com.hazelcast.map.merge

Interface MapMergePolicy

All Superinterfaces:

DataSerializable

All Known Implementing Classes:

HigherHitsMapMergePolicy, IgnoreMergingEntryMapMergePolicy, LatestUpdateMapMergePolicy, PassThroughMergePolicy, PutIfAbsentMapMergePolicy

public interface MapMergePolicy
extends DataSerializable

Policy for merging map entries after a split-brain has been healed.

See Also:

HigherHitsMapMergePolicy, LatestUpdateMapMergePolicy, PassThroughMergePolicy, PutIfAbsentMapMergePolicy

Method Summary

Modifier and Type	Method and Description
Object	merge(String mapName, EntryView mergingEntry, EntryView existingEntry) Selects one of the merging and existing map entries to be merged.

Methods inherited from interface com.hazelcast.nio.serialization.DataSerializable

readData, writeData

Method Detail

merge

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

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

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