Metacat

/**

 *    '$RCSfile: PostgresDatabaseConnectionPool.java,v $'

 *

 *     '$Author: leinfelder $'

 *       '$Date: 2007/10/19 18:50:11 $'

 *   '$Revision: 1.1 $'

 *

 *  For Details: http://ecoinformatics.org

 *

 * Copyright (c) 2007 The Regents of the University of California.

 * All rights reserved.

 * 

 * Permission is hereby granted, without written agreement and without

 * license or royalty fees, to use, copy, modify, and distribute this

 * software and its documentation for any purpose, provided that the

 * above copyright notice and the following two paragraphs appear in

 * all copies of this software.

 * 

 * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY

 * FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES

 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN

 * IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY

 * OF SUCH DAMAGE.

 * 

 * THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,

 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF

 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE

 * PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY

 * OF CALIFORNIA HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT,

 * UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

 */

package edu.ucsb.nceas.metacat.dataquery;

import java.sql.Connection;

import java.sql.SQLException;

import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

import org.ecoinformatics.datamanager.database.ConnectionNotAvailableException;

import org.ecoinformatics.datamanager.database.DatabaseConnectionPoolInterface;

import org.postgresql.jdbc3.Jdbc3PoolingDataSource;

import edu.ucsb.nceas.metacat.properties.PropertyService;

import edu.ucsb.nceas.utilities.PropertyNotFoundException;

/**

 * This class implements DataConnetionPoolInterface to provide a connection for

 * testing. Database information in this class will be read from property file.

 * 

 * @author tao

 * 

 */

public class PostgresDatabaseConnectionPool implements

		DatabaseConnectionPoolInterface {

	public static Log log = LogFactory.getLog(PostgresDatabaseConnectionPool.class);

	/* Configuration properties file */

	private static String serverName = null;

	private static String databaseName = null;

	private static String user = null;

	private static String password = null;

	private static int maxConnections = 0;

	private static String databaseAdapterName = null;

	private static Jdbc3PoolingDataSource source = null;

	private static int connCount = 0;

	/**

	 * Constructor. Loading database parameter from property file

	 * 

	 */

	public PostgresDatabaseConnectionPool() {

		try {

			loadOptions();

		}

		catch (PropertyNotFoundException e) {

			log.error(e.getMessage());

			e.printStackTrace();

		}

		initPool();

	}

	private static void initPool() {

		source = new Jdbc3PoolingDataSource();

		//source.setDataSourceName(databaseAdapterName);

		source.setServerName(serverName);

		source.setDatabaseName(databaseName);

		source.setUser(user);

		source.setPassword(password);

		source.setMaxConnections(maxConnections);

	}

	/**

	 * Loads Data Manager options from a configuration file.

	 * @throws PropertyNotFoundException 

	 */

	private static void loadOptions() throws PropertyNotFoundException {

		serverName = PropertyService.getProperty("datamanager.server");

		databaseName = PropertyService.getProperty("datamanager.database");

		user = PropertyService.getProperty("datamanager.user");

		password = PropertyService.getProperty("datamanager.password");

		maxConnections = 

			Integer.parseInt(

				PropertyService.getProperty("datamanager.maxconnections"));

		databaseAdapterName = PropertyService.getProperty("datamanager.adapter");

	}

	/**

	 * Get dabase adpater name.

	 * 

	 * @return database adapter name

	 */

	public String getDBAdapterName() {

		return databaseAdapterName;

	}

	/**

	 * Gets a database connection from the pool

	 * 

	 * @return checked out connection

	 * @throws SQLException

	 */

	public Connection getConnection() throws SQLException,

			ConnectionNotAvailableException {

		Connection connection = null;

		try {

			connection = source.getConnection();

			connCount++;

		} catch (SQLException e) {

			System.err.println("SQLException: " + e.getMessage());

			throw (e);

		}

		return connection;

	}

	/**

	 * Returns checked out dabase connection to the pool

	 * 

	 * @param conn

	 *            Connection needs to be returned.

	 * @return indicator if the connection was returned successfully

	 */

	public boolean returnConnection(Connection conn) {

		boolean success = false;

		try {

			conn.close();

			success = true;

			connCount--;

		} catch (Exception e) {

			success = false;

		}

		//log.debug(Thread.currentThread().getName() + ": connection count=" + connCount);

		return success;

	}

	public static void main(String arg[]) {

		PostgresDatabaseConnectionPool pool = new PostgresDatabaseConnectionPool();

		try {

			Connection conn = pool.getConnection();

			log.debug("conn=" + conn);

			conn.close();

		} catch (SQLException e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

		} catch (ConnectionNotAvailableException e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

		}

	}

}