001/* 002 * Copyright 2002-2014 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.web.method.annotation; 018 019import org.springframework.core.MethodParameter; 020import org.springframework.ui.Model; 021import org.springframework.web.bind.support.WebDataBinderFactory; 022import org.springframework.web.context.request.NativeWebRequest; 023import org.springframework.web.method.support.HandlerMethodArgumentResolver; 024import org.springframework.web.method.support.HandlerMethodReturnValueHandler; 025import org.springframework.web.method.support.ModelAndViewContainer; 026 027/** 028 * Resolves {@link Model} arguments and handles {@link Model} return values. 029 * 030 * <p>A {@link Model} return type has a set purpose. Therefore this handler 031 * should be configured ahead of handlers that support any return value type 032 * annotated with {@code @ModelAttribute} or {@code @ResponseBody} to ensure 033 * they don't take over. 034 * 035 * @author Rossen Stoyanchev 036 * @since 3.1 037 */ 038public class ModelMethodProcessor implements HandlerMethodArgumentResolver, HandlerMethodReturnValueHandler { 039 040 @Override 041 public boolean supportsParameter(MethodParameter parameter) { 042 return Model.class.isAssignableFrom(parameter.getParameterType()); 043 } 044 045 @Override 046 public Object resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer, 047 NativeWebRequest webRequest, WebDataBinderFactory binderFactory) throws Exception { 048 049 return mavContainer.getModel(); 050 } 051 052 @Override 053 public boolean supportsReturnType(MethodParameter returnType) { 054 return Model.class.isAssignableFrom(returnType.getParameterType()); 055 } 056 057 @Override 058 public void handleReturnValue(Object returnValue, MethodParameter returnType, 059 ModelAndViewContainer mavContainer, NativeWebRequest webRequest) throws Exception { 060 061 if (returnValue == null) { 062 return; 063 } 064 else if (returnValue instanceof Model) { 065 mavContainer.addAllAttributes(((Model) returnValue).asMap()); 066 } 067 else { 068 // should not happen 069 throw new UnsupportedOperationException("Unexpected return type: " + 070 returnType.getParameterType().getName() + " in method: " + returnType.getMethod()); 071 } 072 } 073 074}