messages.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.
 *
 * 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,
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 * 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 2000-2004 (C) Exoffice Technologies Inc. All Rights Reserved.
 */

package org.exolab.jms.persistence;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.Vector;

import javax.jms.Destination;
import javax.jms.JMSException;
import javax.sql.DataSource;

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

import org.exolab.jms.client.JmsDestination;
import org.exolab.jms.client.JmsTopic;
import org.exolab.jms.message.MessageId;
import org.exolab.jms.message.MessageImpl;
import org.exolab.jms.messagemgr.PersistentMessageHandle;


/**
 * This class manages the persistent of message objects. It maintains
 * all the SQL for achieving this.
 *
 * @version     $Revision: 1.24 $ $Date: 2004/01/08 05:55:07 $
 * @author      <a href="mailto:[e-mail]">Tim Anderson</a>
 * @see         org.exolab.jms.message.MessageImpl
 * @see         org.exolab.jms.persistence.RDBMSAdapter
 */
public class Messages {

    /**
     * Caches the singleton instance of this class
     */
    private static Messages _instance;

    /**
     * Cache the transaction retry count
     */
    private static int _retryCount = 10;

    /**
     * Cache the retry interval in milliseconds
     */
    private static long _retryInterval = 50;

    /**
     * Monitor used to synchronize the initialization of this
     * class
     */
    private static final Object _block = new Object();

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


    /**
     * Returns a reference to the singleton instance.
     * <p>
     * Note that initialise() must have been invoked first for this
     * to return a valid instance.
     *
     * @return      Messages            the singleton instance
     */
    public static Messages instance() {
        return _instance;
    }

    /**
     * Create an initialise the singleton istance of this class.
     *
     * @return      Messages           the singleton instance
     */
    public static Messages initialise() {
        if (_instance == null) {
            synchronized (_block) {
                if (_instance == null) {
                    _instance = new Messages();
                }
            }
        }
        return _instance;
    }

    /**
     * Add a message to the database, in the context of the specified
     * transaction and connection.
     *
     * @param connection - execute on this connection
     * @param message - the message to add
     * @throws PersistenceException - an sql related error
     */
    public void add(Connection connection, MessageImpl message)
        throws PersistenceException {

        PreparedStatement insert = null;

        // extract the identity of the message
        String messageId = message.getMessageId().getId();

        // check that the destination is actually registered
        // and map the name to the corresponding id
        String name;
        try {
            name = ((JmsDestination) message.getJMSDestination()).getName();
        } catch (JMSException exception) {
            throw new PersistenceException(
                "Failed to get destination for message=" +
                message.getMessageId(), exception);
        }

        long destinationId = Destinations.instance().getId(name);
        if (destinationId == 0) {
            throw new PersistenceException(
                "Cannot add message=" + message.getMessageId() +
                ", destination=" + name + " (" + destinationId +
                "): destination does not exist");
        }

        try {
            // create, populate and execute the insert
            insert = connection.prepareStatement(
                "insert into messages values " + "(?,?,?,?,?,?,?)");
            insert.setString(1, messageId);
            insert.setLong(2, destinationId);
            insert.setInt(3, message.getJMSPriority());
            insert.setLong(4, message.getAcceptedTime());
            insert.setLong(5, message.getJMSExpiration());
            insert.setInt(6, (message.getProcessed()) ? 1 : 0);

            // serialize the message
            byte[] bytes = serialize(message);
            insert.setBinaryStream(7, new ByteArrayInputStream(bytes),
                bytes.length);
            //insert.setBytes(8, bytes);

            // execute the insert
            if (insert.executeUpdate() != 1) {
                throw new PersistenceException(
                    "Failed to add message=" + message.getMessageId() +
                    ", destination=" + name + " (" + destinationId + ")");
            }
        } catch (PersistenceException exception) {
            throw exception;
        } catch (Exception exception) {
            throw new PersistenceException(
                "Failed to add message=" + message.getMessageId() +
                ", destination=" + name + " (" + destinationId + ")",
                exception);
        } finally {
            SQLHelper.close(insert);
        }
    }

    /**
     * Update the message state in the database. This will be called to set
     * the message state to processed by the provider
     *
     * @param connection - execute on this connection
     * @param message - the message to update
     * @throws PersistenceException - an sql related error
     */
    public void update(Connection connection, MessageImpl message)
        throws PersistenceException {

        PreparedStatement update = null;

        // extract the identity of the message
        String messageId = message.getMessageId().getId();

        try {
            update = connection.prepareStatement(
                "update messages set processed=? where messageId=?");
            update.setInt(1, message.getProcessed() ? 1 : 0);
            update.setString(2, messageId);

            // execute the update
            if (update.executeUpdate() != 1) {
                _log.error("Cannot update message=" + messageId);
            }
        } catch (SQLException exception) {
            throw new PersistenceException(
                "Failed to update message, id=" + messageId, exception);
        } finally {
            SQLHelper.close(update);
        }
    }

    /**
     * Remove a message with the specified identity from the database
     *
     * @param connection - execute on this connection
     * @param messageId - the message id of the message to remove
     * @throws PersistenceException - an sql related error
     */
    public void remove(Connection connection, String messageId)
        throws PersistenceException {

        PreparedStatement delete = null;
        try {
            delete = connection.prepareStatement(
                "delete from messages where messageId=?");
            delete.setString(1, messageId);

            // execute the delete
            if (delete.executeUpdate() != 1) {
                _log.error("Cannot remove message=" + messageId);
            }
        } catch (SQLException exception) {
            throw new PersistenceException(
                "Failed to remove message, id=" + messageId, exception);
        } finally {
            SQLHelper.close(delete);
        }
    }

    /**
     * Return the message identified by the message Id
     *
     * @param connection - execute on this connection
     * @param messageId - id of message to retrieve
     * @return MessageImpl - the associated message
     * @throws PersistenceException - an sql related error
     */
    public MessageImpl get(Connection connection, String messageId)
        throws PersistenceException {

        MessageImpl result = null;
        PreparedStatement select = null;
        ResultSet set = null;
        try {
            select = connection.prepareStatement(
                "select messageBlob, processed from messages where messageId=?");

            select.setString(1, messageId);
            set = select.executeQuery();
            if (set.next()) {
                result = deserialize(set.getBytes(1));
                result.setProcessed((set.getInt(2) == 1 ? true : false));
            }
        } catch (SQLException exception) {
            throw new PersistenceException(
                "Failed to retrieve message, id=" + messageId, exception);
        } finally {
            SQLHelper.close(set);
            SQLHelper.close(select);
        }

        return result;
    }

    /**
     * Delete all messages for the given destination
     *
     * @param connection - execute on this connection
     * @param messageId - id of message to retrieve
     * @return int - the number of messages purged
     * @throws PersistenceException - an sql related error
     */
    public int removeMessages(Connection connection, String destination)
        throws PersistenceException {

        int result = 0;
        PreparedStatement delete = null;

        // map the destination name to an id
        long destinationId = Destinations.instance().getId(destination);
        if (destinationId == 0) {
            throw new PersistenceException("Cannot delete messages for " +
                "destination=" + destination +
                ": destination does not exist");
        }

        try {
            delete = connection.prepareStatement(
                "delete from messages where destinationId = ?");
            delete.setLong(1, destinationId);
            result = delete.executeUpdate();
        } catch (SQLException exception) {
            throw new PersistenceException(
                "Failed to remove messages for destination=" + destination,