2 * Copyright (c) 2014 Cisco Systems, Inc. and others. All rights reserved.
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
9 package org.opendaylight.controller.cluster.raft;
11 import akka.actor.ActorRef;
12 import akka.actor.ActorSelection;
13 import akka.event.Logging;
14 import akka.event.LoggingAdapter;
15 import akka.japi.Procedure;
16 import akka.persistence.RecoveryCompleted;
17 import akka.persistence.SaveSnapshotFailure;
18 import akka.persistence.SaveSnapshotSuccess;
19 import akka.persistence.SnapshotOffer;
20 import akka.persistence.SnapshotSelectionCriteria;
21 import akka.persistence.UntypedPersistentActor;
22 import com.google.common.base.Optional;
23 import com.google.common.base.Stopwatch;
24 import com.google.protobuf.ByteString;
25 import org.opendaylight.controller.cluster.raft.base.messages.ApplyLogEntries;
26 import org.opendaylight.controller.cluster.raft.base.messages.ApplySnapshot;
27 import org.opendaylight.controller.cluster.raft.base.messages.ApplyState;
28 import org.opendaylight.controller.cluster.raft.base.messages.CaptureSnapshot;
29 import org.opendaylight.controller.cluster.raft.base.messages.CaptureSnapshotReply;
30 import org.opendaylight.controller.cluster.raft.base.messages.Replicate;
31 import org.opendaylight.controller.cluster.raft.base.messages.SendHeartBeat;
32 import org.opendaylight.controller.cluster.raft.behaviors.Follower;
33 import org.opendaylight.controller.cluster.raft.behaviors.RaftActorBehavior;
34 import org.opendaylight.controller.cluster.raft.client.messages.AddRaftPeer;
35 import org.opendaylight.controller.cluster.raft.client.messages.FindLeader;
36 import org.opendaylight.controller.cluster.raft.client.messages.FindLeaderReply;
37 import org.opendaylight.controller.cluster.raft.client.messages.RemoveRaftPeer;
38 import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
39 import org.opendaylight.controller.cluster.raft.protobuff.client.messages.Payload;
40 import org.opendaylight.controller.protobuff.messages.cluster.raft.AppendEntriesMessages;
41 import java.io.Serializable;
45 * RaftActor encapsulates a state machine that needs to be kept synchronized
46 * in a cluster. It implements the RAFT algorithm as described in the paper
47 * <a href='https://ramcloud.stanford.edu/wiki/download/attachments/11370504/raft.pdf'>
48 * In Search of an Understandable Consensus Algorithm</a>
50 * RaftActor has 3 states and each state has a certain behavior associated
51 * with it. A Raft actor can behave as,
54 * <li> A Follower (or) </li>
55 * <li> A Candidate </li>
59 * A RaftActor MUST be a Leader in order to accept requests from clients to
60 * change the state of it's encapsulated state machine. Once a RaftActor becomes
61 * a Leader it is also responsible for ensuring that all followers ultimately
62 * have the same log and therefore the same state machine as itself.
65 * The current behavior of a RaftActor determines how election for leadership
66 * is initiated and how peer RaftActors react to request for votes.
69 * Each RaftActor also needs to know the current election term. It uses this
70 * information for a couple of things. One is to simply figure out who it
71 * voted for in the last election. Another is to figure out if the message
72 * it received to update it's state is stale.
75 * The RaftActor uses akka-persistence to store it's replicated log.
76 * Furthermore through it's behaviors a Raft Actor determines
79 * <li> when a log entry should be persisted </li>
80 * <li> when a log entry should be applied to the state machine (and) </li>
81 * <li> when a snapshot should be saved </li>
84 public abstract class RaftActor extends UntypedPersistentActor {
85 protected final LoggingAdapter LOG =
86 Logging.getLogger(getContext().system(), this);
89 * The current state determines the current behavior of a RaftActor
90 * A Raft Actor always starts off in the Follower State
92 private RaftActorBehavior currentBehavior;
95 * This context should NOT be passed directly to any other actor it is
96 * only to be consumed by the RaftActorBehaviors
98 private final RaftActorContext context;
101 * The in-memory journal
103 private ReplicatedLogImpl replicatedLog = new ReplicatedLogImpl();
105 private CaptureSnapshot captureSnapshot = null;
107 private volatile boolean hasSnapshotCaptureInitiated = false;
109 private Stopwatch recoveryTimer;
111 private int currentRecoveryBatchCount;
113 public RaftActor(String id, Map<String, String> peerAddresses) {
114 this(id, peerAddresses, Optional.<ConfigParams>absent());
117 public RaftActor(String id, Map<String, String> peerAddresses,
118 Optional<ConfigParams> configParams) {
120 context = new RaftActorContextImpl(this.getSelf(),
121 this.getContext(), id, new ElectionTermImpl(),
122 -1, -1, replicatedLog, peerAddresses,
123 (configParams.isPresent() ? configParams.get(): new DefaultConfigParamsImpl()),
127 private void initRecoveryTimer() {
128 if(recoveryTimer == null) {
129 recoveryTimer = new Stopwatch();
130 recoveryTimer.start();
135 public void preStart() throws Exception {
136 LOG.info("Starting recovery for {} with journal batch size {}", persistenceId(),
137 context.getConfigParams().getJournalRecoveryLogBatchSize());
142 public void onReceiveRecover(Object message) {
143 if (message instanceof SnapshotOffer) {
144 onRecoveredSnapshot((SnapshotOffer)message);
145 } else if (message instanceof ReplicatedLogEntry) {
146 onRecoveredJournalLogEntry((ReplicatedLogEntry)message);
147 } else if (message instanceof ApplyLogEntries) {
148 onRecoveredApplyLogEntries((ApplyLogEntries)message);
149 } else if (message instanceof DeleteEntries) {
150 replicatedLog.removeFrom(((DeleteEntries) message).getFromIndex());
151 } else if (message instanceof UpdateElectionTerm) {
152 context.getTermInformation().update(((UpdateElectionTerm) message).getCurrentTerm(),
153 ((UpdateElectionTerm) message).getVotedFor());
154 } else if (message instanceof RecoveryCompleted) {
155 onRecoveryCompletedMessage();
159 private void onRecoveredSnapshot(SnapshotOffer offer) {
160 if(LOG.isDebugEnabled()) {
161 LOG.debug("SnapshotOffer called..");
166 Snapshot snapshot = (Snapshot) offer.snapshot();
168 // Create a replicated log with the snapshot information
169 // The replicated log can be used later on to retrieve this snapshot
170 // when we need to install it on a peer
171 replicatedLog = new ReplicatedLogImpl(snapshot);
173 context.setReplicatedLog(replicatedLog);
174 context.setLastApplied(snapshot.getLastAppliedIndex());
175 context.setCommitIndex(snapshot.getLastAppliedIndex());
177 Stopwatch timer = new Stopwatch();
180 // Apply the snapshot to the actors state
181 applyRecoverySnapshot(ByteString.copyFrom(snapshot.getState()));
184 LOG.info("Recovery snapshot applied for {} in {}: snapshotIndex={}, snapshotTerm={}, journal-size=" +
185 replicatedLog.size(), persistenceId(), timer.toString(),
186 replicatedLog.snapshotIndex, replicatedLog.snapshotTerm);
189 private void onRecoveredJournalLogEntry(ReplicatedLogEntry logEntry) {
190 if(LOG.isDebugEnabled()) {
191 LOG.debug("Received ReplicatedLogEntry for recovery: {}", logEntry.getIndex());
194 replicatedLog.append(logEntry);
197 private void onRecoveredApplyLogEntries(ApplyLogEntries ale) {
198 if(LOG.isDebugEnabled()) {
199 LOG.debug("Received ApplyLogEntries for recovery, applying to state: {} to {}",
200 context.getLastApplied() + 1, ale.getToIndex());
203 for (long i = context.getLastApplied() + 1; i <= ale.getToIndex(); i++) {
204 batchRecoveredLogEntry(replicatedLog.get(i));
207 context.setLastApplied(ale.getToIndex());
208 context.setCommitIndex(ale.getToIndex());
211 private void batchRecoveredLogEntry(ReplicatedLogEntry logEntry) {
214 int batchSize = context.getConfigParams().getJournalRecoveryLogBatchSize();
215 if(currentRecoveryBatchCount == 0) {
216 startLogRecoveryBatch(batchSize);
219 appendRecoveredLogEntry(logEntry.getData());
221 if(++currentRecoveryBatchCount >= batchSize) {
222 endCurrentLogRecoveryBatch();
226 private void endCurrentLogRecoveryBatch() {
227 applyCurrentLogRecoveryBatch();
228 currentRecoveryBatchCount = 0;
231 private void onRecoveryCompletedMessage() {
232 if(currentRecoveryBatchCount > 0) {
233 endCurrentLogRecoveryBatch();
236 onRecoveryComplete();
238 String recoveryTime = "";
239 if(recoveryTimer != null) {
240 recoveryTimer.stop();
241 recoveryTime = " in " + recoveryTimer.toString();
242 recoveryTimer = null;
246 "Recovery completed" + recoveryTime + " - Switching actor to Follower - " +
247 "Persistence Id = " + persistenceId() +
248 " Last index in log={}, snapshotIndex={}, snapshotTerm={}, " +
250 replicatedLog.lastIndex(), replicatedLog.snapshotIndex,
251 replicatedLog.snapshotTerm, replicatedLog.size());
253 currentBehavior = new Follower(context);
257 @Override public void onReceiveCommand(Object message) {
258 if (message instanceof ApplyState){
259 ApplyState applyState = (ApplyState) message;
261 if(LOG.isDebugEnabled()) {
262 LOG.debug("Applying state for log index {} data {}",
263 applyState.getReplicatedLogEntry().getIndex(),
264 applyState.getReplicatedLogEntry().getData());
267 applyState(applyState.getClientActor(), applyState.getIdentifier(),
268 applyState.getReplicatedLogEntry().getData());
270 } else if (message instanceof ApplyLogEntries){
271 ApplyLogEntries ale = (ApplyLogEntries) message;
272 if(LOG.isDebugEnabled()) {
273 LOG.debug("Persisting ApplyLogEntries with index={}", ale.getToIndex());
275 persist(new ApplyLogEntries(ale.getToIndex()), new Procedure<ApplyLogEntries>() {
277 public void apply(ApplyLogEntries param) throws Exception {
281 } else if(message instanceof ApplySnapshot ) {
282 Snapshot snapshot = ((ApplySnapshot) message).getSnapshot();
284 if(LOG.isDebugEnabled()) {
285 LOG.debug("ApplySnapshot called on Follower Actor " +
286 "snapshotIndex:{}, snapshotTerm:{}", snapshot.getLastAppliedIndex(),
287 snapshot.getLastAppliedTerm()
290 applySnapshot(ByteString.copyFrom(snapshot.getState()));
292 //clears the followers log, sets the snapshot index to ensure adjusted-index works
293 replicatedLog = new ReplicatedLogImpl(snapshot);
294 context.setReplicatedLog(replicatedLog);
295 context.setLastApplied(snapshot.getLastAppliedIndex());
297 } else if (message instanceof FindLeader) {
299 new FindLeaderReply(getLeaderAddress()),
303 } else if (message instanceof SaveSnapshotSuccess) {
304 SaveSnapshotSuccess success = (SaveSnapshotSuccess) message;
305 LOG.info("SaveSnapshotSuccess received for snapshot");
307 context.getReplicatedLog().snapshotCommit();
309 // TODO: Not sure if we want to be this aggressive with trimming stuff
310 trimPersistentData(success.metadata().sequenceNr());
312 } else if (message instanceof SaveSnapshotFailure) {
313 SaveSnapshotFailure saveSnapshotFailure = (SaveSnapshotFailure) message;
315 LOG.info("saveSnapshotFailure.metadata():{}", saveSnapshotFailure.metadata().toString());
316 LOG.error(saveSnapshotFailure.cause(), "SaveSnapshotFailure received for snapshot Cause:");
318 context.getReplicatedLog().snapshotRollback();
320 LOG.info("Replicated Log rollbacked. Snapshot will be attempted in the next cycle." +
321 "snapshotIndex:{}, snapshotTerm:{}, log-size:{}",
322 context.getReplicatedLog().getSnapshotIndex(),
323 context.getReplicatedLog().getSnapshotTerm(),
324 context.getReplicatedLog().size());
326 } else if (message instanceof AddRaftPeer){
328 // FIXME : Do not add raft peers like this.
329 // When adding a new Peer we have to ensure that the a majority of
330 // the peers know about the new Peer. Doing it this way may cause
331 // a situation where multiple Leaders may emerge
332 AddRaftPeer arp = (AddRaftPeer)message;
333 context.addToPeers(arp.getName(), arp.getAddress());
335 } else if (message instanceof RemoveRaftPeer){
337 RemoveRaftPeer rrp = (RemoveRaftPeer)message;
338 context.removePeer(rrp.getName());
340 } else if (message instanceof CaptureSnapshot) {
341 LOG.info("CaptureSnapshot received by actor");
342 CaptureSnapshot cs = (CaptureSnapshot)message;
343 captureSnapshot = cs;
346 } else if (message instanceof CaptureSnapshotReply){
347 LOG.info("CaptureSnapshotReply received by actor");
348 CaptureSnapshotReply csr = (CaptureSnapshotReply) message;
350 ByteString stateInBytes = csr.getSnapshot();
351 LOG.info("CaptureSnapshotReply stateInBytes size:{}", stateInBytes.size());
352 handleCaptureSnapshotReply(stateInBytes);
355 if (!(message instanceof AppendEntriesMessages.AppendEntries)
356 && !(message instanceof AppendEntriesReply) && !(message instanceof SendHeartBeat)) {
357 if(LOG.isDebugEnabled()) {
358 LOG.debug("onReceiveCommand: message: {}", message.getClass());
362 RaftActorBehavior oldBehavior = currentBehavior;
363 currentBehavior = currentBehavior.handleMessage(getSender(), message);
365 if(oldBehavior != currentBehavior){
369 onLeaderChanged(oldBehavior.getLeaderId(), currentBehavior.getLeaderId());
373 public java.util.Set<String> getPeers() {
374 return context.getPeerAddresses().keySet();
377 protected String getReplicatedLogState() {
378 return "snapshotIndex=" + context.getReplicatedLog().getSnapshotIndex()
379 + ", snapshotTerm=" + context.getReplicatedLog().getSnapshotTerm()
380 + ", im-mem journal size=" + context.getReplicatedLog().size();
385 * When a derived RaftActor needs to persist something it must call
392 protected void persistData(ActorRef clientActor, String identifier,
395 ReplicatedLogEntry replicatedLogEntry = new ReplicatedLogImplEntry(
396 context.getReplicatedLog().lastIndex() + 1,
397 context.getTermInformation().getCurrentTerm(), data);
399 if(LOG.isDebugEnabled()) {
400 LOG.debug("Persist data {}", replicatedLogEntry);
404 .appendAndPersist(clientActor, identifier, replicatedLogEntry);
407 protected String getId() {
408 return context.getId();
412 * Derived actors can call the isLeader method to check if the current
413 * RaftActor is the Leader or not
415 * @return true it this RaftActor is a Leader false otherwise
417 protected boolean isLeader() {
418 return context.getId().equals(currentBehavior.getLeaderId());
422 * Derived actor can call getLeader if they need a reference to the Leader.
423 * This would be useful for example in forwarding a request to an actor
424 * which is the leader
426 * @return A reference to the leader if known, null otherwise
428 protected ActorSelection getLeader(){
429 String leaderAddress = getLeaderAddress();
431 if(leaderAddress == null){
435 return context.actorSelection(leaderAddress);
440 * @return the current leader's id
442 protected String getLeaderId(){
443 return currentBehavior.getLeaderId();
446 protected RaftState getRaftState() {
447 return currentBehavior.state();
450 protected ReplicatedLogEntry getLastLogEntry() {
451 return replicatedLog.last();
454 protected Long getCurrentTerm(){
455 return context.getTermInformation().getCurrentTerm();
458 protected Long getCommitIndex(){
459 return context.getCommitIndex();
462 protected Long getLastApplied(){
463 return context.getLastApplied();
466 protected RaftActorContext getRaftActorContext() {
471 * setPeerAddress sets the address of a known peer at a later time.
473 * This is to account for situations where a we know that a peer
474 * exists but we do not know an address up-front. This may also be used in
475 * situations where a known peer starts off in a different location and we
476 * need to change it's address
478 * Note that if the peerId does not match the list of peers passed to
479 * this actor during construction an IllegalStateException will be thrown.
484 protected void setPeerAddress(String peerId, String peerAddress){
485 context.setPeerAddress(peerId, peerAddress);
491 * The applyState method will be called by the RaftActor when some data
492 * needs to be applied to the actor's state
494 * @param clientActor A reference to the client who sent this message. This
495 * is the same reference that was passed to persistData
496 * by the derived actor. clientActor may be null when
497 * the RaftActor is behaving as a follower or during
499 * @param identifier The identifier of the persisted data. This is also
500 * the same identifier that was passed to persistData by
501 * the derived actor. identifier may be null when
502 * the RaftActor is behaving as a follower or during
504 * @param data A piece of data that was persisted by the persistData call.
505 * This should NEVER be null.
507 protected abstract void applyState(ActorRef clientActor, String identifier,
511 * This method is called during recovery at the start of a batch of state entries. Derived
512 * classes should perform any initialization needed to start a batch.
514 protected abstract void startLogRecoveryBatch(int maxBatchSize);
517 * This method is called during recovery to append state data to the current batch. This method
518 * is called 1 or more times after {@link #startRecoveryStateBatch}.
520 * @param data the state data
522 protected abstract void appendRecoveredLogEntry(Payload data);
525 * This method is called during recovery to reconstruct the state of the actor.
527 * @param snapshot A snapshot of the state of the actor
529 protected abstract void applyRecoverySnapshot(ByteString snapshot);
532 * This method is called during recovery at the end of a batch to apply the current batched
533 * log entries. This method is called after {@link #appendRecoveryLogEntry}.
535 protected abstract void applyCurrentLogRecoveryBatch();
538 * This method is called when recovery is complete.
540 protected abstract void onRecoveryComplete();
543 * This method will be called by the RaftActor when a snapshot needs to be
544 * created. The derived actor should respond with its current state.
546 * During recovery the state that is returned by the derived actor will
547 * be passed back to it by calling the applySnapshot method
549 * @return The current state of the actor
551 protected abstract void createSnapshot();
554 * This method can be called at any other point during normal
555 * operations when the derived actor is out of sync with it's peers
556 * and the only way to bring it in sync is by applying a snapshot
558 * @param snapshot A snapshot of the state of the actor
560 protected abstract void applySnapshot(ByteString snapshot);
563 * This method will be called by the RaftActor when the state of the
564 * RaftActor changes. The derived actor can then use methods like
565 * isLeader or getLeader to do something useful
567 protected abstract void onStateChanged();
569 protected void onLeaderChanged(String oldLeader, String newLeader){};
571 private void trimPersistentData(long sequenceNumber) {
572 // Trim akka snapshots
573 // FIXME : Not sure how exactly the SnapshotSelectionCriteria is applied
574 // For now guessing that it is ANDed.
575 deleteSnapshots(new SnapshotSelectionCriteria(
576 sequenceNumber - context.getConfigParams().getSnapshotBatchCount(), 43200000));
579 deleteMessages(sequenceNumber);
582 private String getLeaderAddress(){
584 return getSelf().path().toString();
586 String leaderId = currentBehavior.getLeaderId();
587 if (leaderId == null) {
590 String peerAddress = context.getPeerAddress(leaderId);
591 if(LOG.isDebugEnabled()) {
592 LOG.debug("getLeaderAddress leaderId = {} peerAddress = {}",
593 leaderId, peerAddress);
599 private void handleCaptureSnapshotReply(ByteString stateInBytes) {
600 // create a snapshot object from the state provided and save it
601 // when snapshot is saved async, SaveSnapshotSuccess is raised.
603 Snapshot sn = Snapshot.create(stateInBytes.toByteArray(),
604 context.getReplicatedLog().getFrom(captureSnapshot.getLastAppliedIndex() + 1),
605 captureSnapshot.getLastIndex(), captureSnapshot.getLastTerm(),
606 captureSnapshot.getLastAppliedIndex(), captureSnapshot.getLastAppliedTerm());
610 LOG.info("Persisting of snapshot done:{}", sn.getLogMessage());
612 //be greedy and remove entries from in-mem journal which are in the snapshot
613 // and update snapshotIndex and snapshotTerm without waiting for the success,
615 context.getReplicatedLog().snapshotPreCommit(stateInBytes,
616 captureSnapshot.getLastAppliedIndex(),
617 captureSnapshot.getLastAppliedTerm());
619 LOG.info("Removed in-memory snapshotted entries, adjusted snaphsotIndex:{} " +
620 "and term:{}", captureSnapshot.getLastAppliedIndex(),
621 captureSnapshot.getLastAppliedTerm());
623 captureSnapshot = null;
624 hasSnapshotCaptureInitiated = false;
628 private class ReplicatedLogImpl extends AbstractReplicatedLogImpl {
630 public ReplicatedLogImpl(Snapshot snapshot) {
631 super(ByteString.copyFrom(snapshot.getState()),
632 snapshot.getLastAppliedIndex(), snapshot.getLastAppliedTerm(),
633 snapshot.getUnAppliedEntries());
636 public ReplicatedLogImpl() {
640 @Override public void removeFromAndPersist(long logEntryIndex) {
641 int adjustedIndex = adjustedIndex(logEntryIndex);
643 if (adjustedIndex < 0) {
647 // FIXME: Maybe this should be done after the command is saved
648 journal.subList(adjustedIndex , journal.size()).clear();
650 persist(new DeleteEntries(adjustedIndex), new Procedure<DeleteEntries>(){
652 @Override public void apply(DeleteEntries param)
654 //FIXME : Doing nothing for now
659 @Override public void appendAndPersist(
660 final ReplicatedLogEntry replicatedLogEntry) {
661 appendAndPersist(null, null, replicatedLogEntry);
664 public void appendAndPersist(final ActorRef clientActor,
665 final String identifier,
666 final ReplicatedLogEntry replicatedLogEntry) {
668 if(LOG.isDebugEnabled()) {
669 LOG.debug("Append log entry and persist {} ", replicatedLogEntry);
672 // FIXME : By adding the replicated log entry to the in-memory journal we are not truly ensuring durability of the logs
673 journal.add(replicatedLogEntry);
675 // When persisting events with persist it is guaranteed that the
676 // persistent actor will not receive further commands between the
677 // persist call and the execution(s) of the associated event
678 // handler. This also holds for multiple persist calls in context
679 // of a single command.
680 persist(replicatedLogEntry,
681 new Procedure<ReplicatedLogEntry>() {
683 public void apply(ReplicatedLogEntry evt) throws Exception {
684 // when a snaphsot is being taken, captureSnapshot != null
685 if (hasSnapshotCaptureInitiated == false &&
686 journal.size() % context.getConfigParams().getSnapshotBatchCount() == 0) {
688 LOG.info("Initiating Snapshot Capture..");
689 long lastAppliedIndex = -1;
690 long lastAppliedTerm = -1;
692 ReplicatedLogEntry lastAppliedEntry = get(context.getLastApplied());
693 if (lastAppliedEntry != null) {
694 lastAppliedIndex = lastAppliedEntry.getIndex();
695 lastAppliedTerm = lastAppliedEntry.getTerm();
698 if(LOG.isDebugEnabled()) {
699 LOG.debug("Snapshot Capture logSize: {}", journal.size());
700 LOG.debug("Snapshot Capture lastApplied:{} ",
701 context.getLastApplied());
702 LOG.debug("Snapshot Capture lastAppliedIndex:{}", lastAppliedIndex);
703 LOG.debug("Snapshot Capture lastAppliedTerm:{}", lastAppliedTerm);
706 // send a CaptureSnapshot to self to make the expensive operation async.
707 getSelf().tell(new CaptureSnapshot(
708 lastIndex(), lastTerm(), lastAppliedIndex, lastAppliedTerm),
710 hasSnapshotCaptureInitiated = true;
712 // Send message for replication
713 if (clientActor != null) {
714 currentBehavior.handleMessage(getSelf(),
715 new Replicate(clientActor, identifier,
726 private static class DeleteEntries implements Serializable {
727 private final int fromIndex;
730 public DeleteEntries(int fromIndex) {
731 this.fromIndex = fromIndex;
734 public int getFromIndex() {
740 private class ElectionTermImpl implements ElectionTerm {
742 * Identifier of the actor whose election term information this is
744 private long currentTerm = 0;
745 private String votedFor = null;
748 public long getCurrentTerm() {
753 public String getVotedFor() {
757 @Override public void update(long currentTerm, String votedFor) {
758 if(LOG.isDebugEnabled()) {
759 LOG.debug("Set currentTerm={}, votedFor={}", currentTerm, votedFor);
761 this.currentTerm = currentTerm;
762 this.votedFor = votedFor;
766 public void updateAndPersist(long currentTerm, String votedFor){
767 update(currentTerm, votedFor);
768 // FIXME : Maybe first persist then update the state
769 persist(new UpdateElectionTerm(this.currentTerm, this.votedFor), new Procedure<UpdateElectionTerm>(){
771 @Override public void apply(UpdateElectionTerm param)
779 private static class UpdateElectionTerm implements Serializable {
780 private final long currentTerm;
781 private final String votedFor;
783 public UpdateElectionTerm(long currentTerm, String votedFor) {
784 this.currentTerm = currentTerm;
785 this.votedFor = votedFor;
788 public long getCurrentTerm() {
792 public String getVotedFor() {