DatabaseDMConnFactory.java

/**************************************************************************************
 * Copyright (C) 2008 EsperTech, Inc. All rights reserved.                            *
 * http://esper.codehaus.org                                                          *
 * http://www.espertech.com                                                           *
 * ---------------------------------------------------------------------------------- *
 * The software in this package is published under the terms of the GPL license       *
 * a copy of which has been included with this distribution in the license.txt file.  *
 **************************************************************************************/
package com.espertech.esper.epl.db;

import com.espertech.esper.client.ConfigurationDBRef;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;

/**
 * Database connection factory using {@link DriverManager} to obtain connections.
 */
public class DatabaseDMConnFactory implements DatabaseConnectionFactory
{
    private final ConfigurationDBRef.DriverManagerConnection driverConfig;
    private final ConfigurationDBRef.ConnectionSettings connectionSettings;

    /**
     * Ctor.
     * @param driverConfig is the driver manager configuration
     * @param connectionSettings are connection-level settings
     * @throws DatabaseConfigException thrown if the driver class cannot be loaded
     */
    public DatabaseDMConnFactory(ConfigurationDBRef.DriverManagerConnection driverConfig,
                                 ConfigurationDBRef.ConnectionSettings connectionSettings)
            throws DatabaseConfigException
    {
        this.driverConfig = driverConfig;
        this.connectionSettings = connectionSettings;

        // load driver class
        String driverClassName = driverConfig.getClassName();
        try
        {
            ClassLoader cl = Thread.currentThread().getContextClassLoader();
            Class.forName(driverClassName, true, cl);
        }
        catch (ClassNotFoundException ex)
        {
            throw new DatabaseConfigException("Error loading driver class '" + driverClassName + '\'', ex);
        }
        catch (RuntimeException ex)
        {
            throw new DatabaseConfigException("Error loading driver class '" + driverClassName + '\'', ex);
        }
    }

    public Connection getConnection() throws DatabaseConfigException
    {
        // use driver manager to get a connection
        Connection connection;
        String url = driverConfig.getUrl();
        Properties properties = driverConfig.getOptionalProperties();
        if (properties == null)
        {
            properties = new Properties();
        }
        try
        {
            String user = driverConfig.getOptionalUserName();
            String pwd = driverConfig.getOptionalPassword();
            if ((user == null) && (pwd == null) && (properties.isEmpty()))
            {
                connection = DriverManager.getConnection(url);
            }
            else if (!properties.isEmpty())
            {
                connection = DriverManager.getConnection(url, properties);
            }
            else
            {
                connection = DriverManager.getConnection(url, user, pwd);
            }
        }
        catch (SQLException ex)
        {
            String detail = "SQLException: " + ex.getMessage() +
                    " SQLState: " + ex.getSQLState() +
                    " VendorError: " + ex.getErrorCode();

            throw new DatabaseConfigException("Error obtaining database connection using url '" + url +
                    "' with detail " + detail
                    , ex);
        }

        setConnectionOptions(connection, connectionSettings);

        return connection;
    }

    /**
     * Method to set connection-level configuration settings.
     * @param connection is the connection to set on
     * @param connectionSettings are the settings to apply
     * @throws DatabaseConfigException is thrown if an SQLException is thrown
     */
    protected static void setConnectionOptions(Connection connection,
                                               ConfigurationDBRef.ConnectionSettings connectionSettings)
            throws DatabaseConfigException
    {
        try
        {
            if (connectionSettings.getReadOnly() != null)
            {
                connection.setReadOnly(connectionSettings.getReadOnly());
            }
        }
        catch (SQLException ex)
        {
            throw new DatabaseConfigException("Error setting read-only to " + connectionSettings.getReadOnly() +
                    " on connection with detail " + getDetail(ex), ex);
        }

        try
        {
            if (connectionSettings.getTransactionIsolation() != null)
            {
                connection.setTransactionIsolation(connectionSettings.getTransactionIsolation());
            }
        }
        catch (SQLException ex)
        {
            throw new DatabaseConfigException("Error setting transaction isolation level to " +
                    connectionSettings.getTransactionIsolation() + " on connection with detail " + getDetail(ex), ex);
        }

        try
        {
            if (connectionSettings.getCatalog() != null)
            {
                connection.setCatalog(connectionSettings.getCatalog());
            }
        }
        catch (SQLException ex)
        {
            throw new DatabaseConfigException("Error setting catalog to '" + connectionSettings.getCatalog() +
                    "' on connection with detail " + getDetail(ex), ex);
        }

        try
        {
            if (connectionSettings.getAutoCommit() != null)
            {
                connection.setCatalog(connectionSettings.getCatalog());
            }
        }
        catch (SQLException ex)
        {
            throw new DatabaseConfigException("Error setting auto-commit to " + connectionSettings.getAutoCommit() +
                    " on connection with detail " + getDetail(ex), ex);
        }
    }

    private static String getDetail(SQLException ex)
    {
        return "SQLException: " + ex.getMessage() +
                " SQLState: " + ex.getSQLState() +
                " VendorError: " + ex.getErrorCode();
    }
}