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.messaging.handler.invocation; 018 019import org.springframework.core.MethodParameter; 020import org.springframework.messaging.Message; 021 022/** 023 * Strategy interface to handle the value returned from the invocation of a 024 * method handling a {@link Message}. 025 * 026 * @author Rossen Stoyanchev 027 * @since 4.0 028 */ 029public interface HandlerMethodReturnValueHandler { 030 031 /** 032 * Whether the given {@linkplain MethodParameter method return type} is 033 * supported by this handler. 034 * @param returnType the method return type to check 035 * @return {@code true} if this handler supports the supplied return type; 036 * {@code false} otherwise 037 */ 038 boolean supportsReturnType(MethodParameter returnType); 039 040 /** 041 * Handle the given return value. 042 * @param returnValue the value returned from the handler method 043 * @param returnType the type of the return value. This type must have previously 044 * been passed to {@link #supportsReturnType(org.springframework.core.MethodParameter)} 045 * and it must have returned {@code true}. 046 * @param message the message that caused this method to be called 047 * @throws Exception if the return value handling results in an error 048 */ 049 void handleReturnValue(Object returnValue, MethodParameter returnType, Message<?> message) 050 throws Exception; 051 052}