com.hazelcast.map.merge

Class LatestUpdateMapMergePolicy

java.lang.Object

com.hazelcast.map.merge.LatestUpdateMapMergePolicy

All Implemented Interfaces:

MapMergePolicy, DataSerializable, IdentifiedDataSerializable

public class LatestUpdateMapMergePolicy
extends Object
implements MapMergePolicy, IdentifiedDataSerializable

Merges 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.

Constructor Summary

Constructors

Constructor and Description
LatestUpdateMapMergePolicy()

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, EntryView mergingEntry, EntryView 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

Constructor Detail

LatestUpdateMapMergePolicy

public LatestUpdateMapMergePolicy()

Method Detail

merge

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

Description copied from interface: MapMergePolicy

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 MapMergePolicy

Parameters:

mapName - name of the map

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

existingEntry - EntryView 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

writeData

public void writeData(ObjectDataOutput out)
               throws IOException

Description copied from interface: DataSerializable

Writes object fields to output stream

Specified by:

writeData in interface DataSerializable

Parameters:

out - output

Throws:

IOException - if an I/O error occurs. In particular, an IOException may be thrown if the output stream has been closed.

readData

public void readData(ObjectDataInput in)
              throws IOException

Description copied from interface: DataSerializable

Reads fields from the input stream

Specified by:

readData in interface DataSerializable

Parameters:

in - input

Throws:

IOException - if an I/O error occurs. In particular, an IOException may be thrown if the input stream has been closed.

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