poolingconnectionprovider.java

定时器开源项目, 相对于 jcrontab, Quartz 算是更完整的一个项目, 随著开发的版本上来, 他已经脱离只是写在程序里面的计时器, 在指定的时间或区间, 处理所指定的事件. 也加入了 se

/*
 * Copyright James House (c) 2001-2004
 * 
 * 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.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND ANY
 * EXPRESS 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 AUTHOR OR 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 product includes software developed by the Apache Software Foundation
 * (http://www.apache.org/)
 */
package org.quartz.utils;

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

import org.apache.commons.dbcp.BasicDataSource;

/**
 * <p>
 * A <code>ConnectionProvider</code> implementation that creates it's own
 * pool of connections.
 * </p>
 * 
 * <p>
 * This class uses <a href="http://jakarta.apache.org/commons/index.html">DBCP
 * </a>, an Apache-Jakarta-Commons product.
 * </p>
 * 
 * @see DBConnectionManager
 * @see ConnectionProvider
 * 
 * @author Sharada Jambula
 * @author James House
 * @author Mohammad Rezaei
 */
public class PoolingConnectionProvider implements ConnectionProvider {

    /*
     * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     * 
     * Constants.
     * 
     * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     */

    public static final String DB_PROPS_PREFIX = "org.quartz.db.";

    public static final String DB_JNDI_DATASOURCE_URL = "jndiURL";

    // The JDBC database driver
    public static final String DB_DRIVER = "driver";

    // The JDBC database URL
    public static final String DB_URL = "URL";

    // The database user name
    public static final String DB_USER = "user";

    // The database user password
    public static final String DB_PASSWORD = "password";

    public static final String DB_MAX_CONNECTIONS = "maxConnections";

    public static final String DB_VALIDATION_QUERY = "validationQuery";

    /*
     * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     * 
     * Data members.
     * 
     * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     */

    private BasicDataSource datasource;

    /*
     * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     * 
     * Constructors.
     * 
     * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     */

    public PoolingConnectionProvider(String dbDriver, String dbURL,
            String dbUser, String dbPassword, int maxConnections,
            String dbValidationQuery) throws SQLException {

        initialize(dbDriver, dbURL, dbUser, dbPassword, maxConnections,
                dbValidationQuery);

    }

    /*
     * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     * 
     * Interface.
     * 
     * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     */

    private void initialize(String dbDriver, String dbURL, String dbUser,
            String dbPassword, int maxConnections, String dbValidationQuery)
            throws SQLException {
        if (dbDriver == null)
                throw new SQLException("DB driver class name cannot be null!");
        if (dbURL == null) throw new SQLException("DB URL cannot be null!");
        if (maxConnections < 0)
                throw new SQLException(
                        "Max connections must be greater than zero!");

        datasource = new BasicDataSource();
        datasource.setDriverClassName(dbDriver);
        datasource.setUrl(dbURL);
        datasource.setUsername(dbUser);
        datasource.setPassword(dbPassword);
        datasource.setMaxActive(maxConnections);
        if (dbValidationQuery != null)
                datasource.setValidationQuery(dbValidationQuery);
    }

    /**
     * <p>
     * Create a connection pool using the given properties.
     * </p>
     * 
     * <p>
     * The properties passed should contain either
     * <UL>
     * <LI>JNDI DataSource URL {@link #DB_JNDI_DATASOURCE_URL}
     * </UL>
     * or
     * <UL>
     * <LI>{@link #DB_DRIVER}- The database driver class name
     * <LI>{@link #DB_URL}- The database URL
     * <LI>{@link #DB_USER}- The database user
     * <LI>{@link #DB_PASSWORD}- The database password
     * <LI>{@link #DB_MAX_CONNECTIONS}- The maximum # connections in the pool
     * </UL>
     * <P>
     * 
     * @param config
     *          configuration properties
     * @exception SQLException
     *              if an error occurs
     */
    public PoolingConnectionProvider(Properties config) throws SQLException {
        PropertiesParser cfg = new PropertiesParser(config);
        String url = config.getProperty(DB_URL);
        try {
            initialize(config.getProperty(DB_DRIVER), url, config
                    .getProperty(DB_USER), config.getProperty(DB_PASSWORD), cfg
                    .getIntProperty(DB_MAX_CONNECTIONS, 3), cfg
                    .getStringProperty(DB_VALIDATION_QUERY));
        } catch (Exception e) {
            throw new SQLException("DBPool '" + url
                    + "' could not be created: " + e.toString());
        }
    }

    public Connection getConnection() throws SQLException {
        return this.datasource.getConnection();
    }
    
    public void shutdown() throws SQLException {
        this.datasource.close();
    }    
}