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/* ====================================================================
 * 
 * The ObjectStyle Group Software License, version 1.1
 * ObjectStyle Group - http://objectstyle.org/
 * 
 * Copyright (c) 2002-2005, Andrei (Andrus) Adamchik and individual authors
 * of the software. All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 
 * 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 end-user documentation included with the redistribution, if any,
 *    must include the following acknowlegement:
 *    "This product includes software developed by independent contributors
 *    and hosted on ObjectStyle Group web site (http://objectstyle.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 * 
 * 4. The names "ObjectStyle Group" and "Cayenne" must not be used to endorse
 *    or promote products derived from this software without prior written
 *    permission. For written permission, email
 *    "andrus at objectstyle dot org".
 * 
 * 5. Products derived from this software may not be called "ObjectStyle"
 *    or "Cayenne", nor may "ObjectStyle" or "Cayenne" appear in their
 *    names without prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED ``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 THE OBJECTSTYLE GROUP 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.
 * ====================================================================
 * 
 * This software consists of voluntary contributions made by many
 * individuals and hosted on ObjectStyle Group web site.  For more
 * information on the ObjectStyle Group, please see
 * .
 */

package org.objectstyle.cayenne.conn;

import java.sql.Connection;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;

import javax.sql.ConnectionEvent;
import javax.sql.ConnectionEventListener;
import javax.sql.DataSource;
import javax.sql.PooledConnection;

import org.apache.log4j.Logger;

/**
 * PooledConnectionImpl is an implementation of a pooling wrapper for the database
 * connection as per JDBC3 spec. Most of the modern JDBC drivers should have its own
 * implementation that may be used instead of this class.
 * 
 * @author Andrei Adamchik
 */
public class PooledConnectionImpl implements PooledConnection {

    private static Logger logObj = Logger.getLogger(PooledConnectionImpl.class);

    private Connection connectionObj;
    private List connectionEventListeners;
    private boolean hadErrors;
    private DataSource connectionSource;
    private String userName;
    private String password;

    protected PooledConnectionImpl() {
        // TODO: maybe remove synchronization and use
        // FastArrayList from commons-collections? After
        // all the only listener is usually pool manager.
        this.connectionEventListeners = Collections.synchronizedList(new ArrayList(10));
    }

    /** Creates new PooledConnection */
    public PooledConnectionImpl(DataSource connectionSource, String userName,
            String password) {

        this();

        this.connectionSource = connectionSource;
        this.userName = userName;
        this.password = password;

    }

    public void reconnect() throws SQLException {
        if (connectionObj != null) {
            try {
                connectionObj.close();
            }
            catch (SQLException ex) {
                // ignore exception, since connection is expected
                // to be in a bad state
            }
            finally {
                connectionObj = null;
            }
        }

        connectionObj = (userName != null) ? connectionSource.getConnection(
                userName,
                password) : connectionSource.getConnection();
    }

    public void addConnectionEventListener(ConnectionEventListener listener) {
        synchronized (connectionEventListeners) {
            if (!connectionEventListeners.contains(listener))
                connectionEventListeners.add(listener);
        }
    }

    public void removeConnectionEventListener(ConnectionEventListener listener) {
        synchronized (connectionEventListeners) {
            connectionEventListeners.remove(listener);
        }
    }

    public void close() throws SQLException {

        synchronized (connectionEventListeners) {
            // remove all listeners
            connectionEventListeners.clear();
        }

        if (connectionObj != null) {
            try {
                connectionObj.close();
            }
            finally {
                connectionObj = null;
            }
        }
    }

    public Connection getConnection() throws SQLException {
        if (connectionObj == null) {
            reconnect();
        }

        // set autocommit to false to return connection
        // always in consistent state
        if (!connectionObj.getAutoCommit()) {

            try {
                connectionObj.setAutoCommit(true);
            }
            catch (SQLException sqlEx) {
                // try applying Sybase patch
                ConnectionWrapper.sybaseAutoCommitPatch(connectionObj, sqlEx, true);
            }
        }

        connectionObj.clearWarnings();
        return new ConnectionWrapper(connectionObj, this);
    }

    protected void returnConnectionToThePool() throws SQLException {
        // do not return to pool bad connections
        if (hadErrors)
            close();
        else
            // notify the listeners that connection is no longer used by application...
            this.connectionClosedNotification();
    }

    /**
     * This method creates and sents an event to listeners when an error occurs in the
     * underlying connection. Listeners can have special logic to analyze the error and do
     * things like closing this PooledConnection (if the error is fatal), etc...
     */
    public void connectionErrorNotification(SQLException exception) {
        // hint for later to avoid returning bad connections to the pool
        hadErrors = true;

        if (logObj.isDebugEnabled()) {
            logObj
                    .debug(
                            "Child connection error, retiring pooled connection.",
                            exception);
        }

        synchronized (connectionEventListeners) {
            if (connectionEventListeners.size() == 0)
                return;

            ConnectionEvent closedEvent = new ConnectionEvent(this, exception);
            Iterator listeners = connectionEventListeners.iterator();
            while (listeners.hasNext()) {
                ConnectionEventListener nextListener = (ConnectionEventListener) listeners
                        .next();
                nextListener.connectionErrorOccurred(closedEvent);
            }
        }
    }

    /**
     * Creates and sends an event to listeners when a user closes java.sql.Connection
     * object belonging to this PooledConnection.
     */
    protected void connectionClosedNotification() {
        synchronized (connectionEventListeners) {
            if (connectionEventListeners.size() == 0)
                return;

            ConnectionEvent closedEvent = new ConnectionEvent(this);
            Iterator listeners = connectionEventListeners.iterator();

            while (listeners.hasNext()) {
                ConnectionEventListener nextListener = (ConnectionEventListener) listeners
                        .next();
                nextListener.connectionClosed(closedEvent);
            }
        }
    }
}