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;
018
019import java.io.IOException;
020import java.util.ArrayList;
021import java.util.Collections;
022import java.util.HashMap;
023import java.util.Iterator;
024import java.util.LinkedList;
025import java.util.List;
026import java.util.Map;
027import java.util.Map.Entry;
028import java.util.concurrent.ExecutorService;
029import java.util.concurrent.Executors;
030import java.util.concurrent.atomic.AtomicBoolean;
031import java.util.concurrent.atomic.AtomicInteger;
032import java.util.concurrent.atomic.AtomicReference;
033
034import javax.jms.IllegalStateException;
035import javax.jms.InvalidDestinationException;
036import javax.jms.JMSException;
037import javax.jms.Message;
038import javax.jms.MessageConsumer;
039import javax.jms.MessageListener;
040import javax.jms.TransactionRolledBackException;
041
042import org.apache.activemq.blob.BlobDownloader;
043import org.apache.activemq.command.ActiveMQBlobMessage;
044import org.apache.activemq.command.ActiveMQDestination;
045import org.apache.activemq.command.ActiveMQMessage;
046import org.apache.activemq.command.ActiveMQObjectMessage;
047import org.apache.activemq.command.ActiveMQTempDestination;
048import org.apache.activemq.command.CommandTypes;
049import org.apache.activemq.command.ConsumerId;
050import org.apache.activemq.command.ConsumerInfo;
051import org.apache.activemq.command.MessageAck;
052import org.apache.activemq.command.MessageDispatch;
053import org.apache.activemq.command.MessageId;
054import org.apache.activemq.command.MessagePull;
055import org.apache.activemq.command.RemoveInfo;
056import org.apache.activemq.command.TransactionId;
057import org.apache.activemq.management.JMSConsumerStatsImpl;
058import org.apache.activemq.management.StatsCapable;
059import org.apache.activemq.management.StatsImpl;
060import org.apache.activemq.selector.SelectorParser;
061import org.apache.activemq.transaction.Synchronization;
062import org.apache.activemq.util.Callback;
063import org.apache.activemq.util.IntrospectionSupport;
064import org.apache.activemq.util.JMSExceptionSupport;
065import org.apache.activemq.util.ThreadPoolUtils;
066import org.slf4j.Logger;
067import org.slf4j.LoggerFactory;
068
069/**
070 * A client uses a <CODE>MessageConsumer</CODE> object to receive messages
071 * from a destination. A <CODE> MessageConsumer</CODE> object is created by
072 * passing a <CODE>Destination</CODE> object to a message-consumer creation
073 * method supplied by a session.
074 * <P>
075 * <CODE>MessageConsumer</CODE> is the parent interface for all message
076 * consumers.
077 * <P>
078 * A message consumer can be created with a message selector. A message selector
079 * allows the client to restrict the messages delivered to the message consumer
080 * to those that match the selector.
081 * <P>
082 * A client may either synchronously receive a message consumer's messages or
083 * have the consumer asynchronously deliver them as they arrive.
084 * <P>
085 * For synchronous receipt, a client can request the next message from a message
086 * consumer using one of its <CODE> receive</CODE> methods. There are several
087 * variations of <CODE>receive</CODE> that allow a client to poll or wait for
088 * the next message.
089 * <P>
090 * For asynchronous delivery, a client can register a
091 * <CODE>MessageListener</CODE> object with a message consumer. As messages
092 * arrive at the message consumer, it delivers them by calling the
093 * <CODE>MessageListener</CODE>'s<CODE>
094 * onMessage</CODE> method.
095 * <P>
096 * It is a client programming error for a <CODE>MessageListener</CODE> to
097 * throw an exception.
098 *
099 *
100 * @see javax.jms.MessageConsumer
101 * @see javax.jms.QueueReceiver
102 * @see javax.jms.TopicSubscriber
103 * @see javax.jms.Session
104 */
105public class ActiveMQMessageConsumer implements MessageAvailableConsumer, StatsCapable, ActiveMQDispatcher {
106
107    @SuppressWarnings("serial")
108    class PreviouslyDeliveredMap<K, V> extends HashMap<K, V> {
109        final TransactionId transactionId;
110        public PreviouslyDeliveredMap(TransactionId transactionId) {
111            this.transactionId = transactionId;
112        }
113    }
114
115    private static final Logger LOG = LoggerFactory.getLogger(ActiveMQMessageConsumer.class);
116    protected final ActiveMQSession session;
117    protected final ConsumerInfo info;
118
119    // These are the messages waiting to be delivered to the client
120    protected final MessageDispatchChannel unconsumedMessages;
121
122    // The are the messages that were delivered to the consumer but that have
123    // not been acknowledged. It's kept in reverse order since we
124    // Always walk list in reverse order.
125    protected final LinkedList<MessageDispatch> deliveredMessages = new LinkedList<MessageDispatch>();
126    // track duplicate deliveries in a transaction such that the tx integrity can be validated
127    private PreviouslyDeliveredMap<MessageId, Boolean> previouslyDeliveredMessages;
128    private int deliveredCounter;
129    private int additionalWindowSize;
130    private long redeliveryDelay;
131    private int ackCounter;
132    private int dispatchedCount;
133    private final AtomicReference<MessageListener> messageListener = new AtomicReference<MessageListener>();
134    private final JMSConsumerStatsImpl stats;
135
136    private final String selector;
137    private boolean synchronizationRegistered;
138    private final AtomicBoolean started = new AtomicBoolean(false);
139
140    private MessageAvailableListener availableListener;
141
142    private RedeliveryPolicy redeliveryPolicy;
143    private boolean optimizeAcknowledge;
144    private final AtomicBoolean deliveryingAcknowledgements = new AtomicBoolean();
145    private ExecutorService executorService;
146    private MessageTransformer transformer;
147    private boolean clearDeliveredList;
148    AtomicInteger inProgressClearRequiredFlag = new AtomicInteger(0);
149
150    private MessageAck pendingAck;
151    private long lastDeliveredSequenceId = -1;
152
153    private IOException failureError;
154
155    private long optimizeAckTimestamp = System.currentTimeMillis();
156    private long optimizeAcknowledgeTimeOut = 0;
157    private long optimizedAckScheduledAckInterval = 0;
158    private Runnable optimizedAckTask;
159    private long failoverRedeliveryWaitPeriod = 0;
160    private boolean transactedIndividualAck = false;
161    private boolean nonBlockingRedelivery = false;
162    private boolean consumerExpiryCheckEnabled = true;
163
164    /**
165     * Create a MessageConsumer
166     *
167     * @param session
168     * @param dest
169     * @param name
170     * @param selector
171     * @param prefetch
172     * @param maximumPendingMessageCount
173     * @param noLocal
174     * @param browser
175     * @param dispatchAsync
176     * @param messageListener
177     * @throws JMSException
178     */
179    public ActiveMQMessageConsumer(ActiveMQSession session, ConsumerId consumerId, ActiveMQDestination dest,
180            String name, String selector, int prefetch,
181            int maximumPendingMessageCount, boolean noLocal, boolean browser,
182            boolean dispatchAsync, MessageListener messageListener) throws JMSException {
183        if (dest == null) {
184            throw new InvalidDestinationException("Don't understand null destinations");
185        } else if (dest.getPhysicalName() == null) {
186            throw new InvalidDestinationException("The destination object was not given a physical name.");
187        } else if (dest.isTemporary()) {
188            String physicalName = dest.getPhysicalName();
189
190            if (physicalName == null) {
191                throw new IllegalArgumentException("Physical name of Destination should be valid: " + dest);
192            }
193
194            String connectionID = session.connection.getConnectionInfo().getConnectionId().getValue();
195
196            if (physicalName.indexOf(connectionID) < 0) {
197                throw new InvalidDestinationException("Cannot use a Temporary destination from another Connection");
198            }
199
200            if (session.connection.isDeleted(dest)) {
201                throw new InvalidDestinationException("Cannot use a Temporary destination that has been deleted");
202            }
203            if (prefetch < 0) {
204                throw new JMSException("Cannot have a prefetch size less than zero");
205            }
206        }
207        if (session.connection.isMessagePrioritySupported()) {
208            this.unconsumedMessages = new SimplePriorityMessageDispatchChannel();
209        }else {
210            this.unconsumedMessages = new FifoMessageDispatchChannel();
211        }
212
213        this.session = session;
214        this.redeliveryPolicy = session.connection.getRedeliveryPolicyMap().getEntryFor(dest);
215        if (this.redeliveryPolicy == null) {
216            this.redeliveryPolicy = new RedeliveryPolicy();
217        }
218        setTransformer(session.getTransformer());
219
220        this.info = new ConsumerInfo(consumerId);
221        this.info.setExclusive(this.session.connection.isExclusiveConsumer());
222        this.info.setClientId(this.session.connection.getClientID());
223        this.info.setSubscriptionName(name);
224        this.info.setPrefetchSize(prefetch);
225        this.info.setCurrentPrefetchSize(prefetch);
226        this.info.setMaximumPendingMessageLimit(maximumPendingMessageCount);
227        this.info.setNoLocal(noLocal);
228        this.info.setDispatchAsync(dispatchAsync);
229        this.info.setRetroactive(this.session.connection.isUseRetroactiveConsumer());
230        this.info.setSelector(null);
231
232        // Allows the options on the destination to configure the consumerInfo
233        if (dest.getOptions() != null) {
234            Map<String, Object> options = IntrospectionSupport.extractProperties(
235                new HashMap<String, Object>(dest.getOptions()), "consumer.");
236            IntrospectionSupport.setProperties(this.info, options);
237            if (options.size() > 0) {
238                String msg = "There are " + options.size()
239                    + " consumer options that couldn't be set on the consumer."
240                    + " Check the options are spelled correctly."
241                    + " Unknown parameters=[" + options + "]."
242                    + " This consumer cannot be started.";
243                LOG.warn(msg);
244                throw new ConfigurationException(msg);
245            }
246        }
247
248        this.info.setDestination(dest);
249        this.info.setBrowser(browser);
250        if (selector != null && selector.trim().length() != 0) {
251            // Validate the selector
252            SelectorParser.parse(selector);
253            this.info.setSelector(selector);
254            this.selector = selector;
255        } else if (info.getSelector() != null) {
256            // Validate the selector
257            SelectorParser.parse(this.info.getSelector());
258            this.selector = this.info.getSelector();
259        } else {
260            this.selector = null;
261        }
262
263        this.stats = new JMSConsumerStatsImpl(session.getSessionStats(), dest);
264        this.optimizeAcknowledge = session.connection.isOptimizeAcknowledge() && session.isAutoAcknowledge()
265                                   && !info.isBrowser();
266        if (this.optimizeAcknowledge) {
267            this.optimizeAcknowledgeTimeOut = session.connection.getOptimizeAcknowledgeTimeOut();
268            setOptimizedAckScheduledAckInterval(session.connection.getOptimizedAckScheduledAckInterval());
269        }
270
271        this.info.setOptimizedAcknowledge(this.optimizeAcknowledge);
272        this.failoverRedeliveryWaitPeriod = session.connection.getConsumerFailoverRedeliveryWaitPeriod();
273        this.nonBlockingRedelivery = session.connection.isNonBlockingRedelivery();
274        this.transactedIndividualAck = session.connection.isTransactedIndividualAck()
275                        || this.nonBlockingRedelivery
276                        || session.connection.isMessagePrioritySupported();
277        this.consumerExpiryCheckEnabled = session.connection.isConsumerExpiryCheckEnabled();
278        if (messageListener != null) {
279            setMessageListener(messageListener);
280        }
281        try {
282            this.session.addConsumer(this);
283            this.session.syncSendPacket(info);
284        } catch (JMSException e) {
285            this.session.removeConsumer(this);
286            throw e;
287        }
288
289        if (session.connection.isStarted()) {
290            start();
291        }
292    }
293
294    private boolean isAutoAcknowledgeEach() {
295        return session.isAutoAcknowledge() || ( session.isDupsOkAcknowledge() && getDestination().isQueue() );
296    }
297
298    private boolean isAutoAcknowledgeBatch() {
299        return session.isDupsOkAcknowledge() && !getDestination().isQueue() ;
300    }
301
302    @Override
303    public StatsImpl getStats() {
304        return stats;
305    }
306
307    public JMSConsumerStatsImpl getConsumerStats() {
308        return stats;
309    }
310
311    public RedeliveryPolicy getRedeliveryPolicy() {
312        return redeliveryPolicy;
313    }
314
315    /**
316     * Sets the redelivery policy used when messages are redelivered
317     */
318    public void setRedeliveryPolicy(RedeliveryPolicy redeliveryPolicy) {
319        this.redeliveryPolicy = redeliveryPolicy;
320    }
321
322    public MessageTransformer getTransformer() {
323        return transformer;
324    }
325
326    /**
327     * Sets the transformer used to transform messages before they are sent on
328     * to the JMS bus
329     */
330    public void setTransformer(MessageTransformer transformer) {
331        this.transformer = transformer;
332    }
333
334    /**
335     * @return Returns the value.
336     */
337    public ConsumerId getConsumerId() {
338        return info.getConsumerId();
339    }
340
341    /**
342     * @return the consumer name - used for durable consumers
343     */
344    public String getConsumerName() {
345        return this.info.getSubscriptionName();
346    }
347
348    /**
349     * @return true if this consumer does not accept locally produced messages
350     */
351    protected boolean isNoLocal() {
352        return info.isNoLocal();
353    }
354
355    /**
356     * Retrieve is a browser
357     *
358     * @return true if a browser
359     */
360    protected boolean isBrowser() {
361        return info.isBrowser();
362    }
363
364    /**
365     * @return ActiveMQDestination
366     */
367    protected ActiveMQDestination getDestination() {
368        return info.getDestination();
369    }
370
371    /**
372     * @return Returns the prefetchNumber.
373     */
374    public int getPrefetchNumber() {
375        return info.getPrefetchSize();
376    }
377
378    /**
379     * @return true if this is a durable topic subscriber
380     */
381    public boolean isDurableSubscriber() {
382        return info.getSubscriptionName() != null && info.getDestination().isTopic();
383    }
384
385    /**
386     * Gets this message consumer's message selector expression.
387     *
388     * @return this message consumer's message selector, or null if no message
389     *         selector exists for the message consumer (that is, if the message
390     *         selector was not set or was set to null or the empty string)
391     * @throws JMSException if the JMS provider fails to receive the next
392     *                 message due to some internal error.
393     */
394    @Override
395    public String getMessageSelector() throws JMSException {
396        checkClosed();
397        return selector;
398    }
399
400    /**
401     * Gets the message consumer's <CODE>MessageListener</CODE>.
402     *
403     * @return the listener for the message consumer, or null if no listener is
404     *         set
405     * @throws JMSException if the JMS provider fails to get the message
406     *                 listener due to some internal error.
407     * @see javax.jms.MessageConsumer#setMessageListener(javax.jms.MessageListener)
408     */
409    @Override
410    public MessageListener getMessageListener() throws JMSException {
411        checkClosed();
412        return this.messageListener.get();
413    }
414
415    /**
416     * Sets the message consumer's <CODE>MessageListener</CODE>.
417     * <P>
418     * Setting the message listener to null is the equivalent of unsetting the
419     * message listener for the message consumer.
420     * <P>
421     * The effect of calling <CODE>MessageConsumer.setMessageListener</CODE>
422     * while messages are being consumed by an existing listener or the consumer
423     * is being used to consume messages synchronously is undefined.
424     *
425     * @param listener the listener to which the messages are to be delivered
426     * @throws JMSException if the JMS provider fails to receive the next
427     *                 message due to some internal error.
428     * @see javax.jms.MessageConsumer#getMessageListener
429     */
430    @Override
431    public void setMessageListener(MessageListener listener) throws JMSException {
432        checkClosed();
433        if (info.getPrefetchSize() == 0) {
434            throw new JMSException("Illegal prefetch size of zero. This setting is not supported for asynchronous consumers please set a value of at least 1");
435        }
436        if (listener != null) {
437            boolean wasRunning = session.isRunning();
438            if (wasRunning) {
439                session.stop();
440            }
441
442            this.messageListener.set(listener);
443            session.redispatch(this, unconsumedMessages);
444
445            if (wasRunning) {
446                session.start();
447            }
448        } else {
449            this.messageListener.set(null);
450        }
451    }
452
453    @Override
454    public MessageAvailableListener getAvailableListener() {
455        return availableListener;
456    }
457
458    /**
459     * Sets the listener used to notify synchronous consumers that there is a
460     * message available so that the {@link MessageConsumer#receiveNoWait()} can
461     * be called.
462     */
463    @Override
464    public void setAvailableListener(MessageAvailableListener availableListener) {
465        this.availableListener = availableListener;
466    }
467
468    /**
469     * Used to get an enqueued message from the unconsumedMessages list. The
470     * amount of time this method blocks is based on the timeout value. - if
471     * timeout==-1 then it blocks until a message is received. - if timeout==0
472     * then it it tries to not block at all, it returns a message if it is
473     * available - if timeout>0 then it blocks up to timeout amount of time.
474     * Expired messages will consumed by this method.
475     *
476     * @throws JMSException
477     * @return null if we timeout or if the consumer is closed.
478     */
479    private MessageDispatch dequeue(long timeout) throws JMSException {
480        try {
481            long deadline = 0;
482            if (timeout > 0) {
483                deadline = System.currentTimeMillis() + timeout;
484            }
485            while (true) {
486                MessageDispatch md = unconsumedMessages.dequeue(timeout);
487                if (md == null) {
488                    if (timeout > 0 && !unconsumedMessages.isClosed()) {
489                        timeout = Math.max(deadline - System.currentTimeMillis(), 0);
490                    } else {
491                        if (failureError != null) {
492                            throw JMSExceptionSupport.create(failureError);
493                        } else {
494                            return null;
495                        }
496                    }
497                } else if (md.getMessage() == null) {
498                    return null;
499                } else if (consumeExpiredMessage(md)) {
500                    LOG.debug("{} received expired message: {}", getConsumerId(), md);
501                    beforeMessageIsConsumed(md);
502                    afterMessageIsConsumed(md, true);
503                    if (timeout > 0) {
504                        timeout = Math.max(deadline - System.currentTimeMillis(), 0);
505                    }
506                    sendPullCommand(timeout);
507                } else if (redeliveryExceeded(md)) {
508                    LOG.debug("{} received with excessive redelivered: {}", getConsumerId(), md);
509                    posionAck(md, "Dispatch[" + md.getRedeliveryCounter() + "] to " + getConsumerId() + " exceeds redelivery policy limit:" + redeliveryPolicy);
510                    if (timeout > 0) {
511                        timeout = Math.max(deadline - System.currentTimeMillis(), 0);
512                    }
513                    sendPullCommand(timeout);
514                } else {
515                    if (LOG.isTraceEnabled()) {
516                        LOG.trace(getConsumerId() + " received message: " + md);
517                    }
518                    return md;
519                }
520            }
521        } catch (InterruptedException e) {
522            Thread.currentThread().interrupt();
523            throw JMSExceptionSupport.create(e);
524        }
525    }
526
527    private boolean consumeExpiredMessage(MessageDispatch dispatch) {
528        return isConsumerExpiryCheckEnabled() && dispatch.getMessage().isExpired();
529    }
530
531    private void posionAck(MessageDispatch md, String cause) throws JMSException {
532        MessageAck posionAck = new MessageAck(md, MessageAck.POSION_ACK_TYPE, 1);
533        posionAck.setFirstMessageId(md.getMessage().getMessageId());
534        posionAck.setPoisonCause(new Throwable(cause));
535        session.sendAck(posionAck);
536    }
537
538    private boolean redeliveryExceeded(MessageDispatch md) {
539        try {
540            return session.getTransacted()
541                    && redeliveryPolicy != null
542                    && redeliveryPolicy.isPreDispatchCheck()
543                    && redeliveryPolicy.getMaximumRedeliveries() != RedeliveryPolicy.NO_MAXIMUM_REDELIVERIES
544                    && md.getRedeliveryCounter() > redeliveryPolicy.getMaximumRedeliveries()
545                    // redeliveryCounter > x expected after resend via brokerRedeliveryPlugin
546                    && md.getMessage().getProperty("redeliveryDelay") == null;
547        } catch (Exception ignored) {
548            return false;
549        }
550    }
551
552    /**
553     * Receives the next message produced for this message consumer.
554     * <P>
555     * This call blocks indefinitely until a message is produced or until this
556     * message consumer is closed.
557     * <P>
558     * If this <CODE>receive</CODE> is done within a transaction, the consumer
559     * retains the message until the transaction commits.
560     *
561     * @return the next message produced for this message consumer, or null if
562     *         this message consumer is concurrently closed
563     */
564    @Override
565    public Message receive() throws JMSException {
566        checkClosed();
567        checkMessageListener();
568
569        sendPullCommand(0);
570        MessageDispatch md = dequeue(-1);
571        if (md == null) {
572            return null;
573        }
574
575        beforeMessageIsConsumed(md);
576        afterMessageIsConsumed(md, false);
577
578        return createActiveMQMessage(md);
579    }
580
581    /**
582     * @param md
583     *      the MessageDispatch that arrived from the Broker.
584     *
585     * @return an ActiveMQMessage initialized from the Message in the dispatch.
586     */
587    private ActiveMQMessage createActiveMQMessage(final MessageDispatch md) throws JMSException {
588        ActiveMQMessage m = (ActiveMQMessage)md.getMessage().copy();
589        if (m.getDataStructureType()==CommandTypes.ACTIVEMQ_BLOB_MESSAGE) {
590            ((ActiveMQBlobMessage)m).setBlobDownloader(new BlobDownloader(session.getBlobTransferPolicy()));
591        }
592        if (m.getDataStructureType() == CommandTypes.ACTIVEMQ_OBJECT_MESSAGE) {
593            ((ActiveMQObjectMessage)m).setTrustAllPackages(session.getConnection().isTrustAllPackages());
594            ((ActiveMQObjectMessage)m).setTrustedPackages(session.getConnection().getTrustedPackages());
595        }
596        if (transformer != null) {
597            Message transformedMessage = transformer.consumerTransform(session, this, m);
598            if (transformedMessage != null) {
599                m = ActiveMQMessageTransformation.transformMessage(transformedMessage, session.connection);
600            }
601        }
602        if (session.isClientAcknowledge()) {
603            m.setAcknowledgeCallback(new Callback() {
604                @Override
605                public void execute() throws Exception {
606                    checkClosed();
607                    session.checkClosed();
608                    session.acknowledge();
609                }
610            });
611        } else if (session.isIndividualAcknowledge()) {
612            m.setAcknowledgeCallback(new Callback() {
613                @Override
614                public void execute() throws Exception {
615                    checkClosed();
616                    session.checkClosed();
617                    acknowledge(md);
618                }
619            });
620        }
621        return m;
622    }
623
624    /**
625     * Receives the next message that arrives within the specified timeout
626     * interval.
627     * <P>
628     * This call blocks until a message arrives, the timeout expires, or this
629     * message consumer is closed. A <CODE>timeout</CODE> of zero never
630     * expires, and the call blocks indefinitely.
631     *
632     * @param timeout the timeout value (in milliseconds), a time out of zero
633     *                never expires.
634     * @return the next message produced for this message consumer, or null if
635     *         the timeout expires or this message consumer is concurrently
636     *         closed
637     */
638    @Override
639    public Message receive(long timeout) throws JMSException {
640        checkClosed();
641        checkMessageListener();
642        if (timeout == 0) {
643            return this.receive();
644        }
645
646        sendPullCommand(timeout);
647        while (timeout > 0) {
648
649            MessageDispatch md;
650            if (info.getPrefetchSize() == 0) {
651                md = dequeue(-1); // We let the broker let us know when we timeout.
652            } else {
653                md = dequeue(timeout);
654            }
655
656            if (md == null) {
657                return null;
658            }
659
660            beforeMessageIsConsumed(md);
661            afterMessageIsConsumed(md, false);
662            return createActiveMQMessage(md);
663        }
664        return null;
665    }
666
667    /**
668     * Receives the next message if one is immediately available.
669     *
670     * @return the next message produced for this message consumer, or null if
671     *         one is not available
672     * @throws JMSException if the JMS provider fails to receive the next
673     *                 message due to some internal error.
674     */
675    @Override
676    public Message receiveNoWait() throws JMSException {
677        checkClosed();
678        checkMessageListener();
679        sendPullCommand(-1);
680
681        MessageDispatch md;
682        if (info.getPrefetchSize() == 0) {
683            md = dequeue(-1); // We let the broker let us know when we
684            // timeout.
685        } else {
686            md = dequeue(0);
687        }
688
689        if (md == null) {
690            return null;
691        }
692
693        beforeMessageIsConsumed(md);
694        afterMessageIsConsumed(md, false);
695        return createActiveMQMessage(md);
696    }
697
698    /**
699     * Closes the message consumer.
700     * <P>
701     * Since a provider may allocate some resources on behalf of a <CODE>
702     * MessageConsumer</CODE>
703     * outside the Java virtual machine, clients should close them when they are
704     * not needed. Relying on garbage collection to eventually reclaim these
705     * resources may not be timely enough.
706     * <P>
707     * This call blocks until a <CODE>receive</CODE> or message listener in
708     * progress has completed. A blocked message consumer <CODE>receive </CODE>
709     * call returns null when this message consumer is closed.
710     *
711     * @throws JMSException if the JMS provider fails to close the consumer due
712     *                 to some internal error.
713     */
714    @Override
715    public void close() throws JMSException {
716        if (!unconsumedMessages.isClosed()) {
717            if (!deliveredMessages.isEmpty() && session.getTransactionContext().isInTransaction()) {
718                session.getTransactionContext().addSynchronization(new Synchronization() {
719                    @Override
720                    public void afterCommit() throws Exception {
721                        doClose();
722                    }
723
724                    @Override
725                    public void afterRollback() throws Exception {
726                        doClose();
727                    }
728                });
729            } else {
730                doClose();
731            }
732        }
733    }
734
735    void doClose() throws JMSException {
736        dispose();
737        RemoveInfo removeCommand = info.createRemoveCommand();
738        LOG.debug("remove: {}, lastDeliveredSequenceId: {}", getConsumerId(), lastDeliveredSequenceId);
739        removeCommand.setLastDeliveredSequenceId(lastDeliveredSequenceId);
740        this.session.asyncSendPacket(removeCommand);
741    }
742
743    void inProgressClearRequired() {
744        inProgressClearRequiredFlag.incrementAndGet();
745        // deal with delivered messages async to avoid lock contention with in progress acks
746        clearDeliveredList = true;
747        // force a rollback if we will be acking in a transaction after/during failover
748        // bc acks are async they may not get there reliably on reconnect and the consumer
749        // may not be aware of the reconnect in a timely fashion if in onMessage
750        if (!deliveredMessages.isEmpty() && session.getTransactionContext().isInTransaction()) {
751            session.getTransactionContext().setRollbackOnly(true);
752        }
753    }
754
755    void clearMessagesInProgress() {
756        if (inProgressClearRequiredFlag.get() > 0) {
757            synchronized (unconsumedMessages.getMutex()) {
758                if (inProgressClearRequiredFlag.get() > 0) {
759                    LOG.debug("{} clearing unconsumed list ({}) on transport interrupt", getConsumerId(), unconsumedMessages.size());
760                    // ensure unconsumed are rolledback up front as they may get redelivered to another consumer
761                    List<MessageDispatch> list = unconsumedMessages.removeAll();
762                    if (!this.info.isBrowser()) {
763                        for (MessageDispatch old : list) {
764                            session.connection.rollbackDuplicate(this, old.getMessage());
765                        }
766                    }
767                    // allow dispatch on this connection to resume
768                    session.connection.transportInterruptionProcessingComplete();
769                    inProgressClearRequiredFlag.decrementAndGet();
770
771                    // Wake up any blockers and allow them to recheck state.
772                    unconsumedMessages.getMutex().notifyAll();
773                }
774            }
775        }
776        clearDeliveredList();
777    }
778
779    void deliverAcks() {
780        MessageAck ack = null;
781        if (deliveryingAcknowledgements.compareAndSet(false, true)) {
782            synchronized(deliveredMessages) {
783                if (isAutoAcknowledgeEach()) {
784                    ack = makeAckForAllDeliveredMessages(MessageAck.STANDARD_ACK_TYPE);
785                    if (ack != null) {
786                        deliveredMessages.clear();
787                        ackCounter = 0;
788                    } else {
789                        ack = pendingAck;
790                        pendingAck = null;
791                    }
792                } else if (pendingAck != null && pendingAck.isStandardAck()) {
793                    ack = pendingAck;
794                    pendingAck = null;
795                }
796            }
797            if (ack != null) {
798                final MessageAck ackToSend = ack;
799
800                if (executorService == null) {
801                    executorService = Executors.newSingleThreadExecutor();
802                }
803                executorService.submit(new Runnable() {
804                    @Override
805                    public void run() {
806                        try {
807                            session.sendAck(ackToSend,true);
808                        } catch (JMSException e) {
809                            LOG.error(getConsumerId() + " failed to delivered acknowledgements", e);
810                        } finally {
811                            deliveryingAcknowledgements.set(false);
812                        }
813                    }
814                });
815            } else {
816                deliveryingAcknowledgements.set(false);
817            }
818        }
819    }
820
821    public void dispose() throws JMSException {
822        if (!unconsumedMessages.isClosed()) {
823
824            // Do we have any acks we need to send out before closing?
825            // Ack any delivered messages now.
826            if (!session.getTransacted()) {
827                deliverAcks();
828                if (isAutoAcknowledgeBatch()) {
829                    acknowledge();
830                }
831            }
832            if (executorService != null) {
833                ThreadPoolUtils.shutdownGraceful(executorService, 60000L);
834                executorService = null;
835            }
836            if (optimizedAckTask != null) {
837                this.session.connection.getScheduler().cancel(optimizedAckTask);
838                optimizedAckTask = null;
839            }
840
841            if (session.isClientAcknowledge() || session.isIndividualAcknowledge()) {
842                if (!this.info.isBrowser()) {
843                    // rollback duplicates that aren't acknowledged
844                    List<MessageDispatch> tmp = null;
845                    synchronized (this.deliveredMessages) {
846                        tmp = new ArrayList<MessageDispatch>(this.deliveredMessages);
847                    }
848                    for (MessageDispatch old : tmp) {
849                        this.session.connection.rollbackDuplicate(this, old.getMessage());
850                    }
851                    tmp.clear();
852                }
853            }
854            if (!session.isTransacted()) {
855                synchronized(deliveredMessages) {
856                    deliveredMessages.clear();
857                }
858            }
859            unconsumedMessages.close();
860            this.session.removeConsumer(this);
861            List<MessageDispatch> list = unconsumedMessages.removeAll();
862            if (!this.info.isBrowser()) {
863                for (MessageDispatch old : list) {
864                    // ensure we don't filter this as a duplicate
865                    if (old.getMessage() != null) {
866                        LOG.debug("on close, rollback duplicate: {}", old.getMessage().getMessageId());
867                    }
868                    session.connection.rollbackDuplicate(this, old.getMessage());
869                }
870            }
871        }
872    }
873
874    /**
875     * @throws IllegalStateException
876     */
877    protected void checkClosed() throws IllegalStateException {
878        if (unconsumedMessages.isClosed()) {
879            throw new IllegalStateException("The Consumer is closed");
880        }
881    }
882
883    /**
884     * If we have a zero prefetch specified then send a pull command to the
885     * broker to pull a message we are about to receive
886     */
887    protected void sendPullCommand(long timeout) throws JMSException {
888        clearDeliveredList();
889        if (info.getCurrentPrefetchSize() == 0 && unconsumedMessages.isEmpty()) {
890            MessagePull messagePull = new MessagePull();
891            messagePull.configure(info);
892            messagePull.setTimeout(timeout);
893            session.asyncSendPacket(messagePull);
894        }
895    }
896
897    protected void checkMessageListener() throws JMSException {
898        session.checkMessageListener();
899    }
900
901    protected void setOptimizeAcknowledge(boolean value) {
902        if (optimizeAcknowledge && !value) {
903            deliverAcks();
904        }
905        optimizeAcknowledge = value;
906    }
907
908    protected void setPrefetchSize(int prefetch) {
909        deliverAcks();
910        this.info.setCurrentPrefetchSize(prefetch);
911    }
912
913    private void beforeMessageIsConsumed(MessageDispatch md) throws JMSException {
914        md.setDeliverySequenceId(session.getNextDeliveryId());
915        lastDeliveredSequenceId = md.getMessage().getMessageId().getBrokerSequenceId();
916        if (!isAutoAcknowledgeBatch()) {
917            synchronized(deliveredMessages) {
918                deliveredMessages.addFirst(md);
919            }
920            if (session.getTransacted()) {
921                if (transactedIndividualAck) {
922                    immediateIndividualTransactedAck(md);
923                } else {
924                    ackLater(md, MessageAck.DELIVERED_ACK_TYPE);
925                }
926            }
927        }
928    }
929
930    private void immediateIndividualTransactedAck(MessageDispatch md) throws JMSException {
931        // acks accumulate on the broker pending transaction completion to indicate
932        // delivery status
933        registerSync();
934        MessageAck ack = new MessageAck(md, MessageAck.INDIVIDUAL_ACK_TYPE, 1);
935        ack.setTransactionId(session.getTransactionContext().getTransactionId());
936        session.sendAck(ack);
937    }
938
939    private void afterMessageIsConsumed(MessageDispatch md, boolean messageExpired) throws JMSException {
940        if (unconsumedMessages.isClosed()) {
941            return;
942        }
943        if (messageExpired) {
944            acknowledge(md, MessageAck.EXPIRED_ACK_TYPE);
945            stats.getExpiredMessageCount().increment();
946        } else {
947            stats.onMessage();
948            if (session.getTransacted()) {
949                // Do nothing.
950            } else if (isAutoAcknowledgeEach()) {
951                if (deliveryingAcknowledgements.compareAndSet(false, true)) {
952                    synchronized (deliveredMessages) {
953                        if (!deliveredMessages.isEmpty()) {
954                            if (optimizeAcknowledge) {
955                                ackCounter++;
956
957                                // AMQ-3956 evaluate both expired and normal msgs as
958                                // otherwise consumer may get stalled
959                                if (ackCounter + deliveredCounter >= (info.getPrefetchSize() * .65) || (optimizeAcknowledgeTimeOut > 0 && System.currentTimeMillis() >= (optimizeAckTimestamp + optimizeAcknowledgeTimeOut))) {
960                                    MessageAck ack = makeAckForAllDeliveredMessages(MessageAck.STANDARD_ACK_TYPE);
961                                    if (ack != null) {
962                                        deliveredMessages.clear();
963                                        ackCounter = 0;
964                                        session.sendAck(ack);
965                                        optimizeAckTimestamp = System.currentTimeMillis();
966                                    }
967                                    // AMQ-3956 - as further optimization send
968                                    // ack for expired msgs when there are any.
969                                    // This resets the deliveredCounter to 0 so that
970                                    // we won't sent standard acks with every msg just
971                                    // because the deliveredCounter just below
972                                    // 0.5 * prefetch as used in ackLater()
973                                    if (pendingAck != null && deliveredCounter > 0) {
974                                        session.sendAck(pendingAck);
975                                        pendingAck = null;
976                                        deliveredCounter = 0;
977                                    }
978                                }
979                            } else {
980                                MessageAck ack = makeAckForAllDeliveredMessages(MessageAck.STANDARD_ACK_TYPE);
981                                if (ack!=null) {
982                                    deliveredMessages.clear();
983                                    session.sendAck(ack);
984                                }
985                            }
986                        }
987                    }
988                    deliveryingAcknowledgements.set(false);
989                }
990            } else if (isAutoAcknowledgeBatch()) {
991                ackLater(md, MessageAck.STANDARD_ACK_TYPE);
992            } else if (session.isClientAcknowledge()||session.isIndividualAcknowledge()) {
993                boolean messageUnackedByConsumer = false;
994                synchronized (deliveredMessages) {
995                    messageUnackedByConsumer = deliveredMessages.contains(md);
996                }
997                if (messageUnackedByConsumer) {
998                    ackLater(md, MessageAck.DELIVERED_ACK_TYPE);
999                }
1000            }
1001            else {
1002                throw new IllegalStateException("Invalid session state.");
1003            }
1004        }
1005    }
1006
1007    /**
1008     * Creates a MessageAck for all messages contained in deliveredMessages.
1009     * Caller should hold the lock for deliveredMessages.
1010     *
1011     * @param type Ack-Type (i.e. MessageAck.STANDARD_ACK_TYPE)
1012     * @return <code>null</code> if nothing to ack.
1013     */
1014    private MessageAck makeAckForAllDeliveredMessages(byte type) {
1015        synchronized (deliveredMessages) {
1016            if (deliveredMessages.isEmpty()) {
1017                return null;
1018            }
1019
1020            MessageDispatch md = deliveredMessages.getFirst();
1021            MessageAck ack = new MessageAck(md, type, deliveredMessages.size());
1022            ack.setFirstMessageId(deliveredMessages.getLast().getMessage().getMessageId());
1023            return ack;
1024        }
1025    }
1026
1027    private void ackLater(MessageDispatch md, byte ackType) throws JMSException {
1028
1029        // Don't acknowledge now, but we may need to let the broker know the
1030        // consumer got the message to expand the pre-fetch window
1031        if (session.getTransacted()) {
1032            registerSync();
1033        }
1034
1035        deliveredCounter++;
1036
1037        synchronized(deliveredMessages) {
1038            MessageAck oldPendingAck = pendingAck;
1039            pendingAck = new MessageAck(md, ackType, deliveredCounter);
1040            pendingAck.setTransactionId(session.getTransactionContext().getTransactionId());
1041            if( oldPendingAck==null ) {
1042                pendingAck.setFirstMessageId(pendingAck.getLastMessageId());
1043            } else if ( oldPendingAck.getAckType() == pendingAck.getAckType() ) {
1044                pendingAck.setFirstMessageId(oldPendingAck.getFirstMessageId());
1045            } else {
1046                // old pending ack being superseded by ack of another type, if is is not a delivered
1047                // ack and hence important, send it now so it is not lost.
1048                if (!oldPendingAck.isDeliveredAck()) {
1049                    LOG.debug("Sending old pending ack {}, new pending: {}", oldPendingAck, pendingAck);
1050                    session.sendAck(oldPendingAck);
1051                } else {
1052                    LOG.debug("dropping old pending ack {}, new pending: {}", oldPendingAck, pendingAck);
1053                }
1054            }
1055            // AMQ-3956 evaluate both expired and normal msgs as
1056            // otherwise consumer may get stalled
1057            if ((0.5 * info.getPrefetchSize()) <= (deliveredCounter + ackCounter - additionalWindowSize)) {
1058                LOG.debug("ackLater: sending: {}", pendingAck);
1059                session.sendAck(pendingAck);
1060                pendingAck=null;
1061                deliveredCounter = 0;
1062                additionalWindowSize = 0;
1063            }
1064        }
1065    }
1066
1067    private void registerSync() throws JMSException {
1068        session.doStartTransaction();
1069        if (!synchronizationRegistered) {
1070            synchronizationRegistered = true;
1071            session.getTransactionContext().addSynchronization(new Synchronization() {
1072                @Override
1073                public void beforeEnd() throws Exception {
1074                    if (transactedIndividualAck) {
1075                        clearDeliveredList();
1076                        waitForRedeliveries();
1077                        synchronized(deliveredMessages) {
1078                            rollbackOnFailedRecoveryRedelivery();
1079                        }
1080                    } else {
1081                        acknowledge();
1082                    }
1083                    synchronizationRegistered = false;
1084                }
1085
1086                @Override
1087                public void afterCommit() throws Exception {
1088                    commit();
1089                    synchronizationRegistered = false;
1090                }
1091
1092                @Override
1093                public void afterRollback() throws Exception {
1094                    rollback();
1095                    synchronizationRegistered = false;
1096                }
1097            });
1098        }
1099    }
1100
1101    /**
1102     * Acknowledge all the messages that have been delivered to the client up to
1103     * this point.
1104     *
1105     * @throws JMSException
1106     */
1107    public void acknowledge() throws JMSException {
1108        clearDeliveredList();
1109        waitForRedeliveries();
1110        synchronized(deliveredMessages) {
1111            // Acknowledge all messages so far.
1112            MessageAck ack = makeAckForAllDeliveredMessages(MessageAck.STANDARD_ACK_TYPE);
1113            if (ack == null) {
1114                return; // no msgs
1115            }
1116
1117            if (session.getTransacted()) {
1118                rollbackOnFailedRecoveryRedelivery();
1119                session.doStartTransaction();
1120                ack.setTransactionId(session.getTransactionContext().getTransactionId());
1121            }
1122
1123            pendingAck = null;
1124            session.sendAck(ack);
1125
1126            // Adjust the counters
1127            deliveredCounter = Math.max(0, deliveredCounter - deliveredMessages.size());
1128            additionalWindowSize = Math.max(0, additionalWindowSize - deliveredMessages.size());
1129
1130            if (!session.getTransacted()) {
1131                deliveredMessages.clear();
1132            }
1133        }
1134    }
1135
1136    private void waitForRedeliveries() {
1137        if (failoverRedeliveryWaitPeriod > 0 && previouslyDeliveredMessages != null) {
1138            long expiry = System.currentTimeMillis() + failoverRedeliveryWaitPeriod;
1139            int numberNotReplayed;
1140            do {
1141                numberNotReplayed = 0;
1142                synchronized(deliveredMessages) {
1143                    if (previouslyDeliveredMessages != null) {
1144                        for (Entry<MessageId, Boolean> entry: previouslyDeliveredMessages.entrySet()) {
1145                            if (!entry.getValue()) {
1146                                numberNotReplayed++;
1147                            }
1148                        }
1149                    }
1150                }
1151                if (numberNotReplayed > 0) {
1152                    LOG.info("waiting for redelivery of {} in transaction: {}, to consumer: {}",
1153                             numberNotReplayed, this.getConsumerId(), previouslyDeliveredMessages.transactionId);
1154                    try {
1155                        Thread.sleep(Math.max(500, failoverRedeliveryWaitPeriod/4));
1156                    } catch (InterruptedException outOfhere) {
1157                        break;
1158                    }
1159                }
1160            } while (numberNotReplayed > 0 && expiry < System.currentTimeMillis());
1161        }
1162    }
1163
1164    /*
1165     * called with deliveredMessages locked
1166     */
1167    private void rollbackOnFailedRecoveryRedelivery() throws JMSException {
1168        if (previouslyDeliveredMessages != null) {
1169            // if any previously delivered messages was not re-delivered, transaction is invalid and must rollback
1170            // as messages have been dispatched else where.
1171            int numberNotReplayed = 0;
1172            for (Entry<MessageId, Boolean> entry: previouslyDeliveredMessages.entrySet()) {
1173                if (!entry.getValue()) {
1174                    numberNotReplayed++;
1175                    LOG.debug("previously delivered message has not been replayed in transaction: {}, messageId: {}",
1176                              previouslyDeliveredMessages.transactionId, entry.getKey());
1177                }
1178            }
1179            if (numberNotReplayed > 0) {
1180                String message = "rolling back transaction ("
1181                    + previouslyDeliveredMessages.transactionId + ") post failover recovery. " + numberNotReplayed
1182                    + " previously delivered message(s) not replayed to consumer: " + this.getConsumerId();
1183                LOG.warn(message);
1184                throw new TransactionRolledBackException(message);
1185            }
1186        }
1187    }
1188
1189    void acknowledge(MessageDispatch md) throws JMSException {
1190        acknowledge(md, MessageAck.INDIVIDUAL_ACK_TYPE);
1191    }
1192
1193    void acknowledge(MessageDispatch md, byte ackType) throws JMSException {
1194        MessageAck ack = new MessageAck(md, ackType, 1);
1195        if (ack.isExpiredAck()) {
1196            ack.setFirstMessageId(ack.getLastMessageId());
1197        }
1198        session.sendAck(ack);
1199        synchronized(deliveredMessages){
1200            deliveredMessages.remove(md);
1201        }
1202    }
1203
1204    public void commit() throws JMSException {
1205        synchronized (deliveredMessages) {
1206            deliveredMessages.clear();
1207            clearPreviouslyDelivered();
1208        }
1209        redeliveryDelay = 0;
1210    }
1211
1212    public void rollback() throws JMSException {
1213        clearDeliveredList();
1214        synchronized (unconsumedMessages.getMutex()) {
1215            if (optimizeAcknowledge) {
1216                // remove messages read but not acked at the broker yet through
1217                // optimizeAcknowledge
1218                if (!this.info.isBrowser()) {
1219                    synchronized(deliveredMessages) {
1220                        for (int i = 0; (i < deliveredMessages.size()) && (i < ackCounter); i++) {
1221                            // ensure we don't filter this as a duplicate
1222                            MessageDispatch md = deliveredMessages.removeLast();
1223                            session.connection.rollbackDuplicate(this, md.getMessage());
1224                        }
1225                    }
1226                }
1227            }
1228            synchronized(deliveredMessages) {
1229                rollbackPreviouslyDeliveredAndNotRedelivered();
1230                if (deliveredMessages.isEmpty()) {
1231                    return;
1232                }
1233
1234                // use initial delay for first redelivery
1235                MessageDispatch lastMd = deliveredMessages.getFirst();
1236                final int currentRedeliveryCount = lastMd.getMessage().getRedeliveryCounter();
1237                if (currentRedeliveryCount > 0) {
1238                    redeliveryDelay = redeliveryPolicy.getNextRedeliveryDelay(redeliveryDelay);
1239                } else {
1240                    redeliveryDelay = redeliveryPolicy.getInitialRedeliveryDelay();
1241                }
1242                MessageId firstMsgId = deliveredMessages.getLast().getMessage().getMessageId();
1243
1244                for (Iterator<MessageDispatch> iter = deliveredMessages.iterator(); iter.hasNext();) {
1245                    MessageDispatch md = iter.next();
1246                    md.getMessage().onMessageRolledBack();
1247                    // ensure we don't filter this as a duplicate
1248                    session.connection.rollbackDuplicate(this, md.getMessage());
1249                }
1250
1251                if (redeliveryPolicy.getMaximumRedeliveries() != RedeliveryPolicy.NO_MAXIMUM_REDELIVERIES
1252                    && lastMd.getMessage().getRedeliveryCounter() > redeliveryPolicy.getMaximumRedeliveries()) {
1253                    // We need to NACK the messages so that they get sent to the
1254                    // DLQ.
1255                    // Acknowledge the last message.
1256
1257                    MessageAck ack = new MessageAck(lastMd, MessageAck.POSION_ACK_TYPE, deliveredMessages.size());
1258                    ack.setFirstMessageId(firstMsgId);
1259                    ack.setPoisonCause(new Throwable("Delivery[" + lastMd.getMessage().getRedeliveryCounter()  + "] exceeds redelivery policy limit:" + redeliveryPolicy
1260                            + ", cause:" + lastMd.getRollbackCause(), lastMd.getRollbackCause()));
1261                    session.sendAck(ack,true);
1262                    // Adjust the window size.
1263                    additionalWindowSize = Math.max(0, additionalWindowSize - deliveredMessages.size());
1264                    redeliveryDelay = 0;
1265
1266                    deliveredCounter -= deliveredMessages.size();
1267                    deliveredMessages.clear();
1268
1269                } else {
1270
1271                    // only redelivery_ack after first delivery
1272                    if (currentRedeliveryCount > 0) {
1273                        MessageAck ack = new MessageAck(lastMd, MessageAck.REDELIVERED_ACK_TYPE, deliveredMessages.size());
1274                        ack.setFirstMessageId(firstMsgId);
1275                        session.sendAck(ack,true);
1276                    }
1277
1278                    // stop the delivery of messages.
1279                    if (nonBlockingRedelivery) {
1280                        if (!unconsumedMessages.isClosed()) {
1281
1282                            final LinkedList<MessageDispatch> pendingRedeliveries =
1283                                new LinkedList<MessageDispatch>(deliveredMessages);
1284
1285                            Collections.reverse(pendingRedeliveries);
1286
1287                            deliveredCounter -= deliveredMessages.size();
1288                            deliveredMessages.clear();
1289
1290                            // Start up the delivery again a little later.
1291                            session.getScheduler().executeAfterDelay(new Runnable() {
1292                                @Override
1293                                public void run() {
1294                                    try {
1295                                        if (!unconsumedMessages.isClosed()) {
1296                                            for(MessageDispatch dispatch : pendingRedeliveries) {
1297                                                session.dispatch(dispatch);
1298                                            }
1299                                        }
1300                                    } catch (Exception e) {
1301                                        session.connection.onAsyncException(e);
1302                                    }
1303                                }
1304                            }, redeliveryDelay);
1305                        }
1306
1307                    } else {
1308                        unconsumedMessages.stop();
1309
1310                        for (MessageDispatch md : deliveredMessages) {
1311                            unconsumedMessages.enqueueFirst(md);
1312                        }
1313
1314                        deliveredCounter -= deliveredMessages.size();
1315                        deliveredMessages.clear();
1316
1317                        if (redeliveryDelay > 0 && !unconsumedMessages.isClosed()) {
1318                            // Start up the delivery again a little later.
1319                            session.getScheduler().executeAfterDelay(new Runnable() {
1320                                @Override
1321                                public void run() {
1322                                    try {
1323                                        if (started.get()) {
1324                                            start();
1325                                        }
1326                                    } catch (JMSException e) {
1327                                        session.connection.onAsyncException(e);
1328                                    }
1329                                }
1330                            }, redeliveryDelay);
1331                        } else {
1332                            start();
1333                        }
1334                    }
1335                }
1336            }
1337        }
1338        if (messageListener.get() != null) {
1339            session.redispatch(this, unconsumedMessages);
1340        }
1341    }
1342
1343    /*
1344     * called with unconsumedMessages && deliveredMessages locked
1345     * remove any message not re-delivered as they can't be replayed to this
1346     * consumer on rollback
1347     */
1348    private void rollbackPreviouslyDeliveredAndNotRedelivered() {
1349        if (previouslyDeliveredMessages != null) {
1350            for (Entry<MessageId, Boolean> entry: previouslyDeliveredMessages.entrySet()) {
1351                if (!entry.getValue()) {
1352                    LOG.trace("rollback non redelivered: {}" + entry.getKey());
1353                    removeFromDeliveredMessages(entry.getKey());
1354                }
1355            }
1356            clearPreviouslyDelivered();
1357        }
1358    }
1359
1360    /*
1361     * called with deliveredMessages locked
1362     */
1363    private void removeFromDeliveredMessages(MessageId key) {
1364        Iterator<MessageDispatch> iterator = deliveredMessages.iterator();
1365        while (iterator.hasNext()) {
1366            MessageDispatch candidate = iterator.next();
1367            if (key.equals(candidate.getMessage().getMessageId())) {
1368                session.connection.rollbackDuplicate(this, candidate.getMessage());
1369                iterator.remove();
1370                break;
1371            }
1372        }
1373    }
1374
1375    /*
1376     * called with deliveredMessages locked
1377     */
1378    private void clearPreviouslyDelivered() {
1379        if (previouslyDeliveredMessages != null) {
1380            previouslyDeliveredMessages.clear();
1381            previouslyDeliveredMessages = null;
1382        }
1383    }
1384
1385    @Override
1386    public void dispatch(MessageDispatch md) {
1387        MessageListener listener = this.messageListener.get();
1388        try {
1389            clearMessagesInProgress();
1390            clearDeliveredList();
1391            synchronized (unconsumedMessages.getMutex()) {
1392                if (!unconsumedMessages.isClosed()) {
1393                    if (this.info.isBrowser() || !session.connection.isDuplicate(this, md.getMessage())) {
1394                        if (listener != null && unconsumedMessages.isRunning()) {
1395                            if (redeliveryExceeded(md)) {
1396                                posionAck(md, "listener dispatch[" + md.getRedeliveryCounter() + "] to " + getConsumerId() + " exceeds redelivery policy limit:" + redeliveryPolicy);
1397                                return;
1398                            }
1399                            ActiveMQMessage message = createActiveMQMessage(md);
1400                            beforeMessageIsConsumed(md);
1401                            try {
1402                                boolean expired = isConsumerExpiryCheckEnabled() && message.isExpired();
1403                                if (!expired) {
1404                                    listener.onMessage(message);
1405                                }
1406                                afterMessageIsConsumed(md, expired);
1407                            } catch (RuntimeException e) {
1408                                LOG.error("{} Exception while processing message: {}", getConsumerId(), md.getMessage().getMessageId(), e);
1409                                md.setRollbackCause(e);
1410                                if (isAutoAcknowledgeBatch() || isAutoAcknowledgeEach() || session.isIndividualAcknowledge()) {
1411                                    // schedual redelivery and possible dlq processing
1412                                    rollback();
1413                                } else {
1414                                    // Transacted or Client ack: Deliver the next message.
1415                                    afterMessageIsConsumed(md, false);
1416                                }
1417                            }
1418                        } else {
1419                            if (!unconsumedMessages.isRunning()) {
1420                                // delayed redelivery, ensure it can be re delivered
1421                                session.connection.rollbackDuplicate(this, md.getMessage());
1422                            }
1423
1424                            if (md.getMessage() == null) {
1425                                // End of browse or pull request timeout.
1426                                unconsumedMessages.enqueue(md);
1427                            } else {
1428                                if (!consumeExpiredMessage(md)) {
1429                                    unconsumedMessages.enqueue(md);
1430                                    if (availableListener != null) {
1431                                        availableListener.onMessageAvailable(this);
1432                                    }
1433                                } else {
1434                                    beforeMessageIsConsumed(md);
1435                                    afterMessageIsConsumed(md, true);
1436
1437                                    // Pull consumer needs to check if pull timed out and send
1438                                    // a new pull command if not.
1439                                    if (info.getCurrentPrefetchSize() == 0) {
1440                                        unconsumedMessages.enqueue(null);
1441                                    }
1442                                }
1443                            }
1444                        }
1445                    } else {
1446                        // deal with duplicate delivery
1447                        ConsumerId consumerWithPendingTransaction;
1448                        if (redeliveryExpectedInCurrentTransaction(md, true)) {
1449                            LOG.debug("{} tracking transacted redelivery {}", getConsumerId(), md.getMessage());
1450                            if (transactedIndividualAck) {
1451                                immediateIndividualTransactedAck(md);
1452                            } else {
1453                                session.sendAck(new MessageAck(md, MessageAck.DELIVERED_ACK_TYPE, 1));
1454                            }
1455                        } else if ((consumerWithPendingTransaction = redeliveryPendingInCompetingTransaction(md)) != null) {
1456                            LOG.warn("{} delivering duplicate {}, pending transaction completion on {} will rollback", getConsumerId(), md.getMessage(), consumerWithPendingTransaction);
1457                            session.getConnection().rollbackDuplicate(this, md.getMessage());
1458                            dispatch(md);
1459                        } else {
1460                            LOG.warn("{} suppressing duplicate delivery on connection, poison acking: {}", getConsumerId(), md);
1461                            posionAck(md, "Suppressing duplicate delivery on connection, consumer " + getConsumerId());
1462                        }
1463                    }
1464                }
1465            }
1466            if (++dispatchedCount % 1000 == 0) {
1467                dispatchedCount = 0;
1468                Thread.yield();
1469            }
1470        } catch (Exception e) {
1471            session.connection.onClientInternalException(e);
1472        }
1473    }
1474
1475    private boolean redeliveryExpectedInCurrentTransaction(MessageDispatch md, boolean markReceipt) {
1476        if (session.isTransacted()) {
1477            synchronized (deliveredMessages) {
1478                if (previouslyDeliveredMessages != null) {
1479                    if (previouslyDeliveredMessages.containsKey(md.getMessage().getMessageId())) {
1480                        if (markReceipt) {
1481                            previouslyDeliveredMessages.put(md.getMessage().getMessageId(), true);
1482                        }
1483                        return true;
1484                    }
1485                }
1486            }
1487        }
1488        return false;
1489    }
1490
1491    private ConsumerId redeliveryPendingInCompetingTransaction(MessageDispatch md) {
1492        for (ActiveMQSession activeMQSession: session.connection.getSessions()) {
1493            for (ActiveMQMessageConsumer activeMQMessageConsumer : activeMQSession.consumers) {
1494                if (activeMQMessageConsumer.redeliveryExpectedInCurrentTransaction(md, false)) {
1495                    return activeMQMessageConsumer.getConsumerId();
1496                }
1497            }
1498        }
1499        return null;
1500    }
1501
1502    // async (on next call) clear or track delivered as they may be flagged as duplicates if they arrive again
1503    private void clearDeliveredList() {
1504        if (clearDeliveredList) {
1505            synchronized (deliveredMessages) {
1506                if (clearDeliveredList) {
1507                    if (!deliveredMessages.isEmpty()) {
1508                        if (session.isTransacted()) {
1509
1510                            if (previouslyDeliveredMessages == null) {
1511                                previouslyDeliveredMessages = new PreviouslyDeliveredMap<MessageId, Boolean>(session.getTransactionContext().getTransactionId());
1512                            }
1513                            for (MessageDispatch delivered : deliveredMessages) {
1514                                previouslyDeliveredMessages.put(delivered.getMessage().getMessageId(), false);
1515                            }
1516                            LOG.debug("{} tracking existing transacted {} delivered list ({}) on transport interrupt",
1517                                      getConsumerId(), previouslyDeliveredMessages.transactionId, deliveredMessages.size());
1518                        } else {
1519                            if (session.isClientAcknowledge()) {
1520                                LOG.debug("{} rolling back delivered list ({}) on transport interrupt", getConsumerId(), deliveredMessages.size());
1521                                // allow redelivery
1522                                if (!this.info.isBrowser()) {
1523                                    for (MessageDispatch md: deliveredMessages) {
1524                                        this.session.connection.rollbackDuplicate(this, md.getMessage());
1525                                    }
1526                                }
1527                            }
1528                            LOG.debug("{} clearing delivered list ({}) on transport interrupt", getConsumerId(), deliveredMessages.size());
1529                            deliveredMessages.clear();
1530                            pendingAck = null;
1531                        }
1532                    }
1533                    clearDeliveredList = false;
1534                }
1535            }
1536        }
1537    }
1538
1539    public int getMessageSize() {
1540        return unconsumedMessages.size();
1541    }
1542
1543    public void start() throws JMSException {
1544        if (unconsumedMessages.isClosed()) {
1545            return;
1546        }
1547        started.set(true);
1548        unconsumedMessages.start();
1549        session.executor.wakeup();
1550    }
1551
1552    public void stop() {
1553        started.set(false);
1554        unconsumedMessages.stop();
1555    }
1556
1557    @Override
1558    public String toString() {
1559        return "ActiveMQMessageConsumer { value=" + info.getConsumerId() + ", started=" + started.get()
1560               + " }";
1561    }
1562
1563    /**
1564     * Delivers a message to the message listener.
1565     *
1566     * @return true if another execution is needed.
1567     *
1568     * @throws JMSException
1569     */
1570    public boolean iterate() {
1571        MessageListener listener = this.messageListener.get();
1572        if (listener != null) {
1573            MessageDispatch md = unconsumedMessages.dequeueNoWait();
1574            if (md != null) {
1575                dispatch(md);
1576                return true;
1577            }
1578        }
1579        return false;
1580    }
1581
1582    public boolean isInUse(ActiveMQTempDestination destination) {
1583        return info.getDestination().equals(destination);
1584    }
1585
1586    public long getLastDeliveredSequenceId() {
1587        return lastDeliveredSequenceId;
1588    }
1589
1590    public IOException getFailureError() {
1591        return failureError;
1592    }
1593
1594    public void setFailureError(IOException failureError) {
1595        this.failureError = failureError;
1596    }
1597
1598    /**
1599     * @return the optimizedAckScheduledAckInterval
1600     */
1601    public long getOptimizedAckScheduledAckInterval() {
1602        return optimizedAckScheduledAckInterval;
1603    }
1604
1605    /**
1606     * @param optimizedAckScheduledAckInterval the optimizedAckScheduledAckInterval to set
1607     */
1608    public void setOptimizedAckScheduledAckInterval(long optimizedAckScheduledAckInterval) throws JMSException {
1609        this.optimizedAckScheduledAckInterval = optimizedAckScheduledAckInterval;
1610
1611        if (this.optimizedAckTask != null) {
1612            try {
1613                this.session.connection.getScheduler().cancel(optimizedAckTask);
1614            } catch (JMSException e) {
1615                LOG.debug("Caught exception while cancelling old optimized ack task", e);
1616                throw e;
1617            }
1618            this.optimizedAckTask = null;
1619        }
1620
1621        // Should we periodically send out all outstanding acks.
1622        if (this.optimizeAcknowledge && this.optimizedAckScheduledAckInterval > 0) {
1623            this.optimizedAckTask = new Runnable() {
1624
1625                @Override
1626                public void run() {
1627                    try {
1628                        if (optimizeAcknowledge && !unconsumedMessages.isClosed()) {
1629                            LOG.info("Consumer:{} is performing scheduled delivery of outstanding optimized Acks", info.getConsumerId());
1630                            deliverAcks();
1631                        }
1632                    } catch (Exception e) {
1633                        LOG.debug("Optimized Ack Task caught exception during ack", e);
1634                    }
1635                }
1636            };
1637
1638            try {
1639                this.session.connection.getScheduler().executePeriodically(optimizedAckTask, optimizedAckScheduledAckInterval);
1640            } catch (JMSException e) {
1641                LOG.debug("Caught exception while scheduling new optimized ack task", e);
1642                throw e;
1643            }
1644        }
1645    }
1646
1647    public boolean hasMessageListener() {
1648        return messageListener.get() != null;
1649    }
1650
1651    public boolean isConsumerExpiryCheckEnabled() {
1652        return consumerExpiryCheckEnabled;
1653    }
1654
1655    public void setConsumerExpiryCheckEnabled(boolean consumerExpiryCheckEnabled) {
1656        this.consumerExpiryCheckEnabled = consumerExpiryCheckEnabled;
1657    }
1658}