com.hazelcast.cp.internal.raft

Interface SnapshotAwareService<T>

Type Parameters:

T - type of snapshot object

All Known Implementing Classes:

AbstractBlockingService, MetadataRaftGroupManager, RaftAtomicLongService, RaftAtomicRefService, RaftCountDownLatchService, RaftLockService, RaftSemaphoreService, RaftService, RaftSessionService

public interface SnapshotAwareService<T>

The service interface required to be implemented by services that behave as a Raft state machine. Each Raft service must be able to generate a snapshot of its committed data and restore it back.

Method Summary

Modifier and Type	Method and Description
void	restoreSnapshot(CPGroupId groupId, long commitIndex, T snapshot) Restores the snapshot for specified CPGroupId.
T	takeSnapshot(CPGroupId groupId, long commitIndex) Creates a snapshot for specified CPGroupId.

Method Detail

takeSnapshot

T takeSnapshot(CPGroupId groupId,
               long commitIndex)

Creates a snapshot for specified CPGroupId. The snapshot object returned from this method will be stored among the Raft log and it can be sent to other Raft nodes anytime. Therefore, this method must not return a snapshot object that can mutate after the takeSnapshot() call.

Parameters:

groupId - CPGroupId which is snapshot requested for

commitIndex - commitIndex of the taken snapshot

Returns:

snapshot for specified CPGroupId.

restoreSnapshot

void restoreSnapshot(CPGroupId groupId,
                     long commitIndex,
                     T snapshot)

Restores the snapshot for specified CPGroupId.

Parameters:

groupId - CPGroupId of the snapshot to be restored

commitIndex - commitIndex of the restored snapshot

snapshot - snapshot for specified CPGroupId