Package io.microraft

Enum RaftRole

java.lang.Object

java.lang.Enum<RaftRole>

io.microraft.RaftRole

All Implemented Interfaces:

Serializable, Comparable<RaftRole>, java.lang.constant.Constable

public enum RaftRole
extends Enum<RaftRole>

The roles of Raft nodes as defined in the Raft consensus algorithm.

At any given time each Raft node is in one of roles defined here.

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Enum

Enum.EnumDesc<E extends Enum<E>>

Enum Constant Summary

Enum Constants

Enum Constant	Description
CANDIDATE	When a follower starts a new leader election, it first turns into a candidate.
FOLLOWER	Followers issue no requests on their own.
LEADER	A leader handles client requests, commit operations and orchestrates a Raft group.
LEARNER	Learners issue no requests on their own.

Method Summary

Modifier and Type	Method	Description
static RaftRole	valueOf(String name)	Returns the enum constant of this type with the specified name.
static RaftRole[]	values()	Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, describeConstable, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Details

LEADER

public static final RaftRole LEADER

A leader handles client requests, commit operations and orchestrates a Raft group.

CANDIDATE

public static final RaftRole CANDIDATE

When a follower starts a new leader election, it first turns into a candidate. A candidate becomes leader if it wins the majority votes.

FOLLOWER

public static final RaftRole FOLLOWER

Followers issue no requests on their own. They respond to append-entries requests sent by leaders. Followers are also voting members. They respond to vote requests sent by candidates. They can also run queries if QueryPolicy.EVENTUAL_CONSISTENCY is used.

LEARNER

public static final RaftRole LEARNER

Learners issue no requests on their own. They only respond to append-entries requests sent by leaders. Learners are non-voting members. They do not turn into candidates and do not receive vote requests from other candidates during leader election rounds. They can also run queries if QueryPolicy.EVENTUAL_CONSISTENCY is used.

Method Details

values

public static RaftRole[] values()

Returns an array containing the constants of this enum type, in the order they are declared.

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static RaftRole valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null