DATACMNS-1237 - Register additional ProxyingHandlerMethodArgumentResolver as first resolver.

We now deploy a custom BeanPostProcessor to customize RequestMappingHandlerAdapter instances by prepending a ProxyingHandlerMethodArgumentResolver (requiring a @ModelAttribute) to the list of resolved HandlerMethodArgumentResolvers to make sure the settings defined in the annotation are applied but the projecting way of data binding is still used.

src/main/java/org/springframework/data/web/ProxyingHandlerMethodArgumentResolver.java

@@ -23,12 +23,14 @@ import org.springframework.beans.MutablePropertyValues;
 import org.springframework.beans.factory.BeanClassLoaderAware;
 import org.springframework.beans.factory.BeanFactory;
 import org.springframework.beans.factory.BeanFactoryAware;
+import org.springframework.beans.factory.ObjectFactory;
 import org.springframework.core.MethodParameter;
 import org.springframework.core.annotation.AnnotatedElementUtils;
 import org.springframework.core.convert.ConversionService;
 import org.springframework.data.projection.SpelAwareProxyProjectionFactory;
 import org.springframework.util.ClassUtils;
 import org.springframework.web.bind.WebDataBinder;
+import org.springframework.web.bind.annotation.ModelAttribute;
 import org.springframework.web.bind.support.WebDataBinderFactory;
 import org.springframework.web.context.request.NativeWebRequest;
 import org.springframework.web.method.annotation.ModelAttributeMethodProcessor;
@@ -46,16 +48,29 @@ public class ProxyingHandlerMethodArgumentResolver extends ModelAttributeMethodP
 	private static final List<String> IGNORED_PACKAGES = Arrays.asList("java", "org.springframework");
 
 	private final SpelAwareProxyProjectionFactory proxyFactory;
-	private final ConversionService conversionService;
+	private final ObjectFactory<ConversionService> conversionService;
+
+	/**
+	 * Creates a new {@link PageableHandlerMethodArgumentResolver} using the given {@link ConversionService} and the
+	 * {@link ModelAttribute} annotation not required.
+	 * 
+	 * @param conversionService must not be {@literal null}.
+	 * @deprecated use {@link #ProxyingHandlerMethodArgumentResolver(ObjectFactory, boolean)} instead.
+	 */
+	@Deprecated
+	public ProxyingHandlerMethodArgumentResolver(final ConversionService conversionService) {
+		this(() -> conversionService, true);
+	}
 
 	/**
 	 * Creates a new {@link PageableHandlerMethodArgumentResolver} using the given {@link ConversionService}.
 	 * 
 	 * @param conversionService must not be {@literal null}.
 	 */
-	public ProxyingHandlerMethodArgumentResolver(ConversionService conversionService) {
+	public ProxyingHandlerMethodArgumentResolver(ObjectFactory<ConversionService> conversionService,
+			boolean annotationNotRequired) {
 
-		super(true);
+		super(annotationNotRequired);
 
 		this.proxyFactory = new SpelAwareProxyProjectionFactory();
 		this.conversionService = conversionService;
@@ -86,6 +101,10 @@ public class ProxyingHandlerMethodArgumentResolver extends ModelAttributeMethodP
 	@Override
 	public boolean supportsParameter(MethodParameter parameter) {
 
+		if (!super.supportsParameter(parameter)) {
+			return false;
+		}
+
 		Class<?> type = parameter.getParameterType();
 
 		if (!type.isInterface()) {
@@ -116,7 +135,7 @@ public class ProxyingHandlerMethodArgumentResolver extends ModelAttributeMethodP
 	protected Object createAttribute(String attributeName, MethodParameter parameter, WebDataBinderFactory binderFactory,
 			NativeWebRequest request) throws Exception {
 
-		MapDataBinder binder = new MapDataBinder(parameter.getParameterType(), conversionService);
+		MapDataBinder binder = new MapDataBinder(parameter.getParameterType(), conversionService.getObject());
 		binder.bind(new MutablePropertyValues(request.getParameterMap()));
 
 		return proxyFactory.createProjection(parameter.getParameterType(), binder.getTarget());

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

@@ -103,6 +103,8 @@ public @interface EnableSpringDataWebSupport {
 
 			List<String> imports = new ArrayList<>();
 
+			imports.add(ProjectingArgumentResolverRegistrar.class.getName());
+
 			imports.add(resourceLoader//
 					.filter(it -> ClassUtils.isPresent("org.springframework.hateoas.Link", it))//
 					.map(it -> HateoasAwareSpringDataWebConfiguration.class.getName())//

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

@@ -0,0 +1,143 @@
+/*
+ * Copyright 2017 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * 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
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.web.config;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.BeanClassLoaderAware;
+import org.springframework.beans.factory.BeanFactory;
+import org.springframework.beans.factory.BeanFactoryAware;
+import org.springframework.beans.factory.ObjectFactory;
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.beans.factory.config.BeanPostProcessor;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.core.convert.ConversionService;
+import org.springframework.data.web.ProxyingHandlerMethodArgumentResolver;
+import org.springframework.lang.Nullable;
+import org.springframework.web.method.support.HandlerMethodArgumentResolver;
+import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter;
+
+/**
+ * Configuration class to register a {@link BeanPostProcessor} to augment {@link RequestMappingHandlerAdapter} with a
+ * {@link ProxyingHandlerMethodArgumentResolver}.
+ * 
+ * @author Oliver Gierke
+ * @soundtrack Apparat With Soap & Skin - Goodbye (Dark Theme Song - https://www.youtube.com/watch?v=66VnOdk6oto)
+ */
+@Configuration
+public class ProjectingArgumentResolverRegistrar {
+
+	/**
+	 * Registers a {@link BeanPostProcessor} to modify {@link RequestMappingHandlerAdapter} beans in the application
+	 * context to get a {@link ProxyingHandlerMethodArgumentResolver} configured as first
+	 * {@link HandlerMethodArgumentResolver}.
+	 * 
+	 * @param conversionService the Spring MVC {@link ConversionService} in a lazy fashion, so that its initialization is
+	 *          not triggered yet.
+	 * @return
+	 */
+	@Bean
+	public static ProjectingArgumentResolverBeanPostProcessor projectingArgumentResolverBeanPostProcessor(
+			@Qualifier("mvcConversionService") ObjectFactory<ConversionService> conversionService) {
+		return new ProjectingArgumentResolverBeanPostProcessor(conversionService);
+	}
+
+	/**
+	 * A {@link BeanPostProcessor} to modify {@link RequestMappingHandlerAdapter} beans in the application context to get
+	 * a {@link ProxyingHandlerMethodArgumentResolver} configured as first {@link HandlerMethodArgumentResolver}.
+	 *
+	 * @author Oliver Gierke
+	 * @soundtrack Apparat With Soap & Skin - Goodbye (Dark Theme Song - https://www.youtube.com/watch?v=66VnOdk6oto)
+	 */
+	private static class ProjectingArgumentResolverBeanPostProcessor
+			implements BeanPostProcessor, BeanFactoryAware, BeanClassLoaderAware {
+
+		private ProxyingHandlerMethodArgumentResolver resolver;
+
+		/**
+		 * A {@link BeanPostProcessor} to modify {@link RequestMappingHandlerAdapter} beans in the application context to
+		 * get a {@link ProxyingHandlerMethodArgumentResolver} configured as first {@link HandlerMethodArgumentResolver}.
+		 * 
+		 * @param conversionService the Spring MVC {@link ConversionService} in a lazy fashion, so that its initialization
+		 *          is not triggered yet.
+		 */
+		public ProjectingArgumentResolverBeanPostProcessor(
+				@Qualifier("mvcConversionService") ObjectFactory<ConversionService> conversionService) {
+			this.resolver = new ProxyingHandlerMethodArgumentResolver(conversionService, false);
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.beans.factory.BeanFactoryAware#setBeanFactory(org.springframework.beans.factory.BeanFactory)
+		 */
+		@Override
+		public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
+			this.resolver.setBeanFactory(beanFactory);
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.beans.factory.BeanClassLoaderAware#setBeanClassLoader(java.lang.ClassLoader)
+		 */
+		@Override
+		public void setBeanClassLoader(ClassLoader classLoader) {
+			this.resolver.setBeanClassLoader(classLoader);
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.beans.factory.config.BeanPostProcessor#postProcessBeforeInitialization(java.lang.Object, java.lang.String)
+		 */
+		@Nullable
+		@Override
+		public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
+			return bean;
+		}
+
+		/* 
+		 * (non-Javadoc)
+		 * @see org.springframework.beans.factory.config.BeanPostProcessor#postProcessAfterInitialization(java.lang.Object, java.lang.String)
+		 */
+		@Nullable
+		@Override
+		public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
+
+			if (!RequestMappingHandlerAdapter.class.isInstance(bean)) {
+				return bean;
+			}
+
+			RequestMappingHandlerAdapter adapter = (RequestMappingHandlerAdapter) bean;
+			List<HandlerMethodArgumentResolver> currentResolvers = adapter.getArgumentResolvers();
+
+			if (currentResolvers == null) {
+				throw new IllegalStateException(
+						String.format("No HandlerMethodArgumentResolvers found in RequestMappingHandlerAdapter %s!", beanName));
+			}
+
+			List<HandlerMethodArgumentResolver> newResolvers = new ArrayList<HandlerMethodArgumentResolver>(
+					currentResolvers.size() + 1);
+			newResolvers.add(resolver);
+			newResolvers.addAll(currentResolvers);
+
+			adapter.setArgumentResolvers(newResolvers);
+
+			return adapter;
+		}
+	}
+}

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

@@ -140,8 +140,7 @@ public class SpringDataWebConfiguration implements WebMvcConfigurer, BeanClassLo
 		argumentResolvers.add(sortResolver());
 		argumentResolvers.add(pageableResolver());
 
-		ProxyingHandlerMethodArgumentResolver resolver = new ProxyingHandlerMethodArgumentResolver(
+		ProxyingHandlerMethodArgumentResolver resolver = new ProxyingHandlerMethodArgumentResolver(conversionService, true);
-				conversionService.getObject());
 		resolver.setBeanFactory(context);
 		forwardBeanClassLoader(resolver);
 

src/test/java/org/springframework/data/web/ProxyingHandlerMethodArgumentResolverUnitTests.java

@@ -35,7 +35,7 @@ import org.springframework.data.web.ProjectingJackson2HttpMessageConverterUnitTe
 public class ProxyingHandlerMethodArgumentResolverUnitTests {
 
 	ProxyingHandlerMethodArgumentResolver resolver = new ProxyingHandlerMethodArgumentResolver(
-			new DefaultConversionService());
+			() -> new DefaultConversionService(), true);
 
 	@Test // DATACMNS-776
 	public void supportAnnotatedInterface() throws Exception {

src/test/java/org/springframework/data/web/config/EnableSpringDataWebSupportIntegrationTests.java

@@ -32,6 +32,7 @@ import org.springframework.data.geo.Distance;
 import org.springframework.data.geo.Point;
 import org.springframework.data.web.PageableHandlerMethodArgumentResolver;
 import org.springframework.data.web.PagedResourcesAssemblerArgumentResolver;
+import org.springframework.data.web.ProxyingHandlerMethodArgumentResolver;
 import org.springframework.data.web.SortHandlerMethodArgumentResolver;
 import org.springframework.data.web.WebTestUtils;
 import org.springframework.hateoas.Link;
@@ -204,6 +205,16 @@ public class EnableSpringDataWebSupportIntegrationTests {
 		assertThat((String) ReflectionTestUtils.getField(resolver, "sortParameter")).isEqualTo("foo");
 	}
 
+	@Test // DATACMNS-1237
+	public void configuresProxyingHandlerMethodArgumentResolver() {
+
+		ApplicationContext context = WebTestUtils.createApplicationContext(SampleConfig.class);
+
+		RequestMappingHandlerAdapter adapter = context.getBean(RequestMappingHandlerAdapter.class);
+
+		assertThat(adapter.getArgumentResolvers().get(0)).isInstanceOf(ProxyingHandlerMethodArgumentResolver.class);
+	}
+
 	private static void assertResolversRegistered(ApplicationContext context, Class<?>... resolverTypes) {
 
 		RequestMappingHandlerAdapter adapter = context.getBean(RequestMappingHandlerAdapter.class);