001 /*--------------------------------------------------------------------------+ 002 $Id: DateUtils.java 29593 2010-08-09 16:01:20Z hummelb $ 003 | | 004 | Copyright 2005-2010 Technische Universitaet Muenchen | 005 | | 006 | Licensed under the Apache License, Version 2.0 (the "License"); | 007 | you may not use this file except in compliance with the License. | 008 | You may obtain a copy of the License at | 009 | | 010 | http://www.apache.org/licenses/LICENSE-2.0 | 011 | | 012 | Unless required by applicable law or agreed to in writing, software | 013 | distributed under the License is distributed on an "AS IS" BASIS, | 014 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | 015 | See the License for the specific language governing permissions and | 016 | limitations under the License. | 017 +--------------------------------------------------------------------------*/ 018 package edu.tum.cs.commons.date; 019 020 import java.util.Collection; 021 import java.util.Collections; 022 import java.util.Date; 023 024 /** 025 * Utility methods for working on date objects. 026 * 027 * @author juergens 028 * @author $Author: hummelb $ 029 * @version $Rev: 29593 $ 030 * @levd.rating GREEN Hash: A327B6CB6CF8E826F60F8D16EBA23DEC 031 */ 032 public class DateUtils { 033 034 /** Returns the latest date in a collection of dates */ 035 public static Date getLatest(Collection<Date> dates) { 036 if (dates.isEmpty()) { 037 return null; 038 } 039 return Collections.max(dates); 040 } 041 042 /** Returns the earliest date in a collection of dates */ 043 public static Date getEarliest(Collection<Date> dates) { 044 if (dates.isEmpty()) { 045 return null; 046 } 047 return Collections.min(dates); 048 } 049 050 /** Returns the earlier of two dates, or null, if one of the dates is null */ 051 public static Date min(Date d1, Date d2) { 052 if (d1 == null || d2 == null) { 053 return null; 054 } 055 056 if (d1.compareTo(d2) < 0) { 057 return d1; 058 } 059 return d2; 060 } 061 062 /** Returns the later of two dates or null, if one of the dates is null. */ 063 public static Date max(Date d1, Date d2) { 064 if (d1 == null || d2 == null) { 065 return null; 066 } 067 068 if (d2.compareTo(d1) > 0) { 069 return d2; 070 } 071 return d1; 072 } 073 074 }