/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.camel.processor.aggregate;
import org.apache.camel.Exchange;
/**
* A specialized {@link AggregationStrategy} which gets a callback when the aggregated {@link Exchange} fails to add
* in the {@link org.apache.camel.spi.OptimisticLockingAggregationRepository} because of
* an {@link org.apache.camel.spi.OptimisticLockingAggregationRepository.OptimisticLockingException}.
* <p/>
* Please note that when aggregating {@link Exchange}'s to be careful not to modify and return the {@code oldExchange}
* from the {@link AggregationStrategy#aggregate(org.apache.camel.Exchange, org.apache.camel.Exchange)} method.
* If you are using the default MemoryAggregationRepository this will mean you have modified the value of an object
* already referenced/stored by the MemoryAggregationRepository. This makes it impossible for optimistic locking
* to work correctly with the MemoryAggregationRepository.
* <p/>
* You should instead return either the new {@code newExchange} or a completely new instance of {@link Exchange}. This
* is due to the nature of how the underlying {@link java.util.concurrent.ConcurrentHashMap} performs CAS operations
* on the value identity.
*
* @see java.util.concurrent.ConcurrentHashMap
*
* @version
*/
public interface OptimisticLockingAwareAggregationStrategy extends AggregationStrategy {
// TODO: In Camel 3.0 we should move this to org.apache.camel package
void onOptimisticLockFailure(Exchange oldExchange, Exchange newExchange);
}