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1 /*** 2 * Redistribution and use of this software and associated documentation 3 * ("Software"), with or without modification, are permitted provided 4 * that the following conditions are met: 5 * 6 * 1. Redistributions of source code must retain copyright 7 * statements and notices. Redistributions must also contain a 8 * copy of this document. 9 * 10 * 2. Redistributions in binary form must reproduce the 11 * above copyright notice, this list of conditions and the 12 * following disclaimer in the documentation and/or other 13 * materials provided with the distribution. 14 * 15 * 3. The name "Exolab" must not be used to endorse or promote 16 * products derived from this Software without prior written 17 * permission of Exoffice Technologies. For written permission, 18 * please contact info@exolab.org. 19 * 20 * 4. Products derived from this Software may not be called "Exolab" 21 * nor may "Exolab" appear in their names without prior written 22 * permission of Exoffice Technologies. Exolab is a registered 23 * trademark of Exoffice Technologies. 24 * 25 * 5. Due credit should be given to the Exolab Project 26 * (http://www.exolab.org/). 27 * 28 * THIS SOFTWARE IS PROVIDED BY EXOFFICE TECHNOLOGIES AND CONTRIBUTORS 29 * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT 30 * NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND 31 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL 32 * EXOFFICE TECHNOLOGIES OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, 33 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 34 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 35 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 37 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 38 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 39 * OF THE POSSIBILITY OF SUCH DAMAGE. 40 * 41 * Copyright 2001-2003 (C) Exoffice Technologies Inc. All Rights Reserved. 42 * 43 * $Id: TopicConsumerEndpoint.java,v 1.40 2003/10/21 14:41:23 tanderson Exp $ 44 * 45 * Date Author Changes 46 * 3/1/2001 jima Created 47 */ 48 package org.exolab.jms.messagemgr; 49 50 import java.sql.Connection; 51 import java.util.HashMap; 52 import java.util.Iterator; 53 54 import javax.jms.InvalidSelectorException; 55 import javax.jms.JMSException; 56 import javax.jms.MessageListener; 57 import javax.jms.Session; 58 import javax.transaction.TransactionManager; 59 60 import org.apache.commons.logging.Log; 61 import org.apache.commons.logging.LogFactory; 62 63 import org.exolab.jms.JMSErrorCodes; 64 import org.exolab.jms.client.JmsDestination; 65 import org.exolab.jms.client.JmsTopic; 66 import org.exolab.jms.message.MessageHandle; 67 import org.exolab.jms.message.MessageImpl; 68 import org.exolab.jms.persistence.PersistenceException; 69 import org.exolab.jms.scheduler.Scheduler; 70 import org.exolab.jms.server.ClientDisconnectionException; 71 import org.exolab.jms.server.JmsServerSession; 72 73 74 /*** 75 * The topic destination cache is specific to a consumer that 76 * subscribes to a topic destination. 77 * 78 * @version $Revision: 1.40 $ $Date: 2003/10/21 14:41:23 $ 79 * @author <a href="mailto:jima@exoffice.com">Jim Alateras</a> 80 */ 81 public class TopicConsumerEndpoint 82 extends ConsumerEndpoint 83 implements DestinationEventListener { 84 85 /*** 86 * Maintains a list of TopicDestinationCache that this endpoint subscribes 87 * too. A wildcard subscription may point to more than one. 88 */ 89 protected HashMap _caches = new HashMap(); 90 91 /*** 92 * Cache the destination that this endpoint subscribes too 93 */ 94 protected JmsTopic _topic = null; 95 96 /*** 97 * The maximum number of messages that a dispatch can deliver at any one 98 * time 99 */ 100 private final int MAX_MESSAGES = 200; 101 102 /*** 103 * The logger 104 */ 105 private static final Log _log = 106 LogFactory.getLog(TopicConsumerEndpoint.class); 107 108 109 /*** 110 * Construct a new <code>TopicConsumerEndpoint</code>.<p/> 111 * The destination and selector determine where it will be sourcing 112 * its messages from, and scheduler is used to asynchronously deliver 113 * messages to the consumer. 114 * 115 * @param session - the owning session 116 * @param clientId - uniquely identifies the remote client within session 117 * @param topic - destination that this object was created for 118 * @param selector - the selector attached to the consumer, if any. 119 * @param scheduler - used to schedule async message delivery. 120 * @throws InvalidSelectorException - if the selector is invalid 121 * @throws JMSException - for other general exceptions 122 */ 123 TopicConsumerEndpoint(JmsServerSession session, long clientId, 124 JmsTopic topic, String selector, Scheduler scheduler) 125 throws InvalidSelectorException, JMSException { 126 super(session, clientId, selector, scheduler); 127 128 // register the endpoint with the destination 129 DestinationManager destmgr = DestinationManager.instance(); 130 if (topic != null) { 131 _topic = topic; 132 133 if (_topic.isWildCard()) { 134 // if the topic is a wild card then we need to retrieve a 135 // set of matching destination caches. 136 _caches = destmgr.getTopicDestinationCaches(topic); 137 // for each cache register this endpoint as a consumer of 138 // it's messages. Before doing so register as a destination 139 // event listener with the DestinationManager 140 destmgr.addDestinationEventListener(this); 141 Iterator iter = _caches.values().iterator(); 142 while (iter.hasNext()) { 143 ((TopicDestinationCache) iter.next()).registerConsumer(this); 144 } 145 } else { 146 // if the topic is not a wildcard then we need to get the 147 // destination cache. If one does not exist then we need to 148 // create it. 149 DestinationCache cache = destmgr.getDestinationCache(topic); 150 if (cache == null) { 151 cache = destmgr.createDestinationCache(topic); 152 } 153 _caches.put(topic, cache); 154 cache.registerConsumer(this); 155 } 156 } 157 } 158 159 /*** 160 * Deliver messages in the cache to the consumer 161 * 162 * @return <code>true</code> if the endpoint should be rescheduled 163 */ 164 public boolean deliverMessages() { 165 boolean reschedule = true; 166 167 for (int index = 0; index < MAX_MESSAGES;) { 168 169 // check if we should exit the loop 170 if (stopDelivery()) { 171 reschedule = false; 172 break; 173 } 174 175 // Process the first message on the list. 176 boolean processed = true; 177 MessageHandle handle = removeFirstMessage(); 178 try { 179 if (_selector != null) { 180 MessageImpl m = handle.getMessage(); 181 if ((m != null) && _selector.selects(m)) { 182 // this message has been selected by the selector 183 handle.setClientId(getClientId()); 184 _listener.onMessage(handle, true); 185 index++; 186 } else { 187 // this message has not been selected 188 handle.destroy(); 189 } 190 } else { 191 // send the message to the consumer 192 handle.setClientId(getClientId()); 193 _listener.onMessage(handle, true); 194 index++; 195 } 196 } catch (ClientDisconnectionException exception) { 197 _listener = null; 198 returnMessage(handle); 199 } catch (JMSException exception) { 200 if (exception.getErrorCode().equals( 201 JMSErrorCodes.FailedToResolveHandle)) { 202 // do not return message back to the cache 203 _log.error("Dropping handle " + handle 204 + " since we cannot resolve it."); 205 } else { 206 _log.error(exception, exception); 207 returnMessage(handle); 208 } 209 } catch (Exception exception) { 210 _log.error(exception, exception); 211 returnMessage(handle); 212 } 213 } 214 return reschedule; 215 } 216 217 // implementation of ConsumerEndpoint.receiveMessage 218 public MessageHandle receiveMessage(long wait) { 219 synchronized (_waitingForMessageMonitor) { 220 MessageHandle handle = receiveNoWait(); 221 if ((handle == null) && 222 (wait >= 0)) { 223 // no message is currently available for this 224 // consumer. So set the flag to indicate that 225 // the consumer is waiting for a message 226 setWaitingForMessage(); 227 } 228 229 return handle; 230 } 231 } 232 233 /*** 234 * Returns the first available message 235 */ 236 public MessageHandle receiveNoWait() { 237 MessageHandle handle = null; 238 while ((handle = removeFirstMessage()) != null) { 239 // make sure we can still get access to the message 240 MessageImpl message = handle.getMessage(); 241 if (message != null) { 242 if (_selector == null || _selector.selects(message)) { 243 // got a message which is applicable for the endpoint 244 handle.setClientId(getClientId()); 245 break; 246 } else { 247 // this message has been filtered out so we can destroy 248 // the handle. 249 handle.destroy(); 250 } 251 } 252 handle = null; 253 } 254 return handle; 255 } 256 257 // override ConsumerEndpoint.messageRemoved 258 public boolean messageRemoved(MessageImpl message) { 259 260 boolean result = false; 261 262 if (message != null) { 263 try { 264 MessageHandle handle = 265 MessageHandleFactory.getHandle(this, message); 266 267 // if the message in the main cache then destroy the 268 // handle 269 if (removeMessage(handle)) { 270 if (handle.getConsumerName() == null) { 271 // @todo - the follwoing is required in order for 272 // MessageMgr to resolve this endpoint when the 273 // handle is destroyed. However, its not clear 274 // why topics need to go through MessageMgr at all... 275 handle.setConsumerName(getPersistentId()); 276 } 277 handle.destroy(); 278 result = true; 279 } 280 281 } catch (JMSException exception) { 282 _log.error("Failed to remove message from endpoint", 283 exception); 284 } 285 } 286 287 return result; 288 } 289 290 // override ConsumerEndpoint.messageRemoved 291 public boolean persistentMessageRemoved(Connection connection, 292 MessageImpl message) 293 throws PersistenceException { 294 295 boolean result = false; 296 297 if (message != null) { 298 try { 299 PersistentMessageHandle handle = (PersistentMessageHandle) 300 MessageHandleFactory.getHandle(this, message); 301 302 // if the message in the main cache then destroy the handle 303 if (removeMessage(handle)) { 304 MessageHandleFactory.destroyPersistentHandle(connection, 305 handle); 306 result = true; 307 } 308 309 } catch (JMSException exception) { 310 _log.error("Failed to remove persistent message from endpoint", 311 exception); 312 } 313 } 314 315 return result; 316 } 317 318 // implementation of ConsumerEndpoint.getDestination 319 public JmsDestination getDestination() { 320 return _topic; 321 } 322 323 // override ConsumerEndpoint.unregister 324 public void unregister() { 325 Iterator iter = _caches.values().iterator(); 326 while (iter.hasNext()) { 327 ((TopicDestinationCache) iter.next()).unregisterConsumer(this); 328 } 329 _caches.clear(); 330 } 331 332 public void recover() { 333 // no-op 334 } 335 336 // implementation of DestinationEventListener.destinationAdded 337 public void destinationAdded(JmsDestination destination, 338 DestinationCache cache) { 339 if ((destination instanceof JmsTopic) && 340 (_topic.match((JmsTopic) destination)) && 341 (!_caches.containsKey(destination))) { 342 synchronized (_caches) { 343 _caches.put(destination, cache); 344 } 345 346 ((TopicDestinationCache) cache).registerConsumer(this); 347 _log.debug(_topic + " registered with " + destination); 348 } 349 } 350 351 // implementation of DestinationEventListener.destinationRemoved 352 public void destinationRemoved(JmsDestination destination, 353 DestinationCache cache) { 354 if ((destination instanceof JmsTopic) && 355 (_caches.containsKey(destination))) { 356 synchronized (_caches) { 357 _caches.remove(destination); 358 } 359 _log.debug(_topic + " unregistered with " + destination); 360 } 361 } 362 363 /*** 364 * Closes this endpoint 365 */ 366 protected void doClose() { 367 // unregister as a destination event listener 368 DestinationManager.instance().removeDestinationEventListener(this); 369 // unregister from the destination before continuing 370 Iterator iter = _caches.values().iterator(); 371 while (iter.hasNext()) { 372 ((TopicDestinationCache) iter.next()).unregisterConsumer(this); 373 } 374 _caches.clear(); 375 } 376 377 } //-- TopicConsumerEndpoint

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