/***
    * Redistribution and use of this software and associated documentation
    * ("Software"), with or without modification, are permitted provided
    * that the following conditions are met:
    *
    * 1. Redistributions of source code must retain copyright
    *    statements and notices.  Redistributions must also contain a
    *    copy of this document.
    *
   * 2. Redistributions in binary form must reproduce the
   *    above copyright notice, this list of conditions and the
   *    following disclaimer in the documentation and/or other
   *    materials provided with the distribution.
   *
   * 3. The name "Exolab" must not be used to endorse or promote
   *    products derived from this Software without prior written
   *    permission of Exoffice Technologies.  For written permission,
   *    please contact info@exolab.org.
   *
   * 4. Products derived from this Software may not be called "Exolab"
   *    nor may "Exolab" appear in their names without prior written
   *    permission of Exoffice Technologies. Exolab is a registered
   *    trademark of Exoffice Technologies.
   *
   * 5. Due credit should be given to the Exolab Project
   *    (http://www.exolab.org/).
   *
   * THIS SOFTWARE IS PROVIDED BY EXOFFICE TECHNOLOGIES AND CONTRIBUTORS
   * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
   * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
   * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
   * EXOFFICE TECHNOLOGIES OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
   * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
   * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
   * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
   * OF THE POSSIBILITY OF SUCH DAMAGE.
   *
   * Copyright 2001-2005 (C) Exoffice Technologies Inc. All Rights Reserved.
   *
   * $Id: ConsumerManagerImpl.java,v 1.3 2005/12/23 12:17:25 tanderson Exp $
   */
  package org.exolab.jms.messagemgr;
  
  import java.sql.Connection;
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.List;
  import javax.jms.InvalidDestinationException;
  import javax.jms.InvalidSelectorException;
  import javax.jms.JMSException;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  import org.exolab.jms.client.JmsDestination;
  import org.exolab.jms.client.JmsQueue;
  import org.exolab.jms.client.JmsTopic;
  import org.exolab.jms.persistence.DatabaseService;
  import org.exolab.jms.persistence.PersistenceAdapter;
  import org.exolab.jms.persistence.PersistenceException;
  import org.exolab.jms.service.Service;
  import org.exolab.jms.service.ServiceException;
  
  
  /***
   * The consumer manager is responsible for creating and managing the lifecycle
   * of consumers. The consumer manager maintains a list of all active consumers.
   *
   * @author <a href="mailto:jima@comware.com.au">Jim Alateras</a>
   * @author <a href="mailto:tma@netspace.net.au">Tim Anderson</a>
   * @version $Revision: 1.3 $ $Date: 2005/12/23 12:17:25 $
   */
  public class ConsumerManagerImpl extends Service implements ConsumerManager {
  
      /***
       * The destination manager.
       */
      private final DestinationManager _destinations;
  
      /***
       * The database service.
       */
      private final DatabaseService _database;
  
      /***
       * Maintains a list of all consumers, durable and non-durable. All durable
       * subscribers are maintained in memory until they are removed from the
       * system entirely. All non-durable subscribers are maintained in memory
       * until their endpoint is removed.
       */
      private HashMap _consumers = new HashMap();
  
      /***
       * The set of all consumer endpoints. This is a map of {@link
       * ConsumerEndpoint} instances, keyed on {@link ConsumerEndpoint#getPersistentId()}
      * if non null; otherwise {@link ConsumerEndpoint#getId()}.
      */
     private HashMap _endpoints = new HashMap();
 
 
     /***
      * Maintains a mapping between destinations and consumers. A destination can
      * have more than one consumer and a consumer can also be registered to more
      * than one destination
      */
     private HashMap _destToConsumerMap = new HashMap();
 
     /***
      * The set of all wildcard consumers, represented by a map of ConsumerEntry
      * -> JmsTopic instances.
      */
     private HashMap _wildcardConsumers = new HashMap();
 
     /***
      * The seed to allocate identifiers to new consumers.
      */
     private long _consumerIdSeed = 0;
 
     /***
      * The logger.
      */
     private static final Log _log = LogFactory.getLog(
             ConsumerManagerImpl.class);
 
 
     /***
      * Construct a new  <code>ConsumerManager</code>.
      *
      * @param destinations the destination manager
      * @param database     the database service
      */
     public ConsumerManagerImpl(DestinationManager destinations,
                                DatabaseService database) {
         if (destinations == null) {
             throw new IllegalArgumentException(
                     "Argument 'destinations' is null");
         }
         if (database == null) {
             throw new IllegalArgumentException("Argument 'database' is null");
         }
         _destinations = destinations;
         _database = database;
     }
 
     /***
      * Create a new durable subscription.
      * <p/>
      * A client can change an existing durable subscription by creating a new
      * subscription with the same name and a new topic. Changing a durable
      * subscriber is equivalent to unsubscribing the old one and creating a new
      * one.
      *
      * @param topic    the topic to subscribe to
      * @param name     the subscription name
      * @param clientID the client identifier. May be <code>null</code>
      * @throws InvalidDestinationException if <code>topic</code> is not a
      *                                     persistent destination, or
      *                                     <code>name</code> is an invalid
      *                                     subscription name
      * @throws JMSException                if the durable consumer can't be
      *                                     created
      */
     public synchronized void subscribe(JmsTopic topic, String name,
                                        String clientID)
             throws JMSException {
         createInactiveDurableConsumer(topic, name, clientID);
     }
 
 
     /***
      * Remove a durable subscription.
      * <p/>
      * A subscription may only be removed if the associated {@link
      * DurableConsumerEndpoint} is inactive.
      *
      * @param name     the subscription name
      * @param clientID the client identifier. May be <code>null</code>
      * @throws InvalidDestinationException if an invalid subscription name is
      *                                     specified.
      * @throws JMSException                if the durable consumer is active, or
      *                                     cannot be removed
      */
     public synchronized void unsubscribe(String name, String clientID)
             throws JMSException {
         if (_log.isDebugEnabled()) {
             _log.debug("unsubscribe(name=" + name + ", clientID="
                        + clientID + ")");
         }
 
         DurableConsumerEndpoint consumer
                 = (DurableConsumerEndpoint) _endpoints.remove(name);
         if (consumer == null) {
             throw new InvalidDestinationException("Durable consumer " + name
                                                   + " is not defined.");
         }
         if (consumer.isActive()) {
             throw new JMSException("Cannot remove durable consumer=" + name
                                    + ": consumer is active");
         }
         consumer.close();
 
         // remove it from the persistent store.
         try {
             _database.begin();
             Connection connection = _database.getConnection();
 
             _database.getAdapter().removeDurableConsumer(connection, name);
             removeConsumerEntry(name);
             _database.commit();
         } catch (PersistenceException exception) {
             String msg = "Failed to remove durable consumer, name=" + name;
             rethrow(msg, exception);
         }
     }
 
     /***
      * Remove all durable subscriptions for a destination.
      * <p/>
      * Subscriptions may only be removed if the associated {@link
      * ConsumerEndpoint}s are inactive.
      *
      * @param topic the topic to remove consumers for
      * @throws JMSException if the subscriptions can't be removed
      */
     public synchronized void unsubscribe(JmsTopic topic) throws JMSException {
         List list = (List) _destToConsumerMap.get(topic);
         if (list != null) {
             ConsumerEntry[] consumers
                     = (ConsumerEntry[]) list.toArray(new ConsumerEntry[0]);
             for (int i = 0; i < consumers.length; ++i) {
                 ConsumerEntry consumer = consumers[i];
                 if (consumer.isDurable()) {
                     // remove the durable consumer. This operation
                     // will fail if the consumer is active.
                     unsubscribe(consumer.getName(), consumer.getClientID());
                 }
             }
         }
 
         // remove all consumers for the specified destination
         removeFromConsumerCache(topic);
     }
 
     /***
      * Create a transient consumer for the specified destination.
      *
      * @param destination  the destination to consume messages from
      * @param connectionId the identity of the connection that owns this
      *                     consumer
      * @param selector     the message selector. May be <code>null</code>
      * @param noLocal      if true, and the destination is a topic, inhibits the
      *                     delivery of messages published by its own connection.
      *                     The behavior for <code>noLocal</code> is not
      *                     specified if the destination is a queue.
      * @return a new transient consumer
      */
     public synchronized ConsumerEndpoint createConsumer(
             JmsDestination destination, long connectionId,
             String selector,
             boolean noLocal)
             throws JMSException, InvalidSelectorException {
 
         if (_log.isDebugEnabled()) {
             _log.debug("createConsumerEndpoint(destination=" + destination
                        + ", connectionId=" + connectionId
                        + ", selector=" + selector
                        + ", noLocal=" + noLocal + ")");
         }
 
         ConsumerEndpoint consumer = null;
 
         // ensure that the destination is valid before proceeding
         getDestination(destination, true);
 
         long consumerId = getNextConsumerId();
 
         try {
             _database.begin();
             // determine what type of consumer to create based on the destination
             // it subscribes to.
             if (destination instanceof JmsTopic) {
                 JmsTopic topic = (JmsTopic) destination;
                 consumer = new TopicConsumerEndpoint(consumerId, connectionId,
                                                      topic, selector, noLocal,
                                                      _destinations);
             } else if (destination instanceof JmsQueue) {
                 QueueDestinationCache cache;
                 cache = (QueueDestinationCache) _destinations.getDestinationCache(
                         destination);
                 consumer = new QueueConsumerEndpoint(consumerId, cache, selector);
             }
 
             if (consumer != null) {
                 // add it to the list of managed consumers. If it has a persistent
                 // identity, use that as the key, otherwise use its transient
                 // identity.
                 Object key = ConsumerEntry.getConsumerKey(consumer);
                 _endpoints.put(key, consumer);
                 addConsumerEntry(key, destination, null, false);
             }
             _database.commit();
         } catch (Exception exception) {
             rethrow("Failed to create consumer", exception);
         }
 
         return consumer;
     }
 
     /***
      * Create a durable consumer.
      *
      * @param topic        the topic to subscribe to
      * @param name         the subscription name
      * @param clientID     the client identifier. May be <code>null</code>.
      * @param connectionId the identity of the connection that owns this
      *                     consumer
      * @param noLocal      if true, and the destination is a topic, inhibits the
      *                     delivery of messages published by its own
      *                     connection.
      * @param selector     the message selector. May be <code>null</code>
      * @return the durable consumer endpoint
      * @throws InvalidDestinationException if <code>topic</code> is not a
      *                                     persistent destination
      * @throws InvalidSelectorException    if the selector is not well formed
      * @throws JMSException                if a durable consumer is already
      *                                     active with the same <code>name</code>
      */
     public synchronized DurableConsumerEndpoint createDurableConsumer(
             JmsTopic topic, String name, String clientID, long connectionId,
             boolean noLocal,
             String selector)
             throws JMSException {
 
         if (_log.isDebugEnabled()) {
             _log.debug("createDurableConsumer(topic=" + topic
                        + ", name=" + name + ", connectionId=" + connectionId
                        + ", selector=" + selector + ", noLocal=" + noLocal
                        + ")");
         }
 
         DurableConsumerEndpoint consumer
                 = createInactiveDurableConsumer(topic, name, clientID);
         consumer.activate(connectionId, selector, noLocal);
 
         return consumer;
     }
 
     /***
      * Create a browser for the specified destination and the selector. A
      * browser is responsible for passing all messages back to the client that
      * reside on the queue
      *
      * @param queue    the queue to browse
      * @param selector the message selector. May be <code>null</code>
      * @return the queue browser endpoint
      * @throws JMSException             if the browser can't be created
      */
     public synchronized ConsumerEndpoint createQueueBrowser(JmsQueue queue,
                                                             String selector)
             throws JMSException {
 
         // ensure that the destination is valid before proceeding
         getDestination(queue, true);
 
         long consumerId = getNextConsumerId();
 
 
         ConsumerEndpoint consumer = null;
         try {
             _database.begin();
             QueueDestinationCache cache;
             cache = (QueueDestinationCache) _destinations.getDestinationCache(
                     queue);
             consumer = new QueueBrowserEndpoint(consumerId, cache, selector);
             Object key = ConsumerEntry.getConsumerKey(consumer);
             _endpoints.put(key, consumer);
             addConsumerEntry(key, queue, null, false);
             _database.commit();
         } catch (Exception exception) {
             rethrow("Failed to create browser", exception);
         }
 
         return consumer;
     }
 
     /***
      * Close a consumer.
      *
      * @param consumer the consumer to close
      */
     public synchronized void closeConsumer(ConsumerEndpoint consumer) {
         if (_log.isDebugEnabled()) {
             _log.debug("closeConsumerEndpoint(consumer=[Id="
                        + consumer.getId() + ", destination="
                        + consumer.getDestination() + ")");
         }
 
         Object key = ConsumerEntry.getConsumerKey(consumer);
 
         ConsumerEndpoint existing = (ConsumerEndpoint) _endpoints.get(key);
         if (existing != null) {
             try {
                  _database.begin();
                 if (consumer.getId() != existing.getId()) {
                     // As a fix for bug 759752, only remove the consumer if it
                     // matches the existing one.
                     // @todo - not sure if this situation can arise any longer
                     _log.error("Existing endpoint doesn't match that to be closed "
                                + "- retaining");
                 } else if (existing instanceof DurableConsumerEndpoint) {
                     DurableConsumerEndpoint durable
                             = (DurableConsumerEndpoint) existing;
                     if (durable.isActive()) {
                         try {
                             durable.deactivate();
                         } catch (JMSException exception) {
                             _log.error("Failed to deactivate durable consumer="
                                        + durable, exception);
                         }
                     }
                 } else {
                     _endpoints.remove(key);
                     consumer.close();
                     removeConsumerEntry(key);
                 }
                 _database.commit();
             } catch (PersistenceException exception) {
                 _log.error("Failed to close consumer=" + consumer, exception);
                 rollback();
             }
         }
     }
 
     /***
      * Return the consumer with the specified identity.
      *
      * @param consumerId the identity of the consumer
      * @return the associated consumer, or <code>null</code> if none exists
      */
     public synchronized ConsumerEndpoint getConsumerEndpoint(long consumerId) {
         return (ConsumerEndpoint) _endpoints.get(new Long(consumerId));
     }
 
     /***
      * Return the consumer with the specified persistent identity.
      *
      * @param persistentId the persistent identity of the consumer
      * @return the associated consumer, or <code>null</code> if none exists
      */
     public synchronized ConsumerEndpoint getConsumerEndpoint(
             String persistentId) {
         return (ConsumerEndpoint) _endpoints.get(persistentId);
     }
 
     /***
      * Determines if there are any active consumers for a destination.
      *
      * @param destination the destination
      * @return <code>true</code> if there is at least one consumer
      */
     public synchronized boolean hasActiveConsumers(JmsDestination destination) {
         boolean result = false;
         ConsumerEndpoint[] consumers = getConsumers();
         for (int i = 0; i < consumers.length; ++i) {
             if (consumers[i].canConsume(destination)) {
                 result = true;
                 break;
             }
         }
         return result;
     }
 
     /***
      * Start the service.
      *
      * @throws ServiceException if the service fails to start
      */
     protected void doStart() throws ServiceException {
         try {
             _database.begin();
             Connection connection = _database.getConnection();
 
             PersistenceAdapter adapter = _database.getAdapter();
 
             // return a list of JmsDestination objects.
             HashMap map = adapter.getAllDurableConsumers(connection);
             Iterator iter = map.keySet().iterator();
 
             // Create an endpoint for each durable consumer
             while (iter.hasNext()) {
                 String consumer = (String) iter.next();
                 String deststr = (String) map.get(consumer);
 
                 JmsDestination dest = _destinations.getDestination(deststr);
                 if (dest == null) {
                     // this maybe a wildcard subscription
                     dest = new JmsTopic(deststr);
                     if (!((JmsTopic) dest).isWildCard()) {
                         dest = null;
                     }
                 }
 
                 if (consumer != null && dest != null &&
                         dest instanceof JmsTopic) {
                     // cache the consumer-destination mapping in memory.
                     addDurableConsumer((JmsTopic) dest, consumer, null);
                 } else {
                     // @todo
                     _log.error("Failure in ConsumerManager.init : " + consumer +
                                ":" + dest);
                 }
             }
             _database.commit();
         } catch (Exception exception) {
             rollback();
             throw new ServiceException("Failed to initialise ConsumerManager",
                                        exception);
         }
     }
 
     /***
      * Stop the service.
      */
     protected synchronized void doStop() {
         // clean up all the destinations
         Object[] endpoints = _endpoints.values().toArray();
         for (int index = 0; index < endpoints.length; index++) {
             closeConsumer((ConsumerEndpoint) endpoints[index]);
         }
         _endpoints.clear();
 
         // remove cache data structures
         _consumers.clear();
         _destToConsumerMap.clear();
         _wildcardConsumers.clear();
     }
 
     /***
      * Create an inactive durable consumer.
      * <p/>
      * If the consumer doesn't exist, it will created in the persistent store.
      * If it does exist, and is inactive, it will be recreated. If it does
      * exist, but is active, an exception will be raised.
      *
      * @param topic    the topic to subscribe to
      * @param name     the subscription name
      * @param clientID the client identifier. May be <code>null</code>.
      * @return the durable consumer
      * @throws InvalidDestinationException if <code>topic</code> is not a
      *                                     persistent destination
      * @throws JMSException                if a durable consumer is already
      *                                     active with the same <code>name</code>,
      *                                     or the consumer can't be created
      */
     private DurableConsumerEndpoint createInactiveDurableConsumer(
             JmsTopic topic, String name, String clientID)
             throws JMSException {
         DurableConsumerEndpoint endpoint;
 
         if (_log.isDebugEnabled()) {
             _log.debug("createInactiveDurableConsumer(topic=" + topic
                        + ", name=" + name + ", clientID=" + clientID + ")");
         }
 
         // check that the destination exists, if the topic is not a wildcard
         if (!topic.isWildCard()) {
             topic = (JmsTopic) getDestination(topic, false);
         }
 
         if (name == null || name.length() == 0) {
             throw new InvalidDestinationException(
                     "Invalid subscription name: " + name);
         }
         endpoint = (DurableConsumerEndpoint) _endpoints.get(name);
         if (endpoint != null) {
             if (endpoint.isActive()) {
                 throw new JMSException(
                         "Durable subscriber already exists with name: " + name);
             }
             if (!endpoint.getDestination().equals(topic)) {
                 // subscribing to a different topic. Need to re-subscribe.
                 unsubscribe(name, clientID);
                 endpoint = null;
             }
         }
         if (endpoint == null) {
             try {
                 _database.begin();
                 PersistenceAdapter adapter = _database.getAdapter();
                 Connection connection = _database.getConnection();
                 adapter.addDurableConsumer(connection, topic.getName(), name);
                 endpoint = addDurableConsumer(topic, name, clientID);
                 _database.commit();
             } catch (Exception exception) {
                 String msg = "Failed to create durable consumer, name=" + name
                         + ", for topic=" + topic.getName();
                 rethrow(msg, exception);
             }
         }
 
         return endpoint;
     }
 
     /***
      * Register an inactive durable consumer.
      *
      * @param topic    the topic to subscribe to
      * @param name     the subscription name
      * @param clientID the client identifier. May be <code>null</code>.
      * @return the durable consumer
      * @throws JMSException for any JMS error
      * @throws PersistenceException for any persistence error
      */
     private DurableConsumerEndpoint addDurableConsumer(JmsTopic topic,
                                                        String name,
                                                        String clientID)
             throws JMSException, PersistenceException {
         DurableConsumerEndpoint consumer;
         // cache the consumer locally
         addConsumerEntry(name, topic, clientID, true);
 
         long consumerId = getNextConsumerId();
         consumer = new DurableConsumerEndpoint(consumerId, topic, name,
                                                _destinations);
         _endpoints.put(consumer.getPersistentId(), consumer);
         return consumer;
     }
 
     /***
      * Add a consumer entry.
      *
      * @param key         a key to identify the entry.
      * @param destination the destination it is subscribed to. It can be a
      *                    wildcard
      * @param clientID    the client identifier. May be <code>null</code>
      * @param durable     indicates whether it is a durable subscription
      * @throws JMSException if key specifies a duplicate entry.
      */
     private void addConsumerEntry(Object key, JmsDestination destination,
                                   String clientID,
                                   boolean durable)
             throws JMSException {
         if (_log.isDebugEnabled()) {
             _log.debug("addConsumerEntry(key=" + key + ", destination="
                        + destination + ", clientID=" + clientID
                        + ", durable=" + durable + ")");
         }
 
         if (_consumers.containsKey(key)) {
             throw new JMSException("Duplicate consumer key:" + key);
         }
 
         ConsumerEntry entry = new ConsumerEntry(key, destination, clientID,
                                                 durable);
         _consumers.put(key, entry);
 
         if (destination instanceof JmsTopic
                 && ((JmsTopic) destination).isWildCard()) {
             // if the specified destination is a JmsTopic and also a wildcard
             // then we need to add it to all matching destinations
             _wildcardConsumers.put(entry, destination);
         } else {
             // we also need to add the reverse mapping
             List consumers = (List) _destToConsumerMap.get(destination);
             if (consumers == null) {
                 consumers = new ArrayList();
                 _destToConsumerMap.put(destination, consumers);
             }
 
             // add the mapping
             consumers.add(entry);
         }
     }
 
     /***
      * Remove the specified consumer from the cache.
      *
      * @param key the consumer key
      */
     private void removeConsumerEntry(Object key) {
         if (_log.isDebugEnabled()) {
             _log.debug("removeConsumerEntry(key=" + key + ")");
         }
 
         ConsumerEntry entry = (ConsumerEntry) _consumers.remove(key);
         if (entry != null) {
             JmsDestination dest = entry.getDestination();
 
             if (dest instanceof JmsTopic && ((JmsTopic) dest).isWildCard()) {
                 // remove it from the wildcard cache.
                 _wildcardConsumers.remove(entry);
             } else {
                 // remove it from the specified destination
                 List consumers = (List) _destToConsumerMap.get(dest);
                 if (consumers != null) {
                     consumers.remove(entry);
 
                     // if consumers is of size 0 then remove it
                     if (consumers.isEmpty()) {
                         _destToConsumerMap.remove(dest);
                     }
                 }
             }
         } else if (_log.isDebugEnabled()) {
             _log.debug("removeConsumerEntry(key=" + key
                        + "): consumer not found");
         }
     }
 
     /***
      * Remove all the consumers for the specified destination from the cache.
      *
      * @param destination the destination to remove
      */
     private void removeFromConsumerCache(JmsDestination destination) {
         _destToConsumerMap.remove(destination);
     }
 
     /***
      * Returns the next seed value to be allocated to a new consumer.
      *
      * @return a unique identifier for a consumer
      */
     private long getNextConsumerId() {
         return ++_consumerIdSeed;
     }
 
     /***
      * Returns the destination managed by {@link DestinationManager}
      * corresponding to that supplied, creating it if needed.
      *
      * @param destination the destination to look up
      * @param create      if <code>true</code> the destination may be created if
      *                    it doesn't exist
      * @return the destination managed by {@link DestinationManager}
      *         corresponding to <code>destination</code>.
      * @throws InvalidDestinationException if the destination doesn't exist and
      *                                     <code>create</code> is false; or the
      *                                     destination's properties don't match
      *                                     the existing destination
      * @throws JMSException                if the destination can't be created
      */
     private JmsDestination getDestination(JmsDestination destination,
                                           boolean create)
             throws InvalidDestinationException, JMSException {
         final String name = destination.getName();
         JmsDestination result;
         JmsDestination existing = _destinations.getDestination(name);
 
         if (existing == null) {
             if (!create) {
                 throw new InvalidDestinationException(
                         "No destination with name=" + name + " exists");
             }
             // register the destination dynamically.
             _destinations.createDestination(destination);
             result = _destinations.getDestination(destination.getName());
         } else {
             // make sure the supplied destination has the same properties
             // as the existing one
             if (!destination.getClass().getName().equals(
                     existing.getClass().getName())) {
                 throw new InvalidDestinationException(
                         "Mismatched destination properties for destination"
                         + " with name=" + name);
             }
             if (existing.getPersistent() != destination.getPersistent()) {
                 throw new InvalidDestinationException(
                         "Mismatched destination properties for destination"
                         + " with name=" + name);
             }
             result = existing;
         }
         return result;
     }
 
     /***
      * Returns the consumers managed by this.
      *
      * @return an array of consumers
      */
     private ConsumerEndpoint[] getConsumers() {
         return (ConsumerEndpoint[]) _endpoints.values().toArray(
                 new ConsumerEndpoint[0]);
     }
 
     /***
      * Rollback any transaction.
      */
     private void rollback() {
         try {
             if (_database.isTransacted()) {
                 _database.rollback();
             }
         } catch (PersistenceException error) {
             _log.warn("Failed to rollback after error", error);
         }
     }
 
     /***
      * Helper to clean up after a failed call, and rethrow.
      * Any transaction will be rolled back.
      *
      * @param message   the message to log
      * @param exception the exception
      * @throws JMSException the original exception adapted to a
      *                      <code>JMSException</code> if necessary
      */
     private void rethrow(String message, Exception exception)
             throws JMSException {
         rollback();
 
         if (exception instanceof JMSException) {
             _log.debug(message, exception);
             throw (JMSException) exception;
         }
         // need to adapt the exception, so log as an error before rethrow
         _log.error(message, exception);
         throw new JMSException(exception.getMessage());
     }
 
     /***
      * Helper class used to maintain consumer information
      */
     private static final class ConsumerEntry {
 
         /***
          * An identifier for the consumer.
          */
         private final Object _key;
 
         /***
          * The destination that the consumer is subscribed to.
          */
         private final JmsDestination _destination;
 
         /***
          * The client identifier. May be <code>null</code>.
          */
         private final String _clientID;
 
         /***
          * Indicated whether this entry is for a durable subscriber
          */
         private final boolean _durable;
 
 
         /***
          * Construct a new <code>ConsumerEntry</code>.
          *
          * @param key         an identifier for the consumer
          * @param destination the destination consumer is subscribed to
          * @param clientID    the client identifier. May be <code>null</code>
          * @param durable     indicates whether it is a durable subscription
          */
         public ConsumerEntry(Object key, JmsDestination destination,
                              String clientID, boolean durable) {
             _key = key;
             _destination = destination;
             _clientID = clientID;
             _durable = durable;
         }
 
         public boolean equals(Object obj) {
             boolean result = false;
             if (obj instanceof ConsumerEntry) {
                 result = ((ConsumerEntry) obj)._key.equals(_key);
             }
 
             return result;
         }
 
         public Object getKey() {
             return _key;
         }
 
         public String getName() {
             return (_key instanceof String) ? (String) _key : null;
         }
 
         public JmsDestination getDestination() {
             return _destination;
         }
 
         public String getClientID() {
             return _clientID;
         }
 
         public boolean isDurable() {
             return _durable;
         }
 
         /***
          * Helper to return a key for identifying {@link ConsumerEndpoint}
          * instances. This returns the consumers persistent identifier if it has
          * one; if not, it returns its transient identifier.
          *
          * @param consumer the consumer
          * @return a key for identifying <code>consumer</code>
          */
         public static Object getConsumerKey(ConsumerEndpoint consumer) {
             Object key = null;
             String id = consumer.getPersistentId();
             if (id != null) {
                 key = id;
             } else {
                 key = new Long(consumer.getId());
             }
             return key;
         }
     }
 
 }