com.hazelcast.cp.internal.raft.impl.state

Class FollowerState

java.lang.Object

com.hazelcast.cp.internal.raft.impl.state.FollowerState

public class FollowerState
extends Object

Mutable state maintained by the leader of the Raft group for each follower. In follower state, three variables are stored:

• nextIndex: index of the next log entry to send to that server (initialized to leader's lastLogIndex + 1)
• matchIndex: index of highest log entry known to be replicated on server (initialized to 0, increases monotonically)
• appendRequestBackoff: a boolean flag indicating that leader is still waiting for a response to the last sent append request

Method Summary

Modifier and Type	Method and Description
void	appendRequestAckReceived() Clears the flag for the append request backoff and updates the timestamp of append entries response
long	appendRequestAckTimestamp() Returns timestamp of the last append entries response
boolean	completeAppendRequestBackoffRound() Completes a single round of append request backoff.
boolean	isAppendRequestBackoffSet() Returns whether leader is waiting for response of the last append request.
long	matchIndex() Returns the match index for follower.
void	matchIndex(long matchIndex) Sets the match index for follower.
long	nextIndex() Returns the next index for follower.
void	nextIndex(long nextIndex) Sets the next index for follower.
void	setAppendRequestBackoff() Sets the flag for append request backoff.
void	setMaxAppendRequestBackoff() Sets the flag for append request backoff to max value.
String	toString()

Methods inherited from class java.lang.Object

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

Method Detail

matchIndex

public long matchIndex()

Returns the match index for follower.

matchIndex

public void matchIndex(long matchIndex)

Sets the match index for follower.

nextIndex

public long nextIndex()

Returns the next index for follower.

nextIndex

public void nextIndex(long nextIndex)

Sets the next index for follower.

isAppendRequestBackoffSet

public boolean isAppendRequestBackoffSet()

Returns whether leader is waiting for response of the last append request.

setAppendRequestBackoff

public void setAppendRequestBackoff()

Sets the flag for append request backoff. A new append request will not be sent to this follower either until it sends an append response or a backoff timeout occurs.

setMaxAppendRequestBackoff

public void setMaxAppendRequestBackoff()

Sets the flag for append request backoff to max value.

completeAppendRequestBackoffRound

public boolean completeAppendRequestBackoffRound()

Completes a single round of append request backoff.

Returns:

true if round number reaches to 0, false otherwise

appendRequestAckReceived

public void appendRequestAckReceived()

Clears the flag for the append request backoff and updates the timestamp of append entries response

appendRequestAckTimestamp

public long appendRequestAckTimestamp()

Returns timestamp of the last append entries response

toString

public String toString()

Overrides:

toString in class Object