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: MessageCache.java,v 1.9 2003/12/29 13:09:25 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.Collections;
52 import java.util.HashMap;
53 import java.util.Map;
54
55 import javax.jms.JMSException;
56
57 import org.apache.commons.logging.Log;
58 import org.apache.commons.logging.LogFactory;
59
60 import org.exolab.jms.message.MessageHandle;
61 import org.exolab.jms.message.MessageId;
62 import org.exolab.jms.message.MessageImpl;
63 import org.exolab.jms.persistence.DatabaseService;
64 import org.exolab.jms.persistence.PersistenceAdapter;
65 import org.exolab.jms.persistence.PersistenceException;
66
67
68 /***
69 * The MessageCache is responsible for managing the collection of persistent
70 * messages for a particular {@link DestinationCache} or {@link Endpoint}.
71 * <p>
72 * Persistent messages and transient messages are stored in different caches
73 * since they behave slightly different. Persistent messages can be passivated
74 * to disk when memory is low.
75 * <p>
76 * We leave garbage collection of messages to the Java Garbage Collection
77 * mechanism.
78 *
79 * @version $Revision: 1.9 $ $Date: 2003/12/29 13:09:25 $
80 * @author <a href="mailto:jima@exoffice.com">Jim Alateras</a>
81 **/
82 class MessageCache {
83
84 /***
85 * Maintain the pool of transient messages.
86 */
87 private transient Map _transient =
88 Collections.synchronizedMap(new HashMap(1023));
89
90 /***
91 * Maintain the pool of persistent messages.
92 */
93 private transient Map _persistent =
94 Collections.synchronizedMap(new HashMap(1023));
95
96 /***
97 * Maintains a list of {@link MessageHandles}, both transient and
98 * persistent. The messages are sorted based on priority
99 */
100 private MessageQueue _handles =
101 new MessageQueue(new MessageHandleComparator());
102
103 /***
104 * The logger
105 */
106 private static final Log _log = LogFactory.getLog(MessageCache.class);
107
108
109 /***
110 * Default constructor
111 */
112 MessageCache() {
113 }
114
115 /***
116 * Add the following message to the cache
117 *
118 * @param id - the message identity
119 * @param message - the message to add
120 */
121 void addMessage(MessageId id, MessageImpl message) {
122 if (message.isPersistent()) {
123 addPersistentMessage(message);
124 } else {
125 addNonPersistentMessage(message);
126 }
127 }
128
129 /***
130 * Add the following handle and associated message to the cache
131 *
132 * @param handle - the message handle to add
133 * @param message - the message to add
134 */
135 void addMessage(MessageHandle handle, MessageImpl message) {
136 addMessage(handle.getMessageId(), message);
137 addHandle(handle);
138 }
139
140 /***
141 * Add the following message handle to the cache
142 *
143 * @param handle - the message handle to add
144 */
145 void addHandle(MessageHandle handle) {
146 _handles.add(handle);
147 }
148
149 /***
150 * Remove the message with the following id from the cache and return
151 * it to the client.
152 *
153 * @param id - the id of the message to remove
154 * @param MessageImpl - the removed message or null
155 */
156 MessageImpl removeMessage(MessageId id) {
157 MessageImpl message = removePersistentMessage(id);
158 if (message == null) {
159 message = removeNonPersistentMessage(id);
160 }
161
162 return message;
163 }
164
165 /***
166 * Remove the specified handle from the cache
167 *
168 * @param handle - the handle to remove
169 * @return boolean - true if successful
170 */
171 boolean removeHandle(MessageHandle handle) {
172 return _handles.remove(handle);
173 }
174
175 /***
176 * Remove and return the first message handle in the cache
177 *
178 * @return MessageHandle - the first handle or null if cache is empty
179 */
180 final MessageHandle removeFirstHandle() {
181 return (MessageHandle) _handles.removeFirst();
182 }
183
184 /***
185 * Return an array of all handles in the cache
186 *
187 * @return Object[]
188 */
189 Object[] getHandleArray() {
190 return _handles.toArray();
191 }
192
193 /***
194 * Check whether the specified handle is cache
195 *
196 * @param handle - the handle to check
197 * @return boolean - true if it is
198 */
199 final boolean containsHandle(MessageHandle handle) {
200 return _handles.contains(handle);
201 }
202
203 /***
204 * Return the message corresponding to the specified handle
205 *
206 * @param handle - the handle to check
207 * @param MessageImpl - the associated message or null
208 */
209 MessageImpl getMessage(final MessageHandle handle) {
210 if (handle == null) {
211 return null;
212 }
213
214 MessageImpl message = null;
215 MessageId id = handle.getMessageId();
216
217 if (handle.isPersistent()) {
218 message = (MessageImpl) _persistent.get(id);
219
220
221
222 if (message == null) {
223
224 PersistentMessageHandle phandle = null;
225 if (handle instanceof PersistentMessageHandle) {
226 phandle = (PersistentMessageHandle) handle;
227 } else {
228
229
230
231 try {
232 phandle = (PersistentMessageHandle)
233 MessageHandleFactory.createPersistentHandle(
234 (TransientMessageHandle) handle);
235 } catch (Exception exception) {
236 _log.error("Failed to retrieve message", exception);
237 }
238 }
239
240
241 if (phandle != null) {
242 PersistenceAdapter adapter = DatabaseService.getAdapter();
243 Connection connection = null;
244 try {
245 connection = DatabaseService.getConnection();
246 message = adapter.getMessage(
247 connection, phandle.getMessageId().getId());
248 connection.commit();
249 } catch (PersistenceException exception) {
250 if (connection != null) {
251 try {
252 connection.rollback();
253 } catch (Exception nested) {
254
255 }
256 }
257 _log.error("Failed to retrieve message", exception);
258 } catch (Exception exception) {
259 _log.error("Failed to retrieve message", exception);
260 } finally {
261 if (connection != null) {
262 try {
263 connection.close();
264 } catch (Exception nested) {
265
266 }
267 }
268 }
269
270
271
272 if (message != null) {
273 synchronized (_persistent) {
274 _persistent.put(id, message);
275 }
276 }
277 }
278 }
279 } else {
280 message = (MessageImpl) _transient.get(id);
281 }
282
283 if ((message != null) &&
284 (!message.getReadOnly())) {
285
286
287 try {
288 message.setReadOnly(true);
289 } catch (JMSException exception) {
290 _log.error(exception);
291 message = null;
292 }
293 }
294
295 return message;
296 }
297
298 /***
299 * Clear the persistent and non-persistent message cache
300 */
301 void clear() {
302 _transient.clear();
303 _persistent.clear();
304 _handles.clear();
305 }
306
307 /***
308 * Clear only the persistent messages in the cache
309 *
310 */
311 void clearPersistentMessages() {
312 _persistent.clear();
313 }
314
315 /***
316 * Clear only the transient messages in the cache
317 *
318 */
319 void clearTransientMessages() {
320 _transient.clear();
321 }
322
323 /***
324 * Add a non-persistent message to the cache
325 *
326 * @param message - the message to add
327 */
328 private void addNonPersistentMessage(MessageImpl message) {
329 synchronized (_transient) {
330 _transient.put(message.getMessageId(), message);
331 }
332 }
333
334 /***
335 * Remove the non persistnet message with the specified identity from the
336 * transient cache.
337 *
338 * @param id - the id of the message to remove
339 * @return MessageImpl - the remove message or null
340 */
341 private MessageImpl removeNonPersistentMessage(MessageId id) {
342 MessageImpl message = null;
343 synchronized (_transient) {
344 message = (MessageImpl) _transient.remove(id);
345 }
346
347 return message;
348 }
349
350 /***
351 * Remove the persistnet message with the specified identity from the
352 * persistent cache.
353 *
354 * @param id - the id of the message to remove
355 * @return MessageImpl - the remove message or null
356 */
357 private MessageImpl removePersistentMessage(MessageId id) {
358 MessageImpl message = null;
359 synchronized (_persistent) {
360 message = (MessageImpl) _persistent.remove(id);
361 }
362
363 return message;
364 }
365
366 /***
367 * Add persistent message to the persistent cache
368 *
369 * @param message - the message to add
370 */
371 private void addPersistentMessage(MessageImpl message) {
372 synchronized (_persistent) {
373 _persistent.put(message.getMessageId(), message);
374 }
375 }
376
377 /***
378 * Return the number of messages in the transient cache
379 *
380 * @return int
381 */
382 public int getTransientCount() {
383 return _transient.size();
384 }
385
386 /***
387 * Return the number of messages in the persistent cache
388 *
389 * @return int
390 */
391 public int getPersistentCount() {
392 return _persistent.size();
393 }
394
395 /***
396 * Return the number of handles in the cache
397 *
398 * @return int
399 */
400 public int getHandleCount() {
401 return _handles.size();
402 }
403 }
404