org.springframework.messaging.converter.SmartMessageConverter Maven / Gradle / Ivy
/*
* Copyright 2002-2017 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.messaging.converter;
import org.springframework.lang.Nullable;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageHeaders;
/**
* An extended {@link MessageConverter} SPI with conversion hint support.
*
* In case of a conversion hint being provided, the framework will call
* these extended methods if a converter implements this interface, instead
* of calling the regular {@code fromMessage} / {@code toMessage} variants.
*
* @author Juergen Hoeller
* @since 4.2.1
*/
public interface SmartMessageConverter extends MessageConverter {
/**
* A variant of {@link #fromMessage(Message, Class)} which takes an extra
* conversion context as an argument, allowing to take e.g. annotations
* on a payload parameter into account.
* @param message the input message
* @param targetClass the target class for the conversion
* @param conversionHint an extra object passed to the {@link MessageConverter},
* e.g. the associated {@code MethodParameter} (may be {@code null}}
* @return the result of the conversion, or {@code null} if the converter cannot
* perform the conversion
* @see #fromMessage(Message, Class)
*/
@Nullable
Object fromMessage(Message message, Class targetClass, @Nullable Object conversionHint);
/**
* A variant of {@link #toMessage(Object, MessageHeaders)} which takes an extra
* conversion context as an argument, allowing to take e.g. annotations
* on a return type into account.
* @param payload the Object to convert
* @param headers optional headers for the message (may be {@code null})
* @param conversionHint an extra object passed to the {@link MessageConverter},
* e.g. the associated {@code MethodParameter} (may be {@code null}}
* @return the new message, or {@code null} if the converter does not support the
* Object type or the target media type
* @see #toMessage(Object, MessageHeaders)
*/
@Nullable
Message toMessage(Object payload, @Nullable MessageHeaders headers, @Nullable Object conversionHint);
}