com.hazelcast.replicatedmap.merge.LatestUpdateMapMergePolicy Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2020, 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.replicatedmap.merge;
import com.hazelcast.nio.ObjectDataInput;
import com.hazelcast.nio.ObjectDataOutput;
import com.hazelcast.nio.serialization.IdentifiedDataSerializable;
import com.hazelcast.replicatedmap.impl.operation.ReplicatedMapDataSerializerHook;
import com.hazelcast.replicatedmap.impl.record.ReplicatedMapEntryView;
/**
* Merges replicated map entries from source to destination map if the source entry
* was updated more recently than the destination entry.
*
* Note: This policy can only be used if the clocks of the nodes are in sync.
*/
public final class LatestUpdateMapMergePolicy implements ReplicatedMapMergePolicy, IdentifiedDataSerializable {
/**
* Single instance of this class.
*/
public static final LatestUpdateMapMergePolicy INSTANCE = new LatestUpdateMapMergePolicy();
private LatestUpdateMapMergePolicy() {
}
@Override
public Object merge(String mapName, ReplicatedMapEntryView mergingEntry, ReplicatedMapEntryView existingEntry) {
if (mergingEntry.getLastUpdateTime() >= existingEntry.getLastUpdateTime()) {
return mergingEntry.getValue();
}
return existingEntry.getValue();
}
@Override
public int getFactoryId() {
return ReplicatedMapDataSerializerHook.F_ID;
}
@Override
public int getId() {
return ReplicatedMapDataSerializerHook.LATEST_UPDATE_MERGE_POLICY;
}
@Override
public void writeData(ObjectDataOutput out) {
}
@Override
public void readData(ObjectDataInput in) {
}
}