opendaylight/config/config-manager/src/main/java/org/opendaylight/controller/config/manager/impl/ConfigRegistryImpl.java

   1 /*
   2  * Copyright (c) 2013 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 package org.opendaylight.controller.config.manager.impl;
   9
  10 import org.opendaylight.controller.config.api.ConflictingVersionException;
  11 import org.opendaylight.controller.config.api.ModuleIdentifier;
  12 import org.opendaylight.controller.config.api.RuntimeBeanRegistratorAwareModule;
  13 import org.opendaylight.controller.config.api.ValidationException;
  14 import org.opendaylight.controller.config.api.jmx.CommitStatus;
  15 import org.opendaylight.controller.config.api.jmx.ObjectNameUtil;
  16 import org.opendaylight.controller.config.manager.impl.dynamicmbean.DynamicReadableWrapper;
  17 import org.opendaylight.controller.config.manager.impl.factoriesresolver.HierarchicalConfigMBeanFactoriesHolder;
  18 import org.opendaylight.controller.config.manager.impl.factoriesresolver.ModuleFactoriesResolver;
  19 import org.opendaylight.controller.config.manager.impl.jmx.BaseJMXRegistrator;
  20 import org.opendaylight.controller.config.manager.impl.jmx.ModuleJMXRegistrator;
  21 import org.opendaylight.controller.config.manager.impl.jmx.RootRuntimeBeanRegistratorImpl;
  22 import org.opendaylight.controller.config.manager.impl.jmx.TransactionJMXRegistrator;
  23 import org.opendaylight.controller.config.manager.impl.osgi.BeanToOsgiServiceManager;
  24 import org.opendaylight.controller.config.manager.impl.osgi.BeanToOsgiServiceManager.OsgiRegistration;
  25 import org.opendaylight.controller.config.manager.impl.util.LookupBeansUtil;
  26 import org.opendaylight.controller.config.spi.Module;
  27 import org.opendaylight.controller.config.spi.ModuleFactory;
  28 import org.osgi.framework.BundleContext;
  29 import org.slf4j.Logger;
  30 import org.slf4j.LoggerFactory;
  31
  32 import javax.annotation.concurrent.GuardedBy;
  33 import javax.annotation.concurrent.NotThreadSafe;
  34 import javax.annotation.concurrent.ThreadSafe;
  35 import javax.management.InstanceAlreadyExistsException;
  36 import javax.management.InstanceNotFoundException;
  37 import javax.management.MBeanServer;
  38 import javax.management.MBeanServerFactory;
  39 import javax.management.ObjectName;
  40 import java.util.ArrayList;
  41 import java.util.Collection;
  42 import java.util.Collections;
  43 import java.util.HashMap;
  44 import java.util.Iterator;
  45 import java.util.LinkedList;
  46 import java.util.List;
  47 import java.util.Map;
  48 import java.util.Map.Entry;
  49 import java.util.Set;
  50
  51 /**
  52  * Singleton that is responsible for creating and committing Config
  53  * Transactions. It is registered in Platform MBean Server.
  54  */
  55 @ThreadSafe
  56 public class ConfigRegistryImpl implements AutoCloseable, ConfigRegistryImplMXBean {
  57     private static final Logger logger = LoggerFactory.getLogger(ConfigRegistryImpl.class);
  58
  59     private final ModuleFactoriesResolver resolver;
  60     private final MBeanServer configMBeanServer;
  61
  62     @GuardedBy("this")
  63     private final BundleContext bundleContext;
  64
  65     @GuardedBy("this")
  66     private long version = 0;
  67     @GuardedBy("this")
  68     private long versionCounter = 0;
  69
  70     /**
  71      * Contains current configuration in form of {moduleName:{instanceName,read
  72      * only module}} for copying state to new transaction. Each running module
  73      * is present just once, no matter how many interfaces it exposes.
  74      */
  75     @GuardedBy("this")
  76     private final ConfigHolder currentConfig = new ConfigHolder();
  77
  78     /**
  79      * Will return true unless there was a transaction that succeeded during
  80      * validation but failed in second phase of commit. In this case the server
  81      * is unstable and its state is undefined.
  82      */
  83     @GuardedBy("this")
  84     private boolean isHealthy = true;
  85
  86     /**
  87      * Holds Map<transactionName, transactionController> and purges it each time
  88      * its content is requested.
  89      */
  90     @GuardedBy("this")
  91     private final TransactionsHolder transactionsHolder = new TransactionsHolder();
  92
  93     private final BaseJMXRegistrator baseJMXRegistrator;
  94
  95     private final BeanToOsgiServiceManager beanToOsgiServiceManager;
  96
  97     // internal jmx server for read only beans
  98     private final MBeanServer registryMBeanServer;
  99     // internal jmx server shared by all transactions
 100     private final MBeanServer transactionsMBeanServer;
 101
 102     @GuardedBy("this")
 103     private List<ModuleFactory> lastListOfFactories = Collections.emptyList();
 104
 105     // constructor
 106     public ConfigRegistryImpl(ModuleFactoriesResolver resolver,
 107             BundleContext bundleContext, MBeanServer configMBeanServer) {
 108         this(resolver, bundleContext, configMBeanServer,
 109                 new BaseJMXRegistrator(configMBeanServer));
 110     }
 111
 112     // constructor
 113     public ConfigRegistryImpl(ModuleFactoriesResolver resolver,
 114             BundleContext bundleContext, MBeanServer configMBeanServer,
 115             BaseJMXRegistrator baseJMXRegistrator) {
 116         this.resolver = resolver;
 117         this.beanToOsgiServiceManager = new BeanToOsgiServiceManager();
 118         this.bundleContext = bundleContext;
 119         this.configMBeanServer = configMBeanServer;
 120         this.baseJMXRegistrator = baseJMXRegistrator;
 121         this.registryMBeanServer = MBeanServerFactory
 122                 .createMBeanServer("ConfigRegistry" + configMBeanServer.getDefaultDomain());
 123         this.transactionsMBeanServer = MBeanServerFactory
 124                 .createMBeanServer("ConfigTransactions" + configMBeanServer.getDefaultDomain());
 125     }
 126
 127     /**
 128      * Create new {@link ConfigTransactionControllerImpl }
 129      */
 130     @Override
 131     public synchronized ObjectName beginConfig() {
 132         return beginConfig(false);
 133     }
 134
 135     /**
 136      * @param blankTransaction true if this transaction is created automatically by
 137      *                         org.opendaylight.controller.config.manager.impl.osgi.BlankTransactionServiceTracker
 138      */
 139     public synchronized ObjectName beginConfig(boolean blankTransaction) {
 140         return beginConfigInternal(blankTransaction).getControllerObjectName();
 141     }
 142
 143     private synchronized ConfigTransactionControllerInternal beginConfigInternal(boolean blankTransaction) {
 144         versionCounter++;
 145         String transactionName = "ConfigTransaction-" + version + "-" + versionCounter;
 146         TransactionJMXRegistrator transactionRegistrator = baseJMXRegistrator
 147                 .createTransactionJMXRegistrator(transactionName);
 148         Map<String, Map.Entry<ModuleFactory, BundleContext>> allCurrentFactories = Collections.unmodifiableMap(resolver.getAllFactories());
 149         ConfigTransactionControllerInternal transactionController = new ConfigTransactionControllerImpl(
 150                 transactionName, transactionRegistrator, version,
 151                 versionCounter, allCurrentFactories, transactionsMBeanServer, configMBeanServer, blankTransaction);
 152         try {
 153             transactionRegistrator.registerMBean(transactionController, transactionController.getControllerObjectName());
 154         } catch (InstanceAlreadyExistsException e) {
 155             throw new IllegalStateException(e);
 156         }
 157
 158         transactionController.copyExistingModulesAndProcessFactoryDiff(currentConfig.getEntries(), lastListOfFactories);
 159
 160         transactionsHolder.add(transactionName, transactionController);
 161         return transactionController;
 162     }
 163
 164     /**
 165      * {@inheritDoc}
 166      */
 167     @Override
 168     public synchronized CommitStatus commitConfig(ObjectName transactionControllerON)
 169             throws ConflictingVersionException, ValidationException {
 170         final String transactionName = ObjectNameUtil
 171                 .getTransactionName(transactionControllerON);
 172         logger.info("About to commit {}. Current parentVersion: {}, versionCounter {}", transactionName, version, versionCounter);
 173
 174         // find ConfigTransactionController
 175         Map<String, ConfigTransactionControllerInternal> transactions = transactionsHolder.getCurrentTransactions();
 176         ConfigTransactionControllerInternal configTransactionController = transactions.get(transactionName);
 177         if (configTransactionController == null) {
 178             throw new IllegalArgumentException(String.format(
 179                     "Transaction with name '%s' not found", transactionName));
 180         }
 181         // check optimistic lock
 182         if (version != configTransactionController.getParentVersion()) {
 183             throw new ConflictingVersionException(
 184                     String.format(
 185                             "Optimistic lock failed. Expected parent version %d, was %d",
 186                             version,
 187                             configTransactionController.getParentVersion()));
 188         }
 189         // optimistic lock ok
 190
 191         CommitInfo commitInfo = configTransactionController.validateBeforeCommitAndLockTransaction();
 192         lastListOfFactories = Collections.unmodifiableList(configTransactionController.getCurrentlyRegisteredFactories());
 193         // non recoverable from here:
 194         try {
 195             return secondPhaseCommit(
 196                     configTransactionController, commitInfo);
 197         } catch (Throwable t) { // some libs throw Errors: e.g.
 198                                 // javax.xml.ws.spi.FactoryFinder$ConfigurationError
 199             isHealthy = false;
 200             logger.error("Configuration Transaction failed on 2PC, server is unhealthy", t);
 201             if (t instanceof RuntimeException) {
 202                 throw (RuntimeException) t;
 203             } else if (t instanceof Error) {
 204                 throw (Error) t;
 205             } else {
 206                 throw new RuntimeException(t);
 207             }
 208         }
 209     }
 210
 211     private CommitStatus secondPhaseCommit(ConfigTransactionControllerInternal configTransactionController,
 212                                            CommitInfo commitInfo) {
 213
 214         // close instances which were destroyed by the user, including
 215         // (hopefully) runtime beans
 216         for (DestroyedModule toBeDestroyed : commitInfo
 217                 .getDestroyedFromPreviousTransactions()) {
 218             toBeDestroyed.close(); // closes instance (which should close
 219                                    // runtime jmx registrator),
 220             // also closes osgi registration and ModuleJMXRegistrator
 221             // registration
 222             currentConfig.remove(toBeDestroyed.getIdentifier());
 223         }
 224
 225         // set RuntimeBeanRegistrators on beans implementing
 226         // RuntimeBeanRegistratorAwareModule, each module
 227         // should have exactly one runtime jmx registrator.
 228         Map<ModuleIdentifier, RootRuntimeBeanRegistratorImpl> runtimeRegistrators = new HashMap<>();
 229         for (ModuleInternalTransactionalInfo entry : commitInfo.getCommitted()
 230                 .values()) {
 231             RootRuntimeBeanRegistratorImpl runtimeBeanRegistrator;
 232             if (entry.hasOldModule() == false) {
 233                 runtimeBeanRegistrator = baseJMXRegistrator
 234                         .createRuntimeBeanRegistrator(entry.getIdentifier());
 235             } else {
 236                 // reuse old JMX registrator
 237                 runtimeBeanRegistrator = entry.getOldInternalInfo()
 238                         .getRuntimeBeanRegistrator();
 239             }
 240             // set runtime jmx registrator if required
 241             Module module = entry.getModule();
 242             if (module instanceof RuntimeBeanRegistratorAwareModule) {
 243                 ((RuntimeBeanRegistratorAwareModule) module)
 244                         .setRuntimeBeanRegistrator(runtimeBeanRegistrator);
 245             }
 246             // save it to info so it is accessible afterwards
 247             runtimeRegistrators.put(entry.getIdentifier(), runtimeBeanRegistrator);
 248         }
 249
 250         // can register runtime beans
 251         List<ModuleIdentifier> orderedModuleIdentifiers = configTransactionController
 252                 .secondPhaseCommit();
 253
 254         // copy configuration to read only mode
 255         List<ObjectName> newInstances = new LinkedList<>();
 256         List<ObjectName> reusedInstances = new LinkedList<>();
 257         List<ObjectName> recreatedInstances = new LinkedList<>();
 258
 259         Map<Module, ModuleInternalInfo> newConfigEntries = new HashMap<>();
 260
 261         int orderingIdx = 0;
 262         for (ModuleIdentifier moduleIdentifier : orderedModuleIdentifiers) {
 263             ModuleInternalTransactionalInfo entry = commitInfo.getCommitted()
 264                     .get(moduleIdentifier);
 265             if (entry == null)
 266                 throw new NullPointerException("Module not found "
 267                         + moduleIdentifier);
 268             Module module = entry.getModule();
 269             ObjectName primaryReadOnlyON = ObjectNameUtil
 270                     .createReadOnlyModuleON(moduleIdentifier);
 271
 272             // determine if current instance was recreated or reused or is new
 273
 274             // rules for closing resources:
 275             // osgi registration - will be reused if possible.
 276             // module jmx registration - will be (re)created every time, needs
 277             // to be closed here
 278             // runtime jmx registration - should be taken care of by module
 279             // itself
 280             // instance - is closed only if it was destroyed
 281             ModuleJMXRegistrator newModuleJMXRegistrator = baseJMXRegistrator
 282                     .createModuleJMXRegistrator();
 283
 284             OsgiRegistration osgiRegistration = null;
 285             if (entry.hasOldModule()) {
 286                 ModuleInternalInfo oldInternalInfo = entry.getOldInternalInfo();
 287                 DynamicReadableWrapper oldReadableConfigBean = oldInternalInfo
 288                         .getReadableModule();
 289                 currentConfig.remove(entry.getIdentifier());
 290
 291                 // test if old instance == new instance
 292                 if (oldReadableConfigBean.getInstance().equals(module.getInstance())) {
 293                     // reused old instance:
 294                     // wrap in readable dynamic mbean
 295                     reusedInstances.add(primaryReadOnlyON);
 296                     osgiRegistration = oldInternalInfo.getOsgiRegistration();
 297                 } else {
 298                     // recreated instance:
 299                     // it is responsibility of module to call the old instance -
 300                     // we just need to unregister configbean
 301                     recreatedInstances.add(primaryReadOnlyON);
 302
 303                     // close old osgi registration
 304                     oldInternalInfo.getOsgiRegistration().close();
 305                 }
 306
 307                 // close old module jmx registrator
 308                 oldInternalInfo.getModuleJMXRegistrator().close();
 309             } else {
 310                 // new instance:
 311                 // wrap in readable dynamic mbean
 312                 newInstances.add(primaryReadOnlyON);
 313             }
 314
 315             DynamicReadableWrapper newReadableConfigBean = new DynamicReadableWrapper(
 316                     module, module.getInstance(), moduleIdentifier,
 317                     registryMBeanServer, configMBeanServer);
 318
 319             // register to JMX
 320             try {
 321                 newModuleJMXRegistrator.registerMBean(newReadableConfigBean,
 322                         primaryReadOnlyON);
 323             } catch (InstanceAlreadyExistsException e) {
 324                 throw new IllegalStateException(e);
 325             }
 326
 327             // register to OSGi
 328             if (osgiRegistration == null) {
 329                 ModuleFactory moduleFactory = entry.getModuleFactory();
 330                 if(moduleFactory != null) {
 331                     BundleContext bc = configTransactionController.
 332                             getModuleFactoryBundleContext(moduleFactory.getImplementationName());
 333                     osgiRegistration = beanToOsgiServiceManager.registerToOsgi(module.getClass(),
 334                             newReadableConfigBean.getInstance(), entry.getIdentifier(), bc);
 335                 } else {
 336                     throw new NullPointerException(entry.getIdentifier().getFactoryName() + " ModuleFactory not found.");
 337                 }
 338
 339             }
 340
 341             RootRuntimeBeanRegistratorImpl runtimeBeanRegistrator = runtimeRegistrators
 342                     .get(entry.getIdentifier());
 343             ModuleInternalInfo newInfo = new ModuleInternalInfo(
 344                     entry.getIdentifier(), newReadableConfigBean, osgiRegistration,
 345                     runtimeBeanRegistrator, newModuleJMXRegistrator,
 346                     orderingIdx, entry.isDefaultBean());
 347
 348             newConfigEntries.put(module, newInfo);
 349             orderingIdx++;
 350         }
 351         currentConfig.addAll(newConfigEntries.values());
 352
 353         // update version
 354         version = configTransactionController.getVersion();
 355         return new CommitStatus(newInstances, reusedInstances,
 356                 recreatedInstances);
 357     }
 358
 359     /**
 360      * {@inheritDoc}
 361      */
 362     @Override
 363     public synchronized List<ObjectName> getOpenConfigs() {
 364         Map<String, ConfigTransactionControllerInternal> transactions = transactionsHolder
 365                 .getCurrentTransactions();
 366         List<ObjectName> result = new ArrayList<>(transactions.size());
 367         for (ConfigTransactionControllerInternal configTransactionController : transactions
 368                 .values()) {
 369             result.add(configTransactionController.getControllerObjectName());
 370         }
 371         return result;
 372     }
 373
 374     /**
 375      * Abort open transactions and unregister read only modules. Since this
 376      * class is not responsible for registering itself under
 377      * {@link org.opendaylight.controller.config.api.ConfigRegistry#OBJECT_NAME}, it will not unregister itself
 378      * here.
 379      */
 380     @Override
 381     public synchronized void close() {
 382         // abort transactions
 383         Map<String, ConfigTransactionControllerInternal> transactions = transactionsHolder
 384                 .getCurrentTransactions();
 385         for (ConfigTransactionControllerInternal configTransactionController : transactions
 386                 .values()) {
 387             try {
 388                 configTransactionController.abortConfig();
 389             } catch (RuntimeException e) {
 390                 logger.warn("Ignoring exception while aborting {}",
 391                         configTransactionController, e);
 392             }
 393         }
 394
 395         // destroy all live objects one after another in order of the dependency
 396         // hierarchy
 397         List<DestroyedModule> destroyedModules = currentConfig
 398                 .getModulesToBeDestroyed();
 399         for (DestroyedModule destroyedModule : destroyedModules) {
 400             destroyedModule.close();
 401         }
 402         // unregister MBeans that failed to unregister properly
 403         baseJMXRegistrator.close();
 404         // remove jmx servers
 405         MBeanServerFactory.releaseMBeanServer(registryMBeanServer);
 406         MBeanServerFactory.releaseMBeanServer(transactionsMBeanServer);
 407
 408     }
 409
 410     /**
 411      * {@inheritDoc}
 412      */
 413     @Override
 414     public long getVersion() {
 415         return version;
 416     }
 417
 418     /**
 419      * {@inheritDoc}
 420      */
 421     @Override
 422     public Set<String> getAvailableModuleNames() {
 423         return new HierarchicalConfigMBeanFactoriesHolder(
 424                 resolver.getAllFactories()).getModuleNames();
 425     }
 426
 427     /**
 428      * {@inheritDoc}
 429      */
 430     @Override
 431     public boolean isHealthy() {
 432         return isHealthy;
 433     }
 434
 435     // filtering methods
 436
 437     /**
 438      * {@inheritDoc}
 439      */
 440     @Override
 441     public Set<ObjectName> lookupConfigBeans() {
 442         return lookupConfigBeans("*", "*");
 443     }
 444
 445     /**
 446      * {@inheritDoc}
 447      */
 448     @Override
 449     public Set<ObjectName> lookupConfigBeans(String moduleName) {
 450         return lookupConfigBeans(moduleName, "*");
 451     }
 452
 453     /**
 454      * {@inheritDoc}
 455      */
 456     @Override
 457     public ObjectName lookupConfigBean(String moduleName, String instanceName)
 458             throws InstanceNotFoundException {
 459         return LookupBeansUtil.lookupConfigBean(this, moduleName, instanceName);
 460     }
 461
 462     /**
 463      * {@inheritDoc}
 464      */
 465     @Override
 466     public Set<ObjectName> lookupConfigBeans(String moduleName,
 467             String instanceName) {
 468         ObjectName namePattern = ObjectNameUtil.createModulePattern(moduleName,
 469                 instanceName);
 470         return baseJMXRegistrator.queryNames(namePattern, null);
 471     }
 472
 473     /**
 474      * {@inheritDoc}
 475      */
 476     @Override
 477     public Set<ObjectName> lookupRuntimeBeans() {
 478         return lookupRuntimeBeans("*", "*");
 479     }
 480
 481     /**
 482      * {@inheritDoc}
 483      */
 484     @Override
 485     public Set<ObjectName> lookupRuntimeBeans(String moduleName,
 486             String instanceName) {
 487         if (moduleName == null)
 488             moduleName = "*";
 489         if (instanceName == null)
 490             instanceName = "*";
 491         ObjectName namePattern = ObjectNameUtil.createRuntimeBeanPattern(
 492                 moduleName, instanceName);
 493         return baseJMXRegistrator.queryNames(namePattern, null);
 494     }
 495
 496 }
 497
 498 /**
 499  * Holds currently running modules
 500  */
 501 @NotThreadSafe
 502 class ConfigHolder {
 503     private final Map<ModuleIdentifier, ModuleInternalInfo> currentConfig = new HashMap<>();
 504
 505     /**
 506      * Add all modules to the internal map. Also add service instance to OSGi
 507      * Service Registry.
 508      */
 509     public void addAll(Collection<ModuleInternalInfo> configInfos) {
 510         if (currentConfig.size() > 0) {
 511             throw new IllegalStateException(
 512                     "Error - some config entries were not removed: "
 513                             + currentConfig);
 514         }
 515         for (ModuleInternalInfo configInfo : configInfos) {
 516             add(configInfo);
 517         }
 518     }
 519
 520     private void add(ModuleInternalInfo configInfo) {
 521         ModuleInternalInfo oldValue = currentConfig.put(configInfo.getName(),
 522                 configInfo);
 523         if (oldValue != null) {
 524             throw new IllegalStateException(
 525                     "Cannot overwrite module with same name:"
 526                             + configInfo.getName() + ":" + configInfo);
 527         }
 528     }
 529
 530     /**
 531      * Remove entry from current config.
 532      */
 533     public void remove(ModuleIdentifier name) {
 534         ModuleInternalInfo removed = currentConfig.remove(name);
 535         if (removed == null) {
 536             throw new IllegalStateException(
 537                     "Cannot remove from ConfigHolder - name not found:" + name);
 538         }
 539     }
 540
 541     public Collection<ModuleInternalInfo> getEntries() {
 542         return currentConfig.values();
 543     }
 544
 545     public List<DestroyedModule> getModulesToBeDestroyed() {
 546         List<DestroyedModule> result = new ArrayList<>();
 547         for (ModuleInternalInfo moduleInternalInfo : getEntries()) {
 548             result.add(moduleInternalInfo.toDestroyedModule());
 549         }
 550         Collections.sort(result);
 551         return result;
 552     }
 553 }
 554
 555 /**
 556  * Holds Map<transactionName, transactionController> and purges it each time its
 557  * content is requested.
 558  */
 559 @NotThreadSafe
 560 class TransactionsHolder {
 561     /**
 562      * This map keeps transaction names and
 563      * {@link ConfigTransactionControllerInternal} instances, because platform
 564      * MBeanServer transforms mbeans into another representation. Map is cleaned
 565      * every time current transactions are requested.
 566      *
 567      */
 568     @GuardedBy("ConfigRegistryImpl.this")
 569     private final Map<String /* transactionName */, ConfigTransactionControllerInternal> transactions = new HashMap<>();
 570
 571     /**
 572      * Can only be called from within synchronized method.
 573      */
 574     public void add(String transactionName,
 575             ConfigTransactionControllerInternal transactionController) {
 576         Object oldValue = transactions.put(transactionName,
 577                 transactionController);
 578         if (oldValue != null) {
 579             throw new IllegalStateException(
 580                     "Error: two transactions with same name");
 581         }
 582     }
 583
 584     /**
 585      * Purges closed transactions from transactions map. Can only be called from
 586      * within synchronized method. Calling this method more than once within the
 587      * method can modify the resulting map that was obtained in previous calls.
 588      *
 589      * @return current view on transactions map.
 590      */
 591     public Map<String, ConfigTransactionControllerInternal> getCurrentTransactions() {
 592         // first, remove closed transaction
 593         for (Iterator<Entry<String, ConfigTransactionControllerInternal>> it = transactions
 594                 .entrySet().iterator(); it.hasNext();) {
 595             Entry<String, ConfigTransactionControllerInternal> entry = it
 596                     .next();
 597             if (entry.getValue().isClosed()) {
 598                 it.remove();
 599             }
 600         }
 601         return Collections.unmodifiableMap(transactions);
 602     }
 603 }