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.servlet.mvc.method.annotation; 018 019import java.io.IOException; 020import java.lang.reflect.Type; 021 022import org.springframework.core.MethodParameter; 023import org.springframework.http.HttpInputMessage; 024import org.springframework.http.converter.HttpMessageConverter; 025import org.springframework.lang.Nullable; 026 027/** 028 * Allows customizing the request before its body is read and converted into an 029 * Object and also allows for processing of the resulting Object before it is 030 * passed into a controller method as an {@code @RequestBody} or an 031 * {@code HttpEntity} method argument. 032 * 033 * <p>Implementations of this contract may be registered directly with the 034 * {@code RequestMappingHandlerAdapter} or more likely annotated with 035 * {@code @ControllerAdvice} in which case they are auto-detected. 036 * 037 * @author Rossen Stoyanchev 038 * @since 4.2 039 */ 040public interface RequestBodyAdvice { 041 042 /** 043 * Invoked first to determine if this interceptor applies. 044 * @param methodParameter the method parameter 045 * @param targetType the target type, not necessarily the same as the method 046 * parameter type, e.g. for {@code HttpEntity<String>}. 047 * @param converterType the selected converter type 048 * @return whether this interceptor should be invoked or not 049 */ 050 boolean supports(MethodParameter methodParameter, Type targetType, 051 Class<? extends HttpMessageConverter<?>> converterType); 052 053 /** 054 * Invoked second before the request body is read and converted. 055 * @param inputMessage the request 056 * @param parameter the target method parameter 057 * @param targetType the target type, not necessarily the same as the method 058 * parameter type, e.g. for {@code HttpEntity<String>}. 059 * @param converterType the converter used to deserialize the body 060 * @return the input request or a new instance, never {@code null} 061 */ 062 HttpInputMessage beforeBodyRead(HttpInputMessage inputMessage, MethodParameter parameter, 063 Type targetType, Class<? extends HttpMessageConverter<?>> converterType) throws IOException; 064 065 /** 066 * Invoked third (and last) after the request body is converted to an Object. 067 * @param body set to the converter Object before the first advice is called 068 * @param inputMessage the request 069 * @param parameter the target method parameter 070 * @param targetType the target type, not necessarily the same as the method 071 * parameter type, e.g. for {@code HttpEntity<String>}. 072 * @param converterType the converter used to deserialize the body 073 * @return the same body or a new instance 074 */ 075 Object afterBodyRead(Object body, HttpInputMessage inputMessage, MethodParameter parameter, 076 Type targetType, Class<? extends HttpMessageConverter<?>> converterType); 077 078 /** 079 * Invoked second (and last) if the body is empty. 080 * @param body usually set to {@code null} before the first advice is called 081 * @param inputMessage the request 082 * @param parameter the method parameter 083 * @param targetType the target type, not necessarily the same as the method 084 * parameter type, e.g. for {@code HttpEntity<String>}. 085 * @param converterType the selected converter type 086 * @return the value to use or {@code null} which may then raise an 087 * {@code HttpMessageNotReadableException} if the argument is required. 088 */ 089 @Nullable 090 Object handleEmptyBody(@Nullable Object body, HttpInputMessage inputMessage, MethodParameter parameter, 091 Type targetType, Class<? extends HttpMessageConverter<?>> converterType); 092 093 094}