001 //$HeadURL: svn+ssh://rbezema@svn.wald.intevation.org/deegree/base/branches/2.2_testing/src/org/deegree/framework/util/IDGenerator.java $
002 /*---------------- FILE HEADER ------------------------------------------
003
004 This file is part of deegree.
005 Copyright (C) 2001-2008 by:
006 EXSE, Department of Geography, University of Bonn
007 http://www.giub.uni-bonn.de/deegree/
008 lat/lon GmbH
009 http://www.lat-lon.de
010
011 This library is free software; you can redistribute it and/or
012 modify it under the terms of the GNU Lesser General Public
013 License as published by the Free Software Foundation; either
014 version 2.1 of the License, or (at your option) any later version.
015
016 This library is distributed in the hope that it will be useful,
017 but WITHOUT ANY WARRANTY; without even the implied warranty of
018 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
019 Lesser General Public License for more details.
020
021 You should have received a copy of the GNU Lesser General Public
022 License along with this library; if not, write to the Free Software
023 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
024
025 Contact:
026
027 Andreas Poth
028 lat/lon GmbH
029 Aennchenstr. 19
030 53115 Bonn
031 Germany
032 E-Mail: poth@lat-lon.de
033
034 Prof. Dr. Klaus Greve
035 Department of Geography
036 University of Bonn
037 Meckenheimer Allee 166
038 53115 Bonn
039 Germany
040 E-Mail: greve@giub.uni-bonn.de
041
042 ----------------------------------------------------------------------------*/
043
044 package org.deegree.framework.util;
045
046 /**
047 * Produces unique IDs (used to generate Request-IDs, for example).
048 * <p>
049 * @author <a href="mailto:mschneider@lat-lon.de">Markus Schneider</a>
050 * @version $Revision: 9339 $ $Date: 2007-12-27 13:31:52 +0100 (Do, 27 Dez 2007) $
051 */
052 public class IDGenerator {
053
054 /**
055 * The only instance of this class.
056 */
057 private static IDGenerator instance = null;
058
059
060 /** The current ID. */
061 private long id = 0;
062
063 /**
064 * Returns the only instance of this class.
065 * @return the only instance of IDGenerator
066 *
067 */
068 synchronized public static IDGenerator getInstance() {
069 if (instance == null)
070 instance = new IDGenerator();
071 return instance;
072 }
073
074 /**
075 * Generates a completly unique ID.
076 * @return a unique ID
077 */
078 synchronized public long generateUniqueID () {
079 return id++;
080 }
081 }