org.springframework.integration.handler.MessageProcessor Maven / Gradle / Ivy
/*
* Copyright 2002-2019 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.integration.handler;
import org.springframework.lang.Nullable;
import org.springframework.messaging.Message;
/**
* This defines the lowest-level strategy of processing a Message and returning
* some Object (or null). Implementations will be focused on generic concerns,
* such as invoking a method, running a script, or evaluating an expression.
*
* Higher level MessageHandler implementations can delegate to these processors
* for such functionality, but it is the responsibility of each handler type to
* add the semantics such as routing, splitting, transforming, etc.
*
* In some cases the return value might be a Message itself, but it does not
* need to be. It is the responsibility of the caller to determine how to treat
* the return value. That may require creating a Message or even creating
* multiple Messages from that value.
*
* This strategy and its various implementations are considered part of the
* internal "support" API, intended for use by Spring Integration's various
* message-handling components. As such, it is subject to change.
*
* @author Mark Fisher
* @author Artem Bilan
*
* @since 2.0
*/
@FunctionalInterface
public interface MessageProcessor {
/**
* Process the Message and return a value (or null).
*
* @param message The message to process.
* @return The result.
*/
@Nullable
T processMessage(Message message);
}