consumermanager.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

/**
 * 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.
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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: ConsumerManager.java,v 1.33 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.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.Vector;

import javax.jms.DeliveryMode;
import javax.jms.InvalidSelectorException;
import javax.jms.JMSException;
import javax.transaction.TransactionManager;

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

import org.exolab.core.service.ServiceException;
import org.exolab.jms.client.JmsDestination;
import org.exolab.jms.client.JmsQueue;
import org.exolab.jms.client.JmsTopic;
import org.exolab.jms.gc.GarbageCollectable;
import org.exolab.jms.gc.GarbageCollectionService;
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 org.exolab.jms.persistence.SQLHelper;
import org.exolab.jms.scheduler.Scheduler;
import org.exolab.jms.server.JmsServerSession;


/**
 * The consumer manager is responsible for creating and managing the
 * lifecycle of Consumer. The consumer manager maintains a list of all
 * active consumers.
 * <p>
 * The consumer manager, in an attempt to make better utilization of
 * resource will also act as a proxy for all inactive durable subscribers
 * So it will act as a DestinationCacheEventListener and process the
 * message on behalf of the inactive consumer.
 *
 * @version     $Revision: 1.33 $ $Date: 2003/09/25 11:24:16 $
 * @author      <a href="mailto:[e-mail]">Jim Alateras</a>
 */
public class ConsumerManager
    implements DestinationCacheEventListener, GarbageCollectable {

    /**
     * Maintains a cache of all active endpoints.
     */
    private HashMap _endpoints = new HashMap();

    /**
     * Maintains a list of all unique consumers, durable and non-durable.
     * Each entry has an associated {@link #ConsumerEntry} record. All
     * durable subscribers are maintained in memory until they are removed
     * from the system entirely. All non-durable subscribers are maintained
     * in memory until their endpoint is removed.
     */
    private HashMap _consumerCache = new HashMap();

    /**
     * Maintais a mapping between destinations and consumers. A destination
     * can have more than one consumer and a consumer can also be registered
     * to more than one destination
     */
    private HashMap _destToConsumerMap = new HashMap();

    /**
     * Maintains a list of wildcard subscriptions using subscription name
     * and the JmsTopic.
     */
    private HashMap _wildcardConsumers = new HashMap();

    /**
     * Cache a copy of the scheduler instance
     */
    private Scheduler _scheduler = null;

    /**
     * The singleton instance of the consumer manager
     */
    private static ConsumerManager _instance = null;

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


    /**
     * Create the singleton instance of the consumer manager
     *
     * @return the singleton instance
     * @throws ServiceException if the service cannot be initialised
     */
    public static ConsumerManager createInstance() throws ServiceException {
        _instance = new ConsumerManager();
        return _instance;
    }

    /**
     * Return the singleton instance of the ConsumerManager
     *
     * @return ConsumerManager
     */
    public static ConsumerManager instance() {
        return _instance;
    }

    /**
     * Construct the <code>ConsumerManager</code>
     *
     * @throws ServiceException - if it fails to initialise
     */
    private ConsumerManager() throws ServiceException {
        // register with the GarbageCollectionService
        GarbageCollectionService.instance().register(this);

        init();
    }

    /**
     * This method creates an actual durable consumer for the specified and
     * caches it. It does not create and endpoint. To create the endpoint the
     * client should call createDurableConsumerEndpoint.
     *
     * @param topic - the topic destination
     * @param name - the consumer name
     * @exception JMSException - if it cannot be created
     */
    public synchronized void createDurableConsumer(JmsTopic topic, String name)
        throws JMSException {

        PersistenceAdapter adapter = DatabaseService.getAdapter();

        Connection connection = null;
        try {

            connection = DatabaseService.getConnection();

            // ensure that we are trying to create a durable consumer to an
            // administered destination.
            if (!adapter.checkDestination(connection, topic.getName())) {
                throw new JMSException(
                    "Cannot create durable consumer, name=" + name +
                    ", for non-administered topic=" + topic.getName());
            }

            if (!adapter.durableConsumerExists(connection, name)) {
                adapter.addDurableConsumer(connection, topic.getName(), name);
            }

            connection.commit();
            // cache the consumer locally
            addToConsumerCache(name, topic, true);
        } catch (JMSException exception) {
            throw exception;
        } catch (Exception exception) { // PersistenceException, SQLException
            SQLHelper.rollback(connection);
            String msg = "Failed to create durable consumer, name=" + name
                + ", for topic=" + topic.getName();
            _log.error(msg, exception);
            throw new JMSException(msg + ": " + exception.getMessage());
        } finally {
            SQLHelper.close(connection);
        }
    }


    /**
     * This method will remove the durable consumer from the database and
     * from transient memory only if it exists and is inactive. If there
     * is an active endpoint then it cannot be deleted and an exception
     * will be raise.
     * <p>
     * If the durable consumer does not exist then an exception is also
     * raised.
     *
     * @param name - the consumer name
     * @exception JMSException - if it cannot be removed
     */
    public synchronized void removeDurableConsumer(String name)
        throws JMSException {
        if (_log.isDebugEnabled()) {
            _log.debug("removeDurableConsumer(name=" + name + ")");
        }

        // check to see that the durable consumer exists
        if (!durableConsumerExists(name)) {
            throw new JMSException("Durable consumer " + name +
                " is not defined.");
        }
        if (isDurableConsumerActive(name)) {
            throw new JMSException(
                "Cannot remove durable consumer=" + name
                + ": consumer is active");
        }

        // remove it from the persistent store.
        Connection connection = null;
        try {
            connection = DatabaseService.getConnection();

            DatabaseService.getAdapter().removeDurableConsumer(connection,
                name);
            // if it has been successfully removed from persistent store then
            // clear up the transient references.
            ConsumerEndpoint endpoint = getConsumerEndpoint(name);
            if (endpoint != null) {
                deleteConsumerEndpoint(endpoint);
            }
            removeFromConsumerCache(name);
            connection.commit();
        } catch (Exception exception) { // PersistenceException, SQLException
            SQLHelper.rollback(connection);
            String msg = "Failed to remove durable consumer, name=" + name;
            _log.error(msg, exception);
            throw new JMSException(msg + ":" + exception.getMessage());
        } finally {
            SQLHelper.close(connection);
        }
    }

    /**
     * This method will remove all the durable consumers from the database and
     * from transient memory whether they are active or not.
     * <p>
     * If we have problems removing the durable consumers then throw the
     * JMSException.
     *
     * @param topic the topic to remove consumers for
     * @throw JMSException if the consumers cannot be removed
     */
    public synchronized void removeDurableConsumers(JmsDestination topic)
        throws JMSException {

        Vector consumers = (Vector) _destToConsumerMap.get(topic);
        if (consumers != null) {
            Enumeration entries = consumers.elements();
            while (entries.hasMoreElements()) {
                ConsumerEntry entry = (ConsumerEntry) entries.nextElement();
                if (entry._durable) {
                    // remove the actual durable consumer from transient and
                    // secondary memory.
                    removeDurableConsumer(entry._name);
                }
            }
        }

        // remove all consumers for the specified destination
        removeFromConsumerCache(topic);
    }

    /**
     * Create a transient consumer for the specified destination. The client
     * can optionally specify a selector to filter messages.
     * <p>
     * The clientId parameter is used to indirectly reference the remote client
     * which is uniquely identifiable within a session and is used during
     * asynchronous message delivery.
     *
     * @param clientId - indirect reference to the remote client
     * @param destination - consumer for this destination
     * @param selector - the consumer's selector if specified.
     * @return transient consumer
     */
    public synchronized ConsumerEndpoint createConsumerEndpoint(
        JmsServerSession session, long clientId, JmsDestination destination,
        String selector)
        throws JMSException, InvalidSelectorException {

        if (_log.isDebugEnabled()) {
            _log.debug("createConsumerEndpoint(session=[sessionId="
                + session.getSessionId() + "], clientId=" + clientId
                + ", destination=" + destination
                + ", selector=" + selector + ")");
        }

        ConsumerEndpoint endpoint = null;
        DestinationManager destmgr = DestinationManager.instance();

        // before we create the destination we need to check the
        // characteristics of the destination. If the destination
        // is an administered destination then it must be already
        // defined. If the destination is a temporary destination
        // then we may need to add it to the cache.
        if (destination.getPersistent()) {
            if (!destmgr.destinationExists(destination)) {
                throw new JMSException("Cannot create consumer endpoint: "
                    + "destination=" + destination
                    + " does not exist");
            }
        } else {
            if (!destmgr.destinationExists(destination)) {
                destmgr.createDestination(destination);
            }
        }

        // determine what type of consumer endpoint to create based on
        // the destination it subscribes too.
        if (destination instanceof JmsTopic) {
            JmsTopic topic = (JmsTopic) destination;
            endpoint = new TopicConsumerEndpoint(session, clientId, topic,
                selector, _scheduler);
        } else if (destination instanceof JmsQueue) {
            // this seems like a good opportunity to clean up any unreferenced
            // endpoints attached to this queue.
            cleanUnreferencedEndpoints(destination);

            // now we can create the endpoint
            endpoint = new QueueConsumerEndpoint(session, clientId,
                (JmsQueue) destination, selector, _scheduler);
        }

        if (endpoint != null) {
            // add it to the list on managed consumers
            String id = endpoint.getPersistentId();
            _endpoints.put(id, endpoint);
            addToConsumerCache(id, destination, false);
        }

        return endpoint;
    }

    /**
     * Create a durable consumer with the specified well-known name.