/**
* 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: QueueBrowserEndpoint.java,v 1.3 2005/08/30 07:26:49 tanderson Exp $
*/
package org.exolab.jms.messagemgr;
import javax.jms.InvalidSelectorException;
import javax.jms.JMSException;
import org.exolab.jms.message.MessageImpl;
/**
* A QueueBrowserEndpoint is a QueueListener to a QueueDestinationCache. This
* enables it to receive all the messages, which it then feeds down to the
* client side.
*
* @author <a href="mailto:jima@comware.com.au">Jim Alateras</a>
* @author <a href="mailto:tma@netspace.net.au">Tim Anderson
* @version $Revision: 1.3 $ $Date: 2005/08/30 07:26:49 $
*/
public class QueueBrowserEndpoint extends AbstractConsumerEndpoint {
/**
* Cache of all handles for this consumer.
*/
private MessageQueue _handles = new MessageQueue();
/**
* The destination that this consumer subscribes to.
*/
private QueueDestinationCache _cache;
/**
* Create a new <code>QueueBrowserEndpoint</code>.
*
* @param consumerId the identity of this consumer
* @param cache the destination cache
* @param selector the message selector. May be <code>null</code>
* @throws InvalidSelectorException if <code>selector</code> is invalid
* @throws JMSException if the destination cache can't be
* created
*/
public QueueBrowserEndpoint(long consumerId, QueueDestinationCache cache,
String selector)
throws InvalidSelectorException, JMSException {
super(consumerId, cache.getDestination(), selector, false);
_cache = cache;
// set up the message cache and register itself as a listener to the
// cache
_cache.addQueueListener(this);
_cache.playbackMessages(this);
}
/**
* This event is called when a non-persistent message is added to a
* <code>DestinationCache</code>..
*
* @param handle a handle to the added message
* @param message the added message
* @return <code>true</code> if the listener accepted the message; otherwise
* <code>false</ode>
*/
public boolean messageAdded(MessageHandle handle, MessageImpl message) {
_handles.add(handle);
// notify the consumer
notifyMessageAvailable();
return true;
}
/**
* This event is called when a persistent message is added to the
* <code>DestinationCache</code>.
*
* @param handle a handle to the added message
* @param message the added message
* @return <code>true</code>
*/
public boolean persistentMessageAdded(MessageHandle handle,
MessageImpl message) {
return messageAdded(handle, message);
}
/**
* This event is called when a message is removed from the
* <code>DestinationCache</code>.
*
* @param messageId the identifier of the removed message
*/
public void messageRemoved(String messageId) {
_handles.remove(messageId);
}
/**
* This event is called when a message is removed from the
* <code>DestinationCache</code>.
*
* @param messageId a handle to the removed message
*/
public void persistentMessageRemoved(String messageId) {
messageRemoved(messageId);
}
/**
* Return the number of unsent messages in the cache for this consumer.
*
* @return the number of unsent messages
*/
public int getMessageCount() {
return _handles.size();
}
/**
* Return the next available message to the client.
*
* @param cancel
* @return the next message, or <code>null</code> if none is available
* @throws JMSException for any error
*/
protected MessageHandle doReceive(Condition cancel) throws JMSException {
MessageHandle result = null;
MessageHandle handle;
while (!cancel.get() && (handle = _handles.removeFirst()) != null) {
// ensure the message still exists
MessageImpl message = handle.getMessage();
if (message != null) {
if (selects(message)) {
result = handle;
// got a message which is applicable for the endpoint
break;
}
}
}
return result;
}
/**
* Closes this endpoint.
*/
protected void doClose() {
// unregister from the DestinationCache
_cache.removeQueueListener(this);
}
}