com.hazelcast.crdt

Interface CRDTReplicationAwareService<T>

Type Parameters:

T - CRDT implementation type

All Known Implementing Classes:

PNCounterService

public interface CRDTReplicationAwareService<T>

Represents a service implementing a CRDT that may be replicated and migrated to other replicas of the same CRDT. The service may optimize the replication operation contents depending on the provided vector clocks. The vector clock map contains mappings from CRDT name to the last successfully replicated CRDT state version. All CRDTs in this map should be of the same type.

Method Summary

Modifier and Type	Method and Description
boolean	clearCRDTState(Map<String,VectorClock> vectorClocks) Removes all of the CRDTs with vector clocks equal to the provided vector clocks.
String	getName() Returns the name of the service
void	merge(String name, T value) Performs a merge of the local name CRDT with the provided state.
CRDTReplicationContainer	prepareMigrationOperation(int maxConfiguredReplicaCount) Returns a migration operation for all of the CRDT states not owned by this member.
CRDTReplicationContainer	prepareReplicationOperation(Map<String,VectorClock> lastReplicatedVectorClock, int targetIndex) Returns a replication operation for the provided vector clocks.
void	prepareToSafeShutdown() Prepares the service for replication and shutdown.

Method Detail

prepareReplicationOperation

CRDTReplicationContainer prepareReplicationOperation(Map<String,VectorClock> lastReplicatedVectorClock,
                                                     int targetIndex)

Returns a replication operation for the provided vector clocks. The vector clock map contains mappings from CRDT name to the last successfully replicated CRDT vector clock. All CRDTs in this map should be of the same type. A return value of null means that there should not be any replication operation.

Parameters:

lastReplicatedVectorClock - last successfully replicated vector clock

targetIndex - the index of the replication target in the membership list containing only data members

Returns:

the replication operation and the replicated vector clocks

getName

String getName()

Returns the name of the service

merge

void merge(String name,
           T value)

Performs a merge of the local name CRDT with the provided state.

Parameters:

name - the CRDT name

value - the CRDT state to merge into the local state

prepareMigrationOperation

CRDTReplicationContainer prepareMigrationOperation(int maxConfiguredReplicaCount)

Returns a migration operation for all of the CRDT states not owned by this member.

Parameters:

maxConfiguredReplicaCount - the maximum configured replica count for the CRDTs to be migrated (excluding)

Returns:

the migration operation and the current vector clocks

clearCRDTState

boolean clearCRDTState(Map<String,VectorClock> vectorClocks)

Removes all of the CRDTs with vector clocks equal to the provided vector clocks. The vector clock map contains mappings from CRDT name to a vector clock. All CRDTs in this map should be of the same type.

Parameters:

vectorClocks - a map from CRDT name to a vector clock

Returns:

true if all of the CRDT states have been cleared, false otherwise

prepareToSafeShutdown

void prepareToSafeShutdown()

Prepares the service for replication and shutdown. After this method has returned, no mutations must be allowed to any existing CRDT state in this service and new CRDT states must be disallowed.