Move feed message converters ahead of jackson/jaxb2

The Atom/RSS message converters are now registered ahead of the
Jackson and the JAXB2 message converters by default. Since the Atom
and RSS converters convert to and from very specific object types
Feed and Channel respectively, that shouldn't introduce any regressions
and will work more intuitively when the requested media type is "*/*".

Issue: SPR-9054

spring-web/src/main/java/org/springframework/web/client/RestTemplate.java

@@ -149,6 +149,10 @@ public class RestTemplate extends InterceptingHttpAccessor implements RestOperat
 		this.messageConverters.add(new ResourceHttpMessageConverter());
 		this.messageConverters.add(new SourceHttpMessageConverter());
 		this.messageConverters.add(new XmlAwareFormHttpMessageConverter());
+		if (romePresent) {
+			this.messageConverters.add(new AtomFeedHttpMessageConverter());
+			this.messageConverters.add(new RssChannelHttpMessageConverter());
+		}
 		if (jaxb2Present) {
 			this.messageConverters.add(new Jaxb2RootElementHttpMessageConverter());
 		}
@@ -158,10 +162,6 @@ public class RestTemplate extends InterceptingHttpAccessor implements RestOperat
 		else if (jacksonPresent) {
 			this.messageConverters.add(new MappingJacksonHttpMessageConverter());
 		}
-		if (romePresent) {
-			this.messageConverters.add(new AtomFeedHttpMessageConverter());
-			this.messageConverters.add(new RssChannelHttpMessageConverter());
-		}
 	}
 
 	/**

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

@@ -302,14 +302,17 @@ class AnnotationDrivenBeanDefinitionParser implements BeanDefinitionParser {
 			messageConverters.setSource(source);
 			messageConverters.add(createConverterBeanDefinition(ByteArrayHttpMessageConverter.class, source));
 
-			RootBeanDefinition stringConverterDef = createConverterBeanDefinition(StringHttpMessageConverter.class,
-					source);
+			RootBeanDefinition stringConverterDef = createConverterBeanDefinition(StringHttpMessageConverter.class, source);
 			stringConverterDef.getPropertyValues().add("writeAcceptCharset", false);
 			messageConverters.add(stringConverterDef);
 
 			messageConverters.add(createConverterBeanDefinition(ResourceHttpMessageConverter.class, source));
 			messageConverters.add(createConverterBeanDefinition(SourceHttpMessageConverter.class, source));
 			messageConverters.add(createConverterBeanDefinition(XmlAwareFormHttpMessageConverter.class, source));
+			if (romePresent) {
+				messageConverters.add(createConverterBeanDefinition(AtomFeedHttpMessageConverter.class, source));
+				messageConverters.add(createConverterBeanDefinition(RssChannelHttpMessageConverter.class, source));
+			}
 			if (jaxb2Present) {
 				messageConverters
 						.add(createConverterBeanDefinition(Jaxb2RootElementHttpMessageConverter.class, source));
@@ -320,16 +323,13 @@ class AnnotationDrivenBeanDefinitionParser implements BeanDefinitionParser {
 			else if (jacksonPresent) {
 				messageConverters.add(createConverterBeanDefinition(MappingJacksonHttpMessageConverter.class, source));
 			}
-			if (romePresent) {
-				messageConverters.add(createConverterBeanDefinition(AtomFeedHttpMessageConverter.class, source));
-				messageConverters.add(createConverterBeanDefinition(RssChannelHttpMessageConverter.class, source));
-			}
 		}
 		return messageConverters;
 	}
 
-	private RootBeanDefinition createConverterBeanDefinition(Class<? extends HttpMessageConverter> converterClass,
-			Object source) {
+	private RootBeanDefinition createConverterBeanDefinition(
+			Class<? extends HttpMessageConverter> converterClass, Object source) {
+
 		RootBeanDefinition beanDefinition = new RootBeanDefinition(converterClass);
 		beanDefinition.setSource(source);
 		beanDefinition.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);

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

@@ -138,6 +138,20 @@ import org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolv
  */
 public class WebMvcConfigurationSupport implements ApplicationContextAware, ServletContextAware {
 
+	private static final boolean jaxb2Present =
+			ClassUtils.isPresent("javax.xml.bind.Binder", WebMvcConfigurationSupport.class.getClassLoader());
+
+	private static final boolean jackson2Present =
+			ClassUtils.isPresent("com.fasterxml.jackson.databind.ObjectMapper", WebMvcConfigurationSupport.class.getClassLoader()) &&
+					ClassUtils.isPresent("com.fasterxml.jackson.core.JsonGenerator", WebMvcConfigurationSupport.class.getClassLoader());
+
+	private static final boolean jacksonPresent =
+			ClassUtils.isPresent("org.codehaus.jackson.map.ObjectMapper", WebMvcConfigurationSupport.class.getClassLoader()) &&
+					ClassUtils.isPresent("org.codehaus.jackson.JsonGenerator", WebMvcConfigurationSupport.class.getClassLoader());
+
+	private static boolean romePresent =
+			ClassUtils.isPresent("com.sun.syndication.feed.WireFeed", WebMvcConfigurationSupport.class.getClassLoader());
+
 	private ServletContext servletContext;
 
 	private ApplicationContext applicationContext;
@@ -435,21 +449,19 @@ public class WebMvcConfigurationSupport implements ApplicationContextAware, Serv
 		messageConverters.add(new ResourceHttpMessageConverter());
 		messageConverters.add(new SourceHttpMessageConverter<Source>());
 		messageConverters.add(new XmlAwareFormHttpMessageConverter());
-
-		ClassLoader classLoader = getClass().getClassLoader();
-		if (ClassUtils.isPresent("javax.xml.bind.Binder", classLoader)) {
+		if (romePresent) {
+			messageConverters.add(new AtomFeedHttpMessageConverter());
+			messageConverters.add(new RssChannelHttpMessageConverter());
+		}
+		if (jaxb2Present) {
 			messageConverters.add(new Jaxb2RootElementHttpMessageConverter());
 		}
-		if (ClassUtils.isPresent("com.fasterxml.jackson.databind.ObjectMapper", classLoader)) {
+		if (jackson2Present) {
 			messageConverters.add(new MappingJackson2HttpMessageConverter());
 		}
-		else if (ClassUtils.isPresent("org.codehaus.jackson.map.ObjectMapper", classLoader)) {
+		else if (jacksonPresent) {
 			messageConverters.add(new MappingJacksonHttpMessageConverter());
 		}
-		if (ClassUtils.isPresent("com.sun.syndication.feed.WireFeed", classLoader)) {
-			messageConverters.add(new AtomFeedHttpMessageConverter());
-			messageConverters.add(new RssChannelHttpMessageConverter());
-		}
 	}
 
 	/**

src/dist/changelog.txt

@@ -20,6 +20,7 @@ Changes in version 3.2 M2 (2012-08-xx)
 * DispatcherPortlet does not forward event exceptions to the render phase by default (SPR-9287)
 * add defaultCharset property to StringHttpMessageConverter
 * add @ExceptionResolver annotation to detect classes with @ExceptionHandler methods
+* move RSS/Atom message converter registration ahead of jackson/jaxb2
 
 
 Changes in version 3.2 M1 (2012-05-28)