com.alipay.sofa.jraft.core

Class StateMachineAdapter

java.lang.Object

com.alipay.sofa.jraft.core.StateMachineAdapter

All Implemented Interfaces:

StateMachine

public abstract class StateMachineAdapter
extends Object
implements StateMachine

State machine adapter that implements all methods with default behavior except StateMachine.onApply(com.alipay.sofa.jraft.Iterator).

Author:

boyan (boyan@alibaba-inc.com) 2018-Mar-30 10:32:27 AM

Constructor Summary

Constructors

Constructor and Description
StateMachineAdapter()

Method Summary

Modifier and Type	Method and Description
void	onConfigurationCommitted(Configuration conf) Invoked when a configuration has been committed to the group.
void	onError(RaftException e) This method is called when a critical error was encountered, after this point, no any further modification is allowed to applied to this node until the error is fixed and this node restarts.
void	onLeaderStart(long term) Invoked when the belonging node becomes the leader of the group at |term| Default: Do nothing
void	onLeaderStop(Status status) Invoked when this node steps down from the leader of the replication group and |status| describes detailed information
void	onShutdown() Invoked once when the raft node was shut down.
boolean	onSnapshotLoad(SnapshotReader reader) User defined snapshot load function get and load snapshot Default: Load nothing and returns error.
void	onSnapshotSave(SnapshotWriter writer, Closure done) User defined snapshot generate function, this method will block StateMachine#onApply(Iterator).
void	onStartFollowing(LeaderChangeContext ctx) This method is called when a follower or candidate starts following a leader and its leaderId (should be NULL before the method is called) is set to the leader's id, situations including: 1.
void	onStopFollowing(LeaderChangeContext ctx) This method is called when a follower stops following a leader and its leaderId becomes null, situations including: 1.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.alipay.sofa.jraft.StateMachine

onApply

Constructor Detail

StateMachineAdapter

public StateMachineAdapter()

Method Detail

onShutdown

public void onShutdown()

Description copied from interface: StateMachine

Invoked once when the raft node was shut down. Default do nothing

Specified by:

onShutdown in interface StateMachine

onSnapshotSave

public void onSnapshotSave(SnapshotWriter writer,
                           Closure done)

Description copied from interface: StateMachine

User defined snapshot generate function, this method will block StateMachine#onApply(Iterator). user can make snapshot async when fsm can be cow(copy-on-write). call done.run(status) when snapshot finished. Default: Save nothing and returns error.

Specified by:

onSnapshotSave in interface StateMachine

Parameters:

writer - snapshot writer

done - callback

onSnapshotLoad

public boolean onSnapshotLoad(SnapshotReader reader)

Description copied from interface: StateMachine

User defined snapshot load function get and load snapshot Default: Load nothing and returns error.

Specified by:

onSnapshotLoad in interface StateMachine

Parameters:

reader - snapshot reader

Returns:

true on success

onLeaderStart

public void onLeaderStart(long term)

Description copied from interface: StateMachine

Invoked when the belonging node becomes the leader of the group at |term| Default: Do nothing

Specified by:

onLeaderStart in interface StateMachine

Parameters:

term - new term num

onLeaderStop

public void onLeaderStop(Status status)

Description copied from interface: StateMachine

Invoked when this node steps down from the leader of the replication group and |status| describes detailed information

Specified by:

onLeaderStop in interface StateMachine

Parameters:

status - status info

onError

public void onError(RaftException e)

Description copied from interface: StateMachine

This method is called when a critical error was encountered, after this point, no any further modification is allowed to applied to this node until the error is fixed and this node restarts.

Specified by:

onError in interface StateMachine

Parameters:

e - raft error message

onConfigurationCommitted

public void onConfigurationCommitted(Configuration conf)

Description copied from interface: StateMachine

Invoked when a configuration has been committed to the group.

Specified by:

onConfigurationCommitted in interface StateMachine

Parameters:

conf - committed configuration

onStopFollowing

public void onStopFollowing(LeaderChangeContext ctx)

Description copied from interface: StateMachine

This method is called when a follower stops following a leader and its leaderId becomes null, situations including: 1. handle election timeout and start preVote 2. receive requests with higher term such as VoteRequest from a candidate or appendEntries request from a new leader 3. receive timeoutNow request from current leader and start request vote. the parameter ctx gives the information(leaderId, term and status) about the very leader whom the follower followed before. User can reset the node's information as it stops following some leader.

Specified by:

onStopFollowing in interface StateMachine

Parameters:

ctx - context of leader change

onStartFollowing

public void onStartFollowing(LeaderChangeContext ctx)

Description copied from interface: StateMachine

This method is called when a follower or candidate starts following a leader and its leaderId (should be NULL before the method is called) is set to the leader's id, situations including: 1. a candidate receives appendEntries request from a leader 2. a follower(without leader) receives appendEntries from a leader the parameter ctx gives the information(leaderId, term and status) about the very leader whom the follower starts to follow. User can reset the node's information as it starts to follow some leader.

Specified by:

onStartFollowing in interface StateMachine

Parameters:

ctx - context of leader change