001    /*
002     * CDDL HEADER START
003     *
004     * The contents of this file are subject to the terms of the
005     * Common Development and Distribution License, Version 1.0 only
006     * (the "License").  You may not use this file except in compliance
007     * with the License.
008     *
009     * You can obtain a copy of the license at
010     * trunk/opends/resource/legal-notices/OpenDS.LICENSE
011     * or https://OpenDS.dev.java.net/OpenDS.LICENSE.
012     * See the License for the specific language governing permissions
013     * and limitations under the License.
014     *
015     * When distributing Covered Code, include this CDDL HEADER in each
016     * file and include the License file at
017     * trunk/opends/resource/legal-notices/OpenDS.LICENSE.  If applicable,
018     * add the following below this CDDL HEADER, with the fields enclosed
019     * by brackets "[]" replaced with your own identifying information:
020     *      Portions Copyright [yyyy] [name of copyright owner]
021     *
022     * CDDL HEADER END
023     *
024     *
025     *      Copyright 2006-2008 Sun Microsystems, Inc.
026     */
027    package org.opends.server.replication.server;
028    
029    import java.util.Comparator;
030    
031    import org.opends.server.replication.common.ChangeNumber;
032    import org.opends.server.replication.protocol.UpdateMessage;
033    
034    /**
035     * Class to use for establishing an order within UpdateMessages.
036     */
037    public class UpdateComparator implements Comparator<UpdateMessage>
038    {
039      /**
040       * The UpdateComparator Singleton.
041       */
042      public static UpdateComparator comparator = new UpdateComparator();
043    
044      /**
045       * Private constructor.
046       */
047      private UpdateComparator()
048      {
049        super();
050      }
051    
052      /**
053       * Compares two UpdateMessages.
054       *
055       * @param msg1 first UpdateMessage to compare
056       * @param msg2 second UpdateMessage to compare
057       * @return -1 if msg1 < msg2
058       *          0 if msg1 == msg2
059       *          1 if msg1 > msg2
060       */
061      public int compare(UpdateMessage msg1, UpdateMessage msg2)
062      {
063        return ChangeNumber.compare(msg1.getChangeNumber(), msg2.getChangeNumber());
064      }
065    }