001    /**
002     * Copyright (c) 2000-2013 Liferay, Inc. All rights reserved.
003     *
004     * This library is free software; you can redistribute it and/or modify it under
005     * the terms of the GNU Lesser General Public License as published by the Free
006     * Software Foundation; either version 2.1 of the License, or (at your option)
007     * any later version.
008     *
009     * This library is distributed in the hope that it will be useful, but WITHOUT
010     * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
011     * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
012     * details.
013     */
014    
015    package com.liferay.portal.kernel.notifications;
016    
017    import java.util.Comparator;
018    
019    /**
020     * @author Edward Han
021     */
022    public class NotificationEventComparator
023            implements Comparator<NotificationEvent> {
024    
025            public NotificationEventComparator() {
026                    this(true);
027            }
028    
029            public NotificationEventComparator(boolean ascending) {
030                    _ascending = ascending;
031            }
032    
033            @Override
034            public int compare(
035                    NotificationEvent notificationEvent1,
036                    NotificationEvent notificationEvent2) {
037    
038                    if (notificationEvent1.equals(notificationEvent2)) {
039                            return 0;
040                    }
041    
042                    long value =
043                            notificationEvent1.getDeliverBy() -
044                                    notificationEvent2.getDeliverBy();
045    
046                    if (value == 0) {
047                            value =
048                                    notificationEvent1.getTimestamp() -
049                                            notificationEvent2.getTimestamp();
050                    }
051    
052                    if (value == 0) {
053                            value =
054                                    notificationEvent1.hashCode() - notificationEvent2.hashCode();
055                    }
056    
057                    if (_ascending) {
058                            return (int)value;
059                    }
060                    else {
061                            return (int)-value;
062                    }
063            }
064    
065            private boolean _ascending;
066    
067    }