Metacat

/**

 *  '$RCSfile$'

 *  Copyright: 2008 Regents of the University of California and the

 *             National Center for Ecological Analysis and Synthesis

 *

 * Author: Benjamin Leinfelder 

 * '$Date:  $'

 * '$Revision:  $'

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

package edu.ucsb.nceas.metacat.dataquery;

import java.sql.ResultSet;

import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

import org.ecoinformatics.datamanager.DataManager;

import org.ecoinformatics.datamanager.database.DatabaseConnectionPoolInterface;

import org.ecoinformatics.datamanager.database.Query;

import org.ecoinformatics.datamanager.database.Union;

import org.ecoinformatics.datamanager.dataquery.DataquerySpecification;

import org.ecoinformatics.datamanager.download.EcogridEndPointInterface;

/**

 * Class to query data

 */

public class DataQuery {

	private static Log log = LogFactory.getLog(DataQuery.class);

	private EcogridEndPointInterface endPointInfo;

	private DatabaseConnectionPoolInterface connectionPool;

	private DataManager dataManager;

	private String parserName = "org.apache.xerces.parsers.SAXParser";

	/**

	 * empty constructor to initialize query

	 */

	public DataQuery() {

		// initialize the endpoint, not authenticated

		endPointInfo = new ConfigurableEcogridEndPoint();

		init();

	}

	public DataQuery(String sessionId) {

		// initialize the necessary parts

		endPointInfo = new ConfigurableAuthenticatedEcogridEndPoint(sessionId);

		init();

	}

	private void init() {

		connectionPool = DatabaseConnectionPoolFactory.getDatabaseConnectionPoolInterface();

		dataManager = 

			DataManager.getInstance(connectionPool, connectionPool.getDBAdapterName());

	}

	public ResultSet executeQuery(String xml) throws Exception {

		long startTime = System.currentTimeMillis();

		// parse the query

		DataquerySpecification specification = 

			new DataquerySpecification(xml, parserName, connectionPool, endPointInfo);

		long endTime = System.currentTimeMillis();

		log.debug((endTime - startTime) + " ms to parse query");

		startTime = System.currentTimeMillis();

		// get the results

		ResultSet resultset = null;

		Union union = specification.getUnion();

		if (union != null) {

			resultset = 

				dataManager.selectData(

						union, 

						specification.getDataPackages());

		} else {

			Query query = specification.getQuery();

			resultset = 

				dataManager.selectData(

						query, 

						specification.getDataPackages());

		}

		endTime = System.currentTimeMillis();

		log.debug((endTime - startTime) + " ms to select results");

		return resultset;

	}

}