SPR-5426 - Allow for custom processing or result objects returned from handler/controller methods

git-svn-id: https://src.springframework.org/svn/spring-framework/trunk@1093 50f2f4bb-b051-0410-bef5-90022cba6387

org.springframework.web.portlet/src/main/java/org/springframework/web/portlet/mvc/annotation/AnnotationMethodHandlerAdapter.java

@@ -93,6 +93,7 @@ import org.springframework.web.portlet.handler.PortletContentGenerator;
 import org.springframework.web.portlet.handler.PortletSessionRequiredException;
 import org.springframework.web.portlet.util.PortletUtils;
 import org.springframework.web.servlet.View;
+import org.springframework.web.servlet.mvc.annotation.ModelAndViewResolver;
 
 /**
  * Implementation of the {@link org.springframework.web.portlet.HandlerAdapter}
@@ -131,6 +132,8 @@ public class AnnotationMethodHandlerAdapter extends PortletContentGenerator impl
 
 	private WebArgumentResolver[] customArgumentResolvers;
 
+	private ModelAndViewResolver[] customModelAndViewResolvers;
+
 	private final Map<Class<?>, PortletHandlerMethodResolver> methodResolverCache =
 			new ConcurrentHashMap<Class<?>, PortletHandlerMethodResolver>();
 
@@ -199,8 +202,8 @@ public class AnnotationMethodHandlerAdapter extends PortletContentGenerator impl
 	}
 
 	/**
-	 * Set a custom ArgumentResolvers to use for special method parameter types.
-	 * Such a custom ArgumentResolver will kick in first, having a chance to
+	 * Set a custom WebArgumentResolvers to use for special method parameter types.
+	 * Such a custom WebArgumentResolver will kick in first, having a chance to
 	 * resolve an argument value before the standard argument handling kicks in.
 	 */
 	public void setCustomArgumentResolver(WebArgumentResolver argumentResolver) {
@@ -208,8 +211,8 @@ public class AnnotationMethodHandlerAdapter extends PortletContentGenerator impl
 	}
 
 	/**
-	 * Set one or more custom ArgumentResolvers to use for special method
-	 * parameter types. Any such custom ArgumentResolver will kick in first,
+	 * Set one or more custom WebArgumentResolvers to use for special method
+	 * parameter types. Any such custom WebArgumentResolver will kick in first,
 	 * having a chance to resolve an argument value before the standard
 	 * argument handling kicks in.
 	 */
@@ -217,6 +220,22 @@ public class AnnotationMethodHandlerAdapter extends PortletContentGenerator impl
 		this.customArgumentResolvers = argumentResolvers;
 	}
 
+	/**
+	 * Set a custom ModelAndViewResolvers to use for special method return types. Such a custom ModelAndViewResolver will kick
+	 * in first, having a chance to resolve an return value before the standard ModelAndView handling kicks in.
+	 */
+	public void setCustomModelAndViewResolver(ModelAndViewResolver customModelAndViewResolver) {
+		this.customModelAndViewResolvers = new ModelAndViewResolver[]{customModelAndViewResolver};
+	}
+
+	/**
+	 * Set one or more custom ModelAndViewResolvers to use for special method return types. Any such custom ModelAndViewResolver
+	 * will kick in first, having a chance to resolve an return value before the standard ModelAndView handling kicks in.
+	 */
+	public void setCustomModelAndViewResolvers(ModelAndViewResolver[] customModelAndViewResolvers) {
+		this.customModelAndViewResolvers = customModelAndViewResolvers;
+	}
+
 
 	public boolean supports(Object handler) {
 		return getMethodResolver(handler).hasHandlerMethods();
@@ -296,7 +315,8 @@ public class AnnotationMethodHandlerAdapter extends PortletContentGenerator impl
 		PortletHandlerMethodInvoker methodInvoker = new PortletHandlerMethodInvoker(methodResolver);
 
 		Object result = methodInvoker.invokeHandlerMethod(handlerMethod, handler, webRequest, implicitModel);
-		ModelAndView mav = methodInvoker.getModelAndView(handlerMethod, handler.getClass(), result, implicitModel);
+		ModelAndView mav = methodInvoker.getModelAndView(handlerMethod, handler.getClass(), result, implicitModel,
+				webRequest);
 		methodInvoker.updateModelAttributes(
 				handler, (mav != null ? mav.getModel() : null), implicitModel, webRequest);
 
@@ -660,8 +680,20 @@ public class AnnotationMethodHandlerAdapter extends PortletContentGenerator impl
 		}
 
 		@SuppressWarnings("unchecked")
-		public ModelAndView getModelAndView(
-				Method handlerMethod, Class handlerType, Object returnValue, ExtendedModelMap implicitModel) {
+		public ModelAndView getModelAndView(Method handlerMethod, Class handlerType, Object returnValue, ExtendedModelMap implicitModel,
+				PortletWebRequest webRequest) {
+			// Invoke custom resolvers if present...
+			if (customModelAndViewResolvers != null) {
+				for (ModelAndViewResolver mavResolver : customModelAndViewResolvers) {
+					org.springframework.web.servlet.ModelAndView smav = mavResolver
+							.resolveModelAndView(handlerMethod, handlerType, returnValue, implicitModel, webRequest);
+					if (smav != ModelAndViewResolver.UNRESOLVED) {
+						return (smav.isReference() ?
+								new ModelAndView(smav.getViewName(), smav.getModelMap()) :
+								new ModelAndView(smav.getView(), smav.getModelMap()));
+					}
+				}
+			}
 
 			if (returnValue instanceof ModelAndView) {
 				ModelAndView mav = (ModelAndView) returnValue;

org.springframework.web.portlet/src/test/java/org/springframework/web/portlet/mvc/annotation/PortletAnnotationControllerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2008 the original author or authors.
+ * Copyright 2002-2009 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.
@@ -17,6 +17,7 @@
 package org.springframework.web.portlet.mvc.annotation;
 
 import java.io.IOException;
+import java.lang.reflect.Method;
 import java.text.SimpleDateFormat;
 import java.util.Date;
 import java.util.LinkedList;
@@ -32,6 +33,8 @@ import javax.portlet.PortletSession;
 import javax.portlet.RenderRequest;
 import javax.portlet.RenderResponse;
 import javax.portlet.UnavailableException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
 
 import junit.framework.TestCase;
 
@@ -72,6 +75,8 @@ import org.springframework.web.portlet.DispatcherPortlet;
 import org.springframework.web.portlet.ModelAndView;
 import org.springframework.web.portlet.context.StaticPortletApplicationContext;
 import org.springframework.web.portlet.mvc.AbstractController;
+import org.springframework.web.servlet.View;
+import org.springframework.web.servlet.mvc.annotation.ModelAndViewResolver;
 
 /**
  * @author Juergen Hoeller
@@ -434,6 +439,28 @@ public class PortletAnnotationControllerTests extends TestCase {
 		assertEquals("mySurpriseView", response.getContentAsString());
 	}
 
+	public void testMavResolver() throws Exception {
+		@SuppressWarnings("serial") DispatcherPortlet portlet = new DispatcherPortlet() {
+			@Override
+			protected ApplicationContext createPortletApplicationContext(ApplicationContext parent) throws BeansException {
+				GenericWebApplicationContext wac = new GenericWebApplicationContext();
+				wac.registerBeanDefinition("controller",
+						new RootBeanDefinition(ModelAndViewResolverController.class));
+				RootBeanDefinition adapterDef = new RootBeanDefinition(AnnotationMethodHandlerAdapter.class);
+				adapterDef.getPropertyValues()
+						.addPropertyValue("customModelAndViewResolver", new MyModelAndViewResolver());
+				wac.registerBeanDefinition("handlerAdapter", adapterDef);
+				wac.refresh();
+				return wac;
+			}
+		};
+		portlet.init(new MockPortletConfig());
+
+		MockRenderRequest request = new MockRenderRequest(PortletMode.VIEW);
+		MockRenderResponse response = new MockRenderResponse();
+		portlet.render(request, response);
+	}
+
 
 	@RequestMapping("VIEW")
 	private static class MyController extends AbstractController {
@@ -769,4 +796,37 @@ public class PortletAnnotationControllerTests extends TestCase {
 		}
 	}
 
+	@Controller
+	public static class ModelAndViewResolverController {
+
+		@RequestMapping("VIEW")
+		public MySpecialArg handle() {
+			return new MySpecialArg("foo");
+		}
+	}
+
+	public static class MyModelAndViewResolver implements ModelAndViewResolver {
+
+		public org.springframework.web.servlet.ModelAndView resolveModelAndView(Method handlerMethod,
+				Class handlerType,
+				Object returnValue,
+				ExtendedModelMap implicitModel,
+				NativeWebRequest webRequest) {
+			if (returnValue instanceof MySpecialArg) {
+				return new org.springframework.web.servlet.ModelAndView(new View() {
+					public String getContentType() {
+						return "text/html";
+					}
+
+					public void render(Map<String, ?> model, HttpServletRequest request, HttpServletResponse response)
+							throws Exception {
+						response.getWriter().write("myValue");
+					}
+
+				});
+			}
+			return UNRESOLVED;
+		}
+	}
+
 }

org.springframework.web.servlet/src/main/java/org/springframework/web/servlet/mvc/annotation/AnnotationMethodHandlerAdapter.java

@@ -150,6 +150,8 @@ public class AnnotationMethodHandlerAdapter extends WebContentGenerator implemen
 
 	private WebArgumentResolver[] customArgumentResolvers;
 
+	private ModelAndViewResolver[] customModelAndViewResolvers;
+
 	private final Map<Class<?>, ServletHandlerMethodResolver> methodResolverCache =
 			new ConcurrentHashMap<Class<?>, ServletHandlerMethodResolver>();
 
@@ -269,7 +271,7 @@ public class AnnotationMethodHandlerAdapter extends WebContentGenerator implemen
 	}
 
 	/**
-	 * Set a custom ArgumentResolvers to use for special method parameter types. Such a custom ArgumentResolver will kick
+	 * Set a custom WebArgumentResolvers to use for special method parameter types. Such a custom WebArgumentResolver will kick
 	 * in first, having a chance to resolve an argument value before the standard argument handling kicks in.
 	 */
 	public void setCustomArgumentResolver(WebArgumentResolver argumentResolver) {
@@ -277,13 +279,29 @@ public class AnnotationMethodHandlerAdapter extends WebContentGenerator implemen
 	}
 
 	/**
-	 * Set one or more custom ArgumentResolvers to use for special method parameter types. Any such custom ArgumentResolver
+	 * Set one or more custom WebArgumentResolvers to use for special method parameter types. Any such custom WebArgumentResolver
 	 * will kick in first, having a chance to resolve an argument value before the standard argument handling kicks in.
 	 */
 	public void setCustomArgumentResolvers(WebArgumentResolver[] argumentResolvers) {
 		this.customArgumentResolvers = argumentResolvers;
 	}
 
+	/**
+	 * Set a custom ModelAndViewResolvers to use for special method return types. Such a custom ModelAndViewResolver will kick
+	 * in first, having a chance to resolve an return value before the standard ModelAndView handling kicks in.
+	 */
+	public void setCustomModelAndViewResolver(ModelAndViewResolver customModelAndViewResolver) {
+		this.customModelAndViewResolvers = new ModelAndViewResolver[]{customModelAndViewResolver};
+	}
+
+	/**
+	 * Set one or more custom ModelAndViewResolvers to use for special method return types. Any such custom ModelAndViewResolver
+	 * will kick in first, having a chance to resolve an return value before the standard ModelAndView handling kicks in.
+	 */
+	public void setCustomModelAndViewResolvers(ModelAndViewResolver[] customModelAndViewResolvers) {
+		this.customModelAndViewResolvers = customModelAndViewResolvers;
+	}
+
 	/**
 	 * Set the message body converters to use. These converters are used to convert from and to HTTP requests and
 	 * responses.
@@ -673,6 +691,16 @@ public class AnnotationMethodHandlerAdapter extends WebContentGenerator implemen
 				ExtendedModelMap implicitModel,
 				ServletWebRequest webRequest) {
 
+			// Invoke custom resolvers if present...
+			if (customModelAndViewResolvers != null) {
+				for (ModelAndViewResolver mavResolver : customModelAndViewResolvers) {
+					ModelAndView mav = mavResolver
+							.resolveModelAndView(handlerMethod, handlerType, returnValue, implicitModel, webRequest);
+					if (mav != ModelAndViewResolver.UNRESOLVED) {
+						return mav;
+					}
+				}
+			}
 			if (handlerMethod.isAnnotationPresent(ResponseStatus.class)) {
 				ResponseStatus responseStatus = handlerMethod.getAnnotation(ResponseStatus.class);
 				HttpServletResponse response = webRequest.getResponse();

org.springframework.web.servlet/src/main/java/org/springframework/web/servlet/mvc/annotation/ModelAndViewResolver.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright 2002-2009 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.web.servlet.mvc.annotation;
+
+import java.lang.reflect.Method;
+
+import org.springframework.ui.ExtendedModelMap;
+import org.springframework.web.context.request.NativeWebRequest;
+import org.springframework.web.servlet.ModelAndView;
+
+/**
+ * SPI for resolving custom return values from a specific handler method. Typically implemented to detect special return
+ * types, resolving well-known result values for them.
+ *
+ * <p>A typical implementation could look like as follows:
+ *
+ * <pre class="code">
+ * public class MyModelAndViewResolver implements ModelAndViewResolver {
+ *
+ *   public ModelAndView resolveModelAndView(Method handlerMethod,
+ *		   			Class handlerType,
+ *		   			Object returnValue,
+ *		 			ExtendedModelMap implicitModel,
+ *		 			NativeWebRequest webRequest) {
+ *     if (returnValue instanceof MySpecialRetVal.class)) {
+ *       return new MySpecialRetVal(returnValue);
+ *     }
+ *     return UNRESOLVED;
+ *   }
+ * }</pre>
+ *
+ * @author Arjen Poutsma
+ * @see org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter#setCustomModelAndViewResolvers
+ * @see org.springframework.web.portlet.mvc.annotation.AnnotationMethodHandlerAdapter#setCustomModelAndViewResolvers
+ * @since 3.0
+ */
+public interface ModelAndViewResolver {
+
+	/** Marker to be returned when the resolver does not know how to handle the given method parameter. */
+	ModelAndView UNRESOLVED = new ModelAndView();
+
+	ModelAndView resolveModelAndView(Method handlerMethod,
+			Class handlerType,
+			Object returnValue,
+			ExtendedModelMap implicitModel,
+			NativeWebRequest webRequest);
+}

org.springframework.web.servlet/src/test/java/org/springframework/web/servlet/mvc/annotation/ServletAnnotationControllerTests.java

@@ -18,6 +18,7 @@ package org.springframework.web.servlet.mvc.annotation;
 
 import java.io.IOException;
 import java.io.Writer;
+import java.lang.reflect.Method;
 import java.security.Principal;
 import java.text.SimpleDateFormat;
 import java.util.Arrays;
@@ -924,6 +925,32 @@ public class ServletAnnotationControllerTests {
 		assertEquals(201, response.getStatus());
 	}
 
+	@Test
+	public void mavResolver() throws ServletException, IOException {
+		@SuppressWarnings("serial") DispatcherServlet servlet = new DispatcherServlet() {
+			@Override
+			protected WebApplicationContext createWebApplicationContext(WebApplicationContext parent) {
+				GenericWebApplicationContext wac = new GenericWebApplicationContext();
+				wac.registerBeanDefinition("controller",
+						new RootBeanDefinition(ModelAndViewResolverController.class));
+				RootBeanDefinition adapterDef = new RootBeanDefinition(AnnotationMethodHandlerAdapter.class);
+				adapterDef.getPropertyValues()
+						.addPropertyValue("customModelAndViewResolver", new MyModelAndViewResolver());
+				wac.registerBeanDefinition("handlerAdapter", adapterDef);
+				wac.refresh();
+				return wac;
+			}
+		};
+		servlet.init(new MockServletConfig());
+
+		MockHttpServletRequest request = new MockHttpServletRequest("GET", "/");
+		MockHttpServletResponse response = new MockHttpServletResponse();
+		servlet.service(request, response);
+		assertEquals("myValue", response.getContentAsString());
+
+	}
+
+
 	/*
 	 * Controllers
 	 */
@@ -1502,6 +1529,27 @@ public class ServletAnnotationControllerTests {
 		}
 	}
 
+	public static class MyMessageConverter implements HttpMessageConverter {
+
+		public boolean supports(Class clazz) {
+			return true;
+		}
+
+		public List getSupportedMediaTypes() {
+			return Collections.singletonList(new MediaType("application", "pdf"));
+		}
+
+		public Object read(Class clazz, HttpInputMessage inputMessage)
+				throws IOException, HttpMessageNotReadableException {
+			throw new HttpMessageNotReadableException("Could not read");
+		}
+
+		public void write(Object o, HttpOutputMessage outputMessage)
+				throws IOException, HttpMessageNotWritableException {
+			throw new UnsupportedOperationException("Not implemented");
+		}
+	}
+
 	@Controller
 	public static class HeadersController {
 
@@ -1526,25 +1574,40 @@ public class ServletAnnotationControllerTests {
 		}
 	}
 
-	public static class MyMessageConverter implements HttpMessageConverter {
 
-		public boolean supports(Class clazz) {
-			return true;
-		}
+	@Controller
+	public static class ModelAndViewResolverController {
 
-		public List getSupportedMediaTypes() {
-			return Collections.singletonList(new MediaType("application", "pdf"));
+		@RequestMapping("/")
+		public MySpecialArg handle() {
+			return new MySpecialArg("foo");
 		}
+	}
 
-		public Object read(Class clazz, HttpInputMessage inputMessage)
-				throws IOException, HttpMessageNotReadableException {
-			throw new HttpMessageNotReadableException("Could not read");
-		}
+	public static class MyModelAndViewResolver implements ModelAndViewResolver {
 
-		public void write(Object o, HttpOutputMessage outputMessage)
-				throws IOException, HttpMessageNotWritableException {
-			throw new UnsupportedOperationException("Not implemented");
+		public ModelAndView resolveModelAndView(Method handlerMethod,
+				Class handlerType,
+				Object returnValue,
+				ExtendedModelMap implicitModel,
+				NativeWebRequest webRequest) {
+			if (returnValue instanceof MySpecialArg) {
+				return new ModelAndView(new View() {
+					public String getContentType() {
+						return "text/html";
+					}
+
+					public void render(Map<String, ?> model, HttpServletRequest request, HttpServletResponse response)
+							throws Exception {
+						response.getWriter().write("myValue");
+					}
+
+				});
+			}
+			return UNRESOLVED;
 		}
 	}
 
+
+
 }