyanchev

spring-webmvc/src/main/java/org/springframework/web/servlet/config/ViewResolversBeanDefinitionParser.java

@@ -133,14 +133,17 @@ else if (contentnNegotiationElements.size() == 1) {
 			beanDef.getPropertyValues().add("viewResolvers", resolvers);
 			ManagedList<Object> list = new ManagedList<Object>(1);
 			list.add(beanDef);
-
 			compositeResolverBeanDef.getPropertyValues().add("order", Ordered.HIGHEST_PRECEDENCE);
 			compositeResolverBeanDef.getPropertyValues().add("viewResolvers", list);
 		}
 		else if (contentnNegotiationElements.size() > 1) {
 			throw new IllegalArgumentException("Only one <content-negotiation> element is allowed.");
 		}
 
+		if (element.hasAttribute("order")) {
+			compositeResolverBeanDef.getPropertyValues().add("order", element.getAttribute("order"));
+		}
+
 		context.getReaderContext().getRegistry().registerBeanDefinition(beanName, compositeResolverBeanDef);
 		context.registerComponent(new BeanComponentDefinition(compositeResolverBeanDef, beanName));
 		context.popAndRegisterContainingComponent();

spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/ViewResolverRegistry.java

@@ -57,7 +57,7 @@ public class ViewResolverRegistry {
 
 	private final List<ViewResolver> viewResolvers = new ArrayList<ViewResolver>(4);
 
-	private int order = Ordered.LOWEST_PRECEDENCE;
+	private Integer order;
 
 	private ContentNegotiationManager contentNegotiationManager;
 
@@ -112,7 +112,7 @@ public void enableContentNegotiation(boolean useNotAcceptableStatus, View... def
 	private void initContentNegotiatingViewResolver(View[] defaultViews) {
 
 		// ContentNegotiatingResolver in the registry: elevate its precedence!
-		this.order = Ordered.HIGHEST_PRECEDENCE;
+		this.order = (this.order == null ? Ordered.HIGHEST_PRECEDENCE : this.order);
 
 		if (this.contentNegotiatingResolver != null) {
 			if (!ObjectUtils.isEmpty(defaultViews)) {
@@ -257,6 +257,22 @@ public void viewResolver(ViewResolver viewResolver) {
 		this.viewResolvers.add(viewResolver);
 	}
 
+	/**
+	 * ViewResolver's registered through this registry are encapsulated in an
+	 * instance of {@link org.springframework.web.servlet.view.ViewResolverComposite
+	 * ViewResolverComposite} and follow the order of registration.
+	 * This property determines the order of the ViewResolverComposite itself
+	 * relative to any additional ViewResolver's (not registered here) present in
+	 * the Spring configuration
+	 * <p>By default this property is not set, which means the resolver is ordered
+	 * at {@link Ordered#LOWEST_PRECEDENCE} unless content negotiation is enabled
+	 * in which case the order (if not set explicitly) is changed to
+	 * {@link Ordered#HIGHEST_PRECEDENCE}.
+	 */
+	public void order(int order) {
+		this.order = order;
+	}
+
 	protected boolean hasBeanOfType(Class<?> beanType) {
 		return !ObjectUtils.isEmpty(BeanFactoryUtils.beanNamesForTypeIncludingAncestors(
 				this.applicationContext, beanType, false, false));

spring-webmvc/src/main/resources/org/springframework/web/servlet/config/spring-mvc-4.1.xsd

@@ -949,6 +949,20 @@
 						</xsd:annotation>
 					</xsd:element>
 			</xsd:choice>
+			<xsd:attribute name="order" type="xsd:int">
+				<xsd:annotation>
+					<xsd:documentation><![CDATA[
+	ViewResolver's registered through this element are encapsulated in an
+	instance of org.springframework.web.servlet.view.ViewResolverComposite and
+	follow the order of registration. This attribute determines the order of the
+	ViewResolverComposite itself relative to any additional ViewResolver's
+	(not registered through this element) present in the Spring configuration
+	By default this property is not set, which means the resolver is ordered at
+	Ordered.LOWEST_PRECEDENCE unless content negotiation is enabled in which case
+	the order (if not set explicitly) is changed to Ordered.HIGHEST_PRECEDENCE.
+					]]></xsd:documentation>
+				</xsd:annotation>
+			</xsd:attribute>
 		</xsd:complexType>
 	</xsd:element>
 

spring-webmvc/src/test/java/org/springframework/web/servlet/config/MvcNamespaceTests.java

@@ -767,6 +767,16 @@ public void testViewResolutionWithContentNegotiation() throws Exception {
 		assertSame(manager, this.appContext.getBean(ContentNegotiationManager.class));
 	}
 
+	@Test
+	public void testViewResolutionWithOrderSet() throws Exception {
+		loadBeanDefinitions("mvc-config-view-resolution-custom-order.xml", 1);
+
+		ViewResolverComposite compositeResolver = this.appContext.getBean(ViewResolverComposite.class);
+		assertNotNull(compositeResolver);
+		assertEquals("Actual: " + compositeResolver.getViewResolvers(), 1, compositeResolver.getViewResolvers().size());
+		assertEquals(123, compositeResolver.getOrder());
+	}
+
 	@Test
 	public void testPathMatchingHandlerMappings() throws Exception {
 		loadBeanDefinitions("mvc-config-path-matching-mappings.xml", 22);

spring-webmvc/src/test/java/org/springframework/web/servlet/config/annotation/WebMvcConfigurationSupportTests.java

@@ -246,6 +246,20 @@ public void mvcViewResolverWithExistingResolver() throws Exception {
 		assertNull(resolver.resolveViewName("anyViewName", Locale.ENGLISH));
 	}
 
+	@Test
+	public void mvcViewResolverWithOrderSet() {
+		ApplicationContext context = initContext(CustomViewResolverOrderConfig.class);
+		ViewResolverComposite resolver = context.getBean("mvcViewResolver", ViewResolverComposite.class);
+
+		Map<String, ViewResolver> map = BeanFactoryUtils.beansOfTypeIncludingAncestors(
+				context, ViewResolver.class, true, false);
+
+		assertNotNull(resolver);
+		assertEquals(1, resolver.getViewResolvers().size());
+		assertEquals(InternalResourceViewResolver.class, resolver.getViewResolvers().get(0).getClass());
+		assertEquals(123, resolver.getOrder());
+	}
+
 	@Test
 	public void defaultPathMatchConfiguration() throws Exception {
 		ApplicationContext context = initContext(WebConfig.class);
@@ -286,6 +300,16 @@ public ViewResolver beanNameViewResolver() {
 		}
 	}
 
+	@EnableWebMvc
+	@Configuration
+	public static class CustomViewResolverOrderConfig extends WebMvcConfigurerAdapter {
+
+		@Override
+		public void configureViewResolvers(ViewResolverRegistry registry) {
+			registry.jsp();
+			registry.order(123);
+		}
+	}
 
 	@Controller
 	public static class TestController {

spring-webmvc/src/test/resources/org/springframework/web/servlet/config/mvc-config-view-resolution-custom-order.xml

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<beans xmlns="http://www.springframework.org/schema/beans"
+	   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	   xmlns:mvc="http://www.springframework.org/schema/mvc"
+	   xsi:schemaLocation="
+		http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
+		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
+
+	<mvc:view-resolvers order="123">
+		<mvc:bean-name />
+	</mvc:view-resolvers>
+
+</beans>
+