/*
* Copyright (c) 2008-2013, Hazelcast, Inc. All Rights Reserved.
*
* 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 com.hazelcast.hibernate;
import com.hazelcast.core.EntryView;
import com.hazelcast.map.merge.MapMergePolicy;
import com.hazelcast.nio.ObjectDataInput;
import com.hazelcast.nio.ObjectDataOutput;
import org.hibernate.cache.entry.CacheEntry;
import java.io.IOException;
/**
* A merge policy implementation to handle split brain remerges based on the timestamps stored in
* the values.
*/
public class VersionAwareMapMergePolicy implements MapMergePolicy {
public Object merge(String mapName, EntryView mergingEntry, EntryView existingEntry) {
final Object existingValue = existingEntry != null ? existingEntry.getValue() : null;
final Object mergingValue = mergingEntry.getValue();
if (existingValue != null && existingValue instanceof CacheEntry
&& mergingValue != null && mergingValue instanceof CacheEntry) {
final CacheEntry existingCacheEntry = (CacheEntry) existingValue;
final CacheEntry mergingCacheEntry = (CacheEntry) mergingValue;
final Object mergingVersionObject = mergingCacheEntry.getVersion();
final Object existingVersionObject = existingCacheEntry.getVersion();
if (mergingVersionObject != null && existingVersionObject != null
&& mergingVersionObject instanceof Comparable && existingVersionObject instanceof Comparable) {
final Comparable mergingVersion = (Comparable) mergingVersionObject;
final Comparable existingVersion = (Comparable) existingVersionObject;
if (mergingVersion.compareTo(existingVersion) > 0) {
return mergingValue;
} else {
return existingValue;
}
}
}
return mergingValue;
}
@Override
public void writeData(ObjectDataOutput out) throws IOException {
}
@Override
public void readData(ObjectDataInput in) throws IOException {
}
}