Source code

001/**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.activemq.broker.region;
018
019import java.io.IOException;
020import java.util.ArrayList;
021import java.util.LinkedList;
022import java.util.List;
023import java.util.Map;
024import java.util.concurrent.CancellationException;
025import java.util.concurrent.ConcurrentHashMap;
026import java.util.concurrent.ConcurrentMap;
027import java.util.concurrent.CopyOnWriteArrayList;
028import java.util.concurrent.Future;
029import java.util.concurrent.locks.ReentrantReadWriteLock;
030
031import org.apache.activemq.advisory.AdvisorySupport;
032import org.apache.activemq.broker.BrokerService;
033import org.apache.activemq.broker.ConnectionContext;
034import org.apache.activemq.broker.ProducerBrokerExchange;
035import org.apache.activemq.broker.region.policy.DispatchPolicy;
036import org.apache.activemq.broker.region.policy.LastImageSubscriptionRecoveryPolicy;
037import org.apache.activemq.broker.region.policy.RetainedMessageSubscriptionRecoveryPolicy;
038import org.apache.activemq.broker.region.policy.SimpleDispatchPolicy;
039import org.apache.activemq.broker.region.policy.SubscriptionRecoveryPolicy;
040import org.apache.activemq.broker.util.InsertionCountList;
041import org.apache.activemq.command.ActiveMQDestination;
042import org.apache.activemq.command.ConsumerInfo;
043import org.apache.activemq.command.ExceptionResponse;
044import org.apache.activemq.command.Message;
045import org.apache.activemq.command.MessageAck;
046import org.apache.activemq.command.MessageId;
047import org.apache.activemq.command.ProducerAck;
048import org.apache.activemq.command.ProducerInfo;
049import org.apache.activemq.command.Response;
050import org.apache.activemq.command.SubscriptionInfo;
051import org.apache.activemq.filter.MessageEvaluationContext;
052import org.apache.activemq.filter.NonCachedMessageEvaluationContext;
053import org.apache.activemq.store.MessageRecoveryListener;
054import org.apache.activemq.store.TopicMessageStore;
055import org.apache.activemq.thread.Task;
056import org.apache.activemq.thread.TaskRunner;
057import org.apache.activemq.thread.TaskRunnerFactory;
058import org.apache.activemq.transaction.Synchronization;
059import org.apache.activemq.util.SubscriptionKey;
060import org.slf4j.Logger;
061import org.slf4j.LoggerFactory;
062
063/**
064 * The Topic is a destination that sends a copy of a message to every active
065 * Subscription registered.
066 */
067public class Topic extends BaseDestination implements Task {
068    protected static final Logger LOG = LoggerFactory.getLogger(Topic.class);
069    private final TopicMessageStore topicStore;
070    protected final CopyOnWriteArrayList<Subscription> consumers = new CopyOnWriteArrayList<Subscription>();
071    private final ReentrantReadWriteLock dispatchLock = new ReentrantReadWriteLock();
072    private DispatchPolicy dispatchPolicy = new SimpleDispatchPolicy();
073    private SubscriptionRecoveryPolicy subscriptionRecoveryPolicy;
074    private final ConcurrentMap<SubscriptionKey, DurableTopicSubscription> durableSubscribers = new ConcurrentHashMap<SubscriptionKey, DurableTopicSubscription>();
075    private final TaskRunner taskRunner;
076    private final LinkedList<Runnable> messagesWaitingForSpace = new LinkedList<Runnable>();
077    private final Runnable sendMessagesWaitingForSpaceTask = new Runnable() {
078        @Override
079        public void run() {
080            try {
081                Topic.this.taskRunner.wakeup();
082            } catch (InterruptedException e) {
083            }
084        };
085    };
086
087    public Topic(BrokerService brokerService, ActiveMQDestination destination, TopicMessageStore store,
088            DestinationStatistics parentStats, TaskRunnerFactory taskFactory) throws Exception {
089        super(brokerService, store, destination, parentStats);
090        this.topicStore = store;
091        subscriptionRecoveryPolicy = new RetainedMessageSubscriptionRecoveryPolicy(null);
092        this.taskRunner = taskFactory.createTaskRunner(this, "Topic  " + destination.getPhysicalName());
093    }
094
095    @Override
096    public void initialize() throws Exception {
097        super.initialize();
098        // set non default subscription recovery policy (override policyEntries)
099        if (AdvisorySupport.isMasterBrokerAdvisoryTopic(destination)) {
100            subscriptionRecoveryPolicy = new LastImageSubscriptionRecoveryPolicy();
101            setAlwaysRetroactive(true);
102        }
103        if (store != null) {
104            // AMQ-2586: Better to leave this stat at zero than to give the user
105            // misleading metrics.
106            // int messageCount = store.getMessageCount();
107            // destinationStatistics.getMessages().setCount(messageCount);
108            store.start();
109        }
110    }
111
112    @Override
113    public List<Subscription> getConsumers() {
114        synchronized (consumers) {
115            return new ArrayList<Subscription>(consumers);
116        }
117    }
118
119    public boolean lock(MessageReference node, LockOwner sub) {
120        return true;
121    }
122
123    @Override
124    public void addSubscription(ConnectionContext context, final Subscription sub) throws Exception {
125        if (!sub.getConsumerInfo().isDurable()) {
126
127            // Do a retroactive recovery if needed.
128            if (sub.getConsumerInfo().isRetroactive() || isAlwaysRetroactive()) {
129
130                // synchronize with dispatch method so that no new messages are sent
131                // while we are recovering a subscription to avoid out of order messages.
132                dispatchLock.writeLock().lock();
133                try {
134                    boolean applyRecovery = false;
135                    synchronized (consumers) {
136                        if (!consumers.contains(sub)){
137                            sub.add(context, this);
138                            consumers.add(sub);
139                            applyRecovery=true;
140                            super.addSubscription(context, sub);
141                        }
142                    }
143                    if (applyRecovery){
144                        subscriptionRecoveryPolicy.recover(context, this, sub);
145                    }
146                } finally {
147                    dispatchLock.writeLock().unlock();
148                }
149
150            } else {
151                synchronized (consumers) {
152                    if (!consumers.contains(sub)){
153                        sub.add(context, this);
154                        consumers.add(sub);
155                        super.addSubscription(context, sub);
156                    }
157                }
158            }
159        } else {
160            DurableTopicSubscription dsub = (DurableTopicSubscription) sub;
161            super.addSubscription(context, sub);
162            sub.add(context, this);
163            if(dsub.isActive()) {
164                synchronized (consumers) {
165                    boolean hasSubscription = false;
166
167                    if (consumers.size() == 0) {
168                        hasSubscription = false;
169                    } else {
170                        for (Subscription currentSub : consumers) {
171                            if (currentSub.getConsumerInfo().isDurable()) {
172                                DurableTopicSubscription dcurrentSub = (DurableTopicSubscription) currentSub;
173                                if (dcurrentSub.getSubscriptionKey().equals(dsub.getSubscriptionKey())) {
174                                    hasSubscription = true;
175                                    break;
176                                }
177                            }
178                        }
179                    }
180
181                    if (!hasSubscription) {
182                        consumers.add(sub);
183                    }
184                }
185            }
186            durableSubscribers.put(dsub.getSubscriptionKey(), dsub);
187        }
188    }
189
190    @Override
191    public void removeSubscription(ConnectionContext context, Subscription sub, long lastDeliveredSequenceId) throws Exception {
192        if (!sub.getConsumerInfo().isDurable()) {
193            super.removeSubscription(context, sub, lastDeliveredSequenceId);
194            synchronized (consumers) {
195                consumers.remove(sub);
196            }
197        }
198        sub.remove(context, this);
199    }
200
201    public void deleteSubscription(ConnectionContext context, SubscriptionKey key) throws Exception {
202        if (topicStore != null) {
203            topicStore.deleteSubscription(key.clientId, key.subscriptionName);
204            DurableTopicSubscription removed = durableSubscribers.remove(key);
205            if (removed != null) {
206                destinationStatistics.getConsumers().decrement();
207                // deactivate and remove
208                removed.deactivate(false, 0l);
209                consumers.remove(removed);
210            }
211        }
212    }
213
214    private boolean hasDurableSubChanged(SubscriptionInfo info1, ConsumerInfo info2) {
215        if (hasSelectorChanged(info1, info2)) {
216            return true;
217        }
218
219        return hasNoLocalChanged(info1, info2);
220    }
221
222    private boolean hasNoLocalChanged(SubscriptionInfo info1, ConsumerInfo info2) {
223        // Prior to V11 the broker did not store the noLocal value for durable subs.
224        if (brokerService.getStoreOpenWireVersion() >= 11) {
225            if (info1.isNoLocal() ^ info2.isNoLocal()) {
226                return true;
227            }
228        }
229
230        return false;
231    }
232
233    private boolean hasSelectorChanged(SubscriptionInfo info1, ConsumerInfo info2) {
234        if (info1.getSelector() != null ^ info2.getSelector() != null) {
235            return true;
236        }
237
238        if (info1.getSelector() != null && !info1.getSelector().equals(info2.getSelector())) {
239            return true;
240        }
241
242        return false;
243    }
244
245    public void activate(ConnectionContext context, final DurableTopicSubscription subscription) throws Exception {
246        // synchronize with dispatch method so that no new messages are sent
247        // while we are recovering a subscription to avoid out of order messages.
248        dispatchLock.writeLock().lock();
249        try {
250
251            if (topicStore == null) {
252                return;
253            }
254
255            // Recover the durable subscription.
256            String clientId = subscription.getSubscriptionKey().getClientId();
257            String subscriptionName = subscription.getSubscriptionKey().getSubscriptionName();
258            SubscriptionInfo info = topicStore.lookupSubscription(clientId, subscriptionName);
259            if (info != null) {
260                // Check to see if selector changed.
261                if (hasDurableSubChanged(info, subscription.getConsumerInfo())) {
262                    // Need to delete the subscription
263                    topicStore.deleteSubscription(clientId, subscriptionName);
264                    info = null;
265                    // Force a rebuild of the selector chain for the subscription otherwise
266                    // the stored subscription is updated but the selector expression is not
267                    // and the subscription will not behave according to the new configuration.
268                    subscription.setSelector(subscription.getConsumerInfo().getSelector());
269                    synchronized (consumers) {
270                        consumers.remove(subscription);
271                    }
272                } else {
273                    synchronized (consumers) {
274                        if (!consumers.contains(subscription)) {
275                            consumers.add(subscription);
276                        }
277                    }
278                }
279            }
280
281            // Do we need to create the subscription?
282            if (info == null) {
283                info = new SubscriptionInfo();
284                info.setClientId(clientId);
285                info.setSelector(subscription.getConsumerInfo().getSelector());
286                info.setSubscriptionName(subscriptionName);
287                info.setDestination(getActiveMQDestination());
288                info.setNoLocal(subscription.getConsumerInfo().isNoLocal());
289                // This destination is an actual destination id.
290                info.setSubscribedDestination(subscription.getConsumerInfo().getDestination());
291                // This destination might be a pattern
292                synchronized (consumers) {
293                    consumers.add(subscription);
294                    topicStore.addSubscription(info, subscription.getConsumerInfo().isRetroactive());
295                }
296            }
297
298            final MessageEvaluationContext msgContext = new NonCachedMessageEvaluationContext();
299            msgContext.setDestination(destination);
300            if (subscription.isRecoveryRequired()) {
301                topicStore.recoverSubscription(clientId, subscriptionName, new MessageRecoveryListener() {
302                    @Override
303                    public boolean recoverMessage(Message message) throws Exception {
304                        message.setRegionDestination(Topic.this);
305                        try {
306                            msgContext.setMessageReference(message);
307                            if (subscription.matches(message, msgContext)) {
308                                subscription.add(message);
309                            }
310                        } catch (IOException e) {
311                            LOG.error("Failed to recover this message {}", message, e);
312                        }
313                        return true;
314                    }
315
316                    @Override
317                    public boolean recoverMessageReference(MessageId messageReference) throws Exception {
318                        throw new RuntimeException("Should not be called.");
319                    }
320
321                    @Override
322                    public boolean hasSpace() {
323                        return true;
324                    }
325
326                    @Override
327                    public boolean isDuplicate(MessageId id) {
328                        return false;
329                    }
330                });
331            }
332        } finally {
333            dispatchLock.writeLock().unlock();
334        }
335    }
336
337    public void deactivate(ConnectionContext context, DurableTopicSubscription sub, List<MessageReference> dispatched) throws Exception {
338        synchronized (consumers) {
339            consumers.remove(sub);
340        }
341        sub.remove(context, this, dispatched);
342    }
343
344    public void recoverRetroactiveMessages(ConnectionContext context, Subscription subscription) throws Exception {
345        if (subscription.getConsumerInfo().isRetroactive()) {
346            subscriptionRecoveryPolicy.recover(context, this, subscription);
347        }
348    }
349
350    @Override
351    public void send(final ProducerBrokerExchange producerExchange, final Message message) throws Exception {
352        final ConnectionContext context = producerExchange.getConnectionContext();
353
354        final ProducerInfo producerInfo = producerExchange.getProducerState().getInfo();
355        producerExchange.incrementSend();
356        final boolean sendProducerAck = !message.isResponseRequired() && producerInfo.getWindowSize() > 0
357                && !context.isInRecoveryMode();
358
359        // There is delay between the client sending it and it arriving at the
360        // destination.. it may have expired.
361        if (message.isExpired()) {
362            broker.messageExpired(context, message, null);
363            getDestinationStatistics().getExpired().increment();
364            if (sendProducerAck) {
365                ProducerAck ack = new ProducerAck(producerInfo.getProducerId(), message.getSize());
366                context.getConnection().dispatchAsync(ack);
367            }
368            return;
369        }
370
371        if (memoryUsage.isFull()) {
372            isFull(context, memoryUsage);
373            fastProducer(context, producerInfo);
374
375            if (isProducerFlowControl() && context.isProducerFlowControl()) {
376
377                if (warnOnProducerFlowControl) {
378                    warnOnProducerFlowControl = false;
379                    LOG.info("{}, Usage Manager memory limit reached {}. Producers will be throttled to the rate at which messages are removed from this destination to prevent flooding it. See http://activemq.apache.org/producer-flow-control.html for more info.",
380                            getActiveMQDestination().getQualifiedName(), memoryUsage.getLimit());
381                }
382
383                if (!context.isNetworkConnection() && systemUsage.isSendFailIfNoSpace()) {
384                    throw new javax.jms.ResourceAllocationException("Usage Manager memory limit ("
385                            + memoryUsage.getLimit() + ") reached. Rejecting send for producer (" + message.getProducerId()
386                            + ") to prevent flooding " + getActiveMQDestination().getQualifiedName() + "."
387                            + " See http://activemq.apache.org/producer-flow-control.html for more info");
388                }
389
390                // We can avoid blocking due to low usage if the producer is sending a sync message or
391                // if it is using a producer window
392                if (producerInfo.getWindowSize() > 0 || message.isResponseRequired()) {
393                    synchronized (messagesWaitingForSpace) {
394                        messagesWaitingForSpace.add(new Runnable() {
395                            @Override
396                            public void run() {
397                                try {
398
399                                    // While waiting for space to free up... the
400                                    // message may have expired.
401                                    if (message.isExpired()) {
402                                        broker.messageExpired(context, message, null);
403                                        getDestinationStatistics().getExpired().increment();
404                                    } else {
405                                        doMessageSend(producerExchange, message);
406                                    }
407
408                                    if (sendProducerAck) {
409                                        ProducerAck ack = new ProducerAck(producerInfo.getProducerId(), message
410                                                .getSize());
411                                        context.getConnection().dispatchAsync(ack);
412                                    } else {
413                                        Response response = new Response();
414                                        response.setCorrelationId(message.getCommandId());
415                                        context.getConnection().dispatchAsync(response);
416                                    }
417
418                                } catch (Exception e) {
419                                    if (!sendProducerAck && !context.isInRecoveryMode()) {
420                                        ExceptionResponse response = new ExceptionResponse(e);
421                                        response.setCorrelationId(message.getCommandId());
422                                        context.getConnection().dispatchAsync(response);
423                                    }
424                                }
425                            }
426                        });
427
428                        registerCallbackForNotFullNotification();
429                        context.setDontSendReponse(true);
430                        return;
431                    }
432
433                } else {
434                    // Producer flow control cannot be used, so we have do the flow control
435                    // at the broker by blocking this thread until there is space available.
436
437                    if (memoryUsage.isFull()) {
438                        if (context.isInTransaction()) {
439
440                            int count = 0;
441                            while (!memoryUsage.waitForSpace(1000)) {
442                                if (context.getStopping().get()) {
443                                    throw new IOException("Connection closed, send aborted.");
444                                }
445                                if (count > 2 && context.isInTransaction()) {
446                                    count = 0;
447                                    int size = context.getTransaction().size();
448                                    LOG.warn("Waiting for space to send transacted message - transaction elements = {} need more space to commit. Message = {}", size, message);
449                                }
450                                count++;
451                            }
452                        } else {
453                            waitForSpace(
454                                    context,
455                                    producerExchange,
456                                    memoryUsage,
457                                    "Usage Manager Memory Usage limit reached. Stopping producer ("
458                                            + message.getProducerId()
459                                            + ") to prevent flooding "
460                                            + getActiveMQDestination().getQualifiedName()
461                                            + "."
462                                            + " See http://activemq.apache.org/producer-flow-control.html for more info");
463                        }
464                    }
465
466                    // The usage manager could have delayed us by the time
467                    // we unblock the message could have expired..
468                    if (message.isExpired()) {
469                        getDestinationStatistics().getExpired().increment();
470                        LOG.debug("Expired message: {}", message);
471                        return;
472                    }
473                }
474            }
475        }
476
477        doMessageSend(producerExchange, message);
478        messageDelivered(context, message);
479        if (sendProducerAck) {
480            ProducerAck ack = new ProducerAck(producerInfo.getProducerId(), message.getSize());
481            context.getConnection().dispatchAsync(ack);
482        }
483    }
484
485    /**
486     * do send the message - this needs to be synchronized to ensure messages
487     * are stored AND dispatched in the right order
488     *
489     * @param producerExchange
490     * @param message
491     * @throws IOException
492     * @throws Exception
493     */
494    synchronized void doMessageSend(final ProducerBrokerExchange producerExchange, final Message message)
495            throws IOException, Exception {
496        final ConnectionContext context = producerExchange.getConnectionContext();
497        message.setRegionDestination(this);
498        message.getMessageId().setBrokerSequenceId(getDestinationSequenceId());
499        Future<Object> result = null;
500
501        if (topicStore != null && message.isPersistent() && !canOptimizeOutPersistence()) {
502            if (systemUsage.getStoreUsage().isFull(getStoreUsageHighWaterMark())) {
503                final String logMessage = "Persistent store is Full, " + getStoreUsageHighWaterMark() + "% of "
504                        + systemUsage.getStoreUsage().getLimit() + ". Stopping producer (" + message.getProducerId()
505                        + ") to prevent flooding " + getActiveMQDestination().getQualifiedName() + "."
506                        + " See http://activemq.apache.org/producer-flow-control.html for more info";
507                if (!context.isNetworkConnection() && systemUsage.isSendFailIfNoSpace()) {
508                    throw new javax.jms.ResourceAllocationException(logMessage);
509                }
510
511                waitForSpace(context,producerExchange, systemUsage.getStoreUsage(), getStoreUsageHighWaterMark(), logMessage);
512            }
513            result = topicStore.asyncAddTopicMessage(context, message,isOptimizeStorage());
514        }
515
516        message.incrementReferenceCount();
517
518        if (context.isInTransaction()) {
519            context.getTransaction().addSynchronization(new Synchronization() {
520                @Override
521                public void afterCommit() throws Exception {
522                    // It could take while before we receive the commit
523                    // operation.. by that time the message could have
524                    // expired..
525                    if (broker.isExpired(message)) {
526                        getDestinationStatistics().getExpired().increment();
527                        broker.messageExpired(context, message, null);
528                        message.decrementReferenceCount();
529                        return;
530                    }
531                    try {
532                        dispatch(context, message);
533                    } finally {
534                        message.decrementReferenceCount();
535                    }
536                }
537
538                @Override
539                public void afterRollback() throws Exception {
540                    message.decrementReferenceCount();
541                }
542            });
543
544        } else {
545            try {
546                dispatch(context, message);
547            } finally {
548                message.decrementReferenceCount();
549            }
550        }
551
552        if (result != null && !result.isCancelled()) {
553            try {
554                result.get();
555            } catch (CancellationException e) {
556                // ignore - the task has been cancelled if the message
557                // has already been deleted
558            }
559        }
560    }
561
562    private boolean canOptimizeOutPersistence() {
563        return durableSubscribers.size() == 0;
564    }
565
566    @Override
567    public String toString() {
568        return "Topic: destination=" + destination.getPhysicalName() + ", subscriptions=" + consumers.size();
569    }
570
571    @Override
572    public void acknowledge(ConnectionContext context, Subscription sub, final MessageAck ack,
573            final MessageReference node) throws IOException {
574        if (topicStore != null && node.isPersistent()) {
575            DurableTopicSubscription dsub = (DurableTopicSubscription) sub;
576            SubscriptionKey key = dsub.getSubscriptionKey();
577            topicStore.acknowledge(context, key.getClientId(), key.getSubscriptionName(), node.getMessageId(),
578                    convertToNonRangedAck(ack, node));
579        }
580        messageConsumed(context, node);
581    }
582
583    @Override
584    public void gc() {
585    }
586
587    public Message loadMessage(MessageId messageId) throws IOException {
588        return topicStore != null ? topicStore.getMessage(messageId) : null;
589    }
590
591    @Override
592    public void start() throws Exception {
593        this.subscriptionRecoveryPolicy.start();
594        if (memoryUsage != null) {
595            memoryUsage.start();
596        }
597
598        if (getExpireMessagesPeriod() > 0 && !AdvisorySupport.isAdvisoryTopic(getActiveMQDestination())) {
599            scheduler.executePeriodically(expireMessagesTask, getExpireMessagesPeriod());
600        }
601    }
602
603    @Override
604    public void stop() throws Exception {
605        if (taskRunner != null) {
606            taskRunner.shutdown();
607        }
608        this.subscriptionRecoveryPolicy.stop();
609        if (memoryUsage != null) {
610            memoryUsage.stop();
611        }
612        if (this.topicStore != null) {
613            this.topicStore.stop();
614        }
615
616         scheduler.cancel(expireMessagesTask);
617    }
618
619    @Override
620    public Message[] browse() {
621        final List<Message> result = new ArrayList<Message>();
622        doBrowse(result, getMaxBrowsePageSize());
623        return result.toArray(new Message[result.size()]);
624    }
625
626    private void doBrowse(final List<Message> browseList, final int max) {
627        try {
628            if (topicStore != null) {
629                final List<Message> toExpire = new ArrayList<Message>();
630                topicStore.recover(new MessageRecoveryListener() {
631                    @Override
632                    public boolean recoverMessage(Message message) throws Exception {
633                        if (message.isExpired()) {
634                            toExpire.add(message);
635                        }
636                        browseList.add(message);
637                        return true;
638                    }
639
640                    @Override
641                    public boolean recoverMessageReference(MessageId messageReference) throws Exception {
642                        return true;
643                    }
644
645                    @Override
646                    public boolean hasSpace() {
647                        return browseList.size() < max;
648                    }
649
650                    @Override
651                    public boolean isDuplicate(MessageId id) {
652                        return false;
653                    }
654                });
655                final ConnectionContext connectionContext = createConnectionContext();
656                for (Message message : toExpire) {
657                    for (DurableTopicSubscription sub : durableSubscribers.values()) {
658                        if (!sub.isActive()) {
659                            messageExpired(connectionContext, sub, message);
660                        }
661                    }
662                }
663                Message[] msgs = subscriptionRecoveryPolicy.browse(getActiveMQDestination());
664                if (msgs != null) {
665                    for (int i = 0; i < msgs.length && browseList.size() < max; i++) {
666                        browseList.add(msgs[i]);
667                    }
668                }
669            }
670        } catch (Throwable e) {
671            LOG.warn("Failed to browse Topic: {}", getActiveMQDestination().getPhysicalName(), e);
672        }
673    }
674
675    @Override
676    public boolean iterate() {
677        synchronized (messagesWaitingForSpace) {
678            while (!memoryUsage.isFull() && !messagesWaitingForSpace.isEmpty()) {
679                Runnable op = messagesWaitingForSpace.removeFirst();
680                op.run();
681            }
682
683            if (!messagesWaitingForSpace.isEmpty()) {
684                registerCallbackForNotFullNotification();
685            }
686        }
687        return false;
688    }
689
690    private void registerCallbackForNotFullNotification() {
691        // If the usage manager is not full, then the task will not
692        // get called..
693        if (!memoryUsage.notifyCallbackWhenNotFull(sendMessagesWaitingForSpaceTask)) {
694            // so call it directly here.
695            sendMessagesWaitingForSpaceTask.run();
696        }
697    }
698
699    // Properties
700    // -------------------------------------------------------------------------
701
702    public DispatchPolicy getDispatchPolicy() {
703        return dispatchPolicy;
704    }
705
706    public void setDispatchPolicy(DispatchPolicy dispatchPolicy) {
707        this.dispatchPolicy = dispatchPolicy;
708    }
709
710    public SubscriptionRecoveryPolicy getSubscriptionRecoveryPolicy() {
711        return subscriptionRecoveryPolicy;
712    }
713
714    public void setSubscriptionRecoveryPolicy(SubscriptionRecoveryPolicy recoveryPolicy) {
715        if (this.subscriptionRecoveryPolicy != null && this.subscriptionRecoveryPolicy instanceof RetainedMessageSubscriptionRecoveryPolicy) {
716            // allow users to combine retained message policy with other ActiveMQ policies
717            RetainedMessageSubscriptionRecoveryPolicy policy = (RetainedMessageSubscriptionRecoveryPolicy) this.subscriptionRecoveryPolicy;
718            policy.setWrapped(recoveryPolicy);
719        } else {
720            this.subscriptionRecoveryPolicy = recoveryPolicy;
721        }
722    }
723
724    // Implementation methods
725    // -------------------------------------------------------------------------
726
727    @Override
728    public final void wakeup() {
729    }
730
731    protected void dispatch(final ConnectionContext context, Message message) throws Exception {
732        // AMQ-2586: Better to leave this stat at zero than to give the user
733        // misleading metrics.
734        // destinationStatistics.getMessages().increment();
735        destinationStatistics.getEnqueues().increment();
736        destinationStatistics.getMessageSize().addSize(message.getSize());
737        MessageEvaluationContext msgContext = null;
738
739        dispatchLock.readLock().lock();
740        try {
741            if (!subscriptionRecoveryPolicy.add(context, message)) {
742                return;
743            }
744            synchronized (consumers) {
745                if (consumers.isEmpty()) {
746                    onMessageWithNoConsumers(context, message);
747                    return;
748                }
749            }
750            msgContext = context.getMessageEvaluationContext();
751            msgContext.setDestination(destination);
752            msgContext.setMessageReference(message);
753            if (!dispatchPolicy.dispatch(message, msgContext, consumers)) {
754                onMessageWithNoConsumers(context, message);
755            }
756
757        } finally {
758            dispatchLock.readLock().unlock();
759            if (msgContext != null) {
760                msgContext.clear();
761            }
762        }
763    }
764
765    private final Runnable expireMessagesTask = new Runnable() {
766        @Override
767        public void run() {
768            List<Message> browsedMessages = new InsertionCountList<Message>();
769            doBrowse(browsedMessages, getMaxExpirePageSize());
770        }
771    };
772
773    @Override
774    public void messageExpired(ConnectionContext context, Subscription subs, MessageReference reference) {
775        broker.messageExpired(context, reference, subs);
776        // AMQ-2586: Better to leave this stat at zero than to give the user
777        // misleading metrics.
778        // destinationStatistics.getMessages().decrement();
779        destinationStatistics.getExpired().increment();
780        MessageAck ack = new MessageAck();
781        ack.setAckType(MessageAck.STANDARD_ACK_TYPE);
782        ack.setDestination(destination);
783        ack.setMessageID(reference.getMessageId());
784        try {
785            if (subs instanceof DurableTopicSubscription) {
786                ((DurableTopicSubscription)subs).removePending(reference);
787            }
788            acknowledge(context, subs, ack, reference);
789        } catch (Exception e) {
790            LOG.error("Failed to remove expired Message from the store ", e);
791        }
792    }
793
794    @Override
795    protected Logger getLog() {
796        return LOG;
797    }
798
799    protected boolean isOptimizeStorage(){
800        boolean result = false;
801
802        if (isDoOptimzeMessageStorage() && durableSubscribers.isEmpty()==false){
803                result = true;
804                for (DurableTopicSubscription s : durableSubscribers.values()) {
805                    if (s.isActive()== false){
806                        result = false;
807                        break;
808                    }
809                    if (s.getPrefetchSize()==0){
810                        result = false;
811                        break;
812                    }
813                    if (s.isSlowConsumer()){
814                        result = false;
815                        break;
816                    }
817                    if (s.getInFlightUsage() > getOptimizeMessageStoreInFlightLimit()){
818                        result = false;
819                        break;
820                    }
821                }
822        }
823        return result;
824    }
825
826    /**
827     * force a reread of the store - after transaction recovery completion
828     */
829    @Override
830    public void clearPendingMessages() {
831        dispatchLock.readLock().lock();
832        try {
833            for (DurableTopicSubscription durableTopicSubscription : durableSubscribers.values()) {
834                clearPendingAndDispatch(durableTopicSubscription);
835            }
836        } finally {
837            dispatchLock.readLock().unlock();
838        }
839    }
840
841    private void clearPendingAndDispatch(DurableTopicSubscription durableTopicSubscription) {
842        synchronized (durableTopicSubscription.pendingLock) {
843            durableTopicSubscription.pending.clear();
844            try {
845                durableTopicSubscription.dispatchPending();
846            } catch (IOException exception) {
847                LOG.warn("After clear of pending, failed to dispatch to: {}, for: {}, pending: {}", new Object[]{
848                        durableTopicSubscription,
849                        destination,
850                        durableTopicSubscription.pending }, exception);
851            }
852        }
853    }
854
855    public Map<SubscriptionKey, DurableTopicSubscription> getDurableTopicSubs() {
856        return durableSubscribers;
857    }
858}