Package org.infinispan.conflict

Interface EntryMergePolicy<K,V>

All Known Implementing Classes:

MergePolicy, MergePolicy.UnsupportedMergePolicy

public interface EntryMergePolicy<K,V>

Since:

9.1

Author:

Ryan Emerson

Method Summary

Modifier and Type	Method	Description
CacheEntry<K,V>	merge(CacheEntry<K,V> preferredEntry, List<CacheEntry<K,V>> otherEntries)	This method is called by ConflictManager.resolveConflicts() for each conflict discovered to determine which CacheEntry should be utilised.

Method Detail

merge

CacheEntry<K,V> merge(CacheEntry<K,V> preferredEntry,
                            List<CacheEntry<K,V>> otherEntries)

This method is called by ConflictManager.resolveConflicts() for each conflict discovered to determine which CacheEntry should be utilised. This merge policy is used when a user explicitly calls ConflictManager.resolveConflicts() as well as when a partition merge occurs with PartitionHandling.ALLOW_READ_WRITES set. In the event of a partition merge, we define the preferred partition as the partition whom's coordinator is coordinating the current merge.

Parameters:

preferredEntry - During a partition merge, the preferredEntry is the primary replica of a CacheEntry stored in the partition that contains the most nodes or if partitions are equal the one with the largest topologyId. In the event of overlapping partitions, i.e. a node A is present in the topology of both partitions {A}, {A,B,C}, we pick {A} as the preferred partition as it will have the higher topologId because the other partition's topology is behind. During a non-merge call to ConflictManager.resolveConflicts(), the preferredEntry is simply the primary owner of an entry

otherEntries - a List of all other CacheEntry associated with a given Key.

Returns:

the winning CacheEntry to be utilised across the cluster, or null if all entries for a key should be removed.