/*
* Copyright 2002-2016 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
*
* http://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.aggregator;
import org.springframework.messaging.Message;
/**
* Strategy for determining how messages can be correlated. Implementations
* should return the correlation key value associated with a particular message.
*
* @author Marius Bogoevici
* @author Iwein Fuld
*/
@FunctionalInterface
public interface CorrelationStrategy {
/**
* Find the correlation key for the given message. If no key can be determined the strategy should not return
* <code>null</code>, but throw an exception.
*
* @param message The message.
* @return The correlation key.
*/
Object getCorrelationKey(Message<?> message);
}