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.http.converter; 018 019import java.io.IOException; 020import java.lang.reflect.Type; 021 022import org.springframework.http.HttpInputMessage; 023import org.springframework.http.HttpOutputMessage; 024import org.springframework.http.MediaType; 025 026/** 027 * A specialization of {@link HttpMessageConverter} that can convert an HTTP request 028 * into a target object of a specified generic type and a source object of a specified 029 * generic type into an HTTP response. 030 * 031 * @author Arjen Poutsma 032 * @author Rossen Stoyanchev 033 * @author Sebastien Deleuze 034 * @since 3.2 035 * @see org.springframework.core.ParameterizedTypeReference 036 */ 037public interface GenericHttpMessageConverter<T> extends HttpMessageConverter<T> { 038 039 /** 040 * Indicates whether the given type can be read by this converter. 041 * This method should perform the same checks than 042 * {@link HttpMessageConverter#canRead(Class, MediaType)} with additional ones 043 * related to the generic type. 044 * @param type the (potentially generic) type to test for readability 045 * @param contextClass a context class for the target type, for example a class 046 * in which the target type appears in a method signature (can be {@code null}) 047 * @param mediaType the media type to read, can be {@code null} if not specified. 048 * Typically the value of a {@code Content-Type} header. 049 * @return {@code true} if readable; {@code false} otherwise 050 */ 051 boolean canRead(Type type, Class<?> contextClass, MediaType mediaType); 052 053 /** 054 * Read an object of the given type form the given input message, and returns it. 055 * @param type the (potentially generic) type of object to return. This type must have 056 * previously been passed to the {@link #canRead canRead} method of this interface, 057 * which must have returned {@code true}. 058 * @param contextClass a context class for the target type, for example a class 059 * in which the target type appears in a method signature (can be {@code null}) 060 * @param inputMessage the HTTP input message to read from 061 * @return the converted object 062 * @throws IOException in case of I/O errors 063 * @throws HttpMessageNotReadableException in case of conversion errors 064 */ 065 T read(Type type, Class<?> contextClass, HttpInputMessage inputMessage) 066 throws IOException, HttpMessageNotReadableException; 067 068 /** 069 * Indicates whether the given class can be written by this converter. 070 * <p>This method should perform the same checks than 071 * {@link HttpMessageConverter#canWrite(Class, MediaType)} with additional ones 072 * related to the generic type. 073 * @param type the (potentially generic) type to test for writability 074 * (can be {@code null} if not specified) 075 * @param clazz the source object class to test for writability 076 * @param mediaType the media type to write (can be {@code null} if not specified); 077 * typically the value of an {@code Accept} header. 078 * @return {@code true} if writable; {@code false} otherwise 079 * @since 4.2 080 */ 081 boolean canWrite(Type type, Class<?> clazz, MediaType mediaType); 082 083 /** 084 * Write an given object to the given output message. 085 * @param t the object to write to the output message. The type of this object must 086 * have previously been passed to the {@link #canWrite canWrite} method of this 087 * interface, which must have returned {@code true}. 088 * @param type the (potentially generic) type of object to write. This type must have 089 * previously been passed to the {@link #canWrite canWrite} method of this interface, 090 * which must have returned {@code true}. Can be {@code null} if not specified. 091 * @param contentType the content type to use when writing. May be {@code null} to 092 * indicate that the default content type of the converter must be used. If not 093 * {@code null}, this media type must have previously been passed to the 094 * {@link #canWrite canWrite} method of this interface, which must have returned 095 * {@code true}. 096 * @param outputMessage the message to write to 097 * @throws IOException in case of I/O errors 098 * @throws HttpMessageNotWritableException in case of conversion errors 099 * @since 4.2 100 */ 101 void write(T t, Type type, MediaType contentType, HttpOutputMessage outputMessage) 102 throws IOException, HttpMessageNotWritableException; 103 104}