durableconsumerendpoint.java

实现了Jms的服务器源码,支持多种适配器,DB,FTP,支持多种数据库

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 *    copy of this document.
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 * 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
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 * 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 [e-mail].
 *
 * 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: DurableConsumerEndpoint.java,v 1.22 2003/09/25 11:24:16 tanderson Exp $
 *
 * Date         Author  Changes
 * 3/1/2001     jima    Created
 */
package org.exolab.jms.messagemgr;

import java.sql.Connection;
import java.util.Enumeration;
import java.util.Vector;

import javax.jms.JMSException;
import javax.jms.Session;
import javax.transaction.TransactionManager;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.exolab.jms.client.JmsTopic;
import org.exolab.jms.message.MessageHandle;
import org.exolab.jms.message.MessageImpl;
import org.exolab.jms.persistence.DatabaseService;
import org.exolab.jms.persistence.PersistenceException;
import org.exolab.jms.scheduler.Scheduler;
import org.exolab.jms.server.JmsServerSession;


/**
 * A durable subscriber extends {@link ConsumerEndpoint} and is only associated
 * with a Topic destination. The state of the durable subscriber is
 * maintained across server invocations by the persistent layer
 *
 * @version     $Revision: 1.22 $ $Date: 2003/09/25 11:24:16 $
 * @author      <a href="mailto:[e-mail]">Jim Alateras</a>
 */
public class DurableConsumerEndpoint
    extends TopicConsumerEndpoint {

    /**
     * The well-known name of the durable subscriber
     */
    private String _name = null;

    /**
     * The logger
     */
    private static final Log _log =
        LogFactory.getLog(DurableConsumerEndpoint.class);


    /**
     * Create an durable consumer endpoint. This is a well-known
     * endpoint which can only be activated by one client at any one time.
     * <p>
     * DurableConsumerEndpoints are always loaded in memory, whether they
     * are active or inactive. When they are inactive they simply process
     * persistent messages. Non-persistent message are ignored when the
     * durable consumer is inactive.
     *
     * @param session - the creating session
     * @param clientId - uniquely identifies the remote client within session
     * @param topic - destination it is subscribing too
     * @param name - the well known name of the durable subscriber
     * @param selector - the selector attached to the consumer, if any.
     * @param scheduler - entity that will delivery messages asynch.
     * @throws JMSException
     */
    DurableConsumerEndpoint(JmsServerSession session, long clientId,
                            JmsTopic topic, String name, String selector,
                            Scheduler scheduler) throws JMSException {
        super(session, clientId, topic, selector, scheduler);
        _name = name;

        // call the persistence adapter to retrieve the state of  this
        // durable consumer. The adaptor will return a linked list of
        // PersistentHandle objects which represent unsent and sent
        // messages.
        Connection connection = null;
        try {
            connection = DatabaseService.getConnection();

            // remove expired messages
            DatabaseService.getAdapter().removeExpiredMessageHandles(
                connection, _name);
            Vector handles = DatabaseService.getAdapter().getMessageHandles(
                connection, getDestination(), _name);
            connection.commit();
            // iterate over each handle and add them to the list of messages
            // for the durable consumer
            Enumeration iter = handles.elements();
            while (iter.hasMoreElements()) {
                addMessage((MessageHandle) iter.nextElement());
            }
        } catch (PersistenceException exception) {
            if (connection != null) {
                try {
                    connection.rollback();
                } catch (Exception nested) {
                    // ignore
                }
            }
            throw new JMSException("DurableConusmerEndpoint not activated " +
                exception);
        } catch (Exception exception) {
            // rethrow as a JMSException
            throw new JMSException("DurableConusmerEndpoint not activated " +
                exception);
        } finally {
            if (connection != null) {
                try {
                    connection.close();
                } catch (Exception nested) {
                    // ignore
                }
            }
        }
    }

    /**
     * Returns the persistent identifier for this consumer.<p/>
     * This is the identity of the consumer which is persistent across
     * subscriptions and server restarts. <p/>
     *
     * This implementation returns the consumer name.
     *
     * @return the persistent identifier for this consumer
     */
    public String getPersistentId() {
        return getName();
    }

    /**
     * Returns the durable subscription name
     *
     * @return the durable subscription name
     */
    public String getName() {
        return _name;
    }

} //-- DurableConsumerEndpoint