001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     * 
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     * 
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    package org.apache.commons.lang.time;
018    
019    import java.text.ParseException;
020    import java.text.ParsePosition;
021    import java.text.SimpleDateFormat;
022    import java.util.Calendar;
023    import java.util.Date;
024    import java.util.Iterator;
025    import java.util.NoSuchElementException;
026    import java.util.TimeZone;
027    
028    import org.apache.commons.lang.StringUtils;
029    
030    /**
031     * <p>A suite of utilities surrounding the use of the
032     * {@link java.util.Calendar} and {@link java.util.Date} object.</p>
033     * 
034     * <p>DateUtils contains a lot of common methods considering manipulations
035     * of Dates or Calendars. Some methods require some extra explanation.
036     * The truncate, ceiling and round methods could be considered the Math.floor(),
037     * Math.ceil() or Math.round versions for dates
038     * This way date-fields will be ignored in bottom-up order.
039     * As a complement to these methods we've introduced some fragment-methods.
040     * With these methods the Date-fields will be ignored in top-down order.
041     * Since a date without a year is not a valid date, you have to decide in what
042     * kind of date-field you want your result, for instance milliseconds or days.
043     * </p>
044     *   
045     *   
046     *
047     * @author Apache Software Foundation
048     * @author <a href="mailto:sergek@lokitech.com">Serge Knystautas</a>
049     * @author Janek Bogucki
050     * @author <a href="mailto:ggregory@seagullsw.com">Gary Gregory</a>
051     * @author Phil Steitz
052     * @author Robert Scholte
053     * @since 2.0
054     * @version $Id: DateUtils.java 911986 2010-02-19 21:19:05Z niallp $
055     */
056    public class DateUtils {
057        
058        /**
059         * The UTC time zone  (often referred to as GMT).
060         */
061        public static final TimeZone UTC_TIME_ZONE = TimeZone.getTimeZone("GMT");
062        /**
063         * Number of milliseconds in a standard second.
064         * @since 2.1
065         */
066        public static final long MILLIS_PER_SECOND = 1000;
067        /**
068         * Number of milliseconds in a standard minute.
069         * @since 2.1
070         */
071        public static final long MILLIS_PER_MINUTE = 60 * MILLIS_PER_SECOND;
072        /**
073         * Number of milliseconds in a standard hour.
074         * @since 2.1
075         */
076        public static final long MILLIS_PER_HOUR = 60 * MILLIS_PER_MINUTE;
077        /**
078         * Number of milliseconds in a standard day.
079         * @since 2.1
080         */
081        public static final long MILLIS_PER_DAY = 24 * MILLIS_PER_HOUR;
082    
083        /**
084         * This is half a month, so this represents whether a date is in the top
085         * or bottom half of the month.
086         */
087        public final static int SEMI_MONTH = 1001;
088    
089        private static final int[][] fields = {
090                {Calendar.MILLISECOND},
091                {Calendar.SECOND},
092                {Calendar.MINUTE},
093                {Calendar.HOUR_OF_DAY, Calendar.HOUR},
094                {Calendar.DATE, Calendar.DAY_OF_MONTH, Calendar.AM_PM 
095                    /* Calendar.DAY_OF_YEAR, Calendar.DAY_OF_WEEK, Calendar.DAY_OF_WEEK_IN_MONTH */
096                },
097                {Calendar.MONTH, DateUtils.SEMI_MONTH},
098                {Calendar.YEAR},
099                {Calendar.ERA}};
100    
101        /**
102         * A week range, starting on Sunday.
103         */
104        public final static int RANGE_WEEK_SUNDAY = 1;
105    
106        /**
107         * A week range, starting on Monday.
108         */
109        public final static int RANGE_WEEK_MONDAY = 2;
110    
111        /**
112         * A week range, starting on the day focused.
113         */
114        public final static int RANGE_WEEK_RELATIVE = 3;
115    
116        /**
117         * A week range, centered around the day focused.
118         */
119        public final static int RANGE_WEEK_CENTER = 4;
120    
121        /**
122         * A month range, the week starting on Sunday.
123         */
124        public final static int RANGE_MONTH_SUNDAY = 5;
125    
126        /**
127         * A month range, the week starting on Monday.
128         */
129        public final static int RANGE_MONTH_MONDAY = 6;
130    
131        /**
132         * Constant marker for truncating 
133         */
134        private final static int MODIFY_TRUNCATE = 0;
135    
136        /**
137         * Constant marker for rounding
138         */
139        private final static int MODIFY_ROUND = 1;
140    
141        /**
142         * Constant marker for ceiling
143         */
144        private final static int MODIFY_CEILING= 2;
145    
146        /**
147         * <p><code>DateUtils</code> instances should NOT be constructed in
148         * standard programming. Instead, the class should be used as
149         * <code>DateUtils.parse(str);</code>.</p>
150         *
151         * <p>This constructor is public to permit tools that require a JavaBean
152         * instance to operate.</p>
153         */
154        public DateUtils() {
155            super();
156        }
157    
158        //-----------------------------------------------------------------------
159        /**
160         * <p>Checks if two date objects are on the same day ignoring time.</p>
161         *
162         * <p>28 Mar 2002 13:45 and 28 Mar 2002 06:01 would return true.
163         * 28 Mar 2002 13:45 and 12 Mar 2002 13:45 would return false.
164         * </p>
165         * 
166         * @param date1  the first date, not altered, not null
167         * @param date2  the second date, not altered, not null
168         * @return true if they represent the same day
169         * @throws IllegalArgumentException if either date is <code>null</code>
170         * @since 2.1
171         */
172        public static boolean isSameDay(Date date1, Date date2) {
173            if (date1 == null || date2 == null) {
174                throw new IllegalArgumentException("The date must not be null");
175            }
176            Calendar cal1 = Calendar.getInstance();
177            cal1.setTime(date1);
178            Calendar cal2 = Calendar.getInstance();
179            cal2.setTime(date2);
180            return isSameDay(cal1, cal2);
181        }
182    
183        /**
184         * <p>Checks if two calendar objects are on the same day ignoring time.</p>
185         *
186         * <p>28 Mar 2002 13:45 and 28 Mar 2002 06:01 would return true.
187         * 28 Mar 2002 13:45 and 12 Mar 2002 13:45 would return false.
188         * </p>
189         * 
190         * @param cal1  the first calendar, not altered, not null
191         * @param cal2  the second calendar, not altered, not null
192         * @return true if they represent the same day
193         * @throws IllegalArgumentException if either calendar is <code>null</code>
194         * @since 2.1
195         */
196        public static boolean isSameDay(Calendar cal1, Calendar cal2) {
197            if (cal1 == null || cal2 == null) {
198                throw new IllegalArgumentException("The date must not be null");
199            }
200            return (cal1.get(Calendar.ERA) == cal2.get(Calendar.ERA) &&
201                    cal1.get(Calendar.YEAR) == cal2.get(Calendar.YEAR) &&
202                    cal1.get(Calendar.DAY_OF_YEAR) == cal2.get(Calendar.DAY_OF_YEAR));
203        }
204    
205        //-----------------------------------------------------------------------
206        /**
207         * <p>Checks if two date objects represent the same instant in time.</p>
208         *
209         * <p>This method compares the long millisecond time of the two objects.</p>
210         * 
211         * @param date1  the first date, not altered, not null
212         * @param date2  the second date, not altered, not null
213         * @return true if they represent the same millisecond instant
214         * @throws IllegalArgumentException if either date is <code>null</code>
215         * @since 2.1
216         */
217        public static boolean isSameInstant(Date date1, Date date2) {
218            if (date1 == null || date2 == null) {
219                throw new IllegalArgumentException("The date must not be null");
220            }
221            return date1.getTime() == date2.getTime();
222        }
223    
224        /**
225         * <p>Checks if two calendar objects represent the same instant in time.</p>
226         *
227         * <p>This method compares the long millisecond time of the two objects.</p>
228         * 
229         * @param cal1  the first calendar, not altered, not null
230         * @param cal2  the second calendar, not altered, not null
231         * @return true if they represent the same millisecond instant
232         * @throws IllegalArgumentException if either date is <code>null</code>
233         * @since 2.1
234         */
235        public static boolean isSameInstant(Calendar cal1, Calendar cal2) {
236            if (cal1 == null || cal2 == null) {
237                throw new IllegalArgumentException("The date must not be null");
238            }
239            return cal1.getTime().getTime() == cal2.getTime().getTime();
240        }
241    
242        //-----------------------------------------------------------------------
243        /**
244         * <p>Checks if two calendar objects represent the same local time.</p>
245         *
246         * <p>This method compares the values of the fields of the two objects.
247         * In addition, both calendars must be the same of the same type.</p>
248         * 
249         * @param cal1  the first calendar, not altered, not null
250         * @param cal2  the second calendar, not altered, not null
251         * @return true if they represent the same millisecond instant
252         * @throws IllegalArgumentException if either date is <code>null</code>
253         * @since 2.1
254         */
255        public static boolean isSameLocalTime(Calendar cal1, Calendar cal2) {
256            if (cal1 == null || cal2 == null) {
257                throw new IllegalArgumentException("The date must not be null");
258            }
259            return (cal1.get(Calendar.MILLISECOND) == cal2.get(Calendar.MILLISECOND) &&
260                    cal1.get(Calendar.SECOND) == cal2.get(Calendar.SECOND) &&
261                    cal1.get(Calendar.MINUTE) == cal2.get(Calendar.MINUTE) &&
262                    cal1.get(Calendar.HOUR) == cal2.get(Calendar.HOUR) &&
263                    cal1.get(Calendar.DAY_OF_YEAR) == cal2.get(Calendar.DAY_OF_YEAR) &&
264                    cal1.get(Calendar.YEAR) == cal2.get(Calendar.YEAR) &&
265                    cal1.get(Calendar.ERA) == cal2.get(Calendar.ERA) &&
266                    cal1.getClass() == cal2.getClass());
267        }
268    
269        //-----------------------------------------------------------------------
270        /**
271         * <p>Parses a string representing a date by trying a variety of different parsers.</p>
272         * 
273         * <p>The parse will try each parse pattern in turn.
274         * A parse is only deemed successful if it parses the whole of the input string.
275         * If no parse patterns match, a ParseException is thrown.</p>
276         * The parser will be lenient toward the parsed date.
277         * 
278         * @param str  the date to parse, not null
279         * @param parsePatterns  the date format patterns to use, see SimpleDateFormat, not null
280         * @return the parsed date
281         * @throws IllegalArgumentException if the date string or pattern array is null
282         * @throws ParseException if none of the date patterns were suitable (or there were none)
283         */
284        public static Date parseDate(String str, String[] parsePatterns) throws ParseException {
285            return parseDateWithLeniency(str, parsePatterns, true);
286        }
287        
288      //-----------------------------------------------------------------------
289        /**
290         * <p>Parses a string representing a date by trying a variety of different parsers.</p>
291         * 
292         * <p>The parse will try each parse pattern in turn.
293         * A parse is only deemed successful if it parses the whole of the input string.
294         * If no parse patterns match, a ParseException is thrown.</p>
295         * The parser parses strictly - it does not allow for dates such as "February 942, 1996". 
296         * 
297         * @param str  the date to parse, not null
298         * @param parsePatterns  the date format patterns to use, see SimpleDateFormat, not null
299         * @return the parsed date
300         * @throws IllegalArgumentException if the date string or pattern array is null
301         * @throws ParseException if none of the date patterns were suitable
302         * @since 2.5
303         */
304        public static Date parseDateStrictly(String str, String[] parsePatterns) throws ParseException {
305            return parseDateWithLeniency(str, parsePatterns, false);
306        }
307    
308        /**
309         * <p>Parses a string representing a date by trying a variety of different parsers.</p>
310         * 
311         * <p>The parse will try each parse pattern in turn.
312         * A parse is only deemed successful if it parses the whole of the input string.
313         * If no parse patterns match, a ParseException is thrown.</p>
314         * 
315         * @param str  the date to parse, not null
316         * @param parsePatterns  the date format patterns to use, see SimpleDateFormat, not null
317         * @param lenient Specify whether or not date/time parsing is to be lenient.
318         * @return the parsed date
319         * @throws IllegalArgumentException if the date string or pattern array is null
320         * @throws ParseException if none of the date patterns were suitable
321         * @see java.util.Calender#isLenient()
322         */
323        private static Date parseDateWithLeniency(String str, String[] parsePatterns,
324                boolean lenient) throws ParseException {
325            if (str == null || parsePatterns == null) {
326                throw new IllegalArgumentException("Date and Patterns must not be null");
327            }
328            
329            SimpleDateFormat parser = new SimpleDateFormat();
330            parser.setLenient(lenient);
331            ParsePosition pos = new ParsePosition(0);
332            for (int i = 0; i < parsePatterns.length; i++) {
333    
334                String pattern = parsePatterns[i];
335    
336                // LANG-530 - need to make sure 'ZZ' output doesn't get passed to SimpleDateFormat
337                if (parsePatterns[i].endsWith("ZZ")) {
338                    pattern = pattern.substring(0, pattern.length() - 1);
339                }
340                
341                parser.applyPattern(pattern);
342                pos.setIndex(0);
343    
344                String str2 = str;
345                // LANG-530 - need to make sure 'ZZ' output doesn't hit SimpleDateFormat as it will ParseException
346                if (parsePatterns[i].endsWith("ZZ")) {
347                    int signIdx  = indexOfSignChars(str2, 0);
348                    while (signIdx >=0) {
349                        str2 = reformatTimezone(str2, signIdx);
350                        signIdx = indexOfSignChars(str2, ++signIdx);
351                    }
352                }
353    
354                Date date = parser.parse(str2, pos);
355                if (date != null && pos.getIndex() == str2.length()) {
356                    return date;
357                }
358            }
359            throw new ParseException("Unable to parse the date: " + str, -1);
360        }
361    
362        /**
363         * Index of sign charaters (i.e. '+' or '-').
364         * 
365         * @param str The string to search
366         * @param startPos The start position
367         * @return the index of the first sign character or -1 if not found
368         */
369        private static int indexOfSignChars(String str, int startPos) {
370            int idx = StringUtils.indexOf(str, '+', startPos);
371            if (idx < 0) {
372                idx = StringUtils.indexOf(str, '-', startPos);
373            }
374            return idx;
375        }
376    
377        /**
378         * Reformat the timezone in a date string.
379         *
380         * @param str The input string
381         * @param signIdx The index position of the sign characters
382         * @return The reformatted string
383         */
384        private static String reformatTimezone(String str, int signIdx) {
385            String str2 = str;
386            if (signIdx >= 0 &&
387                signIdx + 5 < str.length() &&
388                Character.isDigit(str.charAt(signIdx + 1)) &&
389                Character.isDigit(str.charAt(signIdx + 2)) &&
390                str.charAt(signIdx + 3) == ':' &&
391                Character.isDigit(str.charAt(signIdx + 4)) &&
392                Character.isDigit(str.charAt(signIdx + 5))) {
393                str2 = str.substring(0, signIdx + 3) + str.substring(signIdx + 4);
394            }
395            return str2;
396        }
397    
398        //-----------------------------------------------------------------------
399        /**
400         * Adds a number of years to a date returning a new object.
401         * The original date object is unchanged.
402         *
403         * @param date  the date, not null
404         * @param amount  the amount to add, may be negative
405         * @return the new date object with the amount added
406         * @throws IllegalArgumentException if the date is null
407         */
408        public static Date addYears(Date date, int amount) {
409            return add(date, Calendar.YEAR, amount);
410        }
411    
412        //-----------------------------------------------------------------------
413        /**
414         * Adds a number of months to a date returning a new object.
415         * The original date object is unchanged.
416         *
417         * @param date  the date, not null
418         * @param amount  the amount to add, may be negative
419         * @return the new date object with the amount added
420         * @throws IllegalArgumentException if the date is null
421         */
422        public static Date addMonths(Date date, int amount) {
423            return add(date, Calendar.MONTH, amount);
424        }
425    
426        //-----------------------------------------------------------------------
427        /**
428         * Adds a number of weeks to a date returning a new object.
429         * The original date object is unchanged.
430         *
431         * @param date  the date, not null
432         * @param amount  the amount to add, may be negative
433         * @return the new date object with the amount added
434         * @throws IllegalArgumentException if the date is null
435         */
436        public static Date addWeeks(Date date, int amount) {
437            return add(date, Calendar.WEEK_OF_YEAR, amount);
438        }
439    
440        //-----------------------------------------------------------------------
441        /**
442         * Adds a number of days to a date returning a new object.
443         * The original date object is unchanged.
444         *
445         * @param date  the date, not null
446         * @param amount  the amount to add, may be negative
447         * @return the new date object with the amount added
448         * @throws IllegalArgumentException if the date is null
449         */
450        public static Date addDays(Date date, int amount) {
451            return add(date, Calendar.DAY_OF_MONTH, amount);
452        }
453    
454        //-----------------------------------------------------------------------
455        /**
456         * Adds a number of hours to a date returning a new object.
457         * The original date object is unchanged.
458         *
459         * @param date  the date, not null
460         * @param amount  the amount to add, may be negative
461         * @return the new date object with the amount added
462         * @throws IllegalArgumentException if the date is null
463         */
464        public static Date addHours(Date date, int amount) {
465            return add(date, Calendar.HOUR_OF_DAY, amount);
466        }
467    
468        //-----------------------------------------------------------------------
469        /**
470         * Adds a number of minutes to a date returning a new object.
471         * The original date object is unchanged.
472         *
473         * @param date  the date, not null
474         * @param amount  the amount to add, may be negative
475         * @return the new date object with the amount added
476         * @throws IllegalArgumentException if the date is null
477         */
478        public static Date addMinutes(Date date, int amount) {
479            return add(date, Calendar.MINUTE, amount);
480        }
481    
482        //-----------------------------------------------------------------------
483        /**
484         * Adds a number of seconds to a date returning a new object.
485         * The original date object is unchanged.
486         *
487         * @param date  the date, not null
488         * @param amount  the amount to add, may be negative
489         * @return the new date object with the amount added
490         * @throws IllegalArgumentException if the date is null
491         */
492        public static Date addSeconds(Date date, int amount) {
493            return add(date, Calendar.SECOND, amount);
494        }
495    
496        //-----------------------------------------------------------------------
497        /**
498         * Adds a number of milliseconds to a date returning a new object.
499         * The original date object is unchanged.
500         *
501         * @param date  the date, not null
502         * @param amount  the amount to add, may be negative
503         * @return the new date object with the amount added
504         * @throws IllegalArgumentException if the date is null
505         */
506        public static Date addMilliseconds(Date date, int amount) {
507            return add(date, Calendar.MILLISECOND, amount);
508        }
509    
510        //-----------------------------------------------------------------------
511        /**
512         * Adds to a date returning a new object.
513         * The original date object is unchanged.
514         *
515         * @param date  the date, not null
516         * @param calendarField  the calendar field to add to
517         * @param amount  the amount to add, may be negative
518         * @return the new date object with the amount added
519         * @throws IllegalArgumentException if the date is null
520         * @deprecated Will become privately scoped in 3.0
521         */
522        public static Date add(Date date, int calendarField, int amount) {
523            if (date == null) {
524                throw new IllegalArgumentException("The date must not be null");
525            }
526            Calendar c = Calendar.getInstance();
527            c.setTime(date);
528            c.add(calendarField, amount);
529            return c.getTime();
530        }
531        
532        //-----------------------------------------------------------------------
533        /**
534         * Sets the years field to a date returning a new object.
535         * The original date object is unchanged.
536         *
537         * @param date  the date, not null
538         * @param amount the amount to set
539         * @return a new Date object set with the specified value
540         * @throws IllegalArgumentException if the date is null
541         * @since 2.4
542         */
543        public static Date setYears(Date date, int amount) {
544            return set(date, Calendar.YEAR, amount);
545        }
546    
547        //-----------------------------------------------------------------------
548        /**
549         * Sets the months field to a date returning a new object.
550         * The original date object is unchanged.
551         *
552         * @param date  the date, not null
553         * @param amount the amount to set
554         * @return a new Date object set with the specified value
555         * @throws IllegalArgumentException if the date is null
556         * @since 2.4
557         */
558        public static Date setMonths(Date date, int amount) {
559            return set(date, Calendar.MONTH, amount);
560        }
561    
562        //-----------------------------------------------------------------------
563        /**
564         * Sets the day of month field to a date returning a new object.
565         * The original date object is unchanged.
566         *
567         * @param date  the date, not null
568         * @param amount the amount to set
569         * @return a new Date object set with the specified value
570         * @throws IllegalArgumentException if the date is null
571         * @since 2.4
572         */
573        public static Date setDays(Date date, int amount) {
574            return set(date, Calendar.DAY_OF_MONTH, amount);
575        }
576    
577        //-----------------------------------------------------------------------
578        /**
579         * Sets the hours field to a date returning a new object.  Hours range 
580         * from  0-23.
581         * The original date object is unchanged.
582         *
583         * @param date  the date, not null
584         * @param amount the amount to set
585         * @return a new Date object set with the specified value
586         * @throws IllegalArgumentException if the date is null
587         * @since 2.4
588         */
589        public static Date setHours(Date date, int amount) {
590            return set(date, Calendar.HOUR_OF_DAY, amount);
591        }
592    
593        //-----------------------------------------------------------------------
594        /**
595         * Sets the minute field to a date returning a new object.
596         * The original date object is unchanged.
597         *
598         * @param date  the date, not null
599         * @param amount the amount to set
600         * @return a new Date object set with the specified value
601         * @throws IllegalArgumentException if the date is null
602         * @since 2.4
603         */
604        public static Date setMinutes(Date date, int amount) {
605            return set(date, Calendar.MINUTE, amount);
606        }
607        
608        //-----------------------------------------------------------------------
609        /**
610         * Sets the seconds field to a date returning a new object.
611         * The original date object is unchanged.
612         *
613         * @param date  the date, not null
614         * @param amount the amount to set
615         * @return a new Date object set with the specified value
616         * @throws IllegalArgumentException if the date is null
617         * @since 2.4
618         */
619        public static Date setSeconds(Date date, int amount) {
620            return set(date, Calendar.SECOND, amount);
621        }
622    
623        //-----------------------------------------------------------------------
624        /**
625         * Sets the miliseconds field to a date returning a new object.
626         * The original date object is unchanged.
627         *
628         * @param date  the date, not null
629         * @param amount the amount to set
630         * @return a new Date object set with the specified value
631         * @throws IllegalArgumentException if the date is null
632         * @since 2.4
633         */
634        public static Date setMilliseconds(Date date, int amount) {
635            return set(date, Calendar.MILLISECOND, amount);
636        } 
637        
638        //-----------------------------------------------------------------------
639        /**
640         * Sets the specified field to a date returning a new object.  
641         * This does not use a lenient calendar.
642         * The original date object is unchanged.
643         *
644         * @param date  the date, not null
645         * @param calendarField  the calendar field to set the amount to
646         * @param amount the amount to set
647         * @return a new Date object set with the specified value
648         * @throws IllegalArgumentException if the date is null
649         * @since 2.4
650         */
651        private static Date set(Date date, int calendarField, int amount) {
652            if (date == null) {
653                throw new IllegalArgumentException("The date must not be null");
654            }
655            // getInstance() returns a new object, so this method is thread safe.
656            Calendar c = Calendar.getInstance();
657            c.setLenient(false);
658            c.setTime(date);
659            c.set(calendarField, amount);
660            return c.getTime();
661        }   
662        
663        //-----------------------------------------------------------------------
664        /**
665         * <p>Round this date, leaving the field specified as the most
666         * significant field.</p>
667         *
668         * <p>For example, if you had the datetime of 28 Mar 2002
669         * 13:45:01.231, if this was passed with HOUR, it would return
670         * 28 Mar 2002 14:00:00.000. If this was passed with MONTH, it
671         * would return 1 April 2002 0:00:00.000.</p>
672         * 
673         * <p>For a date in a timezone that handles the change to daylight
674         * saving time, rounding to Calendar.HOUR_OF_DAY will behave as follows.
675         * Suppose daylight saving time begins at 02:00 on March 30. Rounding a 
676         * date that crosses this time would produce the following values:
677         * <ul>
678         * <li>March 30, 2003 01:10 rounds to March 30, 2003 01:00</li>
679         * <li>March 30, 2003 01:40 rounds to March 30, 2003 03:00</li>
680         * <li>March 30, 2003 02:10 rounds to March 30, 2003 03:00</li>
681         * <li>March 30, 2003 02:40 rounds to March 30, 2003 04:00</li>
682         * </ul>
683         * </p>
684         * 
685         * @param date  the date to work with
686         * @param field  the field from <code>Calendar</code>
687         *  or <code>SEMI_MONTH</code>
688         * @return the rounded date
689         * @throws IllegalArgumentException if the date is <code>null</code>
690         * @throws ArithmeticException if the year is over 280 million
691         */
692        public static Date round(Date date, int field) {
693            if (date == null) {
694                throw new IllegalArgumentException("The date must not be null");
695            }
696            Calendar gval = Calendar.getInstance();
697            gval.setTime(date);
698            modify(gval, field, MODIFY_ROUND);
699            return gval.getTime();
700        }
701    
702        /**
703         * <p>Round this date, leaving the field specified as the most
704         * significant field.</p>
705         *
706         * <p>For example, if you had the datetime of 28 Mar 2002
707         * 13:45:01.231, if this was passed with HOUR, it would return
708         * 28 Mar 2002 14:00:00.000. If this was passed with MONTH, it
709         * would return 1 April 2002 0:00:00.000.</p>
710         * 
711         * <p>For a date in a timezone that handles the change to daylight
712         * saving time, rounding to Calendar.HOUR_OF_DAY will behave as follows.
713         * Suppose daylight saving time begins at 02:00 on March 30. Rounding a 
714         * date that crosses this time would produce the following values:
715         * <ul>
716         * <li>March 30, 2003 01:10 rounds to March 30, 2003 01:00</li>
717         * <li>March 30, 2003 01:40 rounds to March 30, 2003 03:00</li>
718         * <li>March 30, 2003 02:10 rounds to March 30, 2003 03:00</li>
719         * <li>March 30, 2003 02:40 rounds to March 30, 2003 04:00</li>
720         * </ul>
721         * </p>
722         * 
723         * @param date  the date to work with
724         * @param field  the field from <code>Calendar</code>
725         *  or <code>SEMI_MONTH</code>
726         * @return the rounded date (a different object)
727         * @throws IllegalArgumentException if the date is <code>null</code>
728         * @throws ArithmeticException if the year is over 280 million
729         */
730        public static Calendar round(Calendar date, int field) {
731            if (date == null) {
732                throw new IllegalArgumentException("The date must not be null");
733            }
734            Calendar rounded = (Calendar) date.clone();
735            modify(rounded, field, MODIFY_ROUND);
736            return rounded;
737        }
738    
739        /**
740         * <p>Round this date, leaving the field specified as the most
741         * significant field.</p>
742         *
743         * <p>For example, if you had the datetime of 28 Mar 2002
744         * 13:45:01.231, if this was passed with HOUR, it would return
745         * 28 Mar 2002 14:00:00.000. If this was passed with MONTH, it
746         * would return 1 April 2002 0:00:00.000.</p>
747         * 
748         * <p>For a date in a timezone that handles the change to daylight
749         * saving time, rounding to Calendar.HOUR_OF_DAY will behave as follows.
750         * Suppose daylight saving time begins at 02:00 on March 30. Rounding a 
751         * date that crosses this time would produce the following values:
752         * <ul>
753         * <li>March 30, 2003 01:10 rounds to March 30, 2003 01:00</li>
754         * <li>March 30, 2003 01:40 rounds to March 30, 2003 03:00</li>
755         * <li>March 30, 2003 02:10 rounds to March 30, 2003 03:00</li>
756         * <li>March 30, 2003 02:40 rounds to March 30, 2003 04:00</li>
757         * </ul>
758         * </p>
759         * 
760         * @param date  the date to work with, either Date or Calendar
761         * @param field  the field from <code>Calendar</code>
762         *  or <code>SEMI_MONTH</code>
763         * @return the rounded date
764         * @throws IllegalArgumentException if the date is <code>null</code>
765         * @throws ClassCastException if the object type is not a <code>Date</code>
766         *  or <code>Calendar</code>
767         * @throws ArithmeticException if the year is over 280 million
768         */
769        public static Date round(Object date, int field) {
770            if (date == null) {
771                throw new IllegalArgumentException("The date must not be null");
772            }
773            if (date instanceof Date) {
774                return round((Date) date, field);
775            } else if (date instanceof Calendar) {
776                return round((Calendar) date, field).getTime();
777            } else {
778                throw new ClassCastException("Could not round " + date);
779            }
780        }
781    
782        //-----------------------------------------------------------------------
783        /**
784         * <p>Truncate this date, leaving the field specified as the most
785         * significant field.</p>
786         *
787         * <p>For example, if you had the datetime of 28 Mar 2002
788         * 13:45:01.231, if you passed with HOUR, it would return 28 Mar
789         * 2002 13:00:00.000.  If this was passed with MONTH, it would
790         * return 1 Mar 2002 0:00:00.000.</p>
791         * 
792         * @param date  the date to work with
793         * @param field  the field from <code>Calendar</code>
794         *  or <code>SEMI_MONTH</code>
795         * @return the rounded date
796         * @throws IllegalArgumentException if the date is <code>null</code>
797         * @throws ArithmeticException if the year is over 280 million
798         */
799        public static Date truncate(Date date, int field) {
800            if (date == null) {
801                throw new IllegalArgumentException("The date must not be null");
802            }
803            Calendar gval = Calendar.getInstance();
804            gval.setTime(date);
805            modify(gval, field, MODIFY_TRUNCATE);
806            return gval.getTime();
807        }
808    
809        /**
810         * <p>Truncate this date, leaving the field specified as the most
811         * significant field.</p>
812         *
813         * <p>For example, if you had the datetime of 28 Mar 2002
814         * 13:45:01.231, if you passed with HOUR, it would return 28 Mar
815         * 2002 13:00:00.000.  If this was passed with MONTH, it would
816         * return 1 Mar 2002 0:00:00.000.</p>
817         * 
818         * @param date  the date to work with
819         * @param field  the field from <code>Calendar</code>
820         *  or <code>SEMI_MONTH</code>
821         * @return the rounded date (a different object)
822         * @throws IllegalArgumentException if the date is <code>null</code>
823         * @throws ArithmeticException if the year is over 280 million
824         */
825        public static Calendar truncate(Calendar date, int field) {
826            if (date == null) {
827                throw new IllegalArgumentException("The date must not be null");
828            }
829            Calendar truncated = (Calendar) date.clone();
830            modify(truncated, field, MODIFY_TRUNCATE);
831            return truncated;
832        }
833    
834        /**
835         * <p>Truncate this date, leaving the field specified as the most
836         * significant field.</p>
837         *
838         * <p>For example, if you had the datetime of 28 Mar 2002
839         * 13:45:01.231, if you passed with HOUR, it would return 28 Mar
840         * 2002 13:00:00.000.  If this was passed with MONTH, it would
841         * return 1 Mar 2002 0:00:00.000.</p>
842         * 
843         * @param date  the date to work with, either <code>Date</code>
844         *  or <code>Calendar</code>
845         * @param field  the field from <code>Calendar</code>
846         *  or <code>SEMI_MONTH</code>
847         * @return the rounded date
848         * @throws IllegalArgumentException if the date
849         *  is <code>null</code>
850         * @throws ClassCastException if the object type is not a
851         *  <code>Date</code> or <code>Calendar</code>
852         * @throws ArithmeticException if the year is over 280 million
853         */
854        public static Date truncate(Object date, int field) {
855            if (date == null) {
856                throw new IllegalArgumentException("The date must not be null");
857            }
858            if (date instanceof Date) {
859                return truncate((Date) date, field);
860            } else if (date instanceof Calendar) {
861                return truncate((Calendar) date, field).getTime();
862            } else {
863                throw new ClassCastException("Could not truncate " + date);
864            }
865        }
866        
867      //-----------------------------------------------------------------------
868        /**
869         * <p>Ceil this date, leaving the field specified as the most
870         * significant field.</p>
871         *
872         * <p>For example, if you had the datetime of 28 Mar 2002
873         * 13:45:01.231, if you passed with HOUR, it would return 28 Mar
874         * 2002 13:00:00.000.  If this was passed with MONTH, it would
875         * return 1 Mar 2002 0:00:00.000.</p>
876         * 
877         * @param date  the date to work with
878         * @param field  the field from <code>Calendar</code>
879         *  or <code>SEMI_MONTH</code>
880         * @return the rounded date
881         * @throws IllegalArgumentException if the date is <code>null</code>
882         * @throws ArithmeticException if the year is over 280 million
883         * @since 2.5
884         */
885        public static Date ceiling(Date date, int field) {
886            if (date == null) {
887                throw new IllegalArgumentException("The date must not be null");
888            }
889            Calendar gval = Calendar.getInstance();
890            gval.setTime(date);
891            modify(gval, field, MODIFY_CEILING);
892            return gval.getTime();
893        }
894    
895        /**
896         * <p>Ceil this date, leaving the field specified as the most
897         * significant field.</p>
898         *
899         * <p>For example, if you had the datetime of 28 Mar 2002
900         * 13:45:01.231, if you passed with HOUR, it would return 28 Mar
901         * 2002 13:00:00.000.  If this was passed with MONTH, it would
902         * return 1 Mar 2002 0:00:00.000.</p>
903         * 
904         * @param date  the date to work with
905         * @param field  the field from <code>Calendar</code>
906         *  or <code>SEMI_MONTH</code>
907         * @return the rounded date (a different object)
908         * @throws IllegalArgumentException if the date is <code>null</code>
909         * @throws ArithmeticException if the year is over 280 million
910         * @since 2.5
911         */
912        public static Calendar ceiling(Calendar date, int field) {
913            if (date == null) {
914                throw new IllegalArgumentException("The date must not be null");
915            }
916            Calendar ceiled = (Calendar) date.clone();
917            modify(ceiled, field, MODIFY_CEILING);
918            return ceiled;
919        }
920    
921        /**
922         * <p>Ceil this date, leaving the field specified as the most
923         * significant field.</p>
924         *
925         * <p>For example, if you had the datetime of 28 Mar 2002
926         * 13:45:01.231, if you passed with HOUR, it would return 28 Mar
927         * 2002 13:00:00.000.  If this was passed with MONTH, it would
928         * return 1 Mar 2002 0:00:00.000.</p>
929         * 
930         * @param date  the date to work with, either <code>Date</code>
931         *  or <code>Calendar</code>
932         * @param field  the field from <code>Calendar</code>
933         *  or <code>SEMI_MONTH</code>
934         * @return the rounded date
935         * @throws IllegalArgumentException if the date
936         *  is <code>null</code>
937         * @throws ClassCastException if the object type is not a
938         *  <code>Date</code> or <code>Calendar</code>
939         * @throws ArithmeticException if the year is over 280 million
940         * @since 2.5
941         */
942        public static Date ceiling(Object date, int field) {
943            if (date == null) {
944                throw new IllegalArgumentException("The date must not be null");
945            }
946            if (date instanceof Date) {
947                return ceiling((Date) date, field);
948            } else if (date instanceof Calendar) {
949                return ceiling((Calendar) date, field).getTime();
950            } else {
951                throw new ClassCastException("Could not find ceiling of for type: " + date.getClass());
952            }
953        }
954    
955        //-----------------------------------------------------------------------
956        /**
957         * <p>Internal calculation method.</p>
958         * 
959         * @param val  the calendar
960         * @param field  the field constant
961         * @param modType  type to truncate, round or ceiling
962         * @throws ArithmeticException if the year is over 280 million
963         */
964        private static void modify(Calendar val, int field, int modType) {
965            if (val.get(Calendar.YEAR) > 280000000) {
966                throw new ArithmeticException("Calendar value too large for accurate calculations");
967            }
968            
969            if (field == Calendar.MILLISECOND) {
970                return;
971            }
972    
973            // ----------------- Fix for LANG-59 ---------------------- START ---------------
974            // see http://issues.apache.org/jira/browse/LANG-59
975            //
976            // Manually truncate milliseconds, seconds and minutes, rather than using
977            // Calendar methods.
978    
979            Date date = val.getTime();
980            long time = date.getTime();
981            boolean done = false;
982    
983            // truncate milliseconds
984            int millisecs = val.get(Calendar.MILLISECOND);
985            if (MODIFY_TRUNCATE == modType || millisecs < 500) {
986                time = time - millisecs;
987            }
988            if (field == Calendar.SECOND) {
989                done = true;
990            }
991    
992            // truncate seconds
993            int seconds = val.get(Calendar.SECOND);
994            if (!done && (MODIFY_TRUNCATE == modType || seconds < 30)) {
995                time = time - (seconds * 1000L);
996            }
997            if (field == Calendar.MINUTE) {
998                done = true;
999            }
1000    
1001            // truncate minutes
1002            int minutes = val.get(Calendar.MINUTE);
1003            if (!done && (MODIFY_TRUNCATE == modType || minutes < 30)) {
1004                time = time - (minutes * 60000L);
1005            }
1006    
1007            // reset time
1008            if (date.getTime() != time) {
1009                date.setTime(time);
1010                val.setTime(date);
1011            }
1012            // ----------------- Fix for LANG-59 ----------------------- END ----------------
1013    
1014            boolean roundUp = false;
1015            for (int i = 0; i < fields.length; i++) {
1016                for (int j = 0; j < fields[i].length; j++) {
1017                    if (fields[i][j] == field) {
1018                        //This is our field... we stop looping
1019                        if (modType == MODIFY_CEILING || (modType == MODIFY_ROUND && roundUp)) {
1020                            if (field == DateUtils.SEMI_MONTH) {
1021                                //This is a special case that's hard to generalize
1022                                //If the date is 1, we round up to 16, otherwise
1023                                //  we subtract 15 days and add 1 month
1024                                if (val.get(Calendar.DATE) == 1) {
1025                                    val.add(Calendar.DATE, 15);
1026                                } else {
1027                                    val.add(Calendar.DATE, -15);
1028                                    val.add(Calendar.MONTH, 1);
1029                                }
1030    // ----------------- Fix for LANG-440 ---------------------- START ---------------
1031                            } else if (field == Calendar.AM_PM) {
1032                                // This is a special case
1033                                // If the time is 0, we round up to 12, otherwise
1034                                //  we subtract 12 hours and add 1 day
1035                                if (val.get(Calendar.HOUR_OF_DAY) == 0) {
1036                                    val.add(Calendar.HOUR_OF_DAY, 12);
1037                                } else {
1038                                    val.add(Calendar.HOUR_OF_DAY, -12);
1039                                    val.add(Calendar.DATE, 1);
1040                                }
1041    // ----------------- Fix for LANG-440 ---------------------- END ---------------
1042                            } else {
1043                                //We need at add one to this field since the
1044                                //  last number causes us to round up
1045                                val.add(fields[i][0], 1);
1046                            }
1047                        }
1048                        return;
1049                    }
1050                }
1051                //We have various fields that are not easy roundings
1052                int offset = 0;
1053                boolean offsetSet = false;
1054                //These are special types of fields that require different rounding rules
1055                switch (field) {
1056                    case DateUtils.SEMI_MONTH:
1057                        if (fields[i][0] == Calendar.DATE) {
1058                            //If we're going to drop the DATE field's value,
1059                            //  we want to do this our own way.
1060                            //We need to subtrace 1 since the date has a minimum of 1
1061                            offset = val.get(Calendar.DATE) - 1;
1062                            //If we're above 15 days adjustment, that means we're in the
1063                            //  bottom half of the month and should stay accordingly.
1064                            if (offset >= 15) {
1065                                offset -= 15;
1066                            }
1067                            //Record whether we're in the top or bottom half of that range
1068                            roundUp = offset > 7;
1069                            offsetSet = true;
1070                        }
1071                        break;
1072                    case Calendar.AM_PM:
1073                        if (fields[i][0] == Calendar.HOUR_OF_DAY) {
1074                            //If we're going to drop the HOUR field's value,
1075                            //  we want to do this our own way.
1076                            offset = val.get(Calendar.HOUR_OF_DAY);
1077                            if (offset >= 12) {
1078                                offset -= 12;
1079                            }
1080                            roundUp = offset >= 6;
1081                            offsetSet = true;
1082                        }
1083                        break;
1084                }
1085                if (!offsetSet) {
1086                    int min = val.getActualMinimum(fields[i][0]);
1087                    int max = val.getActualMaximum(fields[i][0]);
1088                    //Calculate the offset from the minimum allowed value
1089                    offset = val.get(fields[i][0]) - min;
1090                    //Set roundUp if this is more than half way between the minimum and maximum
1091                    roundUp = offset > ((max - min) / 2);
1092                }
1093                //We need to remove this field
1094                if (offset != 0) {
1095                    val.set(fields[i][0], val.get(fields[i][0]) - offset);
1096                }
1097            }
1098            throw new IllegalArgumentException("The field " + field + " is not supported");
1099    
1100        }
1101    
1102        //-----------------------------------------------------------------------
1103        /**
1104         * <p>This constructs an <code>Iterator</code> over each day in a date
1105         * range defined by a focus date and range style.</p>
1106         *
1107         * <p>For instance, passing Thursday, July 4, 2002 and a
1108         * <code>RANGE_MONTH_SUNDAY</code> will return an <code>Iterator</code>
1109         * that starts with Sunday, June 30, 2002 and ends with Saturday, August 3,
1110         * 2002, returning a Calendar instance for each intermediate day.</p>
1111         *
1112         * <p>This method provides an iterator that returns Calendar objects.
1113         * The days are progressed using {@link Calendar#add(int, int)}.</p>
1114         *
1115         * @param focus  the date to work with, not null
1116         * @param rangeStyle  the style constant to use. Must be one of
1117         * {@link DateUtils#RANGE_MONTH_SUNDAY}, 
1118         * {@link DateUtils#RANGE_MONTH_MONDAY},
1119         * {@link DateUtils#RANGE_WEEK_SUNDAY},
1120         * {@link DateUtils#RANGE_WEEK_MONDAY},
1121         * {@link DateUtils#RANGE_WEEK_RELATIVE},
1122         * {@link DateUtils#RANGE_WEEK_CENTER}
1123         * @return the date iterator, which always returns Calendar instances
1124         * @throws IllegalArgumentException if the date is <code>null</code>
1125         * @throws IllegalArgumentException if the rangeStyle is invalid
1126         */
1127        public static Iterator iterator(Date focus, int rangeStyle) {
1128            if (focus == null) {
1129                throw new IllegalArgumentException("The date must not be null");
1130            }
1131            Calendar gval = Calendar.getInstance();
1132            gval.setTime(focus);
1133            return iterator(gval, rangeStyle);
1134        }
1135    
1136        /**
1137         * <p>This constructs an <code>Iterator</code> over each day in a date
1138         * range defined by a focus date and range style.</p>
1139         *
1140         * <p>For instance, passing Thursday, July 4, 2002 and a
1141         * <code>RANGE_MONTH_SUNDAY</code> will return an <code>Iterator</code>
1142         * that starts with Sunday, June 30, 2002 and ends with Saturday, August 3,
1143         * 2002, returning a Calendar instance for each intermediate day.</p>
1144         *
1145         * <p>This method provides an iterator that returns Calendar objects.
1146         * The days are progressed using {@link Calendar#add(int, int)}.</p>
1147         *
1148         * @param focus  the date to work with
1149         * @param rangeStyle  the style constant to use. Must be one of
1150         * {@link DateUtils#RANGE_MONTH_SUNDAY}, 
1151         * {@link DateUtils#RANGE_MONTH_MONDAY},
1152         * {@link DateUtils#RANGE_WEEK_SUNDAY},
1153         * {@link DateUtils#RANGE_WEEK_MONDAY},
1154         * {@link DateUtils#RANGE_WEEK_RELATIVE},
1155         * {@link DateUtils#RANGE_WEEK_CENTER}
1156         * @return the date iterator
1157         * @throws IllegalArgumentException if the date is <code>null</code>
1158         * @throws IllegalArgumentException if the rangeStyle is invalid
1159         */
1160        public static Iterator iterator(Calendar focus, int rangeStyle) {
1161            if (focus == null) {
1162                throw new IllegalArgumentException("The date must not be null");
1163            }
1164            Calendar start = null;
1165            Calendar end = null;
1166            int startCutoff = Calendar.SUNDAY;
1167            int endCutoff = Calendar.SATURDAY;
1168            switch (rangeStyle) {
1169                case RANGE_MONTH_SUNDAY:
1170                case RANGE_MONTH_MONDAY:
1171                    //Set start to the first of the month
1172                    start = truncate(focus, Calendar.MONTH);
1173                    //Set end to the last of the month
1174                    end = (Calendar) start.clone();
1175                    end.add(Calendar.MONTH, 1);
1176                    end.add(Calendar.DATE, -1);
1177                    //Loop start back to the previous sunday or monday
1178                    if (rangeStyle == RANGE_MONTH_MONDAY) {
1179                        startCutoff = Calendar.MONDAY;
1180                        endCutoff = Calendar.SUNDAY;
1181                    }
1182                    break;
1183                case RANGE_WEEK_SUNDAY:
1184                case RANGE_WEEK_MONDAY:
1185                case RANGE_WEEK_RELATIVE:
1186                case RANGE_WEEK_CENTER:
1187                    //Set start and end to the current date
1188                    start = truncate(focus, Calendar.DATE);
1189                    end = truncate(focus, Calendar.DATE);
1190                    switch (rangeStyle) {
1191                        case RANGE_WEEK_SUNDAY:
1192                            //already set by default
1193                            break;
1194                        case RANGE_WEEK_MONDAY:
1195                            startCutoff = Calendar.MONDAY;
1196                            endCutoff = Calendar.SUNDAY;
1197                            break;
1198                        case RANGE_WEEK_RELATIVE:
1199                            startCutoff = focus.get(Calendar.DAY_OF_WEEK);
1200                            endCutoff = startCutoff - 1;
1201                            break;
1202                        case RANGE_WEEK_CENTER:
1203                            startCutoff = focus.get(Calendar.DAY_OF_WEEK) - 3;
1204                            endCutoff = focus.get(Calendar.DAY_OF_WEEK) + 3;
1205                            break;
1206                    }
1207                    break;
1208                default:
1209                    throw new IllegalArgumentException("The range style " + rangeStyle + " is not valid.");
1210            }
1211            if (startCutoff < Calendar.SUNDAY) {
1212                startCutoff += 7;
1213            }
1214            if (startCutoff > Calendar.SATURDAY) {
1215                startCutoff -= 7;
1216            }
1217            if (endCutoff < Calendar.SUNDAY) {
1218                endCutoff += 7;
1219            }
1220            if (endCutoff > Calendar.SATURDAY) {
1221                endCutoff -= 7;
1222            }
1223            while (start.get(Calendar.DAY_OF_WEEK) != startCutoff) {
1224                start.add(Calendar.DATE, -1);
1225            }
1226            while (end.get(Calendar.DAY_OF_WEEK) != endCutoff) {
1227                end.add(Calendar.DATE, 1);
1228            }
1229            return new DateIterator(start, end);
1230        }
1231    
1232        /**
1233         * <p>This constructs an <code>Iterator</code> over each day in a date
1234         * range defined by a focus date and range style.</p>
1235         *
1236         * <p>For instance, passing Thursday, July 4, 2002 and a
1237         * <code>RANGE_MONTH_SUNDAY</code> will return an <code>Iterator</code>
1238         * that starts with Sunday, June 30, 2002 and ends with Saturday, August 3,
1239         * 2002, returning a Calendar instance for each intermediate day.</p>
1240         *
1241         * @param focus  the date to work with, either
1242         *  <code>Date</code> or <code>Calendar</code>
1243         * @param rangeStyle  the style constant to use. Must be one of the range
1244         * styles listed for the {@link #iterator(Calendar, int)} method.
1245         * @return the date iterator
1246         * @throws IllegalArgumentException if the date
1247         *  is <code>null</code>
1248         * @throws ClassCastException if the object type is
1249         *  not a <code>Date</code> or <code>Calendar</code>
1250         */
1251        public static Iterator iterator(Object focus, int rangeStyle) {
1252            if (focus == null) {
1253                throw new IllegalArgumentException("The date must not be null");
1254            }
1255            if (focus instanceof Date) {
1256                return iterator((Date) focus, rangeStyle);
1257            } else if (focus instanceof Calendar) {
1258                return iterator((Calendar) focus, rangeStyle);
1259            } else {
1260                throw new ClassCastException("Could not iterate based on " + focus);
1261            }
1262        }
1263        
1264        /**
1265         * <p>Returns the number of milliseconds within the 
1266         * fragment. All datefields greater than the fragment will be ignored.</p>
1267         * 
1268         * <p>Asking the milliseconds of any date will only return the number of milliseconds
1269         * of the current second (resulting in a number between 0 and 999). This 
1270         * method will retrieve the number of milliseconds for any fragment. 
1271         * For example, if you want to calculate the number of milliseconds past today, 
1272         * your fragment is Calendar.DATE or Calendar.DAY_OF_YEAR. The result will
1273         * be all milliseconds of the past hour(s), minutes(s) and second(s).</p>
1274         * 
1275         * <p>Valid fragments are: Calendar.YEAR, Calendar.MONTH, both 
1276         * Calendar.DAY_OF_YEAR and Calendar.DATE, Calendar.HOUR_OF_DAY, 
1277         * Calendar.MINUTE, Calendar.SECOND and Calendar.MILLISECOND
1278         * A fragment less than or equal to a SECOND field will return 0.</p> 
1279         * 
1280         * <p>
1281         * <ul>
1282         *  <li>January 1, 2008 7:15:10.538 with Calendar.SECOND as fragment will return 538</li>
1283         *  <li>January 6, 2008 7:15:10.538 with Calendar.SECOND as fragment will return 538</li>
1284         *  <li>January 6, 2008 7:15:10.538 with Calendar.MINUTE as fragment will return 10538 (10*1000 + 538)</li>
1285         *  <li>January 16, 2008 7:15:10.538 with Calendar.MILLISECOND as fragment will return 0
1286         *   (a millisecond cannot be split in milliseconds)</li>
1287         * </ul>
1288         * </p>
1289         * 
1290         * @param date the date to work with, not null
1291         * @param fragment the Calendar field part of date to calculate 
1292         * @return number of milliseconds within the fragment of date
1293         * @throws IllegalArgumentException if the date is <code>null</code> or
1294         * fragment is not supported
1295         * @since 2.4
1296         */
1297        public static long getFragmentInMilliseconds(Date date, int fragment) {
1298            return getFragment(date, fragment, Calendar.MILLISECOND);    
1299        }
1300        
1301        /**
1302         * <p>Returns the number of seconds within the 
1303         * fragment. All datefields greater than the fragment will be ignored.</p> 
1304         * 
1305         * <p>Asking the seconds of any date will only return the number of seconds
1306         * of the current minute (resulting in a number between 0 and 59). This 
1307         * method will retrieve the number of seconds for any fragment. 
1308         * For example, if you want to calculate the number of seconds past today, 
1309         * your fragment is Calendar.DATE or Calendar.DAY_OF_YEAR. The result will
1310         * be all seconds of the past hour(s) and minutes(s).</p> 
1311         * 
1312         * <p>Valid fragments are: Calendar.YEAR, Calendar.MONTH, both 
1313         * Calendar.DAY_OF_YEAR and Calendar.DATE, Calendar.HOUR_OF_DAY, 
1314         * Calendar.MINUTE, Calendar.SECOND and Calendar.MILLISECOND
1315         * A fragment less than or equal to a SECOND field will return 0.</p> 
1316         * 
1317         * <p>
1318         * <ul>
1319         *  <li>January 1, 2008 7:15:10.538 with Calendar.MINUTE as fragment will return 10
1320         *   (equivalent to deprecated date.getSeconds())</li>
1321         *  <li>January 6, 2008 7:15:10.538 with Calendar.MINUTE as fragment will return 10
1322         *   (equivalent to deprecated date.getSeconds())</li>
1323         *  <li>January 6, 2008 7:15:10.538 with Calendar.DAY_OF_YEAR as fragment will return 26110
1324         *   (7*3600 + 15*60 + 10)</li>
1325         *  <li>January 16, 2008 7:15:10.538 with Calendar.MILLISECOND as fragment will return 0
1326         *   (a millisecond cannot be split in seconds)</li>
1327         * </ul>
1328         * </p>
1329         * 
1330         * @param date the date to work with, not null
1331         * @param fragment the Calendar field part of date to calculate 
1332         * @return number of seconds within the fragment of date
1333         * @throws IllegalArgumentException if the date is <code>null</code> or
1334         * fragment is not supported
1335         * @since 2.4
1336         */
1337        public static long getFragmentInSeconds(Date date, int fragment) {
1338            return getFragment(date, fragment, Calendar.SECOND);
1339        }
1340        
1341        /**
1342         * <p>Returns the number of minutes within the 
1343         * fragment. All datefields greater than the fragment will be ignored.</p> 
1344         * 
1345         * <p>Asking the minutes of any date will only return the number of minutes
1346         * of the current hour (resulting in a number between 0 and 59). This 
1347         * method will retrieve the number of minutes for any fragment. 
1348         * For example, if you want to calculate the number of minutes past this month, 
1349         * your fragment is Calendar.MONTH. The result will be all minutes of the 
1350         * past day(s) and hour(s).</p> 
1351         * 
1352         * <p>Valid fragments are: Calendar.YEAR, Calendar.MONTH, both 
1353         * Calendar.DAY_OF_YEAR and Calendar.DATE, Calendar.HOUR_OF_DAY, 
1354         * Calendar.MINUTE, Calendar.SECOND and Calendar.MILLISECOND
1355         * A fragment less than or equal to a MINUTE field will return 0.</p> 
1356         * 
1357         * <p>
1358         * <ul>
1359         *  <li>January 1, 2008 7:15:10.538 with Calendar.HOUR_OF_DAY as fragment will return 15
1360         *   (equivalent to deprecated date.getMinutes())</li>
1361         *  <li>January 6, 2008 7:15:10.538 with Calendar.HOUR_OF_DAY as fragment will return 15
1362         *   (equivalent to deprecated date.getMinutes())</li>
1363         *  <li>January 1, 2008 7:15:10.538 with Calendar.MONTH as fragment will return 15</li>
1364         *  <li>January 6, 2008 7:15:10.538 with Calendar.MONTH as fragment will return 435 (7*60 + 15)</li>
1365         *  <li>January 16, 2008 7:15:10.538 with Calendar.MILLISECOND as fragment will return 0
1366         *   (a millisecond cannot be split in minutes)</li>
1367         * </ul>
1368         * </p>
1369         * 
1370         * @param date the date to work with, not null
1371         * @param fragment the Calendar field part of date to calculate 
1372         * @return number of minutes within the fragment of date
1373         * @throws IllegalArgumentException if the date is <code>null</code> or 
1374         * fragment is not supported
1375         * @since 2.4
1376         */
1377        public static long getFragmentInMinutes(Date date, int fragment) {
1378            return getFragment(date, fragment, Calendar.MINUTE);
1379        }
1380        
1381        /**
1382         * <p>Returns the number of hours within the 
1383         * fragment. All datefields greater than the fragment will be ignored.</p> 
1384         * 
1385         * <p>Asking the hours of any date will only return the number of hours
1386         * of the current day (resulting in a number between 0 and 23). This 
1387         * method will retrieve the number of hours for any fragment. 
1388         * For example, if you want to calculate the number of hours past this month, 
1389         * your fragment is Calendar.MONTH. The result will be all hours of the 
1390         * past day(s).</p> 
1391         * 
1392         * <p>Valid fragments are: Calendar.YEAR, Calendar.MONTH, both 
1393         * Calendar.DAY_OF_YEAR and Calendar.DATE, Calendar.HOUR_OF_DAY, 
1394         * Calendar.MINUTE, Calendar.SECOND and Calendar.MILLISECOND
1395         * A fragment less than or equal to a HOUR field will return 0.</p> 
1396         * 
1397         * <p>
1398         * <ul>
1399         *  <li>January 1, 2008 7:15:10.538 with Calendar.DAY_OF_YEAR as fragment will return 7
1400         *   (equivalent to deprecated date.getHours())</li>
1401         *  <li>January 6, 2008 7:15:10.538 with Calendar.DAY_OF_YEAR as fragment will return 7
1402         *   (equivalent to deprecated date.getHours())</li>
1403         *  <li>January 1, 2008 7:15:10.538 with Calendar.MONTH as fragment will return 7</li>
1404         *  <li>January 6, 2008 7:15:10.538 with Calendar.MONTH as fragment will return 127 (5*24 + 7)</li>
1405         *  <li>January 16, 2008 7:15:10.538 with Calendar.MILLISECOND as fragment will return 0
1406         *   (a millisecond cannot be split in hours)</li>
1407         * </ul>
1408         * </p>
1409         * 
1410         * @param date the date to work with, not null
1411         * @param fragment the Calendar field part of date to calculate 
1412         * @return number of hours within the fragment of date
1413         * @throws IllegalArgumentException if the date is <code>null</code> or 
1414         * fragment is not supported
1415         * @since 2.4
1416         */
1417        public static long getFragmentInHours(Date date, int fragment) {
1418            return getFragment(date, fragment, Calendar.HOUR_OF_DAY);
1419        }
1420        
1421        /**
1422         * <p>Returns the number of days within the 
1423         * fragment. All datefields greater than the fragment will be ignored.</p> 
1424         * 
1425         * <p>Asking the days of any date will only return the number of days
1426         * of the current month (resulting in a number between 1 and 31). This 
1427         * method will retrieve the number of days for any fragment. 
1428         * For example, if you want to calculate the number of days past this year, 
1429         * your fragment is Calendar.YEAR. The result will be all days of the 
1430         * past month(s).</p> 
1431         * 
1432         * <p>Valid fragments are: Calendar.YEAR, Calendar.MONTH, both 
1433         * Calendar.DAY_OF_YEAR and Calendar.DATE, Calendar.HOUR_OF_DAY, 
1434         * Calendar.MINUTE, Calendar.SECOND and Calendar.MILLISECOND
1435         * A fragment less than or equal to a DAY field will return 0.</p> 
1436         *  
1437         * <p>
1438         * <ul>
1439         *  <li>January 28, 2008 with Calendar.MONTH as fragment will return 28
1440         *   (equivalent to deprecated date.getDay())</li>
1441         *  <li>February 28, 2008 with Calendar.MONTH as fragment will return 28
1442         *   (equivalent to deprecated date.getDay())</li>
1443         *  <li>January 28, 2008 with Calendar.YEAR as fragment will return 28</li>
1444         *  <li>February 28, 2008 with Calendar.YEAR as fragment will return 59</li>
1445         *  <li>January 28, 2008 with Calendar.MILLISECOND as fragment will return 0
1446         *   (a millisecond cannot be split in days)</li>
1447         * </ul>
1448         * </p>
1449         * 
1450         * @param date the date to work with, not null
1451         * @param fragment the Calendar field part of date to calculate 
1452         * @return number of days  within the fragment of date
1453         * @throws IllegalArgumentException if the date is <code>null</code> or 
1454         * fragment is not supported
1455         * @since 2.4
1456         */
1457        public static long getFragmentInDays(Date date, int fragment) {
1458            return getFragment(date, fragment, Calendar.DAY_OF_YEAR);
1459        }
1460    
1461        /**
1462         * <p>Returns the number of milliseconds within the 
1463         * fragment. All datefields greater than the fragment will be ignored.</p> 
1464         * 
1465         * <p>Asking the milliseconds of any date will only return the number of milliseconds
1466         * of the current second (resulting in a number between 0 and 999). This 
1467         * method will retrieve the number of milliseconds for any fragment. 
1468         * For example, if you want to calculate the number of seconds past today, 
1469         * your fragment is Calendar.DATE or Calendar.DAY_OF_YEAR. The result will
1470         * be all seconds of the past hour(s), minutes(s) and second(s).</p> 
1471         * 
1472         * <p>Valid fragments are: Calendar.YEAR, Calendar.MONTH, both 
1473         * Calendar.DAY_OF_YEAR and Calendar.DATE, Calendar.HOUR_OF_DAY, 
1474         * Calendar.MINUTE, Calendar.SECOND and Calendar.MILLISECOND
1475         * A fragment less than or equal to a MILLISECOND field will return 0.</p> 
1476         * 
1477         * <p>
1478         * <ul>
1479         *  <li>January 1, 2008 7:15:10.538 with Calendar.SECOND as fragment will return 538
1480         *   (equivalent to calendar.get(Calendar.MILLISECOND))</li>
1481         *  <li>January 6, 2008 7:15:10.538 with Calendar.SECOND as fragment will return 538
1482         *   (equivalent to calendar.get(Calendar.MILLISECOND))</li>
1483         *  <li>January 6, 2008 7:15:10.538 with Calendar.MINUTE as fragment will return 10538
1484         *   (10*1000 + 538)</li>
1485         *  <li>January 16, 2008 7:15:10.538 with Calendar.MILLISECOND as fragment will return 0
1486         *   (a millisecond cannot be split in milliseconds)</li>
1487         * </ul>
1488         * </p>
1489         * 
1490         * @param calendar the calendar to work with, not null
1491         * @param fragment the Calendar field part of calendar to calculate 
1492         * @return number of milliseconds within the fragment of date
1493         * @throws IllegalArgumentException if the date is <code>null</code> or 
1494         * fragment is not supported
1495         * @since 2.4
1496         */
1497      public static long getFragmentInMilliseconds(Calendar calendar, int fragment) {
1498        return getFragment(calendar, fragment, Calendar.MILLISECOND);
1499      }
1500        /**
1501         * <p>Returns the number of seconds within the 
1502         * fragment. All datefields greater than the fragment will be ignored.</p> 
1503         * 
1504         * <p>Asking the seconds of any date will only return the number of seconds
1505         * of the current minute (resulting in a number between 0 and 59). This 
1506         * method will retrieve the number of seconds for any fragment. 
1507         * For example, if you want to calculate the number of seconds past today, 
1508         * your fragment is Calendar.DATE or Calendar.DAY_OF_YEAR. The result will
1509         * be all seconds of the past hour(s) and minutes(s).</p> 
1510         * 
1511         * <p>Valid fragments are: Calendar.YEAR, Calendar.MONTH, both 
1512         * Calendar.DAY_OF_YEAR and Calendar.DATE, Calendar.HOUR_OF_DAY, 
1513         * Calendar.MINUTE, Calendar.SECOND and Calendar.MILLISECOND
1514         * A fragment less than or equal to a SECOND field will return 0.</p> 
1515         * 
1516         * <p>
1517         * <ul>
1518         *  <li>January 1, 2008 7:15:10.538 with Calendar.MINUTE as fragment will return 10
1519         *   (equivalent to calendar.get(Calendar.SECOND))</li>
1520         *  <li>January 6, 2008 7:15:10.538 with Calendar.MINUTE as fragment will return 10
1521         *   (equivalent to calendar.get(Calendar.SECOND))</li>
1522         *  <li>January 6, 2008 7:15:10.538 with Calendar.DAY_OF_YEAR as fragment will return 26110
1523         *   (7*3600 + 15*60 + 10)</li>
1524         *  <li>January 16, 2008 7:15:10.538 with Calendar.MILLISECOND as fragment will return 0
1525         *   (a millisecond cannot be split in seconds)</li>
1526         * </ul>
1527         * </p>
1528         * 
1529         * @param calendar the calendar to work with, not null
1530         * @param fragment the Calendar field part of calendar to calculate 
1531         * @return number of seconds within the fragment of date
1532         * @throws IllegalArgumentException if the date is <code>null</code> or 
1533         * fragment is not supported
1534         * @since 2.4
1535         */
1536        public static long getFragmentInSeconds(Calendar calendar, int fragment) {
1537            return getFragment(calendar, fragment, Calendar.SECOND);
1538        }
1539        
1540        /**
1541         * <p>Returns the number of minutes within the 
1542         * fragment. All datefields greater than the fragment will be ignored.</p> 
1543         * 
1544         * <p>Asking the minutes of any date will only return the number of minutes
1545         * of the current hour (resulting in a number between 0 and 59). This 
1546         * method will retrieve the number of minutes for any fragment. 
1547         * For example, if you want to calculate the number of minutes past this month, 
1548         * your fragment is Calendar.MONTH. The result will be all minutes of the 
1549         * past day(s) and hour(s).</p> 
1550         * 
1551         * <p>Valid fragments are: Calendar.YEAR, Calendar.MONTH, both 
1552         * Calendar.DAY_OF_YEAR and Calendar.DATE, Calendar.HOUR_OF_DAY, 
1553         * Calendar.MINUTE, Calendar.SECOND and Calendar.MILLISECOND
1554         * A fragment less than or equal to a MINUTE field will return 0.</p> 
1555         * 
1556         * <p>
1557         * <ul>
1558         *  <li>January 1, 2008 7:15:10.538 with Calendar.HOUR_OF_DAY as fragment will return 15
1559         *   (equivalent to calendar.get(Calendar.MINUTES))</li>
1560         *  <li>January 6, 2008 7:15:10.538 with Calendar.HOUR_OF_DAY as fragment will return 15
1561         *   (equivalent to calendar.get(Calendar.MINUTES))</li>
1562         *  <li>January 1, 2008 7:15:10.538 with Calendar.MONTH as fragment will return 15</li>
1563         *  <li>January 6, 2008 7:15:10.538 with Calendar.MONTH as fragment will return 435 (7*60 + 15)</li>
1564         *  <li>January 16, 2008 7:15:10.538 with Calendar.MILLISECOND as fragment will return 0
1565         *   (a millisecond cannot be split in minutes)</li>
1566         * </ul>
1567         * </p>
1568         * 
1569         * @param calendar the calendar to work with, not null
1570         * @param fragment the Calendar field part of calendar to calculate 
1571         * @return number of minutes within the fragment of date
1572         * @throws IllegalArgumentException if the date is <code>null</code> or 
1573         * fragment is not supported
1574         * @since 2.4
1575         */
1576        public static long getFragmentInMinutes(Calendar calendar, int fragment) {
1577            return getFragment(calendar, fragment, Calendar.MINUTE);
1578        }
1579        
1580        /**
1581         * <p>Returns the number of hours within the 
1582         * fragment. All datefields greater than the fragment will be ignored.</p> 
1583         * 
1584         * <p>Asking the hours of any date will only return the number of hours
1585         * of the current day (resulting in a number between 0 and 23). This 
1586         * method will retrieve the number of hours for any fragment. 
1587         * For example, if you want to calculate the number of hours past this month, 
1588         * your fragment is Calendar.MONTH. The result will be all hours of the 
1589         * past day(s).</p> 
1590         * 
1591         * <p>Valid fragments are: Calendar.YEAR, Calendar.MONTH, both 
1592         * Calendar.DAY_OF_YEAR and Calendar.DATE, Calendar.HOUR_OF_DAY, 
1593         * Calendar.MINUTE, Calendar.SECOND and Calendar.MILLISECOND
1594         * A fragment less than or equal to a HOUR field will return 0.</p> 
1595         *  
1596         * <p>
1597         * <ul>
1598         *  <li>January 1, 2008 7:15:10.538 with Calendar.DAY_OF_YEAR as fragment will return 7
1599         *   (equivalent to calendar.get(Calendar.HOUR_OF_DAY))</li>
1600         *  <li>January 6, 2008 7:15:10.538 with Calendar.DAY_OF_YEAR as fragment will return 7
1601         *   (equivalent to calendar.get(Calendar.HOUR_OF_DAY))</li>
1602         *  <li>January 1, 2008 7:15:10.538 with Calendar.MONTH as fragment will return 7</li>
1603         *  <li>January 6, 2008 7:15:10.538 with Calendar.MONTH as fragment will return 127 (5*24 + 7)</li>
1604         *  <li>January 16, 2008 7:15:10.538 with Calendar.MILLISECOND as fragment will return 0
1605         *   (a millisecond cannot be split in hours)</li>
1606         * </ul>
1607         * </p>
1608         *  
1609         * @param calendar the calendar to work with, not null
1610         * @param fragment the Calendar field part of calendar to calculate 
1611         * @return number of hours within the fragment of date
1612         * @throws IllegalArgumentException if the date is <code>null</code> or 
1613         * fragment is not supported
1614         * @since 2.4
1615         */
1616        public static long getFragmentInHours(Calendar calendar, int fragment) {
1617            return getFragment(calendar, fragment, Calendar.HOUR_OF_DAY);
1618        }
1619        
1620        /**
1621         * <p>Returns the number of days within the 
1622         * fragment. All datefields greater than the fragment will be ignored.</p> 
1623         * 
1624         * <p>Asking the days of any date will only return the number of days
1625         * of the current month (resulting in a number between 1 and 31). This 
1626         * method will retrieve the number of days for any fragment. 
1627         * For example, if you want to calculate the number of days past this year, 
1628         * your fragment is Calendar.YEAR. The result will be all days of the 
1629         * past month(s).</p> 
1630         * 
1631         * <p>Valid fragments are: Calendar.YEAR, Calendar.MONTH, both 
1632         * Calendar.DAY_OF_YEAR and Calendar.DATE, Calendar.HOUR_OF_DAY, 
1633         * Calendar.MINUTE, Calendar.SECOND and Calendar.MILLISECOND
1634         * A fragment less than or equal to a DAY field will return 0.</p> 
1635         * 
1636         * <p>
1637         * <ul>
1638         *  <li>January 28, 2008 with Calendar.MONTH as fragment will return 28
1639         *   (equivalent to calendar.get(Calendar.DAY_OF_MONTH))</li>
1640         *  <li>February 28, 2008 with Calendar.MONTH as fragment will return 28
1641         *   (equivalent to calendar.get(Calendar.DAY_OF_MONTH))</li>
1642         *  <li>January 28, 2008 with Calendar.YEAR as fragment will return 28
1643         *   (equivalent to calendar.get(Calendar.DAY_OF_YEAR))</li>
1644         *  <li>February 28, 2008 with Calendar.YEAR as fragment will return 59
1645         *   (equivalent to calendar.get(Calendar.DAY_OF_YEAR))</li>
1646         *  <li>January 28, 2008 with Calendar.MILLISECOND as fragment will return 0
1647         *   (a millisecond cannot be split in days)</li>
1648         * </ul>
1649         * </p>
1650         * 
1651         * @param calendar the calendar to work with, not null
1652         * @param fragment the Calendar field part of calendar to calculate 
1653         * @return number of days within the fragment of date
1654         * @throws IllegalArgumentException if the date is <code>null</code> or 
1655         * fragment is not supported
1656         * @since 2.4
1657         */
1658        public static long getFragmentInDays(Calendar calendar, int fragment) {
1659            return getFragment(calendar, fragment, Calendar.DAY_OF_YEAR);
1660        }
1661        
1662        /**
1663         * Date-version for fragment-calculation in any unit
1664         * 
1665         * @param date the date to work with, not null
1666         * @param fragment the Calendar field part of date to calculate 
1667         * @param unit Calendar field defining the unit
1668         * @return number of units within the fragment of the date
1669         * @throws IllegalArgumentException if the date is <code>null</code> or 
1670         * fragment is not supported
1671         * @since 2.4
1672         */
1673        private static long getFragment(Date date, int fragment, int unit) {
1674            if(date == null) {
1675                throw  new IllegalArgumentException("The date must not be null");
1676            }
1677            Calendar calendar = Calendar.getInstance();
1678            calendar.setTime(date);
1679            return getFragment(calendar, fragment, unit);
1680        }
1681    
1682        /**
1683         * Calendar-version for fragment-calculation in any unit
1684         * 
1685         * @param calendar the calendar to work with, not null
1686         * @param fragment the Calendar field part of calendar to calculate 
1687         * @param unit Calendar field defining the unit
1688         * @return number of units within the fragment of the calendar
1689         * @throws IllegalArgumentException if the date is <code>null</code> or 
1690         * fragment is not supported
1691         * @since 2.4
1692         */
1693        private static long getFragment(Calendar calendar, int fragment, int unit) {
1694            if(calendar == null) {
1695                throw  new IllegalArgumentException("The date must not be null"); 
1696            }
1697            long millisPerUnit = getMillisPerUnit(unit);
1698            long result = 0;
1699            
1700            // Fragments bigger than a day require a breakdown to days
1701            switch (fragment) {
1702                case Calendar.YEAR:
1703                    result += (calendar.get(Calendar.DAY_OF_YEAR) * MILLIS_PER_DAY) / millisPerUnit;
1704                    break;
1705                case Calendar.MONTH:
1706                    result += (calendar.get(Calendar.DAY_OF_MONTH) * MILLIS_PER_DAY) / millisPerUnit;
1707                    break;
1708            }
1709    
1710            switch (fragment) {
1711                // Number of days already calculated for these cases
1712                case Calendar.YEAR:
1713                case Calendar.MONTH:
1714                
1715                // The rest of the valid cases
1716                case Calendar.DAY_OF_YEAR:
1717                case Calendar.DATE:
1718                    result += (calendar.get(Calendar.HOUR_OF_DAY) * MILLIS_PER_HOUR) / millisPerUnit;
1719                    //$FALL-THROUGH$
1720                case Calendar.HOUR_OF_DAY:
1721                    result += (calendar.get(Calendar.MINUTE) * MILLIS_PER_MINUTE) / millisPerUnit;
1722                    //$FALL-THROUGH$
1723                case Calendar.MINUTE:
1724                    result += (calendar.get(Calendar.SECOND) * MILLIS_PER_SECOND) / millisPerUnit;
1725                    //$FALL-THROUGH$
1726                case Calendar.SECOND:
1727                    result += (calendar.get(Calendar.MILLISECOND) * 1) / millisPerUnit;
1728                    break;
1729                case Calendar.MILLISECOND: 
1730                    break;//never useful
1731                default: 
1732                    throw new IllegalArgumentException("The fragment " + fragment + " is not supported");
1733            }
1734            return result;
1735        }
1736        
1737        /**
1738         * Returns the number of millis of a datefield, if this is a constant value
1739         * 
1740         * @param unit A Calendar field which is a valid unit for a fragment
1741         * @return number of millis
1742         * @throws IllegalArgumentException if date can't be represented in millisenconds
1743         * @since 2.4 
1744         */
1745        private static long getMillisPerUnit(int unit) {
1746            long result = Long.MAX_VALUE;
1747            switch (unit) {
1748                case Calendar.DAY_OF_YEAR:
1749                case Calendar.DATE:
1750                    result = MILLIS_PER_DAY;
1751                    break;
1752                case Calendar.HOUR_OF_DAY:
1753                    result = MILLIS_PER_HOUR;
1754                    break;
1755                case Calendar.MINUTE:
1756                    result = MILLIS_PER_MINUTE;
1757                    break;
1758                case Calendar.SECOND:
1759                    result = MILLIS_PER_SECOND;
1760                    break;
1761                case Calendar.MILLISECOND:
1762                    result = 1;
1763                    break;
1764                default: throw new IllegalArgumentException("The unit " + unit + " cannot be represented is milleseconds");
1765            }
1766            return result;
1767        }
1768    
1769        /**
1770         * <p>Date iterator.</p>
1771         */
1772        static class DateIterator implements Iterator {
1773            private final Calendar endFinal;
1774            private final Calendar spot;
1775            
1776            /**
1777             * Constructs a DateIterator that ranges from one date to another. 
1778             *
1779             * @param startFinal start date (inclusive)
1780             * @param endFinal end date (not inclusive)
1781             */
1782            DateIterator(Calendar startFinal, Calendar endFinal) {
1783                super();
1784                this.endFinal = endFinal;
1785                spot = startFinal;
1786                spot.add(Calendar.DATE, -1);
1787            }
1788    
1789            /**
1790             * Has the iterator not reached the end date yet?
1791             *
1792             * @return <code>true</code> if the iterator has yet to reach the end date
1793             */
1794            public boolean hasNext() {
1795                return spot.before(endFinal);
1796            }
1797    
1798            /**
1799             * Return the next calendar in the iteration
1800             *
1801             * @return Object calendar for the next date
1802             */
1803            public Object next() {
1804                if (spot.equals(endFinal)) {
1805                    throw new NoSuchElementException();
1806                }
1807                spot.add(Calendar.DATE, 1);
1808                return spot.clone();
1809            }
1810    
1811            /**
1812             * Always throws UnsupportedOperationException.
1813             * 
1814             * @throws UnsupportedOperationException
1815             * @see java.util.Iterator#remove()
1816             */
1817            public void remove() {
1818                throw new UnsupportedOperationException();
1819            }
1820        }
1821        
1822        //------------------------------------------------------------------------- 
1823        // Deprecated int constants
1824        // TODO: Remove in 3.0
1825        
1826        /**
1827         * Number of milliseconds in a standard second.
1828         * 
1829         * @deprecated Use MILLIS_PER_SECOND. This will be removed in Commons Lang 3.0.
1830         */
1831        public static final int MILLIS_IN_SECOND = 1000;
1832        /**
1833         * Number of milliseconds in a standard minute.
1834         * 
1835         * @deprecated Use MILLIS_PER_MINUTE. This will be removed in Commons Lang 3.0.
1836         */
1837        public static final int MILLIS_IN_MINUTE = 60 * 1000;
1838        /**
1839         * Number of milliseconds in a standard hour.
1840         * 
1841         * @deprecated Use MILLIS_PER_HOUR. This will be removed in Commons Lang 3.0.
1842         */
1843        public static final int MILLIS_IN_HOUR = 60 * 60 * 1000;
1844        /**
1845         * Number of milliseconds in a standard day.
1846         * 
1847         * @deprecated Use MILLIS_PER_DAY. This will be removed in Commons Lang 3.0.
1848         */
1849        public static final int MILLIS_IN_DAY = 24 * 60 * 60 * 1000;
1850        
1851    }