ConnectionManager.java

/*
 * JBoss, Home of Professional Open Source
 * Copyright 2006, Red Hat Middleware LLC, and individual contributors
 * as indicated by the @author tags.
 * See the copyright.txt in the distribution for a
 * full listing of individual contributors.
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU Lesser General Public License, v. 2.1.
 * This program is distributed in the hope that it will be useful, but WITHOUT A
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
 * You should have received a copy of the GNU Lesser General Public License,
 * v.2.1 along with this distribution; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA  02110-1301, USA.
 *
 * (C) 2005-2009,
 * @author JBoss Inc.
 */
/*
 * Copyright (C) 1998, 1999, 2000, 2001,
 *
 * Arjuna Solutions Limited,
 * Newcastle upon Tyne,
 * Tyne and Wear,
 * UK.
 *
 * $Id: ConnectionManager.java 2342 2006-03-30 13:06:17Z  $
 */

package com.arjuna.ats.internal.jdbc;

import java.sql.Connection;
import java.sql.SQLException;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Properties;
import java.util.Set;

import javax.transaction.Transaction;
import javax.transaction.TransactionManager;

import com.arjuna.ats.jdbc.TransactionalDriver;

/*
 * Only ever create a single instance of a given connection, based upon the
 * user/password/url/dynamic_class options. If the connection we have cached
 * has been closed, then create a new one.
 */
public class ConnectionManager
{

    /*
     * Connections are pooled for the duration of a transaction.
     */
    public static synchronized Connection create (String dbUrl, Properties info) throws SQLException
    {
        String user = info.getProperty(TransactionalDriver.userName, "");
        String passwd = info.getProperty(TransactionalDriver.password, "");
        String dynamic = info.getProperty(TransactionalDriver.dynamicClass, "");
        String poolConnections = info.getProperty(TransactionalDriver.poolConnections, "true");
        Object xaDataSource = info.get(TransactionalDriver.XADataSource);

        if (dbUrl == null) {
            dbUrl = "";
        }

        boolean poolingEnabled = "true".equalsIgnoreCase(poolConnections);
        
        if (poolingEnabled)
        {
        	Iterator<ConnectionImple> iterator = _connections.iterator();
            while (iterator.hasNext())
            {
            	ConnectionImple conn = iterator.next();
                ConnectionControl connControl = conn.connectionControl();
                TransactionManager tm = com.arjuna.ats.jta.TransactionManager.transactionManager();
                Transaction tx1, tx2 = null;

                tx1 = connControl.transaction();
                try
                {
                    tx2 = tm.getTransaction();
                }
                catch (javax.transaction.SystemException se)
                {
                    /* Ignore: tx2 is null already */
                }

                /* Check transaction and database connection. */
                if ((tx1 != null && tx1.equals(tx2))
                        && dbUrl.equals(connControl.url())
                        && user.equals(connControl.user())
                        && passwd.equals(connControl.password())
                        && dynamic.equals(connControl.dynamicClass())
                        && (xaDataSource == null || xaDataSource.equals(connControl.xaDataSource()))) // equal ProvidedXADataSourceConnection instances should have the same data source
                {
                    try
                    {
                        /*
                         * Should not overload the meaning of closed. Change!
                         */

                        if (!conn.isClosed())
                        {
                            // ConnectionImple does not actually implement Connection, but its
                            // concrete child classes do. See ConnectionImple javadoc.
                            return (Connection)conn;
                        }
                    }
                    catch (Exception ex)
                    {
                        ex.printStackTrace();
                        SQLException sqlException = new SQLException(ex.getMessage());
                        sqlException.initCause(ex);
                        throw sqlException;
                    }
                }
                else
                {
                    // no longer being used by a transaction, so let's discard. JBTM-764

                    if (tx1 == null)
                        iterator.remove();
                }
            }
        }

        ConnectionImple conn = new ConnectionImple(dbUrl, info);

        /*
       * Will replace any old (closed) connection which had the
       * same connection information.
       */

        if (poolingEnabled)
            _connections.add(conn);

        // ConnectionImple does not actually implement Connection, but its
        // concrete child classes do. See ConnectionImple javadoc.
        return (Connection)conn;
    }

    public static synchronized void remove (ConnectionImple conn)
    {
        _connections.remove(conn);
    }

    private static Set<ConnectionImple> _connections = new HashSet<ConnectionImple>();
}