    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 *      https://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 */
    017package org.apache.commons.lang3.time;
    018
    019import java.text.ParseException;
    020import java.text.ParsePosition;
    021import java.time.LocalDateTime;
    022import java.time.OffsetDateTime;
    023import java.time.ZoneId;
    024import java.time.ZonedDateTime;
    025import java.util.Calendar;
    026import java.util.Date;
    027import java.util.Iterator;
    028import java.util.Locale;
    029import java.util.NoSuchElementException;
    030import java.util.Objects;
    031import java.util.TimeZone;
    032import java.util.concurrent.TimeUnit;
    033
    034import org.apache.commons.lang3.LocaleUtils;
    035
    036/**
    037 * A suite of utilities surrounding the use of the
    038 * {@link java.util.Calendar} and {@link java.util.Date} object.
    039 *
    040 * <p>DateUtils contains a lot of common methods considering manipulations
    041 * of Dates or Calendars. Some methods require some extra explanation.
    042 * The truncate, ceiling and round methods could be considered the Math.floor(),
    043 * Math.ceil() or Math.round versions for dates
    044 * This way date-fields will be ignored in bottom-up order.
    045 * As a complement to these methods we've introduced some fragment-methods.
    046 * With these methods the Date-fields will be ignored in top-down order.
    047 * Since a date without a year is not a valid date, you have to decide in what
    048 * kind of date-field you want your result, for instance milliseconds or days.
    049 * </p>
    050 * <p>
    051 * Several methods are provided for adding to {@link Date} objects, of the form
    052 * {@code addXXX(Date date, int amount)}. It is important to note these methods
    053 * use a {@link Calendar} internally (with default time zone and locale) and may
    054 * be affected by changes to daylight saving time (DST).
    055 * </p>
    056 *
    057 * @since 2.0
    058 */
    059public class DateUtils {
    060
    061    /**
    062     * Date iterator.
    063     */
    064    static final class DateIterator implements Iterator<Calendar> {
    065        private final Calendar endFinal;
    066        private final Calendar spot;
    067
    068        /**
    069         * Constructs a DateIterator that ranges from one date to another.
    070         *
    071         * @param startFinal start date (inclusive)
    072         * @param endFinal end date (inclusive)
    073         */
    074        DateIterator(final Calendar startFinal, final Calendar endFinal) {
    075            this.endFinal = endFinal;
    076            spot = startFinal;
    077            spot.add(Calendar.DATE, -1);
    078        }
    079
    080        /**
    081         * Has the iterator not reached the end date yet?
    082         *
    083         * @return {@code true} if the iterator has yet to reach the end date
    084         */
    085        @Override
    086        public boolean hasNext() {
    087            return spot.before(endFinal);
    088        }
    089
    090        /**
    091         * Returns the next calendar in the iteration
    092         *
    093         * @return Object calendar for the next date
    094         */
    095        @Override
    096        public Calendar next() {
    097            if (spot.equals(endFinal)) {
    098                throw new NoSuchElementException();
    099            }
    100            spot.add(Calendar.DATE, 1);
    101            return (Calendar) spot.clone();
    102        }
    103
    104        /**
    105         * Always throws UnsupportedOperationException.
    106         *
    107         * @throws UnsupportedOperationException Always thrown.
    108         * @see java.util.Iterator#remove()
    109         */
    110        @Override
    111        public void remove() {
    112            throw new UnsupportedOperationException();
    113        }
    114    }
    115
    116    /**
    117     * Calendar modification types.
    118     */
    119    private enum ModifyType {
    120        /**
    121         * Truncation.
    122         */
    123        TRUNCATE,
    124
    125        /**
    126         * Rounding.
    127         */
    128        ROUND,
    129
    130        /**
    131         * Ceiling.
    132         */
    133        CEILING
    134    }
    135
    136    /**
    137     * Number of milliseconds in a standard second.
    138     *
    139     * @since 2.1
    140     */
    141    public static final long MILLIS_PER_SECOND = 1_000;
    142
    143    /**
    144     * Number of milliseconds in a standard minute.
    145     *
    146     * @since 2.1
    147     */
    148    public static final long MILLIS_PER_MINUTE = 60 * MILLIS_PER_SECOND;
    149
    150    /**
    151     * Number of milliseconds in a standard hour.
    152     *
    153     * @since 2.1
    154     */
    155    public static final long MILLIS_PER_HOUR = 60 * MILLIS_PER_MINUTE;
    156
    157    /**
    158     * Number of milliseconds in a standard day.
    159     *
    160     * @since 2.1
    161     */
    162    public static final long MILLIS_PER_DAY = 24 * MILLIS_PER_HOUR;
    163
    164    /**
    165     * This is half a month, so this represents whether a date is in the top
    166     * or bottom half of the month.
    167     */
    168    public static final int SEMI_MONTH = 1001;
    169    private static final int[][] fields = {
    170            {Calendar.MILLISECOND},
    171            {Calendar.SECOND},
    172            {Calendar.MINUTE},
    173            {Calendar.HOUR_OF_DAY, Calendar.HOUR},
    174            {Calendar.DATE, Calendar.DAY_OF_MONTH, Calendar.AM_PM
    175                /* Calendar.DAY_OF_YEAR, Calendar.DAY_OF_WEEK, Calendar.DAY_OF_WEEK_IN_MONTH */
    176            },
    177            {Calendar.MONTH, SEMI_MONTH},
    178            {Calendar.YEAR},
    179            {Calendar.ERA}};
    180    /**
    181     * A week range, starting on Sunday.
    182     */
    183    public static final int RANGE_WEEK_SUNDAY = 1;
    184
    185    /**
    186     * A week range, starting on Monday.
    187     */
    188    public static final int RANGE_WEEK_MONDAY = 2;
    189
    190    /**
    191     * A week range, starting on the day focused.
    192     */
    193    public static final int RANGE_WEEK_RELATIVE = 3;
    194
    195    /**
    196     * A week range, centered around the day focused.
    197     */
    198    public static final int RANGE_WEEK_CENTER = 4;
    199
    200    /**
    201     * A month range, the week starting on Sunday.
    202     */
    203    public static final int RANGE_MONTH_SUNDAY = 5;
    204
    205    /**
    206     * A month range, the week starting on Monday.
    207     */
    208    public static final int RANGE_MONTH_MONDAY = 6;
    209
    210    /**
    211     * Adds to a date returning a new object.
    212     * The original {@link Date} is unchanged.
    213     *
    214     * @param date  the date, not null
    215     * @param calendarField  the calendar field to add to
    216     * @param amount  the amount to add, may be negative
    217     * @return the new {@link Date} with the amount added
    218     * @throws NullPointerException if the date is null
    219     */
    220    private static Date add(final Date date, final int calendarField, final int amount) {
    221        validateDateNotNull(date);
    222        final Calendar c = Calendar.getInstance();
    223        c.setTime(date);
    224        c.add(calendarField, amount);
    225        return c.getTime();
    226    }
    227
    228    /**
    229     * Adds a number of days to a date returning a new object.
    230     * The original {@link Date} is unchanged.
    231     *
    232     * @param date  the date, not null
    233     * @param amount  the amount to add, may be negative
    234     * @return the new {@link Date} with the amount added
    235     * @throws NullPointerException if the date is null
    236     */
    237    public static Date addDays(final Date date, final int amount) {
    238        return add(date, Calendar.DAY_OF_MONTH, amount);
    239    }
    240
    241    /**
    242     * Adds a number of hours to a date returning a new object.
    243     * The original {@link Date} is unchanged.
    244     *
    245     * @param date  the date, not null
    246     * @param amount  the amount to add, may be negative
    247     * @return the new {@link Date} with the amount added
    248     * @throws NullPointerException if the date is null
    249     */
    250    public static Date addHours(final Date date, final int amount) {
    251        return add(date, Calendar.HOUR_OF_DAY, amount);
    252    }
    253
    254    /**
    255     * Adds a number of milliseconds to a date returning a new object.
    256     * The original {@link Date} is unchanged.
    257     *
    258     * @param date  the date, not null
    259     * @param amount  the amount to add, may be negative
    260     * @return the new {@link Date} with the amount added
    261     * @throws NullPointerException if the date is null
    262     */
    263    public static Date addMilliseconds(final Date date, final int amount) {
    264        return add(date, Calendar.MILLISECOND, amount);
    265    }
    266
    267    /**
    268     * Adds a number of minutes to a date returning a new object.
    269     * The original {@link Date} is unchanged.
    270     *
    271     * @param date  the date, not null
    272     * @param amount  the amount to add, may be negative
    273     * @return the new {@link Date} with the amount added
    274     * @throws NullPointerException if the date is null
    275     */
    276    public static Date addMinutes(final Date date, final int amount) {
    277        return add(date, Calendar.MINUTE, amount);
    278    }
    279
    280    /**
    281     * Adds a number of months to a date returning a new object.
    282     * The original {@link Date} is unchanged.
    283     *
    284     * @param date  the date, not null
    285     * @param amount  the amount to add, may be negative
    286     * @return the new {@link Date} with the amount added
    287     * @throws NullPointerException if the date is null
    288     */
    289    public static Date addMonths(final Date date, final int amount) {
    290        return add(date, Calendar.MONTH, amount);
    291    }
    292
    293    /**
    294     * Adds a number of seconds to a date returning a new object.
    295     * The original {@link Date} is unchanged.
    296     *
    297     * @param date  the date, not null
    298     * @param amount  the amount to add, may be negative
    299     * @return the new {@link Date} with the amount added
    300     * @throws NullPointerException if the date is null
    301     */
    302    public static Date addSeconds(final Date date, final int amount) {
    303        return add(date, Calendar.SECOND, amount);
    304    }
    305
    306    /**
    307     * Adds a number of weeks to a date returning a new object.
    308     * The original {@link Date} is unchanged.
    309     *
    310     * @param date  the date, not null
    311     * @param amount  the amount to add, may be negative
    312     * @return the new {@link Date} with the amount added
    313     * @throws NullPointerException if the date is null
    314     */
    315    public static Date addWeeks(final Date date, final int amount) {
    316        return add(date, Calendar.WEEK_OF_YEAR, amount);
    317    }
    318
    319    /**
    320     * Adds a number of years to a date returning a new object.
    321     * The original {@link Date} is unchanged.
    322     *
    323     * @param date  the date, not null
    324     * @param amount  the amount to add, may be negative
    325     * @return the new {@link Date} with the amount added
    326     * @throws NullPointerException if the date is null
    327     */
    328    public static Date addYears(final Date date, final int amount) {
    329        return add(date, Calendar.YEAR, amount);
    330    }
    331
    332    /**
    333     * Gets a date ceiling, leaving the field specified as the most
    334     * significant field.
    335     *
    336     * <p>For example, if you had the date-time of 28 Mar 2002
    337     * 13:45:01.231, if you passed with HOUR, it would return 28 Mar
    338     * 2002 14:00:00.000.  If this was passed with MONTH, it would
    339     * return 1 Apr 2002 0:00:00.000.</p>
    340     *
    341     * @param calendar  the date to work with, not null
    342     * @param field  the field from {@link Calendar} or {@code SEMI_MONTH}
    343     * @return the different ceil date, not null
    344     * @throws NullPointerException if the date is {@code null}
    345     * @throws ArithmeticException if the year is over 280 million
    346     * @since 2.5
    347     */
    348    public static Calendar ceiling(final Calendar calendar, final int field) {
    349        Objects.requireNonNull(calendar, "calendar");
    350        return modify((Calendar) calendar.clone(), field, ModifyType.CEILING);
    351    }
    352
    353    /**
    354     * Gets a date ceiling, leaving the field specified as the most
    355     * significant field.
    356     *
    357     * <p>For example, if you had the date-time of 28 Mar 2002
    358     * 13:45:01.231, if you passed with HOUR, it would return 28 Mar
    359     * 2002 14:00:00.000.  If this was passed with MONTH, it would
    360     * return 1 Apr 2002 0:00:00.000.</p>
    361     *
    362     * @param date  the date to work with, not null
    363     * @param field  the field from {@link Calendar} or {@code SEMI_MONTH}
    364     * @return the different ceil date, not null
    365     * @throws NullPointerException if the date is {@code null}
    366     * @throws ArithmeticException if the year is over 280 million
    367     * @since 2.5
    368     */
    369    public static Date ceiling(final Date date, final int field) {
    370        return modify(toCalendar(date), field, ModifyType.CEILING).getTime();
    371    }
    372
    373    /**
    374     * Gets a date ceiling, leaving the field specified as the most
    375     * significant field.
    376     *
    377     * <p>For example, if you had the date-time of 28 Mar 2002
    378     * 13:45:01.231, if you passed with HOUR, it would return 28 Mar
    379     * 2002 14:00:00.000.  If this was passed with MONTH, it would
    380     * return 1 Apr 2002 0:00:00.000.</p>
    381     *
    382     * @param date  the date to work with, either {@link Date} or {@link Calendar}, not null
    383     * @param field  the field from {@link Calendar} or {@code SEMI_MONTH}
    384     * @return the different ceil date, not null
    385     * @throws NullPointerException if the date is {@code null}
    386     * @throws ClassCastException if the object type is not a {@link Date} or {@link Calendar}
    387     * @throws ArithmeticException if the year is over 280 million
    388     * @since 2.5
    389     */
    390    public static Date ceiling(final Object date, final int field) {
    391        Objects.requireNonNull(date, "date");
    392        if (date instanceof Date) {
    393            return ceiling((Date) date, field);
    394        }
    395        if (date instanceof Calendar) {
    396            return ceiling((Calendar) date, field).getTime();
    397        }
    398        throw new ClassCastException("Could not find ceiling of for type: " + date.getClass());
    399    }
    400
    401    /**
    402     * Gets a Calendar fragment for any unit.
    403     *
    404     * @param calendar the calendar to work with, not null
    405     * @param fragment the Calendar field part of calendar to calculate
    406     * @param unit the time unit
    407     * @return number of units within the fragment of the calendar
    408     * @throws NullPointerException if the date is {@code null} or
    409     * fragment is not supported
    410     * @since 2.4
    411     */
    412    private static long getFragment(final Calendar calendar, final int fragment, final TimeUnit unit) {
    413        Objects.requireNonNull(calendar, "calendar");
    414        long result = 0;
    415        final int offset = unit == TimeUnit.DAYS ? 0 : 1;
    416
    417        // Fragments bigger than a day require a breakdown to days
    418        switch (fragment) {
    419            case Calendar.YEAR:
    420                result += unit.convert(calendar.get(Calendar.DAY_OF_YEAR) - offset, TimeUnit.DAYS);
    421                break;
    422            case Calendar.MONTH:
    423                result += unit.convert(calendar.get(Calendar.DAY_OF_MONTH) - offset, TimeUnit.DAYS);
    424                break;
    425            default:
    426                break;
    427        }
    428
    429        switch (fragment) {
    430            // Number of days already calculated for these cases
    431            case Calendar.YEAR:
    432            case Calendar.MONTH:
    433
    434            // The rest of the valid cases
    435            case Calendar.DAY_OF_YEAR:
    436            case Calendar.DATE:
    437                result += unit.convert(calendar.get(Calendar.HOUR_OF_DAY), TimeUnit.HOURS);
    438                // falls-through
    439            case Calendar.HOUR_OF_DAY:
    440                result += unit.convert(calendar.get(Calendar.MINUTE), TimeUnit.MINUTES);
    441                // falls-through
    442            case Calendar.MINUTE:
    443                result += unit.convert(calendar.get(Calendar.SECOND), TimeUnit.SECONDS);
    444                // falls-through
    445            case Calendar.SECOND:
    446                result += unit.convert(calendar.get(Calendar.MILLISECOND), TimeUnit.MILLISECONDS);
    447                break;
    448            case Calendar.MILLISECOND: break; //never useful
    449                default: throw new IllegalArgumentException("The fragment " + fragment + " is not supported");
    450        }
    451        return result;
    452    }
    453
    454    /**
    455     * Gets a Date fragment for any unit.
    456     *
    457     * @param date the date to work with, not null
    458     * @param fragment the Calendar field part of date to calculate
    459     * @param unit the time unit
    460     * @return number of units within the fragment of the date
    461     * @throws NullPointerException if the date is {@code null}
    462     * @throws IllegalArgumentException if fragment is not supported
    463     * @since 2.4
    464     */
    465    private static long getFragment(final Date date, final int fragment, final TimeUnit unit) {
    466        validateDateNotNull(date);
    467        final Calendar calendar = Calendar.getInstance();
    468        calendar.setTime(date);
    469        return getFragment(calendar, fragment, unit);
    470    }
    471
    472    /**
    473     * Gets the number of days within the
    474     * fragment. All datefields greater than the fragment will be ignored.
    475     *
    476     * <p>Asking the days of any date will only return the number of days
    477     * of the current month (resulting in a number between 1 and 31). This
    478     * method will retrieve the number of days for any fragment.
    479     * For example, if you want to calculate the number of days past this year,
    480     * your fragment is Calendar.YEAR. The result will be all days of the
    481     * past month(s).</p>
    482     *
    483     * <p>Valid fragments are: Calendar.YEAR, Calendar.MONTH, both
    484     * Calendar.DAY_OF_YEAR and Calendar.DATE, Calendar.HOUR_OF_DAY,
    485     * Calendar.MINUTE, Calendar.SECOND and Calendar.MILLISECOND
    486     * A fragment less than or equal to a DAY field will return 0.</p>
    487     *
    488     * <ul>
    489     *  <li>January 28, 2008 with Calendar.MONTH as fragment will return 28
    490     *   (equivalent to calendar.get(Calendar.DAY_OF_MONTH))</li>
    491     *  <li>February 28, 2008 with Calendar.MONTH as fragment will return 28
    492     *   (equivalent to calendar.get(Calendar.DAY_OF_MONTH))</li>
    493     *  <li>January 28, 2008 with Calendar.YEAR as fragment will return 28
    494     *   (equivalent to calendar.get(Calendar.DAY_OF_YEAR))</li>
    495     *  <li>February 28, 2008 with Calendar.YEAR as fragment will return 59
    496     *   (equivalent to calendar.get(Calendar.DAY_OF_YEAR))</li>
    497     *  <li>January 28, 2008 with Calendar.MILLISECOND as fragment will return 0
    498     *   (a millisecond cannot be split in days)</li>
    499     * </ul>
    500     *
    501     * @param calendar the calendar to work with, not null
    502     * @param fragment the {@link Calendar} field part of calendar to calculate
    503     * @return number of days within the fragment of date
    504     * @throws NullPointerException if the date is {@code null} or
    505     * fragment is not supported
    506     * @since 2.4
    507     */
    508    public static long getFragmentInDays(final Calendar calendar, final int fragment) {
    509        return getFragment(calendar, fragment, TimeUnit.DAYS);
    510    }
    511
    512    /**
    513     * Gets the number of days within the
    514     * fragment. All date fields greater than the fragment will be ignored.
    515     *
    516     * <p>Asking the days of any date will only return the number of days
    517     * of the current month (resulting in a number between 1 and 31). This
    518     * method will retrieve the number of days for any fragment.
    519     * For example, if you want to calculate the number of days past this year,
    520     * your fragment is Calendar.YEAR. The result will be all days of the
    521     * past month(s).</p>
    522     *
    523     * <p>Valid fragments are: Calendar.YEAR, Calendar.MONTH, both
    524     * Calendar.DAY_OF_YEAR and Calendar.DATE, Calendar.HOUR_OF_DAY,
    525     * Calendar.MINUTE, Calendar.SECOND and Calendar.MILLISECOND
    526     * A fragment less than or equal to a DAY field will return 0.</p>
    527     *
    528     * <ul>
    529     *  <li>January 28, 2008 with Calendar.MONTH as fragment will return 28
    530     *   (equivalent to deprecated date.getDay())</li>
    531     *  <li>February 28, 2008 with Calendar.MONTH as fragment will return 28
    532     *   (equivalent to deprecated date.getDay())</li>
    533     *  <li>January 28, 2008 with Calendar.YEAR as fragment will return 28</li>
    534     *  <li>February 28, 2008 with Calendar.YEAR as fragment will return 59</li>
    535     *  <li>January 28, 2008 with Calendar.MILLISECOND as fragment will return 0
    536     *   (a millisecond cannot be split in days)</li>
    537     * </ul>
    538     *
    539     * @param date the date to work with, not null
    540     * @param fragment the {@link Calendar} field part of date to calculate
    541     * @return number of days  within the fragment of date
    542     * @throws NullPointerException if the date is {@code null}
    543     * @throws IllegalArgumentException if the fragment is not supported
    544     * @since 2.4
    545     */
    546    public static long getFragmentInDays(final Date date, final int fragment) {
    547        return getFragment(date, fragment, TimeUnit.DAYS);
    548    }
    549
    550    /**
    551     * Gets the number of hours within the
    552     * fragment. All date fields greater than the fragment will be ignored.
    553     *
    554     * <p>Asking the hours of any date will only return the number of hours
    555     * of the current day (resulting in a number between 0 and 23). This
    556     * method will retrieve the number of hours for any fragment.
    557     * For example, if you want to calculate the number of hours past this month,
    558     * your fragment is Calendar.MONTH. The result will be all hours of the
    559     * past day(s).</p>
    560     *
    561     * <p>Valid fragments are: Calendar.YEAR, Calendar.MONTH, both
    562     * Calendar.DAY_OF_YEAR and Calendar.DATE, Calendar.HOUR_OF_DAY,
    563     * Calendar.MINUTE, Calendar.SECOND and Calendar.MILLISECOND
    564     * A fragment less than or equal to a HOUR field will return 0.</p>
    565     *
    566     * <ul>
    567     *  <li>January 1, 2008 7:15:10.538 with Calendar.DAY_OF_YEAR as fragment will return 7
    568     *   (equivalent to calendar.get(Calendar.HOUR_OF_DAY))</li>
    569     *  <li>January 6, 2008 7:15:10.538 with Calendar.DAY_OF_YEAR as fragment will return 7
    570     *   (equivalent to calendar.get(Calendar.HOUR_OF_DAY))</li>
    571     *  <li>January 1, 2008 7:15:10.538 with Calendar.MONTH as fragment will return 7</li>
    572     *  <li>January 6, 2008 7:15:10.538 with Calendar.MONTH as fragment will return 127 (5*24 + 7)</li>
    573     *  <li>January 16, 2008 7:15:10.538 with Calendar.MILLISECOND as fragment will return 0
    574     *   (a millisecond cannot be split in hours)</li>
    575     * </ul>
    576     *
    577     * @param calendar the calendar to work with, not null
    578     * @param fragment the {@link Calendar} field part of calendar to calculate
    579     * @return number of hours within the fragment of date
    580     * @throws NullPointerException if the date is {@code null} or
    581     * fragment is not supported
    582     * @since 2.4
    583     */
    584    public static long getFragmentInHours(final Calendar calendar, final int fragment) {
    585        return getFragment(calendar, fragment, TimeUnit.HOURS);
    586    }
    587
    588    /**
    589     * Gets the number of hours within the
    590     * fragment. All date fields greater than the fragment will be ignored.
    591     *
    592     * <p>Asking the hours of any date will only return the number of hours
    593     * of the current day (resulting in a number between 0 and 23). This
    594     * method will retrieve the number of hours for any fragment.
    595     * For example, if you want to calculate the number of hours past this month,
    596     * your fragment is Calendar.MONTH. The result will be all hours of the
    597     * past day(s).</p>
    598     *
    599     * <p>Valid fragments are: Calendar.YEAR, Calendar.MONTH, both
    600     * Calendar.DAY_OF_YEAR and Calendar.DATE, Calendar.HOUR_OF_DAY,
    601     * Calendar.MINUTE, Calendar.SECOND and Calendar.MILLISECOND
    602     * A fragment less than or equal to a HOUR field will return 0.</p>
    603     *
    604     * <ul>
    605     *  <li>January 1, 2008 7:15:10.538 with Calendar.DAY_OF_YEAR as fragment will return 7
    606     *   (equivalent to deprecated date.getHours())</li>
    607     *  <li>January 6, 2008 7:15:10.538 with Calendar.DAY_OF_YEAR as fragment will return 7
    608     *   (equivalent to deprecated date.getHours())</li>
    609     *  <li>January 1, 2008 7:15:10.538 with Calendar.MONTH as fragment will return 7</li>
    610     *  <li>January 6, 2008 7:15:10.538 with Calendar.MONTH as fragment will return 127 (5*24 + 7)</li>
    611     *  <li>January 16, 2008 7:15:10.538 with Calendar.MILLISECOND as fragment will return 0
    612     *   (a millisecond cannot be split in hours)</li>
    613     * </ul>
    614     *
    615     * @param date the date to work with, not null
    616     * @param fragment the {@link Calendar} field part of date to calculate
    617     * @return number of hours within the fragment of date
    618     * @throws NullPointerException if the date is {@code null}
    619     * @throws IllegalArgumentException if the fragment is not supported
    620     * @since 2.4
    621     */
    622    public static long getFragmentInHours(final Date date, final int fragment) {
    623        return getFragment(date, fragment, TimeUnit.HOURS);
    624    }
    625
    626    /**
    627     * Gets the number of milliseconds within the
    628     * fragment. All date fields greater than the fragment will be ignored.
    629     *
    630     * <p>Asking the milliseconds of any date will only return the number of milliseconds
    631     * of the current second (resulting in a number between 0 and 999). This
    632     * method will retrieve the number of milliseconds for any fragment.
    633     * For example, if you want to calculate the number of seconds past today,
    634     * your fragment is Calendar.DATE or Calendar.DAY_OF_YEAR. The result will
    635     * be all seconds of the past hour(s), minutes(s) and second(s).</p>
    636     *
    637     * <p>Valid fragments are: Calendar.YEAR, Calendar.MONTH, both
    638     * Calendar.DAY_OF_YEAR and Calendar.DATE, Calendar.HOUR_OF_DAY,
    639     * Calendar.MINUTE, Calendar.SECOND and Calendar.MILLISECOND
    640     * A fragment less than or equal to a MILLISECOND field will return 0.</p>
    641     *
    642     * <ul>
    643     *  <li>January 1, 2008 7:15:10.538 with Calendar.SECOND as fragment will return 538
    644     *   (equivalent to calendar.get(Calendar.MILLISECOND))</li>
    645     *  <li>January 6, 2008 7:15:10.538 with Calendar.SECOND as fragment will return 538
    646     *   (equivalent to calendar.get(Calendar.MILLISECOND))</li>
    647     *  <li>January 6, 2008 7:15:10.538 with Calendar.MINUTE as fragment will return 10538
    648     *   (10*1000 + 538)</li>
    649     *  <li>January 16, 2008 7:15:10.538 with Calendar.MILLISECOND as fragment will return 0
    650     *   (a millisecond cannot be split in milliseconds)</li>
    651     * </ul>
    652     *
    653     * @param calendar the calendar to work with, not null
    654     * @param fragment the {@link Calendar} field part of calendar to calculate
    655     * @return number of milliseconds within the fragment of date
    656     * @throws NullPointerException if the date is {@code null} or
    657     * fragment is not supported
    658     * @since 2.4
    659     */
    660  public static long getFragmentInMilliseconds(final Calendar calendar, final int fragment) {
    661    return getFragment(calendar, fragment, TimeUnit.MILLISECONDS);
    662  }
    663
    664    /**
    665     * Gets the number of milliseconds within the
    666     * fragment. All date fields greater than the fragment will be ignored.
    667     *
    668     * <p>Asking the milliseconds of any date will only return the number of milliseconds
    669     * of the current second (resulting in a number between 0 and 999). This
    670     * method will retrieve the number of milliseconds for any fragment.
    671     * For example, if you want to calculate the number of milliseconds past today,
    672     * your fragment is Calendar.DATE or Calendar.DAY_OF_YEAR. The result will
    673     * be all milliseconds of the past hour(s), minutes(s) and second(s).</p>
    674     *
    675     * <p>Valid fragments are: Calendar.YEAR, Calendar.MONTH, both
    676     * Calendar.DAY_OF_YEAR and Calendar.DATE, Calendar.HOUR_OF_DAY,
    677     * Calendar.MINUTE, Calendar.SECOND and Calendar.MILLISECOND
    678     * A fragment less than or equal to a SECOND field will return 0.</p>
    679     *
    680     * <ul>
    681     *  <li>January 1, 2008 7:15:10.538 with Calendar.SECOND as fragment will return 538</li>
    682     *  <li>January 6, 2008 7:15:10.538 with Calendar.SECOND as fragment will return 538</li>
    683     *  <li>January 6, 2008 7:15:10.538 with Calendar.MINUTE as fragment will return 10538 (10*1000 + 538)</li>
    684     *  <li>January 16, 2008 7:15:10.538 with Calendar.MILLISECOND as fragment will return 0
    685     *   (a millisecond cannot be split in milliseconds)</li>
    686     * </ul>
    687     *
    688     * @param date the date to work with, not null
    689     * @param fragment the {@link Calendar} field part of date to calculate
    690     * @return number of milliseconds within the fragment of date
    691     * @throws NullPointerException if the date is {@code null}
    692     * @throws IllegalArgumentException if the fragment is not supported
    693     * @since 2.4
    694     */
    695    public static long getFragmentInMilliseconds(final Date date, final int fragment) {
    696        return getFragment(date, fragment, TimeUnit.MILLISECONDS);
    697    }
    698
    699    /**
    700     * Gets the number of minutes within the
    701     * fragment. All date fields greater than the fragment will be ignored.
    702     *
    703     * <p>Asking the minutes of any date will only return the number of minutes
    704     * of the current hour (resulting in a number between 0 and 59). This
    705     * method will retrieve the number of minutes for any fragment.
    706     * For example, if you want to calculate the number of minutes past this month,
    707     * your fragment is Calendar.MONTH. The result will be all minutes of the
    708     * past day(s) and hour(s).</p>
    709     *
    710     * <p>Valid fragments are: Calendar.YEAR, Calendar.MONTH, both
    711     * Calendar.DAY_OF_YEAR and Calendar.DATE, Calendar.HOUR_OF_DAY,
    712     * Calendar.MINUTE, Calendar.SECOND and Calendar.MILLISECOND
    713     * A fragment less than or equal to a MINUTE field will return 0.</p>
    714     *
    715     * <ul>
    716     *  <li>January 1, 2008 7:15:10.538 with Calendar.HOUR_OF_DAY as fragment will return 15
    717     *   (equivalent to calendar.get(Calendar.MINUTES))</li>
    718     *  <li>January 6, 2008 7:15:10.538 with Calendar.HOUR_OF_DAY as fragment will return 15
    719     *   (equivalent to calendar.get(Calendar.MINUTES))</li>
    720     *  <li>January 1, 2008 7:15:10.538 with Calendar.MONTH as fragment will return 15</li>
    721     *  <li>January 6, 2008 7:15:10.538 with Calendar.MONTH as fragment will return 435 (7*60 + 15)</li>
    722     *  <li>January 16, 2008 7:15:10.538 with Calendar.MILLISECOND as fragment will return 0
    723     *   (a millisecond cannot be split in minutes)</li>
    724     * </ul>
    725     *
    726     * @param calendar the calendar to work with, not null
    727     * @param fragment the {@link Calendar} field part of calendar to calculate
    728     * @return number of minutes within the fragment of date
    729     * @throws NullPointerException if the date is {@code null} or
    730     * fragment is not supported
    731     * @since 2.4
    732     */
    733    public static long getFragmentInMinutes(final Calendar calendar, final int fragment) {
    734        return getFragment(calendar, fragment, TimeUnit.MINUTES);
    735    }
    736
    737    /**
    738     * Gets the number of minutes within the
    739     * fragment. All date fields greater than the fragment will be ignored.
    740     *
    741     * <p>Asking the minutes of any date will only return the number of minutes
    742     * of the current hour (resulting in a number between 0 and 59). This
    743     * method will retrieve the number of minutes for any fragment.
    744     * For example, if you want to calculate the number of minutes past this month,
    745     * your fragment is Calendar.MONTH. The result will be all minutes of the
    746     * past day(s) and hour(s).</p>
    747     *
    748     * <p>Valid fragments are: Calendar.YEAR, Calendar.MONTH, both
    749     * Calendar.DAY_OF_YEAR and Calendar.DATE, Calendar.HOUR_OF_DAY,
    750     * Calendar.MINUTE, Calendar.SECOND and Calendar.MILLISECOND
    751     * A fragment less than or equal to a MINUTE field will return 0.</p>
    752     *
    753     * <ul>
    754     *  <li>January 1, 2008 7:15:10.538 with Calendar.HOUR_OF_DAY as fragment will return 15
    755     *   (equivalent to deprecated date.getMinutes())</li>
    756     *  <li>January 6, 2008 7:15:10.538 with Calendar.HOUR_OF_DAY as fragment will return 15
    757     *   (equivalent to deprecated date.getMinutes())</li>
    758     *  <li>January 1, 2008 7:15:10.538 with Calendar.MONTH as fragment will return 15</li>
    759     *  <li>January 6, 2008 7:15:10.538 with Calendar.MONTH as fragment will return 435 (7*60 + 15)</li>
    760     *  <li>January 16, 2008 7:15:10.538 with Calendar.MILLISECOND as fragment will return 0
    761     *   (a millisecond cannot be split in minutes)</li>
    762     * </ul>
    763     *
    764     * @param date the date to work with, not null
    765     * @param fragment the {@link Calendar} field part of date to calculate
    766     * @return number of minutes within the fragment of date
    767     * @throws NullPointerException if the date is {@code null}
    768     * @throws IllegalArgumentException if the fragment is not supported
    769     * @since 2.4
    770     */
    771    public static long getFragmentInMinutes(final Date date, final int fragment) {
    772        return getFragment(date, fragment, TimeUnit.MINUTES);
    773    }
    774
    775    /**
    776     * Gets the number of seconds within the
    777     * fragment. All date fields greater than the fragment will be ignored.
    778     *
    779     * <p>Asking the seconds of any date will only return the number of seconds
    780     * of the current minute (resulting in a number between 0 and 59). This
    781     * method will retrieve the number of seconds for any fragment.
    782     * For example, if you want to calculate the number of seconds past today,
    783     * your fragment is Calendar.DATE or Calendar.DAY_OF_YEAR. The result will
    784     * be all seconds of the past hour(s) and minutes(s).</p>
    785     *
    786     * <p>Valid fragments are: Calendar.YEAR, Calendar.MONTH, both
    787     * Calendar.DAY_OF_YEAR and Calendar.DATE, Calendar.HOUR_OF_DAY,
    788     * Calendar.MINUTE, Calendar.SECOND and Calendar.MILLISECOND
    789     * A fragment less than or equal to a SECOND field will return 0.</p>
    790     *
    791     * <ul>
    792     *  <li>January 1, 2008 7:15:10.538 with Calendar.MINUTE as fragment will return 10
    793     *   (equivalent to calendar.get(Calendar.SECOND))</li>
    794     *  <li>January 6, 2008 7:15:10.538 with Calendar.MINUTE as fragment will return 10
    795     *   (equivalent to calendar.get(Calendar.SECOND))</li>
    796     *  <li>January 6, 2008 7:15:10.538 with Calendar.DAY_OF_YEAR as fragment will return 26110
    797     *   (7*3600 + 15*60 + 10)</li>
    798     *  <li>January 16, 2008 7:15:10.538 with Calendar.MILLISECOND as fragment will return 0
    799     *   (a millisecond cannot be split in seconds)</li>
    800     * </ul>
    801     *
    802     * @param calendar the calendar to work with, not null
    803     * @param fragment the {@link Calendar} field part of calendar to calculate
    804     * @return number of seconds within the fragment of date
    805     * @throws NullPointerException if the date is {@code null} or
    806     * fragment is not supported
    807     * @since 2.4
    808     */
    809    public static long getFragmentInSeconds(final Calendar calendar, final int fragment) {
    810        return getFragment(calendar, fragment, TimeUnit.SECONDS);
    811    }
    812
    813    /**
    814     * Gets the number of seconds within the
    815     * fragment. All date fields greater than the fragment will be ignored.
    816     *
    817     * <p>Asking the seconds of any date will only return the number of seconds
    818     * of the current minute (resulting in a number between 0 and 59). This
    819     * method will retrieve the number of seconds for any fragment.
    820     * For example, if you want to calculate the number of seconds past today,
    821     * your fragment is Calendar.DATE or Calendar.DAY_OF_YEAR. The result will
    822     * be all seconds of the past hour(s) and minutes(s).</p>
    823     *
    824     * <p>Valid fragments are: Calendar.YEAR, Calendar.MONTH, both
    825     * Calendar.DAY_OF_YEAR and Calendar.DATE, Calendar.HOUR_OF_DAY,
    826     * Calendar.MINUTE, Calendar.SECOND and Calendar.MILLISECOND
    827     * A fragment less than or equal to a SECOND field will return 0.</p>
    828     *
    829     * <ul>
    830     *  <li>January 1, 2008 7:15:10.538 with Calendar.MINUTE as fragment will return 10
    831     *   (equivalent to deprecated date.getSeconds())</li>
    832     *  <li>January 6, 2008 7:15:10.538 with Calendar.MINUTE as fragment will return 10
    833     *   (equivalent to deprecated date.getSeconds())</li>
    834     *  <li>January 6, 2008 7:15:10.538 with Calendar.DAY_OF_YEAR as fragment will return 26110
    835     *   (7*3600 + 15*60 + 10)</li>
    836     *  <li>January 16, 2008 7:15:10.538 with Calendar.MILLISECOND as fragment will return 0
    837     *   (a millisecond cannot be split in seconds)</li>
    838     * </ul>
    839     *
    840     * @param date the date to work with, not null
    841     * @param fragment the {@link Calendar} field part of date to calculate
    842     * @return number of seconds within the fragment of date
    843     * @throws NullPointerException if the date is {@code null}
    844     * @throws IllegalArgumentException if the fragment is not supported
    845     * @since 2.4
    846     */
    847    public static long getFragmentInSeconds(final Date date, final int fragment) {
    848        return getFragment(date, fragment, TimeUnit.SECONDS);
    849    }
    850
    851    /**
    852     * Tests whether two calendar objects are on the same day ignoring time.
    853     *
    854     * <p>28 Mar 2002 13:45 and 28 Mar 2002 06:01 would return true.
    855     * 28 Mar 2002 13:45 and 12 Mar 2002 13:45 would return false.
    856     * </p>
    857     *
    858     * @param cal1  the first calendar, not altered, not null
    859     * @param cal2  the second calendar, not altered, not null
    860     * @return true if they represent the same day
    861     * @throws NullPointerException if either calendar is {@code null}
    862     * @since 2.1
    863     */
    864    public static boolean isSameDay(final Calendar cal1, final Calendar cal2) {
    865        Objects.requireNonNull(cal1, "cal1");
    866        Objects.requireNonNull(cal2, "cal2");
    867        return cal1.get(Calendar.ERA) == cal2.get(Calendar.ERA) &&
    868                cal1.get(Calendar.YEAR) == cal2.get(Calendar.YEAR) &&
    869                cal1.get(Calendar.DAY_OF_YEAR) == cal2.get(Calendar.DAY_OF_YEAR);
    870    }
    871
    872    /**
    873     * Tests whether two date objects are on the same day ignoring time.
    874     *
    875     * <p>28 Mar 2002 13:45 and 28 Mar 2002 06:01 would return true.
    876     * 28 Mar 2002 13:45 and 12 Mar 2002 13:45 would return false.
    877     * </p>
    878     *
    879     * @param date1  the first date, not altered, not null
    880     * @param date2  the second date, not altered, not null
    881     * @return true if they represent the same day
    882     * @throws NullPointerException if either date is {@code null}
    883     * @since 2.1
    884     */
    885    public static boolean isSameDay(final Date date1, final Date date2) {
    886        return isSameDay(toCalendar(date1), toCalendar(date2));
    887    }
    888
    889    /**
    890     * Tests whether two calendar objects represent the same instant in time.
    891     *
    892     * <p>This method compares the long millisecond time of the two objects.</p>
    893     *
    894     * @param cal1  the first calendar, not altered, not null
    895     * @param cal2  the second calendar, not altered, not null
    896     * @return true if they represent the same millisecond instant
    897     * @throws NullPointerException if either date is {@code null}
    898     * @since 2.1
    899     */
    900    public static boolean isSameInstant(final Calendar cal1, final Calendar cal2) {
    901        Objects.requireNonNull(cal1, "cal1");
    902        Objects.requireNonNull(cal2, "cal2");
    903        return cal1.getTime().getTime() == cal2.getTime().getTime();
    904    }
    905
    906    /**
    907     * Tests whether two date objects represent the same instant in time.
    908     *
    909     * <p>This method compares the long millisecond time of the two objects.</p>
    910     *
    911     * @param date1  the first date, not altered, not null
    912     * @param date2  the second date, not altered, not null
    913     * @return true if they represent the same millisecond instant
    914     * @throws NullPointerException if either date is {@code null}
    915     * @since 2.1
    916     */
    917    public static boolean isSameInstant(final Date date1, final Date date2) {
    918        Objects.requireNonNull(date1, "date1");
    919        Objects.requireNonNull(date2, "date2");
    920        return date1.getTime() == date2.getTime();
    921    }
    922
    923    /**
    924     * Tests whether two calendar objects represent the same local time.
    925     *
    926     * <p>This method compares the values of the fields of the two objects.
    927     * In addition, both calendars must be the same of the same type.</p>
    928     *
    929     * @param cal1  the first calendar, not altered, not null
    930     * @param cal2  the second calendar, not altered, not null
    931     * @return true if they represent the same millisecond instant
    932     * @throws NullPointerException if either date is {@code null}
    933     * @since 2.1
    934     */
    935    public static boolean isSameLocalTime(final Calendar cal1, final Calendar cal2) {
    936        Objects.requireNonNull(cal1, "cal1");
    937        Objects.requireNonNull(cal2, "cal2");
    938        return cal1.get(Calendar.MILLISECOND) == cal2.get(Calendar.MILLISECOND) &&
    939                cal1.get(Calendar.SECOND) == cal2.get(Calendar.SECOND) &&
    940                cal1.get(Calendar.MINUTE) == cal2.get(Calendar.MINUTE) &&
    941                cal1.get(Calendar.HOUR_OF_DAY) == cal2.get(Calendar.HOUR_OF_DAY) &&
    942                cal1.get(Calendar.DAY_OF_YEAR) == cal2.get(Calendar.DAY_OF_YEAR) &&
    943                cal1.get(Calendar.YEAR) == cal2.get(Calendar.YEAR) &&
    944                cal1.get(Calendar.ERA) == cal2.get(Calendar.ERA) &&
    945                cal1.getClass() == cal2.getClass();
    946    }
    947
    948    /**
    949     * Constructs an {@link Iterator} over each day in a date
    950     * range defined by a focus date and range style.
    951     *
    952     * <p>For instance, passing Thursday, July 4, 2002 and a
    953     * {@code RANGE_MONTH_SUNDAY} will return an {@link Iterator}
    954     * that starts with Sunday, June 30, 2002 and ends with Saturday, August 3,
    955     * 2002, returning a Calendar instance for each intermediate day.</p>
    956     *
    957     * <p>This method provides an iterator that returns Calendar objects.
    958     * The days are progressed using {@link Calendar#add(int, int)}.</p>
    959     *
    960     * @param calendar  the date to work with, not null
    961     * @param rangeStyle  the style constant to use. Must be one of
    962     * {@link DateUtils#RANGE_MONTH_SUNDAY},
    963     * {@link DateUtils#RANGE_MONTH_MONDAY},
    964     * {@link DateUtils#RANGE_WEEK_SUNDAY},
    965     * {@link DateUtils#RANGE_WEEK_MONDAY},
    966     * {@link DateUtils#RANGE_WEEK_RELATIVE},
    967     * {@link DateUtils#RANGE_WEEK_CENTER}
    968     * @return the date iterator, not null
    969     * @throws NullPointerException if calendar is {@code null}
    970     * @throws IllegalArgumentException if the rangeStyle is invalid
    971     */
    972    public static Iterator<Calendar> iterator(final Calendar calendar, final int rangeStyle) {
    973        Objects.requireNonNull(calendar, "calendar");
    974        final Calendar start;
    975        final Calendar end;
    976        int startCutoff = Calendar.SUNDAY;
    977        int endCutoff = Calendar.SATURDAY;
    978        switch (rangeStyle) {
    979            case RANGE_MONTH_SUNDAY:
    980            case RANGE_MONTH_MONDAY:
    981                //Set start to the first of the month
    982                start = truncate(calendar, Calendar.MONTH);
    983                //Set end to the last of the month
    984                end = (Calendar) start.clone();
    985                end.add(Calendar.MONTH, 1);
    986                end.add(Calendar.DATE, -1);
    987                //Loop start back to the previous sunday or monday
    988                if (rangeStyle == RANGE_MONTH_MONDAY) {
    989                    startCutoff = Calendar.MONDAY;
    990                    endCutoff = Calendar.SUNDAY;
    991                }
    992                break;
    993            case RANGE_WEEK_SUNDAY:
    994            case RANGE_WEEK_MONDAY:
    995            case RANGE_WEEK_RELATIVE:
    996            case RANGE_WEEK_CENTER:
    997                //Set start and end to the current date
    998                start = truncate(calendar, Calendar.DATE);
    999                end = truncate(calendar, Calendar.DATE);
    1000                switch (rangeStyle) {
    1001                    case RANGE_WEEK_SUNDAY:
    1002                        //already set by default
    1003                        break;
    1004                    case RANGE_WEEK_MONDAY:
    1005                        startCutoff = Calendar.MONDAY;
    1006                        endCutoff = Calendar.SUNDAY;
    1007                        break;
    1008                    case RANGE_WEEK_RELATIVE:
    1009                        startCutoff = calendar.get(Calendar.DAY_OF_WEEK);
    1010                        endCutoff = startCutoff - 1;
    1011                        break;
    1012                    case RANGE_WEEK_CENTER:
    1013                        startCutoff = calendar.get(Calendar.DAY_OF_WEEK) - 3;
    1014                        endCutoff = calendar.get(Calendar.DAY_OF_WEEK) + 3;
    1015                        break;
    1016                    default:
    1017                        break;
    1018                }
    1019                break;
    1020            default:
    1021                throw new IllegalArgumentException("The range style " + rangeStyle + " is not valid.");
    1022        }
    1023        if (startCutoff < Calendar.SUNDAY) {
    1024            startCutoff += 7;
    1025        }
    1026        if (startCutoff > Calendar.SATURDAY) {
    1027            startCutoff -= 7;
    1028        }
    1029        if (endCutoff < Calendar.SUNDAY) {
    1030            endCutoff += 7;
    1031        }
    1032        if (endCutoff > Calendar.SATURDAY) {
    1033            endCutoff -= 7;
    1034        }
    1035        while (start.get(Calendar.DAY_OF_WEEK) != startCutoff) {
    1036            start.add(Calendar.DATE, -1);
    1037        }
    1038        while (end.get(Calendar.DAY_OF_WEEK) != endCutoff) {
    1039            end.add(Calendar.DATE, 1);
    1040        }
    1041        return new DateIterator(start, end);
    1042    }
    1043
    1044    /**
    1045     * Constructs an {@link Iterator} over each day in a date
    1046     * range defined by a focus date and range style.
    1047     *
    1048     * <p>For instance, passing Thursday, July 4, 2002 and a
    1049     * {@code RANGE_MONTH_SUNDAY} will return an {@link Iterator}
    1050     * that starts with Sunday, June 30, 2002 and ends with Saturday, August 3,
    1051     * 2002, returning a Calendar instance for each intermediate day.</p>
    1052     *
    1053     * <p>This method provides an iterator that returns Calendar objects.
    1054     * The days are progressed using {@link Calendar#add(int, int)}.</p>
    1055     *
    1056     * @param focus  the date to work with, not null
    1057     * @param rangeStyle  the style constant to use. Must be one of
    1058     * {@link DateUtils#RANGE_MONTH_SUNDAY},
    1059     * {@link DateUtils#RANGE_MONTH_MONDAY},
    1060     * {@link DateUtils#RANGE_WEEK_SUNDAY},
    1061     * {@link DateUtils#RANGE_WEEK_MONDAY},
    1062     * {@link DateUtils#RANGE_WEEK_RELATIVE},
    1063     * {@link DateUtils#RANGE_WEEK_CENTER}
    1064     * @return the date iterator, not null, not null
    1065     * @throws NullPointerException if the date is {@code null}
    1066     * @throws IllegalArgumentException if the rangeStyle is invalid
    1067     */
    1068    public static Iterator<Calendar> iterator(final Date focus, final int rangeStyle) {
    1069        return iterator(toCalendar(focus), rangeStyle);
    1070    }
    1071
    1072    /**
    1073     * Constructs an {@link Iterator} over each day in a date
    1074     * range defined by a focus date and range style.
    1075     *
    1076     * <p>For instance, passing Thursday, July 4, 2002 and a
    1077     * {@code RANGE_MONTH_SUNDAY} will return an {@link Iterator}
    1078     * that starts with Sunday, June 30, 2002 and ends with Saturday, August 3,
    1079     * 2002, returning a Calendar instance for each intermediate day.</p>
    1080     *
    1081     * @param calendar  the date to work with, either {@link Date} or {@link Calendar}, not null
    1082     * @param rangeStyle  the style constant to use. Must be one of the range
    1083     * styles listed for the {@link #iterator(Calendar, int)} method.
    1084     * @return the date iterator, not null
    1085     * @throws NullPointerException if the date is {@code null}
    1086     * @throws ClassCastException if the object type is not a {@link Date} or {@link Calendar}
    1087     */
    1088    public static Iterator<?> iterator(final Object calendar, final int rangeStyle) {
    1089        Objects.requireNonNull(calendar, "calendar");
    1090        if (calendar instanceof Date) {
    1091            return iterator((Date) calendar, rangeStyle);
    1092        }
    1093        if (calendar instanceof Calendar) {
    1094            return iterator((Calendar) calendar, rangeStyle);
    1095        }
    1096        throw new ClassCastException("Could not iterate based on " + calendar);
    1097    }
    1098
    1099    /**
    1100     * Internal calculation method.
    1101     *
    1102     * @param val  the calendar, not null
    1103     * @param field  the field constant
    1104     * @param modType  type to truncate, round or ceiling
    1105     * @return the given calendar
    1106     * @throws ArithmeticException if the year is over 280 million
    1107     */
    1108    private static Calendar modify(final Calendar val, final int field, final ModifyType modType) {
    1109        if (val.get(Calendar.YEAR) > 280000000) {
    1110            throw new ArithmeticException("Calendar value too large for accurate calculations");
    1111        }
    1112
    1113        if (field == Calendar.MILLISECOND) {
    1114            return val;
    1115        }
    1116
    1117        // Fix for LANG-59 START
    1118        // see https://issues.apache.org/jira/browse/LANG-59
    1119        //
    1120        // Manually truncate milliseconds, seconds and minutes, rather than using
    1121        // Calendar methods.
    1122
    1123        final Date date = val.getTime();
    1124        long time = date.getTime();
    1125        boolean done = false;
    1126
    1127        // truncate milliseconds
    1128        final int millisecs = val.get(Calendar.MILLISECOND);
    1129        if (ModifyType.TRUNCATE == modType || millisecs < 500) {
    1130            time -= millisecs;
    1131        }
    1132        if (field == Calendar.SECOND) {
    1133            done = true;
    1134        }
    1135
    1136        // truncate seconds
    1137        final int seconds = val.get(Calendar.SECOND);
    1138        if (!done && (ModifyType.TRUNCATE == modType || seconds < 30)) {
    1139            time = time - seconds * 1000L;
    1140        }
    1141        if (field == Calendar.MINUTE) {
    1142            done = true;
    1143        }
    1144
    1145        // truncate minutes
    1146        final int minutes = val.get(Calendar.MINUTE);
    1147        if (!done && (ModifyType.TRUNCATE == modType || minutes < 30)) {
    1148            time = time - minutes * 60000L;
    1149        }
    1150
    1151        // reset time
    1152        if (date.getTime() != time) {
    1153            date.setTime(time);
    1154            val.setTime(date);
    1155        }
    1156        // Fix for LANG-59 END
    1157
    1158        boolean roundUp = false;
    1159        for (final int[] aField : fields) {
    1160            for (final int element : aField) {
    1161                if (element == field) {
    1162                    //This is our field... we stop looping
    1163                    if (modType == ModifyType.CEILING || modType == ModifyType.ROUND && roundUp) {
    1164                        if (field == SEMI_MONTH) {
    1165                            //This is a special case that's hard to generalize
    1166                            //If the date is 1, we round up to 16, otherwise
    1167                            //  we subtract 15 days and add 1 month
    1168                            if (val.get(Calendar.DATE) == 1) {
    1169                                val.add(Calendar.DATE, 15);
    1170                            } else {
    1171                                val.add(Calendar.DATE, -15);
    1172                                val.add(Calendar.MONTH, 1);
    1173                            }
    1174                        // Fix for LANG-440 START
    1175                        } else if (field == Calendar.AM_PM) {
    1176                            // This is a special case
    1177                            // If the time is 0, we round up to 12, otherwise
    1178                            //  we subtract 12 hours and add 1 day
    1179                            if (val.get(Calendar.HOUR_OF_DAY) == 0) {
    1180                                val.add(Calendar.HOUR_OF_DAY, 12);
    1181                            } else {
    1182                                val.add(Calendar.HOUR_OF_DAY, -12);
    1183                                val.add(Calendar.DATE, 1);
    1184                            }
    1185                            // Fix for LANG-440 END
    1186                        } else {
    1187                            //We need at add one to this field since the
    1188                            //  last number causes us to round up
    1189                            val.add(aField[0], 1);
    1190                        }
    1191                    }
    1192                    return val;
    1193                }
    1194            }
    1195            //We have various fields that are not easy roundings
    1196            int offset = 0;
    1197            boolean offsetSet = false;
    1198            //These are special types of fields that require different rounding rules
    1199            switch (field) {
    1200                case SEMI_MONTH:
    1201                    if (aField[0] == Calendar.DATE) {
    1202                        //If we're going to drop the DATE field's value,
    1203                        //  we want to do this our own way.
    1204                        //We need to subtract 1 since the date has a minimum of 1
    1205                        offset = val.get(Calendar.DATE) - 1;
    1206                        //If we're above 15 days adjustment, that means we're in the
    1207                        //  bottom half of the month and should stay accordingly.
    1208                        if (offset >= 15) {
    1209                            offset -= 15;
    1210                        }
    1211                        //Record whether we're in the top or bottom half of that range
    1212                        roundUp = offset > 7;
    1213                        offsetSet = true;
    1214                    }
    1215                    break;
    1216                case Calendar.AM_PM:
    1217                    if (aField[0] == Calendar.HOUR_OF_DAY) {
    1218                        //If we're going to drop the HOUR field's value,
    1219                        //  we want to do this our own way.
    1220                        offset = val.get(Calendar.HOUR_OF_DAY);
    1221                        if (offset >= 12) {
    1222                            offset -= 12;
    1223                        }
    1224                        roundUp = offset >= 6;
    1225                        offsetSet = true;
    1226                    }
    1227                    break;
    1228                default:
    1229                    break;
    1230            }
    1231            if (!offsetSet) {
    1232                final int min = val.getActualMinimum(aField[0]);
    1233                final int max = val.getActualMaximum(aField[0]);
    1234                //Calculate the offset from the minimum allowed value
    1235                offset = val.get(aField[0]) - min;
    1236                //Set roundUp if this is more than halfway between the minimum and maximum
    1237                roundUp = offset > (max - min) / 2;
    1238            }
    1239            //We need to remove this field
    1240            if (offset != 0) {
    1241                val.set(aField[0], val.get(aField[0]) - offset);
    1242            }
    1243        }
    1244        throw new IllegalArgumentException("The field " + field + " is not supported");
    1245    }
    1246
    1247    /**
    1248     * Parses a string representing a date by trying a variety of different parsers,
    1249     * using the default date format symbols for the given locale.
    1250     *
    1251     * <p>The parse will try each parse pattern in turn.
    1252     * A parse is only deemed successful if it parses the whole of the input string.
    1253     * If no parse patterns match, a ParseException is thrown.</p>
    1254     * The parser will be lenient toward the parsed date.
    1255     *
    1256     * @param str  the date to parse, not null
    1257     * @param locale the locale whose date format symbols should be used. If {@code null},
    1258     * the system locale is used (as per {@link #parseDate(String, String...)}).
    1259     * @param parsePatterns  the date format patterns to use, see SimpleDateFormat, not null
    1260     * @return the parsed date
    1261     * @throws NullPointerException if the date string or pattern array is null
    1262     * @throws ParseException if none of the date patterns were suitable (or there were none)
    1263     * @since 3.2
    1264     */
    1265    public static Date parseDate(final String str, final Locale locale, final String... parsePatterns) throws ParseException {
    1266        return parseDateWithLeniency(str, locale, parsePatterns, true);
    1267    }
    1268
    1269    /**
    1270     * Parses a string representing a date by trying a variety of different parsers.
    1271     *
    1272     * <p>The parse will try each parse pattern in turn.
    1273     * A parse is only deemed successful if it parses the whole of the input string.
    1274     * If no parse patterns match, a ParseException is thrown.</p>
    1275     * The parser will be lenient toward the parsed date.
    1276     *
    1277     * @param str  the date to parse, not null
    1278     * @param parsePatterns  the date format patterns to use, see SimpleDateFormat, not null
    1279     * @return the parsed date
    1280     * @throws NullPointerException if the date string or pattern array is null
    1281     * @throws ParseException if none of the date patterns were suitable (or there were none)
    1282     */
    1283    public static Date parseDate(final String str, final String... parsePatterns) throws ParseException {
    1284        return parseDate(str, null, parsePatterns);
    1285    }
    1286
    1287    /**
    1288     * Parses a string representing a date by trying a variety of different parsers,
    1289     * using the default date format symbols for the given locale.
    1290     *
    1291     * <p>The parse will try each parse pattern in turn.
    1292     * A parse is only deemed successful if it parses the whole of the input string.
    1293     * If no parse patterns match, a ParseException is thrown.</p>
    1294     * The parser parses strictly - it does not allow for dates such as "February 942, 1996".
    1295     *
    1296     * @param str  the date to parse, not null
    1297     * @param locale the locale whose date format symbols should be used. If {@code null},
    1298     * the system locale is used (as per {@link #parseDateStrictly(String, String...)}).
    1299     * @param parsePatterns  the date format patterns to use, see SimpleDateFormat, not null
    1300     * @return the parsed date
    1301     * @throws NullPointerException if the date string or pattern array is null
    1302     * @throws ParseException if none of the date patterns were suitable
    1303     * @since 3.2
    1304     */
    1305    public static Date parseDateStrictly(final String str, final Locale locale, final String... parsePatterns) throws ParseException {
    1306        return parseDateWithLeniency(str, locale, parsePatterns, false);
    1307    }
    1308
    1309    /**
    1310     * Parses a string representing a date by trying a variety of different parsers.
    1311     *
    1312     * <p>The parse will try each parse pattern in turn.
    1313     * A parse is only deemed successful if it parses the whole of the input string.
    1314     * If no parse patterns match, a ParseException is thrown.</p>
    1315     * The parser parses strictly - it does not allow for dates such as "February 942, 1996".
    1316     *
    1317     * @param str  the date to parse, not null
    1318     * @param parsePatterns  the date format patterns to use, see SimpleDateFormat, not null
    1319     * @return the parsed date
    1320     * @throws NullPointerException if the date string or pattern array is null
    1321     * @throws ParseException if none of the date patterns were suitable
    1322     * @since 2.5
    1323     */
    1324    public static Date parseDateStrictly(final String str, final String... parsePatterns) throws ParseException {
    1325        return parseDateStrictly(str, null, parsePatterns);
    1326    }
    1327
    1328    /**
    1329     * Parses a string representing a date by trying a variety of different parsers.
    1330     *
    1331     * <p>The parse will try each parse pattern in turn.
    1332     * A parse is only deemed successful if it parses the whole of the input string.
    1333     * If no parse patterns match, a ParseException is thrown.</p>
    1334     *
    1335     * @param dateStr  the date to parse, not null
    1336     * @param locale the locale to use when interpreting the pattern, can be null in which
    1337     * case the default system locale is used
    1338     * @param parsePatterns  the date format patterns to use, see SimpleDateFormat, not null
    1339     * @param lenient Specify whether or not date/time parsing is to be lenient.
    1340     * @return the parsed date
    1341     * @throws NullPointerException if the date string or pattern array is null
    1342     * @throws ParseException if none of the date patterns were suitable
    1343     * @see java.util.Calendar#isLenient()
    1344     */
    1345    private static Date parseDateWithLeniency(final String dateStr, final Locale locale, final String[] parsePatterns,
    1346        final boolean lenient) throws ParseException {
    1347        Objects.requireNonNull(dateStr, "str");
    1348        Objects.requireNonNull(parsePatterns, "parsePatterns");
    1349
    1350        final TimeZone tz = TimeZone.getDefault();
    1351        final Locale lcl = LocaleUtils.toLocale(locale);
    1352        final ParsePosition pos = new ParsePosition(0);
    1353        final Calendar calendar = Calendar.getInstance(tz, lcl);
    1354        calendar.setLenient(lenient);
    1355
    1356        for (final String parsePattern : parsePatterns) {
    1357            final FastDateParser fdp = new FastDateParser(parsePattern, tz, lcl);
    1358            calendar.clear();
    1359            try {
    1360                if (fdp.parse(dateStr, pos, calendar) && pos.getIndex() == dateStr.length()) {
    1361                    return calendar.getTime();
    1362                }
    1363            } catch (final IllegalArgumentException ignored) {
    1364                // leniency is preventing calendar from being set
    1365            }
    1366            pos.setIndex(0);
    1367        }
    1368        throw new ParseException("Unable to parse the date: " + dateStr, -1);
    1369    }
    1370
    1371    /**
    1372     * Rounds a date, leaving the field specified as the most
    1373     * significant field.
    1374     *
    1375     * <p>For example, if you had the date-time of 28 Mar 2002
    1376     * 13:45:01.231, if this was passed with HOUR, it would return
    1377     * 28 Mar 2002 14:00:00.000. If this was passed with MONTH, it
    1378     * would return 1 April 2002 0:00:00.000.</p>
    1379     *
    1380     * <p>For a date in a time zone that handles the change to daylight
    1381     * saving time, rounding to Calendar.HOUR_OF_DAY will behave as follows.
    1382     * Suppose daylight saving time begins at 02:00 on March 30. Rounding a
    1383     * date that crosses this time would produce the following values:
    1384     * </p>
    1385     * <ul>
    1386     * <li>March 30, 2003 01:10 rounds to March 30, 2003 01:00</li>
    1387     * <li>March 30, 2003 01:40 rounds to March 30, 2003 03:00</li>
    1388     * <li>March 30, 2003 02:10 rounds to March 30, 2003 03:00</li>
    1389     * <li>March 30, 2003 02:40 rounds to March 30, 2003 04:00</li>
    1390     * </ul>
    1391     *
    1392     * @param calendar  the date to work with, not null
    1393     * @param field  the field from {@link Calendar} or {@code SEMI_MONTH}
    1394     * @return the different rounded date, not null
    1395     * @throws NullPointerException if the date is {@code null}
    1396     * @throws ArithmeticException if the year is over 280 million
    1397     */
    1398    public static Calendar round(final Calendar calendar, final int field) {
    1399        Objects.requireNonNull(calendar, "calendar");
    1400        return modify((Calendar) calendar.clone(), field, ModifyType.ROUND);
    1401    }
    1402
    1403    /**
    1404     * Rounds a date, leaving the field specified as the most
    1405     * significant field.
    1406     *
    1407     * <p>For example, if you had the date-time of 28 Mar 2002
    1408     * 13:45:01.231, if this was passed with HOUR, it would return
    1409     * 28 Mar 2002 14:00:00.000. If this was passed with MONTH, it
    1410     * would return 1 April 2002 0:00:00.000.</p>
    1411     *
    1412     * <p>For a date in a time zone that handles the change to daylight
    1413     * saving time, rounding to Calendar.HOUR_OF_DAY will behave as follows.
    1414     * Suppose daylight saving time begins at 02:00 on March 30. Rounding a
    1415     * date that crosses this time would produce the following values:
    1416     * </p>
    1417     * <ul>
    1418     * <li>March 30, 2003 01:10 rounds to March 30, 2003 01:00</li>
    1419     * <li>March 30, 2003 01:40 rounds to March 30, 2003 03:00</li>
    1420     * <li>March 30, 2003 02:10 rounds to March 30, 2003 03:00</li>
    1421     * <li>March 30, 2003 02:40 rounds to March 30, 2003 04:00</li>
    1422     * </ul>
    1423     *
    1424     * @param date  the date to work with, not null
    1425     * @param field  the field from {@link Calendar} or {@code SEMI_MONTH}
    1426     * @return the different rounded date, not null
    1427     * @throws NullPointerException if the date is null
    1428     * @throws ArithmeticException if the year is over 280 million
    1429     */
    1430    public static Date round(final Date date, final int field) {
    1431        return modify(toCalendar(date), field, ModifyType.ROUND).getTime();
    1432    }
    1433
    1434    /**
    1435     * Rounds a date, leaving the field specified as the most
    1436     * significant field.
    1437     *
    1438     * <p>For example, if you had the date-time of 28 Mar 2002
    1439     * 13:45:01.231, if this was passed with HOUR, it would return
    1440     * 28 Mar 2002 14:00:00.000. If this was passed with MONTH, it
    1441     * would return 1 April 2002 0:00:00.000.</p>
    1442     *
    1443     * <p>For a date in a time zone that handles the change to daylight
    1444     * saving time, rounding to Calendar.HOUR_OF_DAY will behave as follows.
    1445     * Suppose daylight saving time begins at 02:00 on March 30. Rounding a
    1446     * date that crosses this time would produce the following values:
    1447     * </p>
    1448     * <ul>
    1449     * <li>March 30, 2003 01:10 rounds to March 30, 2003 01:00</li>
    1450     * <li>March 30, 2003 01:40 rounds to March 30, 2003 03:00</li>
    1451     * <li>March 30, 2003 02:10 rounds to March 30, 2003 03:00</li>
    1452     * <li>March 30, 2003 02:40 rounds to March 30, 2003 04:00</li>
    1453     * </ul>
    1454     *
    1455     * @param date  the date to work with, either {@link Date} or {@link Calendar}, not null
    1456     * @param field  the field from {@link Calendar} or {@code SEMI_MONTH}
    1457     * @return the different rounded date, not null
    1458     * @throws NullPointerException if the date is {@code null}
    1459     * @throws ClassCastException if the object type is not a {@link Date} or {@link Calendar}
    1460     * @throws ArithmeticException if the year is over 280 million
    1461     */
    1462    public static Date round(final Object date, final int field) {
    1463        Objects.requireNonNull(date, "date");
    1464        if (date instanceof Date) {
    1465            return round((Date) date, field);
    1466        }
    1467        if (date instanceof Calendar) {
    1468            return round((Calendar) date, field).getTime();
    1469        }
    1470        throw new ClassCastException("Could not round " + date);
    1471    }
    1472
    1473    /**
    1474     * Sets the specified field to a date returning a new object.
    1475     * This does not use a lenient calendar.
    1476     * The original {@link Date} is unchanged.
    1477     *
    1478     * @param date  the date, not null
    1479     * @param calendarField  the {@link Calendar} field to set the amount to
    1480     * @param amount the amount to set
    1481     * @return a new {@link Date} set with the specified value
    1482     * @throws NullPointerException if the date is null
    1483     * @since 2.4
    1484     */
    1485    private static Date set(final Date date, final int calendarField, final int amount) {
    1486        validateDateNotNull(date);
    1487        // getInstance() returns a new object, so this method is thread safe.
    1488        final Calendar c = Calendar.getInstance();
    1489        c.setLenient(false);
    1490        c.setTime(date);
    1491        c.set(calendarField, amount);
    1492        return c.getTime();
    1493    }
    1494
    1495    /**
    1496     * Sets the day of month field to a date returning a new object.
    1497     * The original {@link Date} is unchanged.
    1498     *
    1499     * @param date  the date, not null
    1500     * @param amount the amount to set
    1501     * @return a new {@link Date} set with the specified value
    1502     * @throws NullPointerException if the date is null
    1503     * @throws IllegalArgumentException if {@code amount} is not in the range
    1504     *  {@code 1 <= amount <= 31}
    1505     * @since 2.4
    1506     */
    1507    public static Date setDays(final Date date, final int amount) {
    1508        return set(date, Calendar.DAY_OF_MONTH, amount);
    1509    }
    1510
    1511    /**
    1512     * Sets the hours field to a date returning a new object.  Hours range
    1513     * from  0-23.
    1514     * The original {@link Date} is unchanged.
    1515     *
    1516     * @param date  the date, not null
    1517     * @param amount the amount to set
    1518     * @return a new {@link Date} set with the specified value
    1519     * @throws NullPointerException if the date is null
    1520     * @throws IllegalArgumentException if {@code amount} is not in the range
    1521     *  {@code 0 <= amount <= 23}
    1522     * @since 2.4
    1523     */
    1524    public static Date setHours(final Date date, final int amount) {
    1525        return set(date, Calendar.HOUR_OF_DAY, amount);
    1526    }
    1527
    1528    /**
    1529     * Sets the milliseconds field to a date returning a new object.
    1530     * The original {@link Date} is unchanged.
    1531     *
    1532     * @param date  the date, not null
    1533     * @param amount the amount to set
    1534     * @return a new {@link Date} set with the specified value
    1535     * @throws NullPointerException if the date is null
    1536     * @throws IllegalArgumentException if {@code amount} is not in the range
    1537     *  {@code 0 <= amount <= 999}
    1538     * @since 2.4
    1539     */
    1540    public static Date setMilliseconds(final Date date, final int amount) {
    1541        return set(date, Calendar.MILLISECOND, amount);
    1542    }
    1543
    1544    /**
    1545     * Sets the minute field to a date returning a new object.
    1546     * The original {@link Date} is unchanged.
    1547     *
    1548     * @param date  the date, not null
    1549     * @param amount the amount to set
    1550     * @return a new {@link Date} set with the specified value
    1551     * @throws NullPointerException if the date is null
    1552     * @throws IllegalArgumentException if {@code amount} is not in the range
    1553     *  {@code 0 <= amount <= 59}
    1554     * @since 2.4
    1555     */
    1556    public static Date setMinutes(final Date date, final int amount) {
    1557        return set(date, Calendar.MINUTE, amount);
    1558    }
    1559
    1560    /**
    1561     * Sets the months field to a date returning a new object.
    1562     * The original {@link Date} is unchanged.
    1563     *
    1564     * @param date  the date, not null
    1565     * @param amount the amount to set
    1566     * @return a new {@link Date} set with the specified value
    1567     * @throws NullPointerException if the date is null
    1568     * @throws IllegalArgumentException if {@code amount} is not in the range
    1569     *  {@code 0 <= amount <= 11}
    1570     * @since 2.4
    1571     */
    1572    public static Date setMonths(final Date date, final int amount) {
    1573        return set(date, Calendar.MONTH, amount);
    1574    }
    1575
    1576    /**
    1577     * Sets the seconds field to a date returning a new object.
    1578     * The original {@link Date} is unchanged.
    1579     *
    1580     * @param date  the date, not null
    1581     * @param amount the amount to set
    1582     * @return a new {@link Date} set with the specified value
    1583     * @throws NullPointerException if the date is null
    1584     * @throws IllegalArgumentException if {@code amount} is not in the range
    1585     *  {@code 0 <= amount <= 59}
    1586     * @since 2.4
    1587     */
    1588    public static Date setSeconds(final Date date, final int amount) {
    1589        return set(date, Calendar.SECOND, amount);
    1590    }
    1591    /**
    1592     * Sets the years field to a date returning a new object.
    1593     * The original {@link Date} is unchanged.
    1594     *
    1595     * @param date  the date, not null
    1596     * @param amount the amount to set
    1597     * @return a new {@link Date} set with the specified value
    1598     * @throws NullPointerException if the date is null
    1599     * @since 2.4
    1600     */
    1601    public static Date setYears(final Date date, final int amount) {
    1602        return set(date, Calendar.YEAR, amount);
    1603    }
    1604
    1605    /**
    1606     * Converts a {@link Date} into a {@link Calendar}.
    1607     *
    1608     * @param date the date to convert to a Calendar
    1609     * @return the created Calendar
    1610     * @throws NullPointerException if null is passed in
    1611     * @since 3.0
    1612     */
    1613    public static Calendar toCalendar(final Date date) {
    1614        final Calendar c = Calendar.getInstance();
    1615        c.setTime(Objects.requireNonNull(date, "date"));
    1616        return c;
    1617    }
    1618
    1619    /**
    1620     * Converts a {@link Date} of a given {@link TimeZone} into a {@link Calendar}.
    1621     *
    1622     * @param date the date to convert to a Calendar
    1623     * @param tz the time zone of the {@code date}
    1624     * @return the created Calendar
    1625     * @throws NullPointerException if {@code date} or {@code tz} is null
    1626     */
    1627    public static Calendar toCalendar(final Date date, final TimeZone tz) {
    1628        final Calendar c = Calendar.getInstance(tz);
    1629        c.setTime(Objects.requireNonNull(date, "date"));
    1630        return c;
    1631    }
    1632
    1633    /**
    1634     * Converts a {@link Date} to a {@link LocalDateTime}.
    1635     *
    1636     * @param date the Date to convert, not null.
    1637     * @return a new LocalDateTime.
    1638     * @since 3.19.0
    1639     */
    1640    public static LocalDateTime toLocalDateTime(final Date date) {
    1641        return toLocalDateTime(date, TimeZone.getDefault());
    1642    }
    1643
    1644    /**
    1645     * Converts a {@link Date} to a {@link LocalDateTime}.
    1646     *
    1647     * @param date     the Date to convert to a LocalDateTime, not null.
    1648     * @param timeZone the time zone, null maps to to the default time zone.
    1649     * @return a new LocalDateTime.
    1650     * @since 3.19.0
    1651     */
    1652    public static LocalDateTime toLocalDateTime(final Date date, final TimeZone timeZone) {
    1653        return LocalDateTime.ofInstant(date.toInstant(), toZoneId(timeZone));
    1654    }
    1655
    1656    /**
    1657     * Converts a {@link Date} to a {@link OffsetDateTime}.
    1658     *
    1659     * @param date the Date to convert, not null.
    1660     * @return a new OffsetDateTime.
    1661     * @since 3.19.0
    1662     */
    1663    public static OffsetDateTime toOffsetDateTime(final Date date) {
    1664        return toOffsetDateTime(date, TimeZone.getDefault());
    1665    }
    1666
    1667    /**
    1668     * Converts a {@link Date} to a {@link OffsetDateTime}.
    1669     *
    1670     * @param date     the Date to convert to a OffsetDateTime, not null.
    1671     * @param timeZone the time zone, null maps to to the default time zone.
    1672     * @return a new OffsetDateTime.
    1673     * @since 3.19.0
    1674     */
    1675    public static OffsetDateTime toOffsetDateTime(final Date date, final TimeZone timeZone) {
    1676        return OffsetDateTime.ofInstant(date.toInstant(), toZoneId(timeZone));
    1677    }
    1678
    1679    /**
    1680     * Converts a {@link Date} to a {@link ZonedDateTime}.
    1681     *
    1682     * @param date the Date to convert, not null.
    1683     * @return a new ZonedDateTime.
    1684     * @since 3.19.0
    1685     */
    1686    public static ZonedDateTime toZonedDateTime(final Date date) {
    1687        return toZonedDateTime(date, TimeZone.getDefault());
    1688    }
    1689
    1690    /**
    1691     * Converts a {@link Date} to a {@link ZonedDateTime}.
    1692     *
    1693     * @param date     the Date to convert to a ZonedDateTime, not null.
    1694     * @param timeZone the time zone, null maps to to the default time zone.
    1695     * @return a new ZonedDateTime.
    1696     * @since 3.19.0
    1697     */
    1698    public static ZonedDateTime toZonedDateTime(final Date date, final TimeZone timeZone) {
    1699        return ZonedDateTime.ofInstant(date.toInstant(), toZoneId(timeZone));
    1700    }
    1701
    1702    private static ZoneId toZoneId(final TimeZone timeZone) {
    1703        return TimeZones.toTimeZone(timeZone).toZoneId();
    1704    }
    1705
    1706    /**
    1707     * Truncates a date, leaving the field specified as the most
    1708     * significant field.
    1709     *
    1710     * <p>For example, if you had the date-time of 28 Mar 2002
    1711     * 13:45:01.231, if you passed with HOUR, it would return 28 Mar
    1712     * 2002 13:00:00.000.  If this was passed with MONTH, it would
    1713     * return 1 Mar 2002 0:00:00.000.</p>
    1714     *
    1715     * @param date  the date to work with, not null
    1716     * @param field  the field from {@link Calendar} or {@code SEMI_MONTH}
    1717     * @return the different truncated date, not null
    1718     * @throws NullPointerException if the date is {@code null}
    1719     * @throws ArithmeticException if the year is over 280 million
    1720     */
    1721    public static Calendar truncate(final Calendar date, final int field) {
    1722        Objects.requireNonNull(date, "date");
    1723        return modify((Calendar) date.clone(), field, ModifyType.TRUNCATE);
    1724    }
    1725
    1726    /**
    1727     * Truncates a date, leaving the field specified as the most
    1728     * significant field.
    1729     *
    1730     * <p>For example, if you had the date-time of 28 Mar 2002
    1731     * 13:45:01.231, if you passed with HOUR, it would return 28 Mar
    1732     * 2002 13:00:00.000.  If this was passed with MONTH, it would
    1733     * return 1 Mar 2002 0:00:00.000.</p>
    1734     *
    1735     * @param date  the date to work with, not null
    1736     * @param field  the field from {@link Calendar} or {@code SEMI_MONTH}
    1737     * @return the different truncated date, not null
    1738     * @throws NullPointerException if the date is {@code null}
    1739     * @throws ArithmeticException if the year is over 280 million
    1740     */
    1741    public static Date truncate(final Date date, final int field) {
    1742        return modify(toCalendar(date), field, ModifyType.TRUNCATE).getTime();
    1743    }
    1744
    1745    /**
    1746     * Truncates a date, leaving the field specified as the most
    1747     * significant field.
    1748     *
    1749     * <p>For example, if you had the date-time of 28 Mar 2002
    1750     * 13:45:01.231, if you passed with HOUR, it would return 28 Mar
    1751     * 2002 13:00:00.000.  If this was passed with MONTH, it would
    1752     * return 1 Mar 2002 0:00:00.000.</p>
    1753     *
    1754     * @param date  the date to work with, either {@link Date} or {@link Calendar}, not null
    1755     * @param field  the field from {@link Calendar} or {@code SEMI_MONTH}
    1756     * @return the different truncated date, not null
    1757     * @throws NullPointerException if the date is {@code null}
    1758     * @throws ClassCastException if the object type is not a {@link Date} or {@link Calendar}
    1759     * @throws ArithmeticException if the year is over 280 million
    1760     */
    1761    public static Date truncate(final Object date, final int field) {
    1762        Objects.requireNonNull(date, "date");
    1763        if (date instanceof Date) {
    1764            return truncate((Date) date, field);
    1765        }
    1766        if (date instanceof Calendar) {
    1767            return truncate((Calendar) date, field).getTime();
    1768        }
    1769        throw new ClassCastException("Could not truncate " + date);
    1770    }
    1771
    1772    /**
    1773     * Determines how two calendars compare up to no more than the specified
    1774     * most significant field.
    1775     *
    1776     * @param cal1 the first calendar, not {@code null}
    1777     * @param cal2 the second calendar, not {@code null}
    1778     * @param field the field from {@link Calendar}
    1779     * @return a negative integer, zero, or a positive integer as the first
    1780     * calendar is less than, equal to, or greater than the second.
    1781     * @throws NullPointerException if any argument is {@code null}
    1782     * @see #truncate(Calendar, int)
    1783     * @see #truncatedCompareTo(Date, Date, int)
    1784     * @since 3.0
    1785     */
    1786    public static int truncatedCompareTo(final Calendar cal1, final Calendar cal2, final int field) {
    1787        final Calendar truncatedCal1 = truncate(cal1, field);
    1788        final Calendar truncatedCal2 = truncate(cal2, field);
    1789        return truncatedCal1.compareTo(truncatedCal2);
    1790    }
    1791
    1792    /**
    1793     * Determines how two dates compare up to no more than the specified
    1794     * most significant field.
    1795     *
    1796     * @param date1 the first date, not {@code null}
    1797     * @param date2 the second date, not {@code null}
    1798     * @param field the field from {@link Calendar}
    1799     * @return a negative integer, zero, or a positive integer as the first
    1800     * date is less than, equal to, or greater than the second.
    1801     * @throws NullPointerException if any argument is {@code null}
    1802     * @see #truncate(Calendar, int)
    1803     * @see #truncatedCompareTo(Date, Date, int)
    1804     * @since 3.0
    1805     */
    1806    public static int truncatedCompareTo(final Date date1, final Date date2, final int field) {
    1807        final Date truncatedDate1 = truncate(date1, field);
    1808        final Date truncatedDate2 = truncate(date2, field);
    1809        return truncatedDate1.compareTo(truncatedDate2);
    1810    }
    1811
    1812    /**
    1813     * Determines if two calendars are equal up to no more than the specified
    1814     * most significant field.
    1815     *
    1816     * @param cal1 the first calendar, not {@code null}
    1817     * @param cal2 the second calendar, not {@code null}
    1818     * @param field the field from {@link Calendar}
    1819     * @return {@code true} if equal; otherwise {@code false}
    1820     * @throws NullPointerException if any argument is {@code null}
    1821     * @see #truncate(Calendar, int)
    1822     * @see #truncatedEquals(Date, Date, int)
    1823     * @since 3.0
    1824     */
    1825    public static boolean truncatedEquals(final Calendar cal1, final Calendar cal2, final int field) {
    1826        return truncatedCompareTo(cal1, cal2, field) == 0;
    1827    }
    1828
    1829    /**
    1830     * Determines if two dates are equal up to no more than the specified
    1831     * most significant field.
    1832     *
    1833     * @param date1 the first date, not {@code null}
    1834     * @param date2 the second date, not {@code null}
    1835     * @param field the field from {@link Calendar}
    1836     * @return {@code true} if equal; otherwise {@code false}
    1837     * @throws NullPointerException if any argument is {@code null}
    1838     * @see #truncate(Date, int)
    1839     * @see #truncatedEquals(Calendar, Calendar, int)
    1840     * @since 3.0
    1841     */
    1842    public static boolean truncatedEquals(final Date date1, final Date date2, final int field) {
    1843        return truncatedCompareTo(date1, date2, field) == 0;
    1844    }
    1845
    1846    /**
    1847     * @param date Date to validate.
    1848     * @throws NullPointerException if {@code date == null}
    1849     */
    1850    private static void validateDateNotNull(final Date date) {
    1851        Objects.requireNonNull(date, "date");
    1852    }
    1853
    1854    /**
    1855     * {@link DateUtils} instances should NOT be constructed in
    1856     * standard programming. Instead, the static methods on the class should
    1857     * be used, such as {@code DateUtils.parseDate(str);}.
    1858     *
    1859     * <p>This constructor is public to permit tools that require a JavaBean
    1860     * instance to operate.</p>
    1861     *
    1862     * @deprecated TODO Make private in 4.0.
    1863     */
    1864    @Deprecated
    1865    public DateUtils() {
    1866        // empty
    1867    }
    1868
    1869}