com.hazelcast.cp.internal.raft.impl.RaftRole Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2020, Hazelcast, Inc. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.hazelcast.cp.internal.raft.impl;
/**
* Represents role of a member in a Raft group.
*
* At any given time each member is in one of three roles: {@link #LEADER},
* {@link #FOLLOWER}, or {@link #CANDIDATE}.
*
* Normally, there is exactly one leader and all of the other members are
* followers. But during leader election some of the followers can become
* candidates.
*/
public enum RaftRole {
/**
* Followers are passive, they issue no requests on their own
* but simply respond to requests from leaders and candidates.
*/
FOLLOWER,
/**
* Candidate is used to elect a new leader. When a candidate wins votes of
* majority, it becomes the leader. Otherwise it becomes follower
* or candidate again.
*/
CANDIDATE,
/**
* The leader handles all client requests (append entry, membership change,
* etc.) and replicates them to followers.
*/
LEADER
}