001 //$HeadURL: svn+ssh://jwilden@svn.wald.intevation.org/deegree/base/branches/2.5_testing/src/org/deegree/framework/util/IDGenerator.java $
002 /*----------------------------------------------------------------------------
003 This file is part of deegree, http://deegree.org/
004 Copyright (C) 2001-2009 by:
005 Department of Geography, University of Bonn
006 and
007 lat/lon GmbH
008
009 This library is free software; you can redistribute it and/or modify it under
010 the terms of the GNU Lesser General Public License as published by the Free
011 Software Foundation; either version 2.1 of the License, or (at your option)
012 any later version.
013 This library is distributed in the hope that it will be useful, but WITHOUT
014 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
015 FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
016 details.
017 You should have received a copy of the GNU Lesser General Public License
018 along with this library; if not, write to the Free Software Foundation, Inc.,
019 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
020
021 Contact information:
022
023 lat/lon GmbH
024 Aennchenstr. 19, 53177 Bonn
025 Germany
026 http://lat-lon.de/
027
028 Department of Geography, University of Bonn
029 Prof. Dr. Klaus Greve
030 Postfach 1147, 53001 Bonn
031 Germany
032 http://www.geographie.uni-bonn.de/deegree/
033
034 e-mail: info@deegree.org
035 ----------------------------------------------------------------------------*/
036
037 package org.deegree.framework.util;
038
039 /**
040 * Produces unique IDs (used to generate Request-IDs, for example).
041 * <p>
042 *
043 * @author <a href="mailto:mschneider@lat-lon.de">Markus Schneider</a>
044 * @version $Revision: 18195 $ $Date: 2009-06-18 17:55:39 +0200 (Do, 18 Jun 2009) $
045 */
046 public class IDGenerator {
047
048 /**
049 * The only instance of this class.
050 */
051 private static IDGenerator instance = null;
052
053 /** The current ID. */
054 private long id = 0;
055
056 /**
057 * Returns the only instance of this class.
058 *
059 * @return the only instance of IDGenerator
060 *
061 */
062 synchronized public static IDGenerator getInstance() {
063 if ( instance == null )
064 instance = new IDGenerator();
065 return instance;
066 }
067
068 /**
069 * Generates a completly unique ID.
070 *
071 * @return a unique ID
072 */
073 synchronized public long generateUniqueID() {
074 return id++;
075 }
076 }