Parameterize ResponseBodyInterceptor on the type level

Issue: SPR-10859

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

@@ -425,8 +425,9 @@ public class WebMvcConfigurationSupport implements ApplicationContextAware, Serv
 		adapter.setCustomReturnValueHandlers(returnValueHandlers);
 
 		if (jackson2Present) {
-			ResponseBodyInterceptor interceptor = new JsonViewResponseBodyInterceptor();
-			adapter.setResponseBodyInterceptors(Arrays.asList(interceptor));
+			List<ResponseBodyInterceptor<?>> interceptors = new ArrayList<ResponseBodyInterceptor<?>>();
+			interceptors.add(new JsonViewResponseBodyInterceptor());
+			adapter.setResponseBodyInterceptors(interceptors);
 		}
 
 		AsyncSupportConfigurer configurer = new AsyncSupportConfigurer();
@@ -711,8 +712,9 @@ public class WebMvcConfigurationSupport implements ApplicationContextAware, Serv
 		exceptionHandlerExceptionResolver.setContentNegotiationManager(mvcContentNegotiationManager());
 		exceptionHandlerExceptionResolver.setMessageConverters(getMessageConverters());
 		if (jackson2Present) {
-			ResponseBodyInterceptor interceptor = new JsonViewResponseBodyInterceptor();
-			exceptionHandlerExceptionResolver.setResponseBodyInterceptors(Arrays.asList(interceptor));
+			List<ResponseBodyInterceptor<?>> interceptors = new ArrayList<ResponseBodyInterceptor<?>>();
+			interceptors.add(new JsonViewResponseBodyInterceptor());
+			exceptionHandlerExceptionResolver.setResponseBodyInterceptors(interceptors);
 		}
 		exceptionHandlerExceptionResolver.afterPropertiesSet();
 

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/AbstractMappingJacksonResponseBodyInterceptor.java

@@ -33,25 +33,27 @@ import org.springframework.http.server.ServerHttpResponse;
  * @author Rossen Stoyanchev
  * @since 4.1
  */
-public abstract class AbstractMappingJacksonResponseBodyInterceptor implements ResponseBodyInterceptor {
+public abstract class AbstractMappingJacksonResponseBodyInterceptor
+		implements ResponseBodyInterceptor<Object> {
 
 
 	protected AbstractMappingJacksonResponseBodyInterceptor() {
 	}
 
 
-	@SuppressWarnings("unchecked")
 	@Override
-	public final <T> T beforeBodyWrite(T body, MediaType contentType,
-			Class<? extends HttpMessageConverter<T>> converterType,
-			MethodParameter returnType, ServerHttpRequest request, ServerHttpResponse response) {
+	public boolean supports(MethodParameter returnType, Class<? extends HttpMessageConverter<?>> converterType) {
+		return MappingJackson2HttpMessageConverter.class.equals(converterType);
+	}
+
+	@Override
+	public final Object beforeBodyWrite(Object body, MethodParameter returnType,
+			MediaType contentType, Class<? extends HttpMessageConverter<?>> converterType,
+			ServerHttpRequest request, ServerHttpResponse response) {
 
-		if (!MappingJackson2HttpMessageConverter.class.equals(converterType)) {
-			return body;
-		}
 		MappingJacksonValue container = getOrCreateContainer(body);
 		beforeBodyWriteInternal(container, contentType, returnType, request, response);
-		return (T) container;
+		return container;
 	}
 
 	/**

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/AbstractMessageConverterMethodProcessor.java

@@ -31,6 +31,7 @@ import org.springframework.http.MediaType;
 import org.springframework.http.converter.HttpMessageConverter;
 import org.springframework.http.server.ServletServerHttpRequest;
 import org.springframework.http.server.ServletServerHttpResponse;
+import org.springframework.util.ClassUtils;
 import org.springframework.util.CollectionUtils;
 import org.springframework.web.HttpMediaTypeNotAcceptableException;
 import org.springframework.web.accept.ContentNegotiationManager;
@@ -148,9 +149,8 @@ public abstract class AbstractMessageConverterMethodProcessor extends AbstractMe
 			selectedMediaType = selectedMediaType.removeQualityValue();
 			for (HttpMessageConverter<?> messageConverter : this.messageConverters) {
 				if (messageConverter.canWrite(returnValueClass, selectedMediaType)) {
-					returnValue = this.interceptorChain.invoke(returnValue, selectedMediaType,
-							(Class<HttpMessageConverter<T>>) messageConverter.getClass(),
-							returnType, inputMessage, outputMessage);
+					returnValue = this.interceptorChain.invoke(returnValue, returnType, selectedMediaType,
+							(Class<HttpMessageConverter<?>>) messageConverter.getClass(), inputMessage, outputMessage);
 					((HttpMessageConverter<T>) messageConverter).write(returnValue, selectedMediaType, outputMessage);
 					if (logger.isDebugEnabled()) {
 						logger.debug("Written [" + returnValue + "] as \"" + selectedMediaType + "\" using [" +

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/ExceptionHandlerExceptionResolver.java

@@ -115,7 +115,7 @@ public class ExceptionHandlerExceptionResolver extends AbstractHandlerMethodExce
 	 * but before the body is written to the response with the selected
 	 * {@code HttpMessageConverter}.
 	 */
-	public void setResponseBodyInterceptors(List<ResponseBodyInterceptor> responseBodyInterceptors) {
+	public void setResponseBodyInterceptors(List<ResponseBodyInterceptor<?>> responseBodyInterceptors) {
 		this.responseBodyInterceptors.clear();
 		if (responseBodyInterceptors != null) {
 			this.responseBodyInterceptors.addAll(responseBodyInterceptors);

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/JsonViewResponseBodyInterceptor.java

@@ -19,6 +19,7 @@ package org.springframework.web.servlet.mvc.method.annotation;
 import com.fasterxml.jackson.annotation.JsonView;
 import org.springframework.core.MethodParameter;
 import org.springframework.http.MediaType;
+import org.springframework.http.converter.HttpMessageConverter;
 import org.springframework.http.converter.json.MappingJacksonValue;
 import org.springframework.http.server.ServerHttpRequest;
 import org.springframework.http.server.ServerHttpResponse;
@@ -40,18 +41,17 @@ import org.springframework.util.Assert;
 public class JsonViewResponseBodyInterceptor extends AbstractMappingJacksonResponseBodyInterceptor {
 
 
+	@Override
+	public boolean supports(MethodParameter returnType, Class<? extends HttpMessageConverter<?>> converterType) {
+		return (super.supports(returnType, converterType) && returnType.getMethodAnnotation(JsonView.class) != null);
+	}
+
 	@Override
 	protected void beforeBodyWriteInternal(MappingJacksonValue bodyContainer, MediaType contentType,
 			MethodParameter returnType, ServerHttpRequest request, ServerHttpResponse response) {
 
 		JsonView annotation = returnType.getMethodAnnotation(JsonView.class);
-		if (annotation == null) {
-			return;
-		}
-
-		Assert.isTrue(annotation.value().length != 0,
-				"Expected at least one serialization view class in JsonView annotation on " + returnType);
-
+		Assert.isTrue(annotation.value().length != 0, "No view class in JsonView annotation on " + returnType);
 		bodyContainer.setSerializationView(annotation.value()[0]);
 	}
 

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/RequestMappingHandlerAdapter.java

@@ -339,7 +339,7 @@ public class RequestMappingHandlerAdapter extends AbstractHandlerMethodAdapter
 	 * but before the body is written to the response with the selected
 	 * {@code HttpMessageConverter}.
 	 */
-	public void setResponseBodyInterceptors(List<ResponseBodyInterceptor> responseBodyInterceptors) {
+	public void setResponseBodyInterceptors(List<ResponseBodyInterceptor<?>> responseBodyInterceptors) {
 		this.responseBodyInterceptors.clear();
 		if (responseBodyInterceptors != null) {
 			this.responseBodyInterceptors.addAll(responseBodyInterceptors);

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/ResponseBodyInterceptor.java

@@ -30,23 +30,33 @@ import org.springframework.http.server.ServerHttpResponse;
  * @author Rossen Stoyanchev
  * @since 4.1
  */
-public interface ResponseBodyInterceptor {
+public interface ResponseBodyInterceptor<T> {
+
+	/**
+	 * Whether this interceptor supports the given controller method return type
+	 * and the selected {@code HttpMessageConverter} type.
+	 *
+	 * @param returnType the return type
+	 * @param converterType the selected converter type
+	 * @return {@code true} if beforeBodyWrite should be invoked, {@code false} otherwise
+	 */
+	boolean supports(MethodParameter returnType, Class<? extends HttpMessageConverter<?>> converterType);
 
 	/**
 	 * Invoked after an {@code HttpMessageConverter} is selected and just before
 	 * its write method is invoked.
 	 *
 	 * @param body the body to be written
-	 * @param contentType the selected content type
-	 * @param converterType the selected converter that will write the body
 	 * @param returnType the return type of the controller method
+	 * @param selectedContentType the content type selected through content negotiation
+	 * @param selectedConverterType the converter type selected to write to the response
 	 * @param request the current request
 	 * @param response the current response
-	 * @param <T> the type supported by the message converter
 	 *
 	 * @return the body that was passed in or a modified, possibly new instance
 	 */
-	<T> T beforeBodyWrite(T body, MediaType contentType, Class<? extends HttpMessageConverter<T>> converterType,
-			MethodParameter returnType, ServerHttpRequest request, ServerHttpResponse response);
+	T beforeBodyWrite(T body, MethodParameter returnType,
+			MediaType selectedContentType, Class<? extends HttpMessageConverter<?>> selectedConverterType,
+			ServerHttpRequest request, ServerHttpResponse response);
 
 }

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/ResponseBodyInterceptorChain.java

@@ -23,7 +23,6 @@ import org.springframework.http.MediaType;
 import org.springframework.http.converter.HttpMessageConverter;
 import org.springframework.http.server.ServerHttpRequest;
 import org.springframework.http.server.ServerHttpResponse;
-import org.springframework.util.Assert;
 import org.springframework.web.method.ControllerAdviceBean;
 
 import java.util.List;
@@ -46,8 +45,10 @@ class ResponseBodyInterceptorChain {
 	}
 
 
-	public <T> T invoke(T body, MediaType contentType, Class<? extends HttpMessageConverter<T>> converterType,
-			MethodParameter returnType, ServerHttpRequest request, ServerHttpResponse response) {
+	@SuppressWarnings("unchecked")
+	public <T> T invoke(T body, MethodParameter returnType,
+			MediaType selectedContentType, Class<? extends HttpMessageConverter<?>> selectedConverterType,
+			ServerHttpRequest request, ServerHttpResponse response) {
 
 		if (this.interceptors != null) {
 			if (logger.isDebugEnabled()) {
@@ -61,9 +62,16 @@ class ResponseBodyInterceptorChain {
 					}
 					interceptor = adviceBean.resolveBean();
 				}
-				Assert.state(interceptor instanceof  ResponseBodyInterceptor);
-				body = ((ResponseBodyInterceptor) interceptor).beforeBodyWrite(
-						body, contentType, converterType, returnType, request, response);
+				if (interceptor instanceof ResponseBodyInterceptor) {
+					ResponseBodyInterceptor<T> typedInterceptor = (ResponseBodyInterceptor<T>) interceptor;
+					if (typedInterceptor.supports(returnType, selectedConverterType)) {
+						body = typedInterceptor.beforeBodyWrite(body, returnType,
+								selectedContentType, selectedConverterType, request, response);
+					}
+				}
+				else {
+					throw new IllegalStateException("Expected a ResponseBodyInterceptor: " + interceptor);
+				}
 			}
 			if (logger.isDebugEnabled()) {
 				logger.debug("After interceptor chain body=" + body);

spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/ResponseBodyInterceptorChainTests.java

@@ -53,7 +53,7 @@ public class ResponseBodyInterceptorChainTests {
 
 	private MediaType contentType;
 
-	private Class<? extends HttpMessageConverter<String>> converterType;
+	private Class<? extends HttpMessageConverter<?>> converterType;
 
 	private MethodParameter returnType;
 
@@ -75,16 +75,17 @@ public class ResponseBodyInterceptorChainTests {
 	@Test
 	public void responseBodyInterceptor() {
 
-		ResponseBodyInterceptor interceptor = Mockito.mock(ResponseBodyInterceptor.class);
+		@SuppressWarnings("unchecked")
+		ResponseBodyInterceptor<String> interceptor = Mockito.mock(ResponseBodyInterceptor.class);
 		ResponseBodyInterceptorChain chain = new ResponseBodyInterceptorChain(Arrays.asList(interceptor));
 
 		String expected = "body++";
-		when(interceptor.beforeBodyWrite(
-				eq(this.body), eq(this.contentType), eq(this.converterType), eq(this.returnType),
-				same(this.request), same(this.response))).thenReturn(expected);
+		when(interceptor.supports(this.returnType, this.converterType)).thenReturn(true);
+		when(interceptor.beforeBodyWrite(eq(this.body), eq(this.returnType), eq(this.contentType),
+				eq(this.converterType), same(this.request), same(this.response))).thenReturn(expected);
 
-		String actual = chain.invoke(this.body, this.contentType,
-				this.converterType, this.returnType, this.request, this.response);
+		String actual = chain.invoke(this.body, this.returnType,
+				this.contentType, this.converterType, this.request, this.response);
 
 		assertEquals(expected, actual);
 	}
@@ -95,8 +96,8 @@ public class ResponseBodyInterceptorChainTests {
 		Object interceptor = new ControllerAdviceBean(new MyControllerAdvice());
 		ResponseBodyInterceptorChain chain = new ResponseBodyInterceptorChain(Arrays.asList(interceptor));
 
-		String actual = chain.invoke(this.body, this.contentType,
-				this.converterType, this.returnType, this.request, this.response);
+		String actual = chain.invoke(this.body, this.returnType,
+				this.contentType, this.converterType, this.request, this.response);
 
 		assertEquals("body-MyControllerAdvice", actual);
 	}
@@ -107,36 +108,46 @@ public class ResponseBodyInterceptorChainTests {
 		Object interceptor = new ControllerAdviceBean(new TargetedControllerAdvice());
 		ResponseBodyInterceptorChain chain = new ResponseBodyInterceptorChain(Arrays.asList(interceptor));
 
-		String actual = chain.invoke(this.body, this.contentType,
-				this.converterType, this.returnType, this.request, this.response);
+		String actual = chain.invoke(this.body, this.returnType,
+				this.contentType, this.converterType, this.request, this.response);
 
 		assertEquals(this.body, actual);
 	}
 
 
 	@ControllerAdvice
-	private static class MyControllerAdvice implements ResponseBodyInterceptor {
+	private static class MyControllerAdvice implements ResponseBodyInterceptor<String> {
+
+		@Override
+		public boolean supports(MethodParameter returnType, Class<? extends HttpMessageConverter<?>> converterType) {
+			return true;
+		}
 
 		@SuppressWarnings("unchecked")
 		@Override
-		public <T> T beforeBodyWrite(T body, MediaType contentType,
-				Class<? extends HttpMessageConverter<T>> converterType,
-				MethodParameter returnType, ServerHttpRequest request, ServerHttpResponse response) {
+		public String beforeBodyWrite(String body, MethodParameter returnType,
+				MediaType contentType, Class<? extends HttpMessageConverter<?>> converterType,
+				ServerHttpRequest request, ServerHttpResponse response) {
 
-			return (T) (body + "-MyControllerAdvice");
+			return body + "-MyControllerAdvice";
 		}
 	}
 
 	@ControllerAdvice(annotations = Controller.class)
-	private static class TargetedControllerAdvice implements ResponseBodyInterceptor {
+	private static class TargetedControllerAdvice implements ResponseBodyInterceptor<String> {
+
+		@Override
+		public boolean supports(MethodParameter returnType, Class<? extends HttpMessageConverter<?>> converterType) {
+			return true;
+		}
 
 		@SuppressWarnings("unchecked")
 		@Override
-		public <T> T beforeBodyWrite(T body, MediaType contentType,
-				Class<? extends HttpMessageConverter<T>> converterType,
-				MethodParameter returnType, ServerHttpRequest request, ServerHttpResponse response) {
+		public String beforeBodyWrite(String body, MethodParameter returnType,
+				MediaType contentType, Class<? extends HttpMessageConverter<?>> converterType,
+				ServerHttpRequest request, ServerHttpResponse response) {
 
-			return (T) (body + "-TargetedControllerAdvice");
+			return body + "-TargetedControllerAdvice";
 		}
 	}