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.Failure;
  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.ArrayList;
  17 import java.util.HashMap;
  18 import java.util.Iterator;
  19 import java.util.LinkedList;
  20 import java.util.List;
  21 import java.util.Map;
  22 import java.util.Queue;
  23 import java.util.concurrent.ExecutionException;
  24 import java.util.concurrent.TimeUnit;
  25 import org.opendaylight.controller.cluster.datastore.messages.AbortTransactionReply;
  26 import org.opendaylight.controller.cluster.datastore.messages.BatchedModifications;
  27 import org.opendaylight.controller.cluster.datastore.messages.BatchedModificationsReply;
  28 import org.opendaylight.controller.cluster.datastore.messages.CanCommitTransactionReply;
  29 import org.opendaylight.controller.cluster.datastore.messages.ForwardedReadyTransaction;
  30 import org.opendaylight.controller.cluster.datastore.messages.ReadyLocalTransaction;
  31 import org.opendaylight.controller.cluster.datastore.messages.ReadyTransactionReply;
  32 import org.opendaylight.controller.cluster.datastore.modification.Modification;
  33 import org.opendaylight.controller.md.sal.common.api.data.TransactionCommitFailedException;
  34 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidate;
  35 import org.slf4j.Logger;
  36
  37 /**
  38  * Coordinates commits for a shard ensuring only one concurrent 3-phase commit.
  39  *
  40  * @author Thomas Pantelis
  41  */
  42 class ShardCommitCoordinator {
  43
  44     // Interface hook for unit tests to replace or decorate the DOMStoreThreePhaseCommitCohorts.
  45     public interface CohortDecorator {
  46         ShardDataTreeCohort decorate(String transactionID, ShardDataTreeCohort actual);
  47     }
  48
  49     private final Map<String, CohortEntry> cohortCache = new HashMap<>();
  50
  51     private CohortEntry currentCohortEntry;
  52
  53     private final ShardDataTree dataTree;
  54
  55     // We use a LinkedList here to avoid synchronization overhead with concurrent queue impls
  56     // since this should only be accessed on the shard's dispatcher.
  57     private final Queue<CohortEntry> queuedCohortEntries = new LinkedList<>();
  58
  59     private int queueCapacity;
  60
  61     private final Logger log;
  62
  63     private final String name;
  64
  65     private final long cacheExpiryTimeoutInMillis;
  66
  67     // This is a hook for unit tests to replace or decorate the DOMStoreThreePhaseCommitCohorts.
  68     private CohortDecorator cohortDecorator;
  69
  70     private ReadyTransactionReply readyTransactionReply;
  71
  72     private Runnable runOnPendingTransactionsComplete;
  73
  74     ShardCommitCoordinator(ShardDataTree dataTree,
  75             long cacheExpiryTimeoutInMillis, int queueCapacity, Logger log, String name) {
  76
  77         this.queueCapacity = queueCapacity;
  78         this.log = log;
  79         this.name = name;
  80         this.dataTree = Preconditions.checkNotNull(dataTree);
  81         this.cacheExpiryTimeoutInMillis = cacheExpiryTimeoutInMillis;
  82     }
  83
  84     int getQueueSize() {
  85         return queuedCohortEntries.size();
  86     }
  87
  88     int getCohortCacheSize() {
  89         return cohortCache.size();
  90     }
  91
  92     void setQueueCapacity(int queueCapacity) {
  93         this.queueCapacity = queueCapacity;
  94     }
  95
  96     private ReadyTransactionReply readyTransactionReply(Shard shard) {
  97         if(readyTransactionReply == null) {
  98             readyTransactionReply = new ReadyTransactionReply(Serialization.serializedActorPath(shard.self()));
  99         }
 100
 101         return readyTransactionReply;
 102     }
 103
 104     private boolean queueCohortEntry(CohortEntry cohortEntry, ActorRef sender, Shard shard) {
 105         if(queuedCohortEntries.size() < queueCapacity) {
 106             queuedCohortEntries.offer(cohortEntry);
 107
 108             log.debug("{}: Enqueued transaction {}, queue size {}", name, cohortEntry.getTransactionID(),
 109                     queuedCohortEntries.size());
 110
 111             return true;
 112         } else {
 113             cohortCache.remove(cohortEntry.getTransactionID());
 114
 115             RuntimeException ex = new RuntimeException(
 116                     String.format("%s: Could not enqueue transaction %s - the maximum commit queue"+
 117                                   " capacity %d has been reached.",
 118                                   name, cohortEntry.getTransactionID(), queueCapacity));
 119             log.error(ex.getMessage());
 120             sender.tell(new Failure(ex), shard.self());
 121             return false;
 122         }
 123     }
 124
 125     /**
 126      * This method is called to ready a transaction that was prepared by ShardTransaction actor. It caches
 127      * the prepared cohort entry for the given transactions ID in preparation for the subsequent 3-phase commit.
 128      *
 129      * @param ready the ForwardedReadyTransaction message to process
 130      * @param sender the sender of the message
 131      * @param shard the transaction's shard actor
 132      */
 133     void handleForwardedReadyTransaction(ForwardedReadyTransaction ready, ActorRef sender, Shard shard) {
 134         log.debug("{}: Readying transaction {}, client version {}", name,
 135                 ready.getTransactionID(), ready.getTxnClientVersion());
 136
 137         ShardDataTreeCohort cohort = ready.getTransaction().ready();
 138         CohortEntry cohortEntry = new CohortEntry(ready.getTransactionID(), cohort, ready.getTxnClientVersion());
 139         cohortCache.put(ready.getTransactionID(), cohortEntry);
 140
 141         if(!queueCohortEntry(cohortEntry, sender, shard)) {
 142             return;
 143         }
 144
 145         if(ready.isDoImmediateCommit()) {
 146             cohortEntry.setDoImmediateCommit(true);
 147             cohortEntry.setReplySender(sender);
 148             cohortEntry.setShard(shard);
 149             handleCanCommit(cohortEntry);
 150         } else {
 151             // The caller does not want immediate commit - the 3-phase commit will be coordinated by the
 152             // front-end so send back a ReadyTransactionReply with our actor path.
 153             sender.tell(readyTransactionReply(shard), shard.self());
 154         }
 155     }
 156
 157     /**
 158      * This method handles a BatchedModifications message for a transaction being prepared directly on the
 159      * Shard actor instead of via a ShardTransaction actor. If there's no currently cached
 160      * DOMStoreWriteTransaction, one is created. The batched modifications are applied to the write Tx. If
 161      * the BatchedModifications is ready to commit then a DOMStoreThreePhaseCommitCohort is created.
 162      *
 163      * @param batched the BatchedModifications message to process
 164      * @param sender the sender of the message
 165      * @param shard the transaction's shard actor
 166      */
 167     void handleBatchedModifications(BatchedModifications batched, ActorRef sender, Shard shard) {
 168         CohortEntry cohortEntry = cohortCache.get(batched.getTransactionID());
 169         if(cohortEntry == null) {
 170             cohortEntry = new CohortEntry(batched.getTransactionID(),
 171                     dataTree.newReadWriteTransaction(batched.getTransactionID(),
 172                         batched.getTransactionChainID()), batched.getVersion());
 173             cohortCache.put(batched.getTransactionID(), cohortEntry);
 174         }
 175
 176         if(log.isDebugEnabled()) {
 177             log.debug("{}: Applying {} batched modifications for Tx {}", name,
 178                     batched.getModifications().size(), batched.getTransactionID());
 179         }
 180
 181         cohortEntry.applyModifications(batched.getModifications());
 182
 183         if(batched.isReady()) {
 184             if(cohortEntry.getLastBatchedModificationsException() != null) {
 185                 cohortCache.remove(cohortEntry.getTransactionID());
 186                 throw cohortEntry.getLastBatchedModificationsException();
 187             }
 188
 189             if(cohortEntry.getTotalBatchedModificationsReceived() != batched.getTotalMessagesSent()) {
 190                 cohortCache.remove(cohortEntry.getTransactionID());
 191                 throw new IllegalStateException(String.format(
 192                         "The total number of batched messages received %d does not match the number sent %d",
 193                         cohortEntry.getTotalBatchedModificationsReceived(), batched.getTotalMessagesSent()));
 194             }
 195
 196             if(!queueCohortEntry(cohortEntry, sender, shard)) {
 197                 return;
 198             }
 199
 200             if(log.isDebugEnabled()) {
 201                 log.debug("{}: Readying Tx {}, client version {}", name,
 202                         batched.getTransactionID(), batched.getVersion());
 203             }
 204
 205             cohortEntry.ready(cohortDecorator, batched.isDoCommitOnReady());
 206
 207             if(batched.isDoCommitOnReady()) {
 208                 cohortEntry.setReplySender(sender);
 209                 cohortEntry.setShard(shard);
 210                 handleCanCommit(cohortEntry);
 211             } else {
 212                 sender.tell(readyTransactionReply(shard), shard.self());
 213             }
 214         } else {
 215             sender.tell(new BatchedModificationsReply(batched.getModifications().size()), shard.self());
 216         }
 217     }
 218
 219     /**
 220      * This method handles {@link ReadyLocalTransaction} message. All transaction modifications have
 221      * been prepared beforehand by the sender and we just need to drive them through into the dataTree.
 222      *
 223      * @param message the ReadyLocalTransaction message to process
 224      * @param sender the sender of the message
 225      * @param shard the transaction's shard actor
 226      */
 227     void handleReadyLocalTransaction(ReadyLocalTransaction message, ActorRef sender, Shard shard) {
 228         final ShardDataTreeCohort cohort = new SimpleShardDataTreeCohort(dataTree, message.getModification(),
 229                 message.getTransactionID());
 230         final CohortEntry cohortEntry = new CohortEntry(message.getTransactionID(), cohort,
 231                 DataStoreVersions.CURRENT_VERSION);
 232         cohortCache.put(message.getTransactionID(), cohortEntry);
 233         cohortEntry.setDoImmediateCommit(message.isDoCommitOnReady());
 234
 235         if(!queueCohortEntry(cohortEntry, sender, shard)) {
 236             return;
 237         }
 238
 239         log.debug("{}: Applying local modifications for Tx {}", name, message.getTransactionID());
 240
 241         if (message.isDoCommitOnReady()) {
 242             cohortEntry.setReplySender(sender);
 243             cohortEntry.setShard(shard);
 244             handleCanCommit(cohortEntry);
 245         } else {
 246             sender.tell(readyTransactionReply(shard), shard.self());
 247         }
 248     }
 249
 250     private void handleCanCommit(CohortEntry cohortEntry) {
 251         String transactionID = cohortEntry.getTransactionID();
 252
 253         cohortEntry.updateLastAccessTime();
 254
 255         if(currentCohortEntry != null) {
 256             // There's already a Tx commit in progress so we can't process this entry yet - but it's in the
 257             // queue and will get processed after all prior entries complete.
 258
 259             if(log.isDebugEnabled()) {
 260                 log.debug("{}: Commit for Tx {} already in progress - skipping canCommit for {} for now",
 261                         name, currentCohortEntry.getTransactionID(), transactionID);
 262             }
 263
 264             return;
 265         }
 266
 267         // No Tx commit currently in progress - check if this entry is the next one in the queue, If so make
 268         // it the current entry and proceed with canCommit.
 269         // Purposely checking reference equality here.
 270         if(queuedCohortEntries.peek() == cohortEntry) {
 271             currentCohortEntry = queuedCohortEntries.poll();
 272             doCanCommit(currentCohortEntry);
 273         } else {
 274             if(log.isDebugEnabled()) {
 275                 log.debug("{}: Tx {} is the next pending canCommit - skipping {} for now",
 276                         name, queuedCohortEntries.peek().getTransactionID(), transactionID);
 277             }
 278         }
 279     }
 280
 281     /**
 282      * This method handles the canCommit phase for a transaction.
 283      *
 284      * @param transactionID the ID of the transaction to canCommit
 285      * @param sender the actor to which to send the response
 286      * @param shard the transaction's shard actor
 287      */
 288     void handleCanCommit(String transactionID, final ActorRef sender, final Shard shard) {
 289         // Lookup the cohort entry that was cached previously (or should have been) by
 290         // transactionReady (via the ForwardedReadyTransaction message).
 291         final CohortEntry cohortEntry = cohortCache.get(transactionID);
 292         if(cohortEntry == null) {
 293             // Either canCommit was invoked before ready(shouldn't happen)  or a long time passed
 294             // between canCommit and ready and the entry was expired from the cache.
 295             IllegalStateException ex = new IllegalStateException(
 296                     String.format("%s: No cohort entry found for transaction %s", name, transactionID));
 297             log.error(ex.getMessage());
 298             sender.tell(new Failure(ex), shard.self());
 299             return;
 300         }
 301
 302         cohortEntry.setReplySender(sender);
 303         cohortEntry.setShard(shard);
 304
 305         handleCanCommit(cohortEntry);
 306     }
 307
 308     private void doCanCommit(final CohortEntry cohortEntry) {
 309         boolean canCommit = false;
 310         try {
 311             canCommit = cohortEntry.canCommit();
 312
 313             log.debug("{}: canCommit for {}: {}", name, cohortEntry.getTransactionID(), canCommit);
 314
 315             if(cohortEntry.isDoImmediateCommit()) {
 316                 if(canCommit) {
 317                     doCommit(cohortEntry);
 318                 } else {
 319                     cohortEntry.getReplySender().tell(new Failure(new TransactionCommitFailedException(
 320                                 "Can Commit failed, no detailed cause available.")), cohortEntry.getShard().self());
 321                 }
 322             } else {
 323                 // FIXME - use caller's version
 324                 cohortEntry.getReplySender().tell(
 325                         canCommit ? CanCommitTransactionReply.yes(cohortEntry.getClientVersion()).toSerializable() :
 326                             CanCommitTransactionReply.no(cohortEntry.getClientVersion()).toSerializable(),
 327                         cohortEntry.getShard().self());
 328             }
 329         } catch (Exception e) {
 330             log.debug("{}: An exception occurred during canCommit", name, e);
 331
 332             Throwable failure = e;
 333             if(e instanceof ExecutionException) {
 334                 failure = e.getCause();
 335             }
 336
 337             cohortEntry.getReplySender().tell(new Failure(failure), cohortEntry.getShard().self());
 338         } finally {
 339             if(!canCommit) {
 340                 // Remove the entry from the cache now.
 341                 currentTransactionComplete(cohortEntry.getTransactionID(), true);
 342             }
 343         }
 344     }
 345
 346     private boolean doCommit(CohortEntry cohortEntry) {
 347         log.debug("{}: Committing transaction {}", name, cohortEntry.getTransactionID());
 348
 349         boolean success = false;
 350
 351         // We perform the preCommit phase here atomically with the commit phase. This is an
 352         // optimization to eliminate the overhead of an extra preCommit message. We lose front-end
 353         // coordination of preCommit across shards in case of failure but preCommit should not
 354         // normally fail since we ensure only one concurrent 3-phase commit.
 355
 356         try {
 357             cohortEntry.preCommit();
 358
 359             cohortEntry.getShard().continueCommit(cohortEntry);
 360
 361             cohortEntry.updateLastAccessTime();
 362
 363             success = true;
 364         } catch (Exception e) {
 365             log.error("{} An exception occurred while preCommitting transaction {}",
 366                     name, cohortEntry.getTransactionID(), e);
 367             cohortEntry.getReplySender().tell(new Failure(e), cohortEntry.getShard().self());
 368
 369             currentTransactionComplete(cohortEntry.getTransactionID(), true);
 370         }
 371
 372         return success;
 373     }
 374
 375     /**
 376      * This method handles the preCommit and commit phases for a transaction.
 377      *
 378      * @param transactionID the ID of the transaction to commit
 379      * @param sender the actor to which to send the response
 380      * @param shard the transaction's shard actor
 381      * @return true if the transaction was successfully prepared, false otherwise.
 382      */
 383     boolean handleCommit(final String transactionID, final ActorRef sender, final Shard shard) {
 384         // Get the current in-progress cohort entry in the commitCoordinator if it corresponds to
 385         // this transaction.
 386         final CohortEntry cohortEntry = getCohortEntryIfCurrent(transactionID);
 387         if(cohortEntry == null) {
 388             // We're not the current Tx - the Tx was likely expired b/c it took too long in
 389             // between the canCommit and commit messages.
 390             IllegalStateException ex = new IllegalStateException(
 391                     String.format("%s: Cannot commit transaction %s - it is not the current transaction",
 392                             name, transactionID));
 393             log.error(ex.getMessage());
 394             sender.tell(new Failure(ex), shard.self());
 395             return false;
 396         }
 397
 398         cohortEntry.setReplySender(sender);
 399         return doCommit(cohortEntry);
 400     }
 401
 402     void handleAbort(final String transactionID, final ActorRef sender, final Shard shard) {
 403         CohortEntry cohortEntry = getCohortEntryIfCurrent(transactionID);
 404         if(cohortEntry != null) {
 405             // We don't remove the cached cohort entry here (ie pass false) in case the Tx was
 406             // aborted during replication in which case we may still commit locally if replication
 407             // succeeds.
 408             currentTransactionComplete(transactionID, false);
 409         } else {
 410             cohortEntry = getAndRemoveCohortEntry(transactionID);
 411         }
 412
 413         if(cohortEntry == null) {
 414             return;
 415         }
 416
 417         log.debug("{}: Aborting transaction {}", name, transactionID);
 418
 419         final ActorRef self = shard.getSelf();
 420         try {
 421             cohortEntry.abort();
 422
 423             shard.getShardMBean().incrementAbortTransactionsCount();
 424
 425             if(sender != null) {
 426                 sender.tell(AbortTransactionReply.instance(cohortEntry.getClientVersion()).toSerializable(), self);
 427             }
 428         } catch (Exception e) {
 429             log.error("{}: An exception happened during abort", name, e);
 430
 431             if(sender != null) {
 432                 sender.tell(new Failure(e), self);
 433             }
 434         }
 435     }
 436
 437     void checkForExpiredTransactions(final long timeout, final Shard shard) {
 438         CohortEntry cohortEntry = getCurrentCohortEntry();
 439         if(cohortEntry != null) {
 440             if(cohortEntry.isExpired(timeout)) {
 441                 log.warn("{}: Current transaction {} has timed out after {} ms - aborting",
 442                         name, cohortEntry.getTransactionID(), timeout);
 443
 444                 handleAbort(cohortEntry.getTransactionID(), null, shard);
 445             }
 446         }
 447
 448         cleanupExpiredCohortEntries();
 449     }
 450
 451     void abortPendingTransactions(final String reason, final Shard shard) {
 452         if(currentCohortEntry == null && queuedCohortEntries.isEmpty()) {
 453             return;
 454         }
 455
 456         List<CohortEntry> cohortEntries = new ArrayList<>();
 457
 458         if(currentCohortEntry != null) {
 459             cohortEntries.add(currentCohortEntry);
 460             currentCohortEntry = null;
 461         }
 462
 463         cohortEntries.addAll(queuedCohortEntries);
 464         queuedCohortEntries.clear();
 465
 466         for(CohortEntry cohortEntry: cohortEntries) {
 467             if(cohortEntry.getReplySender() != null) {
 468                 cohortEntry.getReplySender().tell(new Failure(new RuntimeException(reason)), shard.self());
 469             }
 470         }
 471     }
 472
 473     /**
 474      * Returns the cohort entry for the Tx commit currently in progress if the given transaction ID
 475      * matches the current entry.
 476      *
 477      * @param transactionID the ID of the transaction
 478      * @return the current CohortEntry or null if the given transaction ID does not match the
 479      *         current entry.
 480      */
 481     CohortEntry getCohortEntryIfCurrent(String transactionID) {
 482         if(isCurrentTransaction(transactionID)) {
 483             return currentCohortEntry;
 484         }
 485
 486         return null;
 487     }
 488
 489     CohortEntry getCurrentCohortEntry() {
 490         return currentCohortEntry;
 491     }
 492
 493     CohortEntry getAndRemoveCohortEntry(String transactionID) {
 494         return cohortCache.remove(transactionID);
 495     }
 496
 497     boolean isCurrentTransaction(String transactionID) {
 498         return currentCohortEntry != null &&
 499                 currentCohortEntry.getTransactionID().equals(transactionID);
 500     }
 501
 502     /**
 503      * This method is called when a transaction is complete, successful or not. If the given
 504      * given transaction ID matches the current in-progress transaction, the next cohort entry,
 505      * if any, is dequeued and processed.
 506      *
 507      * @param transactionID the ID of the completed transaction
 508      * @param removeCohortEntry if true the CohortEntry for the transaction is also removed from
 509      *        the cache.
 510      */
 511     void currentTransactionComplete(String transactionID, boolean removeCohortEntry) {
 512         if(removeCohortEntry) {
 513             cohortCache.remove(transactionID);
 514         }
 515
 516         if(isCurrentTransaction(transactionID)) {
 517             currentCohortEntry = null;
 518
 519             log.debug("{}: currentTransactionComplete: {}", name, transactionID);
 520
 521             maybeProcessNextCohortEntry();
 522         }
 523     }
 524
 525     private void maybeProcessNextCohortEntry() {
 526         // Check if there's a next cohort entry waiting in the queue and if it is ready to commit. Also
 527         // clean out expired entries.
 528         Iterator<CohortEntry> iter = queuedCohortEntries.iterator();
 529         while(iter.hasNext()) {
 530             CohortEntry next = iter.next();
 531             if(next.isReadyToCommit()) {
 532                 if(currentCohortEntry == null) {
 533                     if(log.isDebugEnabled()) {
 534                         log.debug("{}: Next entry to canCommit {}", name, next);
 535                     }
 536
 537                     iter.remove();
 538                     currentCohortEntry = next;
 539                     currentCohortEntry.updateLastAccessTime();
 540                     doCanCommit(currentCohortEntry);
 541                 }
 542
 543                 break;
 544             } else if(next.isExpired(cacheExpiryTimeoutInMillis)) {
 545                 log.warn("{}: canCommit for transaction {} was not received within {} ms - entry removed from cache",
 546                         name, next.getTransactionID(), cacheExpiryTimeoutInMillis);
 547             } else if(!next.isAborted()) {
 548                 break;
 549             }
 550
 551             iter.remove();
 552             cohortCache.remove(next.getTransactionID());
 553         }
 554
 555         maybeRunOperationOnPendingTransactionsComplete();
 556     }
 557
 558     void cleanupExpiredCohortEntries() {
 559         maybeProcessNextCohortEntry();
 560     }
 561
 562     void setRunOnPendingTransactionsComplete(Runnable operation) {
 563         runOnPendingTransactionsComplete = operation;
 564         maybeRunOperationOnPendingTransactionsComplete();
 565     }
 566
 567     private void maybeRunOperationOnPendingTransactionsComplete() {
 568         if(runOnPendingTransactionsComplete != null && currentCohortEntry == null && queuedCohortEntries.isEmpty()) {
 569             log.debug("{}: Pending transactions complete - running operation {}", name, runOnPendingTransactionsComplete);
 570
 571             runOnPendingTransactionsComplete.run();
 572             runOnPendingTransactionsComplete = null;
 573         }
 574     }
 575
 576     @VisibleForTesting
 577     void setCohortDecorator(CohortDecorator cohortDecorator) {
 578         this.cohortDecorator = cohortDecorator;
 579     }
 580
 581     static class CohortEntry {
 582         private final String transactionID;
 583         private ShardDataTreeCohort cohort;
 584         private final ReadWriteShardDataTreeTransaction transaction;
 585         private RuntimeException lastBatchedModificationsException;
 586         private ActorRef replySender;
 587         private Shard shard;
 588         private boolean doImmediateCommit;
 589         private final Stopwatch lastAccessTimer = Stopwatch.createStarted();
 590         private int totalBatchedModificationsReceived;
 591         private boolean aborted;
 592         private final short clientVersion;
 593
 594         CohortEntry(String transactionID, ReadWriteShardDataTreeTransaction transaction, short clientVersion) {
 595             this.transaction = Preconditions.checkNotNull(transaction);
 596             this.transactionID = transactionID;
 597             this.clientVersion = clientVersion;
 598         }
 599
 600         CohortEntry(String transactionID, ShardDataTreeCohort cohort, short clientVersion) {
 601             this.transactionID = transactionID;
 602             this.cohort = cohort;
 603             this.transaction = null;
 604             this.clientVersion = clientVersion;
 605         }
 606
 607         void updateLastAccessTime() {
 608             lastAccessTimer.reset();
 609             lastAccessTimer.start();
 610         }
 611
 612         String getTransactionID() {
 613             return transactionID;
 614         }
 615
 616         short getClientVersion() {
 617             return clientVersion;
 618         }
 619
 620         DataTreeCandidate getCandidate() {
 621             return cohort.getCandidate();
 622         }
 623
 624         int getTotalBatchedModificationsReceived() {
 625             return totalBatchedModificationsReceived;
 626         }
 627
 628         RuntimeException getLastBatchedModificationsException() {
 629             return lastBatchedModificationsException;
 630         }
 631
 632         void applyModifications(Iterable<Modification> modifications) {
 633             totalBatchedModificationsReceived++;
 634             if(lastBatchedModificationsException == null) {
 635                 for (Modification modification : modifications) {
 636                         try {
 637                             modification.apply(transaction.getSnapshot());
 638                         } catch (RuntimeException e) {
 639                             lastBatchedModificationsException = e;
 640                             throw e;
 641                         }
 642                 }
 643             }
 644         }
 645
 646         boolean canCommit() throws InterruptedException, ExecutionException {
 647             // We block on the future here (and also preCommit(), commit(), abort()) so we don't have to worry
 648             // about possibly accessing our state on a different thread outside of our dispatcher.
 649             // TODO: the ShardDataTreeCohort returns immediate Futures anyway which begs the question - why
 650             // bother even returning Futures from ShardDataTreeCohort if we have to treat them synchronously
 651             // anyway?. The Futures are really a remnant from when we were using the InMemoryDataBroker.
 652             return cohort.canCommit().get();
 653         }
 654
 655         void preCommit() throws InterruptedException, ExecutionException {
 656             cohort.preCommit().get();
 657         }
 658
 659         void commit() throws InterruptedException, ExecutionException {
 660             cohort.commit().get();
 661         }
 662
 663         void abort() throws InterruptedException, ExecutionException {
 664             aborted = true;
 665             cohort.abort().get();
 666         }
 667
 668         void ready(CohortDecorator cohortDecorator, boolean doImmediateCommit) {
 669             Preconditions.checkState(cohort == null, "cohort was already set");
 670
 671             setDoImmediateCommit(doImmediateCommit);
 672
 673             cohort = transaction.ready();
 674
 675             if(cohortDecorator != null) {
 676                 // Call the hook for unit tests.
 677                 cohort = cohortDecorator.decorate(transactionID, cohort);
 678             }
 679         }
 680
 681         boolean isReadyToCommit() {
 682             return replySender != null;
 683         }
 684
 685         boolean isExpired(long expireTimeInMillis) {
 686             return lastAccessTimer.elapsed(TimeUnit.MILLISECONDS) >= expireTimeInMillis;
 687         }
 688
 689         boolean isDoImmediateCommit() {
 690             return doImmediateCommit;
 691         }
 692
 693         void setDoImmediateCommit(boolean doImmediateCommit) {
 694             this.doImmediateCommit = doImmediateCommit;
 695         }
 696
 697         ActorRef getReplySender() {
 698             return replySender;
 699         }
 700
 701         void setReplySender(ActorRef replySender) {
 702             this.replySender = replySender;
 703         }
 704
 705         Shard getShard() {
 706             return shard;
 707         }
 708
 709         void setShard(Shard shard) {
 710             this.shard = shard;
 711         }
 712
 713
 714         boolean isAborted() {
 715             return aborted;
 716         }
 717
 718         @Override
 719         public String toString() {
 720             StringBuilder builder = new StringBuilder();
 721             builder.append("CohortEntry [transactionID=").append(transactionID).append(", doImmediateCommit=")
 722                     .append(doImmediateCommit).append("]");
 723             return builder.toString();
 724         }
 725     }
 726 }