DATACMNS-330, DATACMNS-331 - Improved web configuration support.

Updated backing implementation of @EnableSpringDataWebSupport to use WebMvcConfigurerAdapter instead of WebMvcConfigurationSupport as the latter is a very custom beast in terms of configuration. Let the Spring HATEOAS specific configuration class extend the default one to register additional components. The default one accesses the FormattingConversionService through a qualified autowiring. It issues a warning in case none has been configured and asks the user to enable Spring MVC.

Updated Sonargraph architecture description to allow logging from web config layer.

src/main/java/org/springframework/data/web/config/EnableSpringDataWebSupport.java

@@ -20,8 +20,6 @@ import java.lang.annotation.Inherited;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
-import java.util.ArrayList;
-import java.util.List;
 
 import org.springframework.context.annotation.Import;
 import org.springframework.context.annotation.ImportSelector;
@@ -84,15 +82,8 @@ public @interface EnableSpringDataWebSupport {
 		 */
 		@Override
 		public String[] selectImports(AnnotationMetadata importingClassMetadata) {
-
-			List<String> configs = new ArrayList<String>();
-
-			if (HATEOAS_PRESENT) {
-				configs.add(HateoasAwareSpringDataWebConfiguration.class.getName());
-			}
-
-			configs.add(SpringDataWebConfiguration.class.getName());
-			return configs.toArray(new String[configs.size()]);
+			return new String[] { HATEOAS_PRESENT ? HateoasAwareSpringDataWebConfiguration.class.getName()
+					: SpringDataWebConfiguration.class.getName() };
 		}
 	}
 }

src/main/java/org/springframework/data/web/config/HateoasAwareSpringDataWebConfiguration.java

@@ -17,13 +17,11 @@ package org.springframework.data.web.config;
 
 import java.util.List;
 
-import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.data.web.PagedResourcesAssembler;
 import org.springframework.data.web.PagedResourcesAssemblerArgumentResolver;
 import org.springframework.web.method.support.HandlerMethodArgumentResolver;
-import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;
 
 /**
  * JavaConfig class to register {@link PagedResourcesAssembler} and {@link PagedResourcesAssemblerArgumentResolver}.
@@ -32,19 +30,16 @@ import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupp
  * @author Oliver Gierke
  */
 @Configuration
-class HateoasAwareSpringDataWebConfiguration extends WebMvcConfigurationSupport {
-
-	@Autowired
-	SpringDataWebConfiguration config;
+class HateoasAwareSpringDataWebConfiguration extends SpringDataWebConfiguration {
 
 	@Bean
 	public PagedResourcesAssembler<?> pagedResourcesAssembler() {
-		return new PagedResourcesAssembler<Object>(config.pageableResolver(), null);
+		return new PagedResourcesAssembler<Object>(pageableResolver(), null);
 	}
 
 	@Bean
 	public PagedResourcesAssemblerArgumentResolver pagedResourcesAssemblerArgumentResolver() {
-		return new PagedResourcesAssemblerArgumentResolver(config.pageableResolver(), null);
+		return new PagedResourcesAssemblerArgumentResolver(pageableResolver(), null);
 	}
 
 	/* 
@@ -52,8 +47,8 @@ class HateoasAwareSpringDataWebConfiguration extends WebMvcConfigurationSupport
 	 * @see org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport#addArgumentResolvers(java.util.List)
 	 */
 	@Override
-	protected void addArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers) {
-		config.addArgumentResolvers(argumentResolvers);
+	public void addArgumentResolvers(List<HandlerMethodArgumentResolver> argumentResolvers) {
+		super.addArgumentResolvers(argumentResolvers);
 		argumentResolvers.add(pagedResourcesAssemblerArgumentResolver());
 	}
 }

src/main/java/org/springframework/data/web/config/SpringDataWebConfiguration.java

@@ -17,6 +17,10 @@ package org.springframework.data.web.config;
 
 import java.util.List;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Qualifier;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.data.repository.support.DomainClassConverter;
@@ -24,7 +28,7 @@ import org.springframework.data.web.PageableHandlerMethodArgumentResolver;
 import org.springframework.data.web.SortHandlerMethodArgumentResolver;
 import org.springframework.format.support.FormattingConversionService;
 import org.springframework.web.method.support.HandlerMethodArgumentResolver;
-import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupport;
+import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
 
 /**
  * Configuration class to register {@link PageableHandlerMethodArgumentResolver},
@@ -34,7 +38,13 @@ import org.springframework.web.servlet.config.annotation.WebMvcConfigurationSupp
  * @author Oliver Gierke
  */
 @Configuration
-class SpringDataWebConfiguration extends WebMvcConfigurationSupport {
+class SpringDataWebConfiguration extends WebMvcConfigurerAdapter {
+
+	private static final Logger LOGGER = LoggerFactory.getLogger(SpringDataWebConfiguration.class);
+
+	@Autowired(required = false)
+	@Qualifier("mvcConversionService")
+	FormattingConversionService conversionService;
 
 	@Bean
 	public PageableHandlerMethodArgumentResolver pageableResolver() {
@@ -48,7 +58,16 @@ class SpringDataWebConfiguration extends WebMvcConfigurationSupport {
 
 	@Bean
 	public DomainClassConverter<FormattingConversionService> mvcDomainClassConverter() {
-		return new DomainClassConverter<FormattingConversionService>(mvcConversionService());
+
+		if (conversionService == null) {
+
+			LOGGER.warn("No default Spring MVC FormattingConversionService registered! Have you forgotten to "
+					+ "use @EnableWebMvc or register a configuration class extending WebMvcConfigurationSupport?");
+
+			return null;
+		}
+
+		return new DomainClassConverter<FormattingConversionService>(conversionService);
 	}
 
 	/*