/**
* 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 2001-2003 (C) Exoffice Technologies Inc. All Rights Reserved.
*
* $Id: DefaultMessageCache.java,v 1.5 2007/01/24 12:00:28 tanderson Exp $
*
* Date Author Changes
* 3/1/2001 jima Created
*/
package org.exolab.jms.messagemgr;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.exolab.jms.message.MessageImpl;
import org.exolab.jms.persistence.DatabaseService;
import org.exolab.jms.persistence.PersistenceAdapter;
import org.exolab.jms.persistence.PersistenceException;
import javax.jms.JMSException;
import java.sql.Connection;
import java.util.HashMap;
import java.util.Map;
/**
* Default implementation of the {@link MessageCache} interface.
*
* @author <a href="mailto:jima@comware.com.au">Jim Alateras</a>
* @author <a href="mailto:tma@netspace.net.au">Tim Anderson</a>
* @version $Revision: 1.5 $ $Date: 2007/01/24 12:00:28 $
*/
final class DefaultMessageCache implements MessageCache {
/**
* Maintains the pool of transient messages.
*/
private final Map _transient = new HashMap(1023);
/**
* Maintains the pool of persistent messages.
*/
private final Map _persistent = new HashMap(1023);
/**
* Maintains the references to messages.
*/
private final Map _references = new HashMap(1023);
/**
* The logger.
*/
private static final Log _log = LogFactory.getLog(
DefaultMessageCache.class);
/**
* Add a reference and its corresponding message to the cache.
*
* @param reference the reference to the message
* @param message the message
*/
public synchronized void addMessage(MessageRef reference,
MessageImpl message) {
String messageId = reference.getMessageId();
if (reference.isPersistent()) {
_persistent.put(messageId, message);
} else {
_transient.put(messageId, message);
}
addMessageRef(messageId, reference);
}
/**
* Adds a message reference to the cache.
*
* @param reference the message reference to add
*/
public synchronized void addMessageRef(MessageRef reference) {
addMessageRef(reference.getMessageId(), reference);
}
/**
* Returns a message reference, given its identifier.
*
* @param messageId the message identifier
* @return the message reference associated with <code>messageId</code>, or
* <code>null</code> if none exists
*/
public synchronized MessageRef getMessageRef(String messageId) {
return (MessageRef) _references.get(messageId);
}
/**
* Returns the message corresponding to the specified reference.
*
* @param reference the message reference
* @return the associated message, or <code>null</code> if none exists
* @throws JMSException for any error
*/
public synchronized MessageImpl getMessage(MessageRef reference)
throws JMSException {
MessageImpl message;
final String messageId = reference.getMessageId();
if (reference.isPersistent()) {
message = (MessageImpl) _persistent.get(messageId);
// if the message is not cached then try and retrieve it from the
// database and cache it.
if (message == null) {
// fault in at least the next message from the database
try {
DatabaseService service = DatabaseService.getInstance();
PersistenceAdapter adapter = service.getAdapter();
Connection connection = service.getConnection();
message = adapter.getMessage(connection, messageId);
} catch (PersistenceException exception) {
final String msg = "Failed to retrieve message";
_log.error(msg, exception);
throw new JMSException(msg + ": " + exception.getMessage());
}
// add the message to the persistent cache once it has been
// retrieved from the datastore
if (message != null) {
_persistent.put(messageId, message);
}
}
} else {
message = (MessageImpl) _transient.get(messageId);
}
if (message != null && !message.getReadOnly()) {
// mark the message as read-only
message.setReadOnly(true);
}
return message;
}
/**
* Destroys the message corresponding to the reference.
*
* @throws JMSException for any error
*/
public synchronized void destroy(MessageRef reference) throws JMSException {
final String messageId = reference.getMessageId();
if (_references.remove(messageId) != null) {
if (reference.isPersistent()) {
try {
DatabaseService service = DatabaseService.getInstance();
Connection connection = service.getConnection();
PersistenceAdapter adapter = service.getAdapter();
adapter.removeMessage(connection, messageId);
} catch (Exception exception) {
_log.error("Failed to remove message", exception);
throw new JMSException("Failed to remove message: "
+ exception.getMessage());
}
_persistent.remove(messageId);
} else {
_transient.remove(messageId);
}
}
}
/**
* Clear the persistent and non-persistent message cache.
*/
public synchronized void clear() {
_transient.clear();
_persistent.clear();
_references.clear();
}
/**
* Clear only the persistent messages in the cache.
*/
public synchronized void clearPersistentMessages() {
_persistent.clear();
}
/**
* Return the number of messages in the transient cache.
*
* @return the number of messages in the transient cache
*/
public synchronized int getTransientCount() {
return _transient.size();
}
/**
* Return the number of messages in the persistent cache.
*
* @return the number of messages in the persistent cache
*/
public synchronized int getPersistentCount() {
return _persistent.size();
}
/**
* Return the number of message references in the cache.
*
* @return the number of message references in the cache
*/
public synchronized int getMessageCount() {
return _references.size();
}
/**
* Add a message reference to the cache.
*
* @param messageId the message identifier
* @param reference the message reference
*/
private void addMessageRef(String messageId, MessageRef reference) {
_references.put(messageId, reference);
}
}