opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/Follower.java

   1 /*
   2  * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8
   9 package org.opendaylight.controller.cluster.raft.behaviors;
  10
  11 import akka.actor.ActorRef;
  12 import org.opendaylight.controller.cluster.raft.RaftActorContext;
  13 import org.opendaylight.controller.cluster.raft.RaftState;
  14 import org.opendaylight.controller.cluster.raft.internal.messages.ElectionTimeout;
  15 import org.opendaylight.controller.cluster.raft.messages.AppendEntries;
  16 import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
  17 import org.opendaylight.controller.cluster.raft.messages.RequestVoteReply;
  18
  19 /**
  20  * The behavior of a RaftActor in the Follower state
  21  *
  22  * <ul>
  23  * <li> Respond to RPCs from candidates and leaders
  24  * <li> If election timeout elapses without receiving AppendEntries
  25  * RPC from current leader or granting vote to candidate:
  26  * convert to candidate
  27  * </ul>
  28  *
  29  */
  30 public class Follower extends AbstractRaftActorBehavior {
  31     public Follower(RaftActorContext context) {
  32         super(context);
  33
  34         scheduleElection(electionDuration());
  35     }
  36
  37     @Override protected RaftState handleAppendEntries(ActorRef sender,
  38         AppendEntries appendEntries, RaftState suggestedState) {
  39         return suggestedState;
  40     }
  41
  42     @Override protected RaftState handleAppendEntriesReply(ActorRef sender,
  43         AppendEntriesReply appendEntriesReply, RaftState suggestedState) {
  44         return suggestedState;
  45     }
  46
  47     @Override protected RaftState handleRequestVoteReply(ActorRef sender,
  48         RequestVoteReply requestVoteReply, RaftState suggestedState) {
  49         return suggestedState;
  50     }
  51
  52     @Override protected RaftState state() {
  53         return RaftState.Follower;
  54     }
  55
  56     @Override public RaftState handleMessage(ActorRef sender, Object message) {
  57         if(message instanceof ElectionTimeout){
  58             return RaftState.Candidate;
  59         }
  60
  61         scheduleElection(electionDuration());
  62
  63         return super.handleMessage(sender, message);
  64     }
  65 }