org.springframework.http.converter.SmartHttpMessageConverter Maven / Gradle / Ivy
/*
* Copyright 2002-2024 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.http.converter;
import java.io.IOException;
import java.util.Map;
import org.springframework.core.ResolvableType;
import org.springframework.http.HttpInputMessage;
import org.springframework.http.HttpOutputMessage;
import org.springframework.http.MediaType;
import org.springframework.lang.Nullable;
/**
* A specialization of {@link HttpMessageConverter} that can convert an HTTP request
* into a target object of a specified {@link ResolvableType} and a source object of
* a specified {@link ResolvableType} into an HTTP response with optional hints.
*
* It provides default methods for {@link HttpMessageConverter} in order to allow
* subclasses to only have to implement the smart APIs.
*
* @author Sebastien Deleuze
* @since 6.2
* @param the converted object type
*/
public interface SmartHttpMessageConverter extends HttpMessageConverter {
/**
* Indicates whether the given type can be read by this converter.
* This method should perform the same checks as
* {@link HttpMessageConverter#canRead(Class, MediaType)} with additional ones
* related to the generic type.
* @param type the (potentially generic) type to test for readability. The
* {@linkplain ResolvableType#getSource() type source} may be used for retrieving
* additional information (the related method signature for example) when relevant.
* @param mediaType the media type to read, can be {@code null} if not specified.
* Typically, the value of a {@code Content-Type} header.
* @return {@code true} if readable; {@code false} otherwise
*/
boolean canRead(ResolvableType type, @Nullable MediaType mediaType);
@Override
default boolean canRead(Class clazz, @Nullable MediaType mediaType) {
return canRead(ResolvableType.forClass(clazz), mediaType);
}
/**
* Read an object of the given type from the given input message, and returns it.
* @param type the (potentially generic) type of object to return. This type must have
* previously been passed to the {@link #canRead(ResolvableType, MediaType) canRead}
* method of this interface, which must have returned {@code true}. The
* {@linkplain ResolvableType#getSource() type source} may be used for retrieving
* additional information (the related method signature for example) when relevant.
* @param inputMessage the HTTP input message to read from
* @param hints additional information about how to encode
* @return the converted object
* @throws IOException in case of I/O errors
* @throws HttpMessageNotReadableException in case of conversion errors
*/
T read(ResolvableType type, HttpInputMessage inputMessage, @Nullable Map hints)
throws IOException, HttpMessageNotReadableException;
@Override
default T read(Class clazz, HttpInputMessage inputMessage)
throws IOException, HttpMessageNotReadableException {
return read(ResolvableType.forClass(clazz), inputMessage, null);
}
/**
* Indicates whether the given class can be written by this converter.
* This method should perform the same checks as
* {@link HttpMessageConverter#canWrite(Class, MediaType)} with additional ones
* related to the generic type.
* @param targetType the (potentially generic) target type to test for writability
* (can be {@link ResolvableType#NONE} if not specified). The {@linkplain ResolvableType#getSource() type source}
* may be used for retrieving additional information (the related method signature for example) when relevant.
* @param valueClass the source object class to test for writability
* @param mediaType the media type to write (can be {@code null} if not specified);
* typically the value of an {@code Accept} header.
* @return {@code true} if writable; {@code false} otherwise
*/
boolean canWrite(ResolvableType targetType, Class valueClass, @Nullable MediaType mediaType);
@Override
default boolean canWrite(Class clazz, @Nullable MediaType mediaType) {
return canWrite(ResolvableType.forClass(clazz), clazz, mediaType);
}
/**
* Write a given object to the given output message.
* @param t the object to write to the output message. The type of this object must
* have previously been passed to the {@link #canWrite canWrite} method of this
* interface, which must have returned {@code true}.
* @param type the (potentially generic) type of object to write. This type must have
* previously been passed to the {@link #canWrite canWrite} method of this interface,
* which must have returned {@code true}. Can be {@link ResolvableType#NONE} if not specified.
* The {@linkplain ResolvableType#getSource() type source} may be used for retrieving additional
* information (the related method signature for example) when relevant.
* @param contentType the content type to use when writing. May be {@code null} to
* indicate that the default content type of the converter must be used. If not
* {@code null}, this media type must have previously been passed to the
* {@link #canWrite canWrite} method of this interface, which must have returned
* {@code true}.
* @param outputMessage the message to write to
* @param hints additional information about how to encode
* @throws IOException in case of I/O errors
* @throws HttpMessageNotWritableException in case of conversion errors
*/
void write(T t, ResolvableType type, @Nullable MediaType contentType, HttpOutputMessage outputMessage,
@Nullable Map hints) throws IOException, HttpMessageNotWritableException;
@Override
default void write(T t, @Nullable MediaType contentType, HttpOutputMessage outputMessage)
throws IOException, HttpMessageNotWritableException {
write(t, ResolvableType.forInstance(t), contentType, outputMessage, null);
}
}