001 /*
002 * $RCSfile: FileCatalog.java,v $
003 *
004 * Created on December 13, 2002, 12:54 PM
005 *
006 * This file is part of the STAR Scheduler.
007 * Copyright (c) 2002-2006 STAR Collaboration - Brookhaven National Laboratory
008 *
009 * STAR Scheduler is free software; you can redistribute it and/or modify
010 * it under the terms of the GNU General Public License as published by
011 * the Free Software Foundation; either version 2 of the License, or
012 * (at your option) any later version.
013 *
014 * STAR Scheduler is distributed in the hope that it will be useful,
015 * but WITHOUT ANY WARRANTY; without even the implied warranty of
016 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
017 * GNU General Public License for more details.
018 *
019 * You should have received a copy of the GNU General Public License
020 * along with STAR Scheduler; if not, write to the Free Software
021 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
022 */
023 package gov.bnl.star.offline.scheduler.catalog;
024
025 import gov.bnl.star.offline.scheduler.ComponentLibrary;
026 import java.util.Iterator;
027 import java.util.logging.Logger;
028
029
030
031 /** @deprecated please see gov.bnl.star.offline.scheduler.dataset.* for replacements.
032 *
033 * Represent the file catalog interface. To make the scheduler interoperate with
034 * other file catalog, just implement this interface in a new class.
035 *
036 * @author Gabriele Carcassi
037 * @version $Revision: 1.11 $ $Date: 2006/11/21 00:41:31 $
038 */
039 public abstract class FileCatalog {
040 static private Logger log = Logger.getLogger(FileCatalog.class.getName());
041 private static FileCatalog catalog;
042
043 /** Gets the default file catalog Class.
044 * @return the file catalog
045 */
046 public static FileCatalog getCatalog() {
047 if (catalog == null) initCatalog();
048 // TODO: The catalog factory might need to be extend. Different catalog
049 // "hosts" might require different implementations.
050 return catalog;
051 }
052
053 private static void initCatalog() {
054 catalog = ComponentLibrary.getInstance().getDefaultFileCatalog();
055 }
056
057 static void initCatalog(FileCatalog catalog) {
058 FileCatalog.catalog = catalog;
059 }
060
061 /** Executes the query and returns all the results.
062 * @param query the query to be executed
063 * @return a PhysicalFile iterator
064 */
065 public abstract Iterator executeQuery(String query);
066
067 /** Executes the query with an estimate on the number of results. The catalog should
068 * be able to make some optimizations in this case.
069 * @param query the query to be executed
070 * @param nExpectedResults an estimate of input files that are required
071 * @return a PhysicalFile iterator
072 */
073 public abstract Iterator executeQuery(String query, int nExpectedResults);
074
075 /** Executes the query with the star/limit syntax.
076 * @param query the query to be executed
077 * @param start the offset from which start to read
078 * @param limit the number of records returned
079 * @return a PhysicalFile iterator
080 */
081 public abstract Iterator executeQuery(String query, int start, int limit);
082 }