org.opendaylight.controller.cluster.raft.behaviors

Class PreLeader

java.lang.Object

org.opendaylight.controller.cluster.raft.behaviors.AbstractRaftActorBehavior

org.opendaylight.controller.cluster.raft.behaviors.AbstractLeader

org.opendaylight.controller.cluster.raft.behaviors.PreLeader

All Implemented Interfaces:

AutoCloseable, RaftActorBehavior

public class PreLeader
extends AbstractLeader

The behavior of a RaftActor when it is in the PreLeader state. This state performs all the duties of Leader with the added behavior of attempting to commit all uncommitted entries from the previous leader's term. Raft does not allow a leader to commit entries from a previous term by simply counting replicas - only entries from the leader's current term can be committed (§5.4.2). Rather then waiting for a client interaction to commit a new entry, the PreLeader state immediately appends a no-op entry (NoopPayload) to the log with the leader's current term. Once the no-op entry is committed, all prior entries are committed indirectly. Once all entries are committed, ie commitIndex matches the last log index, it switches to the normal Leader state.

The use of a no-op entry in this manner is outlined in the last paragraph in §8 of the extended raft version.

Author:

Thomas Pantelis

Field Summary

Fields inherited from class org.opendaylight.controller.cluster.raft.behaviors.AbstractRaftActorBehavior

context, log

Constructor Summary

Constructors

Constructor and Description
PreLeader(RaftActorContext context)

Method Summary

Modifier and Type	Method and Description
RaftActorBehavior	handleMessage(akka.actor.ActorRef sender, Object message) Handle a message.

Methods inherited from class org.opendaylight.controller.cluster.raft.behaviors.AbstractLeader

addFollower, beforeSendHeartbeat, close, followerLogSize, getFollower, getFollowerIds, getLeaderId, getLeaderPayloadVersion, getMinIsolatedLeaderPeerCount, handleAppendEntries, handleAppendEntriesReply, handleRequestVoteReply, initiateCaptureSnapshot, isLeaderIsolated, printFollowerStates, removeClientRequestTracker, removeFollower, sendAppendEntries, updateMinReplicaCount

Methods inherited from class org.opendaylight.controller.cluster.raft.behaviors.AbstractRaftActorBehavior

actor, appendEntries, applyLogToStateMachine, canGrantVote, canStartElection, createBehavior, currentTerm, electionDuration, getId, getLogEntryIndex, getLogEntryOrSnapshotTerm, getLogEntryTerm, getMajorityVoteCount, getReplicatedToAllIndex, internalSwitchBehavior, internalSwitchBehavior, lastIndex, lastTerm, logName, performSnapshotWithoutCapture, requestVote, scheduleElection, setReplicatedToAllIndex, state, stopElection, switchBehavior, votedFor

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

PreLeader

public PreLeader(RaftActorContext context)

Method Detail

handleMessage

public RaftActorBehavior handleMessage(akka.actor.ActorRef sender,
                                       Object message)

Description copied from interface: RaftActorBehavior

Handle a message. If the processing of the message warrants a state change then a new behavior should be returned otherwise this method should return the current behavior.

Specified by:

handleMessage in interface RaftActorBehavior

Overrides:

handleMessage in class AbstractLeader

Parameters:

sender - The sender of the message

message - A message that needs to be processed

Returns:

The new behavior or current behavior, or null if the message was not handled.