001/*
002 * Copyright 2002-2017 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.support;
018
019import org.springframework.core.MethodParameter;
020import org.springframework.lang.Nullable;
021import org.springframework.web.context.request.NativeWebRequest;
022
023/**
024 * Strategy interface to handle the value returned from the invocation of a
025 * handler method .
026 *
027 * @author Arjen Poutsma
028 * @since 3.1
029 * @see HandlerMethodArgumentResolver
030 */
031public interface HandlerMethodReturnValueHandler {
032
033        /**
034         * Whether the given {@linkplain MethodParameter method return type} is
035         * supported by this handler.
036         * @param returnType the method return type to check
037         * @return {@code true} if this handler supports the supplied return type;
038         * {@code false} otherwise
039         */
040        boolean supportsReturnType(MethodParameter returnType);
041
042        /**
043         * Handle the given return value by adding attributes to the model and
044         * setting a view or setting the
045         * {@link ModelAndViewContainer#setRequestHandled} flag to {@code true}
046         * to indicate the response has been handled directly.
047         * @param returnValue the value returned from the handler method
048         * @param returnType the type of the return value. This type must have
049         * previously been passed to {@link #supportsReturnType} which must
050         * have returned {@code true}.
051         * @param mavContainer the ModelAndViewContainer for the current request
052         * @param webRequest the current request
053         * @throws Exception if the return value handling results in an error
054         */
055        void handleReturnValue(@Nullable Object returnValue, MethodParameter returnType,
056                        ModelAndViewContainer mavContainer, NativeWebRequest webRequest) throws Exception;
057
058}