com.hazelcast.replicatedmap.merge

Class LatestUpdateMapMergePolicy

java.lang.Object

com.hazelcast.replicatedmap.merge.LatestUpdateMapMergePolicy

All Implemented Interfaces:

DataSerializable, IdentifiedDataSerializable, ReplicatedMapMergePolicy, Serializable

public final class LatestUpdateMapMergePolicy
extends Object
implements ReplicatedMapMergePolicy, IdentifiedDataSerializable

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.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static LatestUpdateMapMergePolicy	INSTANCE Single instance of this class.

Method Summary

Modifier and Type	Method and Description
int	getFactoryId() Returns DataSerializableFactory factory ID for this class.
int	getId() Returns type identifier for this class.
Object	merge(String mapName, ReplicatedMapEntryView mergingEntry, ReplicatedMapEntryView existingEntry) Selects one of the merging and existing map entries to be merged.
void	readData(ObjectDataInput in) Reads fields from the input stream
void	writeData(ObjectDataOutput out) Writes object fields to output stream

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

INSTANCE

public static final LatestUpdateMapMergePolicy INSTANCE

Single instance of this class.

Method Detail

merge

public Object merge(String mapName,
                    ReplicatedMapEntryView mergingEntry,
                    ReplicatedMapEntryView existingEntry)

Description copied from interface: ReplicatedMapMergePolicy

Selects one of the merging and existing map entries to be merged.

Note that the existingEntry may be null if there is no entry with the same key in the destination map. This happens, when the entry for that key was

• only created in the smaller sub-cluster during the split-brain
• removed in the larger sub-cluster during the split-brain

Specified by:

merge in interface ReplicatedMapMergePolicy

Parameters:

mapName - name of the replicated map

mergingEntry - ReplicatedMapEntryView instance that has the map entry to be merged

existingEntry - ReplicatedMapEntryView instance that has the existing map entry or null if there is no existing map entry

Returns:

the selected value for merging or null if the entry should be removed

getFactoryId

public int getFactoryId()

Description copied from interface: IdentifiedDataSerializable

Returns DataSerializableFactory factory ID for this class.

Specified by:

getFactoryId in interface IdentifiedDataSerializable

Returns:

factory ID

getId

public int getId()

Description copied from interface: IdentifiedDataSerializable

Returns type identifier for this class. It should be unique per DataSerializableFactory.

Specified by:

getId in interface IdentifiedDataSerializable

Returns:

type ID

writeData

public void writeData(ObjectDataOutput out)

Description copied from interface: DataSerializable

Writes object fields to output stream

Specified by:

writeData in interface DataSerializable

Parameters:

out - output

readData

public void readData(ObjectDataInput in)

Description copied from interface: DataSerializable

Reads fields from the input stream

Specified by:

readData in interface DataSerializable

Parameters:

in - input