opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/ShardCommitCoordinator.java

   1 /*
   2  * Copyright (c) 2014 Brocade Communications 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 package org.opendaylight.controller.cluster.datastore;
   9
  10 import akka.actor.ActorRef;
  11 import akka.actor.Status;
  12 import akka.serialization.Serialization;
  13 import com.google.common.annotations.VisibleForTesting;
  14 import com.google.common.base.Preconditions;
  15 import com.google.common.base.Stopwatch;
  16 import java.util.HashMap;
  17 import java.util.Iterator;
  18 import java.util.LinkedList;
  19 import java.util.Map;
  20 import java.util.Queue;
  21 import java.util.concurrent.ExecutionException;
  22 import java.util.concurrent.TimeUnit;
  23 import org.opendaylight.controller.cluster.datastore.compat.BackwardsCompatibleThreePhaseCommitCohort;
  24 import org.opendaylight.controller.cluster.datastore.messages.AbortTransactionReply;
  25 import org.opendaylight.controller.cluster.datastore.messages.BatchedModifications;
  26 import org.opendaylight.controller.cluster.datastore.messages.BatchedModificationsReply;
  27 import org.opendaylight.controller.cluster.datastore.messages.CanCommitTransactionReply;
  28 import org.opendaylight.controller.cluster.datastore.messages.ForwardedReadyTransaction;
  29 import org.opendaylight.controller.cluster.datastore.messages.ReadyLocalTransaction;
  30 import org.opendaylight.controller.cluster.datastore.messages.ReadyTransactionReply;
  31 import org.opendaylight.controller.cluster.datastore.modification.Modification;
  32 import org.opendaylight.controller.md.sal.common.api.data.TransactionCommitFailedException;
  33 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidate;
  34 import org.slf4j.Logger;
  35
  36 /**
  37  * Coordinates commits for a shard ensuring only one concurrent 3-phase commit.
  38  *
  39  * @author Thomas Pantelis
  40  */
  41 class ShardCommitCoordinator {
  42
  43     // Interface hook for unit tests to replace or decorate the DOMStoreThreePhaseCommitCohorts.
  44     public interface CohortDecorator {
  45         ShardDataTreeCohort decorate(String transactionID, ShardDataTreeCohort actual);
  46     }
  47
  48     private final Map<String, CohortEntry> cohortCache = new HashMap<>();
  49
  50     private CohortEntry currentCohortEntry;
  51
  52     private final ShardDataTree dataTree;
  53
  54     // We use a LinkedList here to avoid synchronization overhead with concurrent queue impls
  55     // since this should only be accessed on the shard's dispatcher.
  56     private final Queue<CohortEntry> queuedCohortEntries = new LinkedList<>();
  57
  58     private int queueCapacity;
  59
  60     private final Logger log;
  61
  62     private final String name;
  63
  64     private final long cacheExpiryTimeoutInMillis;
  65
  66     // This is a hook for unit tests to replace or decorate the DOMStoreThreePhaseCommitCohorts.
  67     private CohortDecorator cohortDecorator;
  68
  69     private ReadyTransactionReply readyTransactionReply;
  70
  71     ShardCommitCoordinator(ShardDataTree dataTree,
  72             long cacheExpiryTimeoutInMillis, int queueCapacity, Logger log, String name) {
  73
  74         this.queueCapacity = queueCapacity;
  75         this.log = log;
  76         this.name = name;
  77         this.dataTree = Preconditions.checkNotNull(dataTree);
  78         this.cacheExpiryTimeoutInMillis = cacheExpiryTimeoutInMillis;
  79     }
  80
  81     int getQueueSize() {
  82         return queuedCohortEntries.size();
  83     }
  84
  85     void setQueueCapacity(int queueCapacity) {
  86         this.queueCapacity = queueCapacity;
  87     }
  88
  89     private ReadyTransactionReply readyTransactionReply(Shard shard) {
  90         if(readyTransactionReply == null) {
  91             readyTransactionReply = new ReadyTransactionReply(Serialization.serializedActorPath(shard.self()));
  92         }
  93
  94         return readyTransactionReply;
  95     }
  96
  97     private boolean queueCohortEntry(CohortEntry cohortEntry, ActorRef sender, Shard shard) {
  98         if(queuedCohortEntries.size() < queueCapacity) {
  99             queuedCohortEntries.offer(cohortEntry);
 100
 101             log.debug("{}: Enqueued transaction {}, queue size {}", name, cohortEntry.getTransactionID(),
 102                     queuedCohortEntries.size());
 103
 104             return true;
 105         } else {
 106             cohortCache.remove(cohortEntry.getTransactionID());
 107
 108             RuntimeException ex = new RuntimeException(
 109                     String.format("%s: Could not enqueue transaction %s - the maximum commit queue"+
 110                                   " capacity %d has been reached.",
 111                                   name, cohortEntry.getTransactionID(), queueCapacity));
 112             log.error(ex.getMessage());
 113             sender.tell(new Status.Failure(ex), shard.self());
 114             return false;
 115         }
 116     }
 117
 118     /**
 119      * This method is called to ready a transaction that was prepared by ShardTransaction actor. It caches
 120      * the prepared cohort entry for the given transactions ID in preparation for the subsequent 3-phase commit.
 121      *
 122      * @param ready the ForwardedReadyTransaction message to process
 123      * @param sender the sender of the message
 124      * @param shard the transaction's shard actor
 125      */
 126     void handleForwardedReadyTransaction(ForwardedReadyTransaction ready, ActorRef sender, Shard shard) {
 127         log.debug("{}: Readying transaction {}, client version {}", name,
 128                 ready.getTransactionID(), ready.getTxnClientVersion());
 129
 130         ShardDataTreeCohort cohort = ready.getTransaction().ready();
 131         CohortEntry cohortEntry = new CohortEntry(ready.getTransactionID(), cohort);
 132         cohortCache.put(ready.getTransactionID(), cohortEntry);
 133
 134         if(!queueCohortEntry(cohortEntry, sender, shard)) {
 135             return;
 136         }
 137
 138         if(ready.getTxnClientVersion() < DataStoreVersions.LITHIUM_VERSION) {
 139             // Return our actor path as we'll handle the three phase commit except if the Tx client
 140             // version < Helium-1 version which means the Tx was initiated by a base Helium version node.
 141             // In that case, the subsequent 3-phase commit messages won't contain the transactionId so to
 142             // maintain backwards compatibility, we create a separate cohort actor to provide the compatible behavior.
 143             ActorRef replyActorPath = shard.self();
 144             if(ready.getTxnClientVersion() < DataStoreVersions.HELIUM_1_VERSION) {
 145                 log.debug("{}: Creating BackwardsCompatibleThreePhaseCommitCohort", name);
 146                 replyActorPath = shard.getContext().actorOf(BackwardsCompatibleThreePhaseCommitCohort.props(
 147                         ready.getTransactionID()));
 148             }
 149
 150             ReadyTransactionReply readyTransactionReply =
 151                     new ReadyTransactionReply(Serialization.serializedActorPath(replyActorPath),
 152                             ready.getTxnClientVersion());
 153             sender.tell(ready.isReturnSerialized() ? readyTransactionReply.toSerializable() :
 154                 readyTransactionReply, shard.self());
 155         } else {
 156             if(ready.isDoImmediateCommit()) {
 157                 cohortEntry.setDoImmediateCommit(true);
 158                 cohortEntry.setReplySender(sender);
 159                 cohortEntry.setShard(shard);
 160                 handleCanCommit(cohortEntry);
 161             } else {
 162                 // The caller does not want immediate commit - the 3-phase commit will be coordinated by the
 163                 // front-end so send back a ReadyTransactionReply with our actor path.
 164                 sender.tell(readyTransactionReply(shard), shard.self());
 165             }
 166         }
 167     }
 168
 169     /**
 170      * This method handles a BatchedModifications message for a transaction being prepared directly on the
 171      * Shard actor instead of via a ShardTransaction actor. If there's no currently cached
 172      * DOMStoreWriteTransaction, one is created. The batched modifications are applied to the write Tx. If
 173      * the BatchedModifications is ready to commit then a DOMStoreThreePhaseCommitCohort is created.
 174      *
 175      * @param batched the BatchedModifications message to process
 176      * @param sender the sender of the message
 177      * @param shard the transaction's shard actor
 178      */
 179     void handleBatchedModifications(BatchedModifications batched, ActorRef sender, Shard shard) {
 180         CohortEntry cohortEntry = cohortCache.get(batched.getTransactionID());
 181         if(cohortEntry == null) {
 182             cohortEntry = new CohortEntry(batched.getTransactionID(),
 183                     dataTree.newReadWriteTransaction(batched.getTransactionID(),
 184                         batched.getTransactionChainID()));
 185             cohortCache.put(batched.getTransactionID(), cohortEntry);
 186         }
 187
 188         if(log.isDebugEnabled()) {
 189             log.debug("{}: Applying {} batched modifications for Tx {}", name,
 190                     batched.getModifications().size(), batched.getTransactionID());
 191         }
 192
 193         cohortEntry.applyModifications(batched.getModifications());
 194
 195         if(batched.isReady()) {
 196             if(cohortEntry.getLastBatchedModificationsException() != null) {
 197                 cohortCache.remove(cohortEntry.getTransactionID());
 198                 throw cohortEntry.getLastBatchedModificationsException();
 199             }
 200
 201             if(cohortEntry.getTotalBatchedModificationsReceived() != batched.getTotalMessagesSent()) {
 202                 cohortCache.remove(cohortEntry.getTransactionID());
 203                 throw new IllegalStateException(String.format(
 204                         "The total number of batched messages received %d does not match the number sent %d",
 205                         cohortEntry.getTotalBatchedModificationsReceived(), batched.getTotalMessagesSent()));
 206             }
 207
 208             if(!queueCohortEntry(cohortEntry, sender, shard)) {
 209                 return;
 210             }
 211
 212             if(log.isDebugEnabled()) {
 213                 log.debug("{}: Readying Tx {}, client version {}", name,
 214                         batched.getTransactionID(), batched.getVersion());
 215             }
 216
 217             cohortEntry.ready(cohortDecorator, batched.isDoCommitOnReady());
 218
 219             if(batched.isDoCommitOnReady()) {
 220                 cohortEntry.setReplySender(sender);
 221                 cohortEntry.setShard(shard);
 222                 handleCanCommit(cohortEntry);
 223             } else {
 224                 sender.tell(readyTransactionReply(shard), shard.self());
 225             }
 226         } else {
 227             sender.tell(new BatchedModificationsReply(batched.getModifications().size()), shard.self());
 228         }
 229     }
 230
 231     /**
 232      * This method handles {@link ReadyLocalTransaction} message. All transaction modifications have
 233      * been prepared beforehand by the sender and we just need to drive them through into the dataTree.
 234      *
 235      * @param message the ReadyLocalTransaction message to process
 236      * @param sender the sender of the message
 237      * @param shard the transaction's shard actor
 238      */
 239     void handleReadyLocalTransaction(ReadyLocalTransaction message, ActorRef sender, Shard shard) {
 240         final ShardDataTreeCohort cohort = new SimpleShardDataTreeCohort(dataTree, message.getModification(),
 241                 message.getTransactionID());
 242         final CohortEntry cohortEntry = new CohortEntry(message.getTransactionID(), cohort);
 243         cohortCache.put(message.getTransactionID(), cohortEntry);
 244         cohortEntry.setDoImmediateCommit(message.isDoCommitOnReady());
 245
 246         if(!queueCohortEntry(cohortEntry, sender, shard)) {
 247             return;
 248         }
 249
 250         log.debug("{}: Applying local modifications for Tx {}", name, message.getTransactionID());
 251
 252         if (message.isDoCommitOnReady()) {
 253             cohortEntry.setReplySender(sender);
 254             cohortEntry.setShard(shard);
 255             handleCanCommit(cohortEntry);
 256         } else {
 257             sender.tell(readyTransactionReply(shard), shard.self());
 258         }
 259     }
 260
 261     private void handleCanCommit(CohortEntry cohortEntry) {
 262         String transactionID = cohortEntry.getTransactionID();
 263
 264         cohortEntry.updateLastAccessTime();
 265
 266         if(currentCohortEntry != null) {
 267             // There's already a Tx commit in progress so we can't process this entry yet - but it's in the
 268             // queue and will get processed after all prior entries complete.
 269
 270             if(log.isDebugEnabled()) {
 271                 log.debug("{}: Commit for Tx {} already in progress - skipping canCommit for {} for now",
 272                         name, currentCohortEntry.getTransactionID(), transactionID);
 273             }
 274
 275             return;
 276         }
 277
 278         // No Tx commit currently in progress - check if this entry is the next one in the queue, If so make
 279         // it the current entry and proceed with canCommit.
 280         // Purposely checking reference equality here.
 281         if(queuedCohortEntries.peek() == cohortEntry) {
 282             currentCohortEntry = queuedCohortEntries.poll();
 283             doCanCommit(currentCohortEntry);
 284         } else {
 285             if(log.isDebugEnabled()) {
 286                 log.debug("{}: Tx {} is the next pending canCommit - skipping {} for now",
 287                         name, queuedCohortEntries.peek().getTransactionID(), transactionID);
 288             }
 289         }
 290     }
 291
 292     /**
 293      * This method handles the canCommit phase for a transaction.
 294      *
 295      * @param transactionID the ID of the transaction to canCommit
 296      * @param sender the actor to which to send the response
 297      * @param shard the transaction's shard actor
 298      */
 299     void handleCanCommit(String transactionID, final ActorRef sender, final Shard shard) {
 300         // Lookup the cohort entry that was cached previously (or should have been) by
 301         // transactionReady (via the ForwardedReadyTransaction message).
 302         final CohortEntry cohortEntry = cohortCache.get(transactionID);
 303         if(cohortEntry == null) {
 304             // Either canCommit was invoked before ready(shouldn't happen)  or a long time passed
 305             // between canCommit and ready and the entry was expired from the cache.
 306             IllegalStateException ex = new IllegalStateException(
 307                     String.format("%s: No cohort entry found for transaction %s", name, transactionID));
 308             log.error(ex.getMessage());
 309             sender.tell(new Status.Failure(ex), shard.self());
 310             return;
 311         }
 312
 313         cohortEntry.setReplySender(sender);
 314         cohortEntry.setShard(shard);
 315
 316         handleCanCommit(cohortEntry);
 317     }
 318
 319     private void doCanCommit(final CohortEntry cohortEntry) {
 320         boolean canCommit = false;
 321         try {
 322             canCommit = cohortEntry.canCommit();
 323
 324             log.debug("{}: canCommit for {}: {}", name, cohortEntry.getTransactionID(), canCommit);
 325
 326             if(cohortEntry.isDoImmediateCommit()) {
 327                 if(canCommit) {
 328                     doCommit(cohortEntry);
 329                 } else {
 330                     cohortEntry.getReplySender().tell(new Status.Failure(new TransactionCommitFailedException(
 331                                 "Can Commit failed, no detailed cause available.")), cohortEntry.getShard().self());
 332                 }
 333             } else {
 334                 cohortEntry.getReplySender().tell(
 335                         canCommit ? CanCommitTransactionReply.YES.toSerializable() :
 336                             CanCommitTransactionReply.NO.toSerializable(), cohortEntry.getShard().self());
 337             }
 338         } catch (Exception e) {
 339             log.debug("{}: An exception occurred during canCommit", name, e);
 340
 341             Throwable failure = e;
 342             if(e instanceof ExecutionException) {
 343                 failure = e.getCause();
 344             }
 345
 346             cohortEntry.getReplySender().tell(new Status.Failure(failure), cohortEntry.getShard().self());
 347         } finally {
 348             if(!canCommit) {
 349                 // Remove the entry from the cache now.
 350                 currentTransactionComplete(cohortEntry.getTransactionID(), true);
 351             }
 352         }
 353     }
 354
 355     private boolean doCommit(CohortEntry cohortEntry) {
 356         log.debug("{}: Committing transaction {}", name, cohortEntry.getTransactionID());
 357
 358         boolean success = false;
 359
 360         // We perform the preCommit phase here atomically with the commit phase. This is an
 361         // optimization to eliminate the overhead of an extra preCommit message. We lose front-end
 362         // coordination of preCommit across shards in case of failure but preCommit should not
 363         // normally fail since we ensure only one concurrent 3-phase commit.
 364
 365         try {
 366             cohortEntry.preCommit();
 367
 368             cohortEntry.getShard().continueCommit(cohortEntry);
 369
 370             cohortEntry.updateLastAccessTime();
 371
 372             success = true;
 373         } catch (Exception e) {
 374             log.error("{} An exception occurred while preCommitting transaction {}",
 375                     name, cohortEntry.getTransactionID(), e);
 376             cohortEntry.getReplySender().tell(new akka.actor.Status.Failure(e), cohortEntry.getShard().self());
 377
 378             currentTransactionComplete(cohortEntry.getTransactionID(), true);
 379         }
 380
 381         return success;
 382     }
 383
 384     /**
 385      * This method handles the preCommit and commit phases for a transaction.
 386      *
 387      * @param transactionID the ID of the transaction to commit
 388      * @param sender the actor to which to send the response
 389      * @param shard the transaction's shard actor
 390      * @return true if the transaction was successfully prepared, false otherwise.
 391      */
 392     boolean handleCommit(final String transactionID, final ActorRef sender, final Shard shard) {
 393         // Get the current in-progress cohort entry in the commitCoordinator if it corresponds to
 394         // this transaction.
 395         final CohortEntry cohortEntry = getCohortEntryIfCurrent(transactionID);
 396         if(cohortEntry == null) {
 397             // We're not the current Tx - the Tx was likely expired b/c it took too long in
 398             // between the canCommit and commit messages.
 399             IllegalStateException ex = new IllegalStateException(
 400                     String.format("%s: Cannot commit transaction %s - it is not the current transaction",
 401                             name, transactionID));
 402             log.error(ex.getMessage());
 403             sender.tell(new akka.actor.Status.Failure(ex), shard.self());
 404             return false;
 405         }
 406
 407         cohortEntry.setReplySender(sender);
 408         return doCommit(cohortEntry);
 409     }
 410
 411     void handleAbort(final String transactionID, final ActorRef sender, final Shard shard) {
 412         CohortEntry cohortEntry = getCohortEntryIfCurrent(transactionID);
 413         if(cohortEntry != null) {
 414             // We don't remove the cached cohort entry here (ie pass false) in case the Tx was
 415             // aborted during replication in which case we may still commit locally if replication
 416             // succeeds.
 417             currentTransactionComplete(transactionID, false);
 418         } else {
 419             cohortEntry = getAndRemoveCohortEntry(transactionID);
 420         }
 421
 422         if(cohortEntry == null) {
 423             return;
 424         }
 425
 426         log.debug("{}: Aborting transaction {}", name, transactionID);
 427
 428         final ActorRef self = shard.getSelf();
 429         try {
 430             cohortEntry.abort();
 431
 432             shard.getShardMBean().incrementAbortTransactionsCount();
 433
 434             if(sender != null) {
 435                 sender.tell(new AbortTransactionReply().toSerializable(), self);
 436             }
 437         } catch (Exception e) {
 438             log.error("{}: An exception happened during abort", name, e);
 439
 440             if(sender != null) {
 441                 sender.tell(new akka.actor.Status.Failure(e), self);
 442             }
 443         }
 444     }
 445
 446     /**
 447      * Returns the cohort entry for the Tx commit currently in progress if the given transaction ID
 448      * matches the current entry.
 449      *
 450      * @param transactionID the ID of the transaction
 451      * @return the current CohortEntry or null if the given transaction ID does not match the
 452      *         current entry.
 453      */
 454     public CohortEntry getCohortEntryIfCurrent(String transactionID) {
 455         if(isCurrentTransaction(transactionID)) {
 456             return currentCohortEntry;
 457         }
 458
 459         return null;
 460     }
 461
 462     public CohortEntry getCurrentCohortEntry() {
 463         return currentCohortEntry;
 464     }
 465
 466     public CohortEntry getAndRemoveCohortEntry(String transactionID) {
 467         return cohortCache.remove(transactionID);
 468     }
 469
 470     public boolean isCurrentTransaction(String transactionID) {
 471         return currentCohortEntry != null &&
 472                 currentCohortEntry.getTransactionID().equals(transactionID);
 473     }
 474
 475     /**
 476      * This method is called when a transaction is complete, successful or not. If the given
 477      * given transaction ID matches the current in-progress transaction, the next cohort entry,
 478      * if any, is dequeued and processed.
 479      *
 480      * @param transactionID the ID of the completed transaction
 481      * @param removeCohortEntry if true the CohortEntry for the transaction is also removed from
 482      *        the cache.
 483      */
 484     public void currentTransactionComplete(String transactionID, boolean removeCohortEntry) {
 485         if(removeCohortEntry) {
 486             cohortCache.remove(transactionID);
 487         }
 488
 489         if(isCurrentTransaction(transactionID)) {
 490             currentCohortEntry = null;
 491
 492             log.debug("{}: currentTransactionComplete: {}", name, transactionID);
 493
 494             maybeProcessNextCohortEntry();
 495         }
 496     }
 497
 498     private void maybeProcessNextCohortEntry() {
 499         // Check if there's a next cohort entry waiting in the queue and if it is ready to commit. Also
 500         // clean out expired entries.
 501         Iterator<CohortEntry> iter = queuedCohortEntries.iterator();
 502         while(iter.hasNext()) {
 503             CohortEntry next = iter.next();
 504             if(next.isReadyToCommit()) {
 505                 if(currentCohortEntry == null) {
 506                     if(log.isDebugEnabled()) {
 507                         log.debug("{}: Next entry to canCommit {}", name, next);
 508                     }
 509
 510                     iter.remove();
 511                     currentCohortEntry = next;
 512                     currentCohortEntry.updateLastAccessTime();
 513                     doCanCommit(currentCohortEntry);
 514                 }
 515
 516                 break;
 517             } else if(next.isExpired(cacheExpiryTimeoutInMillis)) {
 518                 log.warn("{}: canCommit for transaction {} was not received within {} ms - entry removed from cache",
 519                         name, next.getTransactionID(), cacheExpiryTimeoutInMillis);
 520             } else if(!next.isAborted()) {
 521                 break;
 522             }
 523
 524             iter.remove();
 525             cohortCache.remove(next.getTransactionID());
 526         }
 527     }
 528
 529     void cleanupExpiredCohortEntries() {
 530         maybeProcessNextCohortEntry();
 531     }
 532
 533     @VisibleForTesting
 534     void setCohortDecorator(CohortDecorator cohortDecorator) {
 535         this.cohortDecorator = cohortDecorator;
 536     }
 537
 538     static class CohortEntry {
 539         private final String transactionID;
 540         private ShardDataTreeCohort cohort;
 541         private final ReadWriteShardDataTreeTransaction transaction;
 542         private RuntimeException lastBatchedModificationsException;
 543         private ActorRef replySender;
 544         private Shard shard;
 545         private boolean doImmediateCommit;
 546         private final Stopwatch lastAccessTimer = Stopwatch.createStarted();
 547         private int totalBatchedModificationsReceived;
 548         private boolean aborted;
 549
 550         CohortEntry(String transactionID, ReadWriteShardDataTreeTransaction transaction) {
 551             this.transaction = Preconditions.checkNotNull(transaction);
 552             this.transactionID = transactionID;
 553         }
 554
 555         CohortEntry(String transactionID, ShardDataTreeCohort cohort) {
 556             this.transactionID = transactionID;
 557             this.cohort = cohort;
 558             this.transaction = null;
 559         }
 560
 561         void updateLastAccessTime() {
 562             lastAccessTimer.reset();
 563             lastAccessTimer.start();
 564         }
 565
 566         String getTransactionID() {
 567             return transactionID;
 568         }
 569
 570         DataTreeCandidate getCandidate() {
 571             return cohort.getCandidate();
 572         }
 573
 574         int getTotalBatchedModificationsReceived() {
 575             return totalBatchedModificationsReceived;
 576         }
 577
 578         RuntimeException getLastBatchedModificationsException() {
 579             return lastBatchedModificationsException;
 580         }
 581
 582         void applyModifications(Iterable<Modification> modifications) {
 583             totalBatchedModificationsReceived++;
 584             if(lastBatchedModificationsException == null) {
 585                 for (Modification modification : modifications) {
 586                         try {
 587                             modification.apply(transaction.getSnapshot());
 588                         } catch (RuntimeException e) {
 589                             lastBatchedModificationsException = e;
 590                             throw e;
 591                         }
 592                 }
 593             }
 594         }
 595
 596         boolean canCommit() throws InterruptedException, ExecutionException {
 597             // We block on the future here (and also preCommit(), commit(), abort()) so we don't have to worry
 598             // about possibly accessing our state on a different thread outside of our dispatcher.
 599             // TODO: the ShardDataTreeCohort returns immediate Futures anyway which begs the question - why
 600             // bother even returning Futures from ShardDataTreeCohort if we have to treat them synchronously
 601             // anyway?. The Futures are really a remnant from when we were using the InMemoryDataBroker.
 602             return cohort.canCommit().get();
 603         }
 604
 605         void preCommit() throws InterruptedException, ExecutionException {
 606             cohort.preCommit().get();
 607         }
 608
 609         void commit() throws InterruptedException, ExecutionException {
 610             cohort.commit().get();
 611         }
 612
 613         void abort() throws InterruptedException, ExecutionException {
 614             aborted = true;
 615             cohort.abort().get();
 616         }
 617
 618         void ready(CohortDecorator cohortDecorator, boolean doImmediateCommit) {
 619             Preconditions.checkState(cohort == null, "cohort was already set");
 620
 621             setDoImmediateCommit(doImmediateCommit);
 622
 623             cohort = transaction.ready();
 624
 625             if(cohortDecorator != null) {
 626                 // Call the hook for unit tests.
 627                 cohort = cohortDecorator.decorate(transactionID, cohort);
 628             }
 629         }
 630
 631         boolean isReadyToCommit() {
 632             return replySender != null;
 633         }
 634
 635         boolean isExpired(long expireTimeInMillis) {
 636             return lastAccessTimer.elapsed(TimeUnit.MILLISECONDS) >= expireTimeInMillis;
 637         }
 638
 639         boolean isDoImmediateCommit() {
 640             return doImmediateCommit;
 641         }
 642
 643         void setDoImmediateCommit(boolean doImmediateCommit) {
 644             this.doImmediateCommit = doImmediateCommit;
 645         }
 646
 647         ActorRef getReplySender() {
 648             return replySender;
 649         }
 650
 651         void setReplySender(ActorRef replySender) {
 652             this.replySender = replySender;
 653         }
 654
 655         Shard getShard() {
 656             return shard;
 657         }
 658
 659         void setShard(Shard shard) {
 660             this.shard = shard;
 661         }
 662
 663
 664         boolean isAborted() {
 665             return aborted;
 666         }
 667
 668         @Override
 669         public String toString() {
 670             StringBuilder builder = new StringBuilder();
 671             builder.append("CohortEntry [transactionID=").append(transactionID).append(", doImmediateCommit=")
 672                     .append(doImmediateCommit).append("]");
 673             return builder.toString();
 674         }
 675     }
 676 }