    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    }