Package java.util

Source Code of java.util.GregorianCalendar

/*
* @(#)GregorianCalendar.java  1.92 06/06/20
*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/

/*
* (C) Copyright Taligent, Inc. 1996-1998 - All Rights Reserved
* (C) Copyright IBM Corp. 1996-1998 - All Rights Reserved
*
*   The original version of this source code and documentation is copyrighted
* and owned by Taligent, Inc., a wholly-owned subsidiary of IBM. These
* materials are provided under terms of a License Agreement between Taligent
* and Sun. This technology is protected by multiple US and International
* patents. This notice and attribution to Taligent may not be removed.
*   Taligent is a registered trademark of Taligent, Inc.
*
*/

package java.util;

import java.io.IOException;
import java.io.ObjectInputStream;
import sun.util.calendar.BaseCalendar;
import sun.util.calendar.CalendarDate;
import sun.util.calendar.CalendarSystem;
import sun.util.calendar.CalendarUtils;
import sun.util.calendar.Era;
import sun.util.calendar.Gregorian;
import sun.util.calendar.JulianCalendar;
import sun.util.calendar.ZoneInfo;

/**
* <code>GregorianCalendar</code> is a concrete subclass of
* <code>Calendar</code> and provides the standard calendar system
* used by most of the world.
*
* <p> <code>GregorianCalendar</code> is a hybrid calendar that
* supports both the Julian and Gregorian calendar systems with the
* support of a single discontinuity, which corresponds by default to
* the Gregorian date when the Gregorian calendar was instituted
* (October 15, 1582 in some countries, later in others).  The cutover
* date may be changed by the caller by calling {@link
* #setGregorianChange(Date) setGregorianChange()}.
*
* <p>
* Historically, in those countries which adopted the Gregorian calendar first,
* October 4, 1582 (Julian) was thus followed by October 15, 1582 (Gregorian). This calendar models
* this correctly.  Before the Gregorian cutover, <code>GregorianCalendar</code>
* implements the Julian calendar.  The only difference between the Gregorian
* and the Julian calendar is the leap year rule. The Julian calendar specifies
* leap years every four years, whereas the Gregorian calendar omits century
* years which are not divisible by 400.
*
* <p>
* <code>GregorianCalendar</code> implements <em>proleptic</em> Gregorian and
* Julian calendars. That is, dates are computed by extrapolating the current
* rules indefinitely far backward and forward in time. As a result,
* <code>GregorianCalendar</code> may be used for all years to generate
* meaningful and consistent results. However, dates obtained using
* <code>GregorianCalendar</code> are historically accurate only from March 1, 4
* AD onward, when modern Julian calendar rules were adopted.  Before this date,
* leap year rules were applied irregularly, and before 45 BC the Julian
* calendar did not even exist.
*
* <p>
* Prior to the institution of the Gregorian calendar, New Year's Day was
* March 25. To avoid confusion, this calendar always uses January 1. A manual
* adjustment may be made if desired for dates that are prior to the Gregorian
* changeover and which fall between January 1 and March 24.
*
* <p>Values calculated for the <code>WEEK_OF_YEAR</code> field range from 1 to
* 53.  Week 1 for a year is the earliest seven day period starting on
* <code>getFirstDayOfWeek()</code> that contains at least
* <code>getMinimalDaysInFirstWeek()</code> days from that year.  It thus
* depends on the values of <code>getMinimalDaysInFirstWeek()</code>,
* <code>getFirstDayOfWeek()</code>, and the day of the week of January 1.
* Weeks between week 1 of one year and week 1 of the following year are
* numbered sequentially from 2 to 52 or 53 (as needed).

* <p>For example, January 1, 1998 was a Thursday.  If
* <code>getFirstDayOfWeek()</code> is <code>MONDAY</code> and
* <code>getMinimalDaysInFirstWeek()</code> is 4 (these are the values
* reflecting ISO 8601 and many national standards), then week 1 of 1998 starts
* on December 29, 1997, and ends on January 4, 1998.  If, however,
* <code>getFirstDayOfWeek()</code> is <code>SUNDAY</code>, then week 1 of 1998
* starts on January 4, 1998, and ends on January 10, 1998; the first three days
* of 1998 then are part of week 53 of 1997.
*
* <p>Values calculated for the <code>WEEK_OF_MONTH</code> field range from 0
* to 6.  Week 1 of a month (the days with <code>WEEK_OF_MONTH =
* 1</code>) is the earliest set of at least
* <code>getMinimalDaysInFirstWeek()</code> contiguous days in that month,
* ending on the day before <code>getFirstDayOfWeek()</code>.  Unlike
* week 1 of a year, week 1 of a month may be shorter than 7 days, need
* not start on <code>getFirstDayOfWeek()</code>, and will not include days of
* the previous month.  Days of a month before week 1 have a
* <code>WEEK_OF_MONTH</code> of 0.
*
* <p>For example, if <code>getFirstDayOfWeek()</code> is <code>SUNDAY</code>
* and <code>getMinimalDaysInFirstWeek()</code> is 4, then the first week of
* January 1998 is Sunday, January 4 through Saturday, January 10.  These days
* have a <code>WEEK_OF_MONTH</code> of 1.  Thursday, January 1 through
* Saturday, January 3 have a <code>WEEK_OF_MONTH</code> of 0.  If
* <code>getMinimalDaysInFirstWeek()</code> is changed to 3, then January 1
* through January 3 have a <code>WEEK_OF_MONTH</code> of 1.
*
* <p>The <code>clear</code> methods set calendar field(s)
* undefined. <code>GregorianCalendar</code> uses the following
* default value for each calendar field if its value is undefined.
*
* <table cellpadding="0" cellspacing="3" border="0"
*    summary="GregorianCalendar default field values"
*    style="text-align: left; width: 66%;">
*   <tbody>
*     <tr>
*       <th style="vertical-align: top; background-color: rgb(204, 204, 255);
*       text-align: center;">Field<br>
*       </th>
*       <th style="vertical-align: top; background-color: rgb(204, 204, 255);
*       text-align: center;">Default Value<br>
*       </th>
*     </tr>
*     <tr>
*       <td style="vertical-align: middle;">
*    <code>ERA<br></code>
*   </td>
*       <td style="vertical-align: middle;">
*    <code>AD<br></code>
*   </td>
*     </tr>
*     <tr>
*       <td style="vertical-align: middle; background-color: rgb(238, 238, 255);">
*    <code>YEAR<br></code>
*   </td>
*       <td style="vertical-align: middle; background-color: rgb(238, 238, 255);">
*    <code>1970<br></code>
*   </td>
*     </tr>
*     <tr>
*       <td style="vertical-align: middle;">
*    <code>MONTH<br></code>
*   </td>
*       <td style="vertical-align: middle;">
*    <code>JANUARY<br></code>
*   </td>
*     </tr>
*     <tr>
*       <td style="vertical-align: top; background-color: rgb(238, 238, 255);">
*    <code>DAY_OF_MONTH<br></code>
*   </td>
*       <td style="vertical-align: top; background-color: rgb(238, 238, 255);">
*    <code>1<br></code>
*   </td>
*     </tr>
*     <tr>
*       <td style="vertical-align: middle;">
*    <code>DAY_OF_WEEK<br></code>
*   </td>
*       <td style="vertical-align: middle;">
*    <code>the first day of week<br></code>
*   </td>
*     </tr>
*     <tr>
*       <td style="vertical-align: top; background-color: rgb(238, 238, 255);">
*    <code>WEEK_OF_MONTH<br></code>
*       </td>
*       <td style="vertical-align: top; background-color: rgb(238, 238, 255);">
*    <code>0<br></code>
*       </td>
*     </tr>
*     <tr>
*       <td style="vertical-align: top;">
*    <code>DAY_OF_WEEK_IN_MONTH<br></code>
*       </td>
*       <td style="vertical-align: top;">
*    <code>1<br></code>
*       </td>
*     </tr>
*     <tr>
*       <td style="vertical-align: middle; background-color: rgb(238, 238, 255);">
*    <code>AM_PM<br></code>
*       </td>
*       <td style="vertical-align: middle; background-color: rgb(238, 238, 255);">
*    <code>AM<br></code>
*       </td>
*     </tr>
*     <tr>
*       <td style="vertical-align: middle;">
*    <code>HOUR, HOUR_OF_DAY, MINUTE, SECOND, MILLISECOND<br></code>
*       </td>
*       <td style="vertical-align: middle;">
*    <code>0<br></code>
*       </td>
*     </tr>
*   </tbody>
* </table>
* <br>Default values are not applicable for the fields not listed above.
*
* <p>
* <strong>Example:</strong>
* <blockquote>
* <pre>
* // get the supported ids for GMT-08:00 (Pacific Standard Time)
* String[] ids = TimeZone.getAvailableIDs(-8 * 60 * 60 * 1000);
* // if no ids were returned, something is wrong. get out.
* if (ids.length == 0)
*     System.exit(0);
*
*  // begin output
* System.out.println("Current Time");
*
* // create a Pacific Standard Time time zone
* SimpleTimeZone pdt = new SimpleTimeZone(-8 * 60 * 60 * 1000, ids[0]);
*
* // set up rules for daylight savings time
* pdt.setStartRule(Calendar.APRIL, 1, Calendar.SUNDAY, 2 * 60 * 60 * 1000);
* pdt.setEndRule(Calendar.OCTOBER, -1, Calendar.SUNDAY, 2 * 60 * 60 * 1000);
*
* // create a GregorianCalendar with the Pacific Daylight time zone
* // and the current date and time
* Calendar calendar = new GregorianCalendar(pdt);
* Date trialTime = new Date();
* calendar.setTime(trialTime);
*
* // print out a bunch of interesting things
* System.out.println("ERA: " + calendar.get(Calendar.ERA));
* System.out.println("YEAR: " + calendar.get(Calendar.YEAR));
* System.out.println("MONTH: " + calendar.get(Calendar.MONTH));
* System.out.println("WEEK_OF_YEAR: " + calendar.get(Calendar.WEEK_OF_YEAR));
* System.out.println("WEEK_OF_MONTH: " + calendar.get(Calendar.WEEK_OF_MONTH));
* System.out.println("DATE: " + calendar.get(Calendar.DATE));
* System.out.println("DAY_OF_MONTH: " + calendar.get(Calendar.DAY_OF_MONTH));
* System.out.println("DAY_OF_YEAR: " + calendar.get(Calendar.DAY_OF_YEAR));
* System.out.println("DAY_OF_WEEK: " + calendar.get(Calendar.DAY_OF_WEEK));
* System.out.println("DAY_OF_WEEK_IN_MONTH: "
*                    + calendar.get(Calendar.DAY_OF_WEEK_IN_MONTH));
* System.out.println("AM_PM: " + calendar.get(Calendar.AM_PM));
* System.out.println("HOUR: " + calendar.get(Calendar.HOUR));
* System.out.println("HOUR_OF_DAY: " + calendar.get(Calendar.HOUR_OF_DAY));
* System.out.println("MINUTE: " + calendar.get(Calendar.MINUTE));
* System.out.println("SECOND: " + calendar.get(Calendar.SECOND));
* System.out.println("MILLISECOND: " + calendar.get(Calendar.MILLISECOND));
* System.out.println("ZONE_OFFSET: "
*                    + (calendar.get(Calendar.ZONE_OFFSET)/(60*60*1000)));
* System.out.println("DST_OFFSET: "
*                    + (calendar.get(Calendar.DST_OFFSET)/(60*60*1000)));

* System.out.println("Current Time, with hour reset to 3");
* calendar.clear(Calendar.HOUR_OF_DAY); // so doesn't override
* calendar.set(Calendar.HOUR, 3);
* System.out.println("ERA: " + calendar.get(Calendar.ERA));
* System.out.println("YEAR: " + calendar.get(Calendar.YEAR));
* System.out.println("MONTH: " + calendar.get(Calendar.MONTH));
* System.out.println("WEEK_OF_YEAR: " + calendar.get(Calendar.WEEK_OF_YEAR));
* System.out.println("WEEK_OF_MONTH: " + calendar.get(Calendar.WEEK_OF_MONTH));
* System.out.println("DATE: " + calendar.get(Calendar.DATE));
* System.out.println("DAY_OF_MONTH: " + calendar.get(Calendar.DAY_OF_MONTH));
* System.out.println("DAY_OF_YEAR: " + calendar.get(Calendar.DAY_OF_YEAR));
* System.out.println("DAY_OF_WEEK: " + calendar.get(Calendar.DAY_OF_WEEK));
* System.out.println("DAY_OF_WEEK_IN_MONTH: "
*                    + calendar.get(Calendar.DAY_OF_WEEK_IN_MONTH));
* System.out.println("AM_PM: " + calendar.get(Calendar.AM_PM));
* System.out.println("HOUR: " + calendar.get(Calendar.HOUR));
* System.out.println("HOUR_OF_DAY: " + calendar.get(Calendar.HOUR_OF_DAY));
* System.out.println("MINUTE: " + calendar.get(Calendar.MINUTE));
* System.out.println("SECOND: " + calendar.get(Calendar.SECOND));
* System.out.println("MILLISECOND: " + calendar.get(Calendar.MILLISECOND));
* System.out.println("ZONE_OFFSET: "
*        + (calendar.get(Calendar.ZONE_OFFSET)/(60*60*1000))); // in hours
* System.out.println("DST_OFFSET: "
*        + (calendar.get(Calendar.DST_OFFSET)/(60*60*1000))); // in hours
* </pre>
* </blockquote>
*
* @see          TimeZone
* @version      1.92
* @author David Goldsmith, Mark Davis, Chen-Lieh Huang, Alan Liu
* @since JDK1.1
*/
public class GregorianCalendar extends Calendar {
    /*
     * Implementation Notes
     *
     * The epoch is the number of days or milliseconds from some defined
     * starting point. The epoch for java.util.Date is used here; that is,
     * milliseconds from January 1, 1970 (Gregorian), midnight UTC.  Other
     * epochs which are used are January 1, year 1 (Gregorian), which is day 1
     * of the Gregorian calendar, and December 30, year 0 (Gregorian), which is
     * day 1 of the Julian calendar.
     *
     * We implement the proleptic Julian and Gregorian calendars.  This means we
     * implement the modern definition of the calendar even though the
     * historical usage differs.  For example, if the Gregorian change is set
     * to new Date(Long.MIN_VALUE), we have a pure Gregorian calendar which
     * labels dates preceding the invention of the Gregorian calendar in 1582 as
     * if the calendar existed then.
     *
     * Likewise, with the Julian calendar, we assume a consistent
     * 4-year leap year rule, even though the historical pattern of
     * leap years is irregular, being every 3 years from 45 BCE
     * through 9 BCE, then every 4 years from 8 CE onwards, with no
     * leap years in-between.  Thus date computations and functions
     * such as isLeapYear() are not intended to be historically
     * accurate.
     */

//////////////////
// Class Variables
//////////////////

    /**
     * Value of the <code>ERA</code> field indicating
     * the period before the common era (before Christ), also known as BCE.
     * The sequence of years at the transition from <code>BC</code> to <code>AD</code> is
     * ..., 2 BC, 1 BC, 1 AD, 2 AD,...
     *
     * @see #ERA
     */
    public static final int BC = 0;

    /**
     * Value of the {@link #ERA} field indicating
     * the period before the common era, the same value as {@link #BC}.
     *
     * @see #CE
     */
    static final int BCE = 0;

    /**
     * Value of the <code>ERA</code> field indicating
     * the common era (Anno Domini), also known as CE.
     * The sequence of years at the transition from <code>BC</code> to <code>AD</code> is
     * ..., 2 BC, 1 BC, 1 AD, 2 AD,...
     *
     * @see #ERA
     */
    public static final int AD = 1;

    /**
     * Value of the {@link #ERA} field indicating
     * the common era, the same value as {@link #AD}.
     *
     * @see #BCE
     */
    static final int CE = 1;

    private static final int EPOCH_OFFSET   = 719163; // Fixed date of January 1, 1970 (Gregorian)
    private static final int EPOCH_YEAR     = 1970;

    static final int MONTH_LENGTH[]
        = {31,28,31,30,31,30,31,31,30,31,30,31}; // 0-based
    static final int LEAP_MONTH_LENGTH[]
        = {31,29,31,30,31,30,31,31,30,31,30,31}; // 0-based

    // Useful millisecond constants.  Although ONE_DAY and ONE_WEEK can fit
    // into ints, they must be longs in order to prevent arithmetic overflow
    // when performing (bug 4173516).
    private static final int  ONE_SECOND = 1000;
    private static final int  ONE_MINUTE = 60*ONE_SECOND;
    private static final int  ONE_HOUR   = 60*ONE_MINUTE;
    private static final long ONE_DAY    = 24*ONE_HOUR;
    private static final long ONE_WEEK   = 7*ONE_DAY;

    /*
     * <pre>
     *                            Greatest       Least
     * Field name        Minimum   Minimum     Maximum     Maximum
     * ----------        -------   -------     -------     -------
     * ERA                     0         0           1           1
     * YEAR                    1         1   292269054   292278994
     * MONTH                   0         0          11          11
     * WEEK_OF_YEAR            1         1          52*         53
     * WEEK_OF_MONTH           0         0           4*          6
     * DAY_OF_MONTH            1         1          28*         31
     * DAY_OF_YEAR             1         1         365*        366
     * DAY_OF_WEEK             1         1           7           7
     * DAY_OF_WEEK_IN_MONTH   -1        -1           4*          6
     * AM_PM                   0         0           1           1
     * HOUR                    0         0          11          11
     * HOUR_OF_DAY             0         0          23          23
     * MINUTE                  0         0          59          59
     * SECOND                  0         0          59          59
     * MILLISECOND             0         0         999         999
     * ZONE_OFFSET        -13:00    -13:00       14:00       14:00
     * DST_OFFSET           0:00      0:00        0:20        2:00
     * </pre>
     * *: depends on the Gregorian change date
     */
    static final int MIN_VALUES[] = {
        BCE,    // ERA
  1,    // YEAR
  JANUARY,  // MONTH
  1,    // WEEK_OF_YEAR
  0,    // WEEK_OF_MONTH
  1,    // DAY_OF_MONTH
  1,    // DAY_OF_YEAR
  SUNDAY,    // DAY_OF_WEEK
  1,    // DAY_OF_WEEK_IN_MONTH
  AM,    // AM_PM
  0,    // HOUR
  0,    // HOUR_OF_DAY
  0,    // MINUTE
  0,    // SECOND
  0,    // MILLISECOND
  -13*ONE_HOUR,  // ZONE_OFFSET (UNIX compatibility)
  0    // DST_OFFSET
    };
    static final int LEAST_MAX_VALUES[] = {
        CE,    // ERA
  292269054// YEAR
  DECEMBER,  // MONTH
  52,    // WEEK_OF_YEAR
  4,    // WEEK_OF_MONTH
  28,    // DAY_OF_MONTH
  365,    // DAY_OF_YEAR
  SATURDAY,  // DAY_OF_WEEK
  4,    // DAY_OF_WEEK_IN
  PM,    // AM_PM
  11,    // HOUR
  23,    // HOUR_OF_DAY
  59,    // MINUTE
  59,    // SECOND
  999,    // MILLISECOND
  14*ONE_HOUR,  // ZONE_OFFSET
  20*ONE_MINUTE  // DST_OFFSET (historical least maximum)
    };
    static final int MAX_VALUES[] = {
        CE,    // ERA
  292278994// YEAR
  DECEMBER,  // MONTH
  53,    // WEEK_OF_YEAR
  6,    // WEEK_OF_MONTH
  31,    // DAY_OF_MONTH
  366,    // DAY_OF_YEAR
  SATURDAY,  // DAY_OF_WEEK
  6,    // DAY_OF_WEEK_IN
  PM,    // AM_PM
  11,    // HOUR
  23,    // HOUR_OF_DAY
  59,    // MINUTE
  59,    // SECOND
  999,    // MILLISECOND
  14*ONE_HOUR,  // ZONE_OFFSET
  2*ONE_HOUR  // DST_OFFSET (double summer time)
    };

    // Proclaim serialization compatibility with JDK 1.1
    static final long serialVersionUID = -8125100834729963327L;

    // Reference to the sun.util.calendar.Gregorian instance (singleton).
    private static final Gregorian gcal =
        CalendarSystem.getGregorianCalendar();

    // Reference to the JulianCalendar instance (singleton), set as needed. See
    // getJulianCalendarSystem().
    private static JulianCalendar jcal;

    // JulianCalendar eras. See getJulianCalendarSystem().
    private static Era[] jeras;

    // The default value of gregorianCutover.
    static final long DEFAULT_GREGORIAN_CUTOVER = -12219292800000L;

/////////////////////
// Instance Variables
/////////////////////

    /**
     * The point at which the Gregorian calendar rules are used, measured in
     * milliseconds from the standard epoch.  Default is October 15, 1582
     * (Gregorian) 00:00:00 UTC or -12219292800000L.  For this value, October 4,
     * 1582 (Julian) is followed by October 15, 1582 (Gregorian).  This
     * corresponds to Julian day number 2299161.
     * @serial
     */
    private long gregorianCutover = DEFAULT_GREGORIAN_CUTOVER;

    /**
     * The fixed date of the gregorianCutover.
     */
    private transient long gregorianCutoverDate =
      (((DEFAULT_GREGORIAN_CUTOVER + 1)/ONE_DAY) - 1) + EPOCH_OFFSET;  // == 577736

    /**
     * The normalized year of the gregorianCutover in Gregorian, with
     * 0 representing 1 BCE, -1 representing 2 BCE, etc.
     */
    private transient int gregorianCutoverYear = 1582;

    /**
     * The normalized year of the gregorianCutover in Julian, with 0
     * representing 1 BCE, -1 representing 2 BCE, etc.
     */
    private transient int gregorianCutoverYearJulian = 1582;

    /**
     * gdate always has a sun.util.calendar.Gregorian.Date instance to
     * avoid overhead of creating it. The assumption is that most
     * applications will need only Gregorian calendar calculations.
     */
    private transient BaseCalendar.Date gdate;

    /**
     * Reference to either gdate or a JulianCalendar.Date
     * instance. After calling complete(), this value is guaranteed to
     * be set.
     */
    private transient BaseCalendar.Date cdate;

    /**
     * The CalendarSystem used to calculate the date in cdate. After
     * calling complete(), this value is guaranteed to be set and
     * consistent with the cdate value.
     */
    private transient BaseCalendar calsys;

    /**
     * Temporary int[2] to get time zone offsets. zoneOffsets[0] gets
     * the GMT offset value and zoneOffsets[1] gets the DST saving
     * value.
     */
    private transient int[] zoneOffsets;

    /**
     * Temporary storage for saving original fields[] values in
     * non-lenient mode.
     */
    private transient int[] originalFields;

///////////////
// Constructors
///////////////

    /**
     * Constructs a default <code>GregorianCalendar</code> using the current time
     * in the default time zone with the default locale.
     */
    public GregorianCalendar() {
        this(TimeZone.getDefaultRef(), Locale.getDefault());
  setZoneShared(true);
    }

    /**
     * Constructs a <code>GregorianCalendar</code> based on the current time
     * in the given time zone with the default locale.
     *
     * @param zone the given time zone.
     */
    public GregorianCalendar(TimeZone zone) {
        this(zone, Locale.getDefault());
    }

    /**
     * Constructs a <code>GregorianCalendar</code> based on the current time
     * in the default time zone with the given locale.
     *
     * @param aLocale the given locale.
     */
    public GregorianCalendar(Locale aLocale) {
        this(TimeZone.getDefaultRef(), aLocale);
  setZoneShared(true);
    }

    /**
     * Constructs a <code>GregorianCalendar</code> based on the current time
     * in the given time zone with the given locale.
     *
     * @param zone the given time zone.
     * @param aLocale the given locale.
     */
    public GregorianCalendar(TimeZone zone, Locale aLocale) {
        super(zone, aLocale);
  gdate = (BaseCalendar.Date) gcal.newCalendarDate(zone);
        setTimeInMillis(System.currentTimeMillis());
    }

    /**
     * Constructs a <code>GregorianCalendar</code> with the given date set
     * in the default time zone with the default locale.
     *
     * @param year the value used to set the <code>YEAR</code> calendar field in the calendar.
     * @param month the value used to set the <code>MONTH</code> calendar field in the calendar.
     * Month value is 0-based. e.g., 0 for January.
     * @param dayOfMonth the value used to set the <code>DAY_OF_MONTH</code> calendar field in the calendar.
     */
    public GregorianCalendar(int year, int month, int dayOfMonth) {
  this(year, month, dayOfMonth, 0, 0, 0, 0);
    }

    /**
     * Constructs a <code>GregorianCalendar</code> with the given date
     * and time set for the default time zone with the default locale.
     *
     * @param year the value used to set the <code>YEAR</code> calendar field in the calendar.
     * @param month the value used to set the <code>MONTH</code> calendar field in the calendar.
     * Month value is 0-based. e.g., 0 for January.
     * @param dayOfMonth the value used to set the <code>DAY_OF_MONTH</code> calendar field in the calendar.
     * @param hourOfDay the value used to set the <code>HOUR_OF_DAY</code> calendar field
     * in the calendar.
     * @param minute the value used to set the <code>MINUTE</code> calendar field
     * in the calendar.
     */
    public GregorianCalendar(int year, int month, int dayOfMonth, int hourOfDay,
                             int minute) {
  this(year, month, dayOfMonth, hourOfDay, minute, 0, 0);
    }

    /**
     * Constructs a GregorianCalendar with the given date
     * and time set for the default time zone with the default locale.
     *
     * @param year the value used to set the <code>YEAR</code> calendar field in the calendar.
     * @param month the value used to set the <code>MONTH</code> calendar field in the calendar.
     * Month value is 0-based. e.g., 0 for January.
     * @param dayOfMonth the value used to set the <code>DAY_OF_MONTH</code> calendar field in the calendar.
     * @param hourOfDay the value used to set the <code>HOUR_OF_DAY</code> calendar field
     * in the calendar.
     * @param minute the value used to set the <code>MINUTE</code> calendar field
     * in the calendar.
     * @param second the value used to set the <code>SECOND</code> calendar field
     * in the calendar.
     */
    public GregorianCalendar(int year, int month, int dayOfMonth, int hourOfDay,
                             int minute, int second) {
  this(year, month, dayOfMonth, hourOfDay, minute, second, 0);
    }

    /**
     * Constructs a <code>GregorianCalendar</code> with the given date
     * and time set for the default time zone with the default locale.
     *
     * @param year the value used to set the <code>YEAR</code> calendar field in the calendar.
     * @param month the value used to set the <code>MONTH</code> calendar field in the calendar.
     * Month value is 0-based. e.g., 0 for January.
     * @param dayOfMonth the value used to set the <code>DAY_OF_MONTH</code> calendar field in the calendar.
     * @param hourOfDay the value used to set the <code>HOUR_OF_DAY</code> calendar field
     * in the calendar.
     * @param minute the value used to set the <code>MINUTE</code> calendar field
     * in the calendar.
     * @param second the value used to set the <code>SECOND</code> calendar field
     * in the calendar.
     * @param millis the value used to set the <code>MILLISECOND</code> calendar field
     */
    GregorianCalendar(int year, int month, int dayOfMonth,
          int hourOfDay, int minute, int second, int millis) {
        super();
  gdate = (BaseCalendar.Date) gcal.newCalendarDate(getZone());
        this.set(YEAR, year);
        this.set(MONTH, month);
        this.set(DAY_OF_MONTH, dayOfMonth);

  // Set AM_PM and HOUR here to set their stamp values before
  // setting HOUR_OF_DAY (6178071).
  if (hourOfDay >= 12 && hourOfDay <= 23) {
      // If hourOfDay is a valid PM hour, set the correct PM values
      // so that it won't throw an exception in case it's set to
      // non-lenient later.
      this.internalSet(AM_PM, PM);
      this.internalSet(HOUR, hourOfDay - 12);
  } else {
      // The default value for AM_PM is AM.
      // We don't care any out of range value here for leniency.
      this.internalSet(HOUR, hourOfDay);
  }
  // The stamp values of AM_PM and HOUR must be COMPUTED. (6440854)
  setFieldsComputed(HOUR_MASK|AM_PM_MASK);

        this.set(HOUR_OF_DAY, hourOfDay);
        this.set(MINUTE, minute);
        this.set(SECOND, second);
  // should be changed to set() when this constructor is made
  // public.
  this.internalSet(MILLISECOND, millis);
    }
/////////////////
// Public methods
/////////////////

    /**
     * Sets the <code>GregorianCalendar</code> change date. This is the point when the switch
     * from Julian dates to Gregorian dates occurred. Default is October 15,
     * 1582 (Gregorian). Previous to this, dates will be in the Julian calendar.
     * <p>
     * To obtain a pure Julian calendar, set the change date to
     * <code>Date(Long.MAX_VALUE)</code>.  To obtain a pure Gregorian calendar,
     * set the change date to <code>Date(Long.MIN_VALUE)</code>.
     *
     * @param date the given Gregorian cutover date.
     */
    public void setGregorianChange(Date date) {
  long cutoverTime = date.getTime();
  if (cutoverTime == gregorianCutover) {
      return;
  }
  // Before changing the cutover date, make sure to have the
  // time of this calendar.
  complete();
  setGregorianChange(cutoverTime);
    }

    private void setGregorianChange(long cutoverTime) {
        gregorianCutover = cutoverTime;
        gregorianCutoverDate = CalendarUtils.floorDivide(cutoverTime, ONE_DAY)
        + EPOCH_OFFSET;

  // To provide the "pure" Julian calendar as advertised.
  // Strictly speaking, the last millisecond should be a
  // Gregorian date. However, the API doc specifies that setting
  // the cutover date to Long.MAX_VALUE will make this calendar
  // a pure Julian calendar. (See 4167995)
  if (cutoverTime == Long.MAX_VALUE) {
      gregorianCutoverDate++;
  }

  BaseCalendar.Date d = getGregorianCutoverDate();

  // Set the cutover year (in the Gregorian year numbering)
        gregorianCutoverYear = d.getYear();

  BaseCalendar jcal = getJulianCalendarSystem();
  d = (BaseCalendar.Date) jcal.newCalendarDate(TimeZone.NO_TIMEZONE);
  jcal.getCalendarDateFromFixedDate(d, gregorianCutoverDate - 1);
  gregorianCutoverYearJulian = d.getNormalizedYear();

  if (time < gregorianCutover) {
      // The field values are no longer valid under the new
      // cutover date.
      setUnnormalized();
  }
    }

    /**
     * Gets the Gregorian Calendar change date.  This is the point when the
     * switch from Julian dates to Gregorian dates occurred. Default is
     * October 15, 1582 (Gregorian). Previous to this, dates will be in the Julian
     * calendar.
     *
     * @return the Gregorian cutover date for this <code>GregorianCalendar</code> object.
     */
    public final Date getGregorianChange() {
        return new Date(gregorianCutover);
    }

    /**
     * Determines if the given year is a leap year. Returns <code>true</code> if
     * the given year is a leap year. To specify BC year numbers,
     * <code>1 - year number</code> must be given. For example, year BC 4 is
     * specified as -3.
     *
     * @param year the given year.
     * @return <code>true</code> if the given year is a leap year; <code>false</code> otherwise.
     */
    public boolean isLeapYear(int year) {
  if ((year & 3) != 0) {
      return false;
  }

        if (year > gregorianCutoverYear) {
            return (year%100 != 0) || (year%400 == 0); // Gregorian
  }
  if (year < gregorianCutoverYearJulian) {
            return true; // Julian
  }
  boolean gregorian;
  // If the given year is the Gregorian cutover year, we need to
  // determine which calendar system to be applied to February in the year.
  if (gregorianCutoverYear == gregorianCutoverYearJulian) {
      BaseCalendar.Date d = getCalendarDate(gregorianCutoverDate); // Gregorian
      gregorian = d.getMonth() < BaseCalendar.MARCH;
  } else {
      gregorian = year == gregorianCutoverYear;
  }
  return gregorian ? (year%100 != 0) || (year%400 == 0) : true;
    }

    /**
     * Compares this <code>GregorianCalendar</code> to the specified
     * <code>Object</code>. The result is <code>true</code> if and
     * only if the argument is a <code>GregorianCalendar</code> object
     * that represents the same time value (millisecond offset from
     * the <a href="Calendar.html#Epoch">Epoch</a>) under the same
     * <code>Calendar</code> parameters and Gregorian change date as
     * this object.
     *
     * @param obj the object to compare with.
     * @return <code>true</code> if this object is equal to <code>obj</code>;
     * <code>false</code> otherwise.
     * @see Calendar#compareTo(Calendar)
     */
    public boolean equals(Object obj) {
        return obj instanceof GregorianCalendar &&
      super.equals(obj) &&
            gregorianCutover == ((GregorianCalendar)obj).gregorianCutover;
    }
   
    /**
     * Generates the hash code for this <code>GregorianCalendar</code> object.
     */
    public int hashCode() {
        return super.hashCode() ^ (int)gregorianCutoverDate;
    }

    /**
     * Adds the specified (signed) amount of time to the given calendar field,
     * based on the calendar's rules.
     *
     * <p><em>Add rule 1</em>. The value of <code>field</code>
     * after the call minus the value of <code>field</code> before the
     * call is <code>amount</code>, modulo any overflow that has occurred in
     * <code>field</code>. Overflow occurs when a field value exceeds its
     * range and, as a result, the next larger field is incremented or
     * decremented and the field value is adjusted back into its range.</p>
     *
     * <p><em>Add rule 2</em>. If a smaller field is expected to be
     * invariant, but it is impossible for it to be equal to its
     * prior value because of changes in its minimum or maximum after
     * <code>field</code> is changed, then its value is adjusted to be as close
     * as possible to its expected value. A smaller field represents a
     * smaller unit of time. <code>HOUR</code> is a smaller field than
     * <code>DAY_OF_MONTH</code>. No adjustment is made to smaller fields
     * that are not expected to be invariant. The calendar system
     * determines what fields are expected to be invariant.</p>
     *
     * @param field the calendar field.
     * @param amount the amount of date or time to be added to the field.
     * @exception IllegalArgumentException if <code>field</code> is
     * <code>ZONE_OFFSET</code>, <code>DST_OFFSET</code>, or unknown,
     * or if any calendar fields have out-of-range values in
     * non-lenient mode.
     */
    public void add(int field, int amount) {
  // If amount == 0, do nothing even the given field is out of
  // range. This is tested by JCK.
        if (amount == 0) {
      return;   // Do nothing!
  }

  if (field < 0 || field >= ZONE_OFFSET) {
      throw new IllegalArgumentException();
  }

  // Sync the time and calendar fields.
        complete();

        if (field == YEAR) {
            int year = internalGet(YEAR);
            if (internalGetEra() == CE) {
                year += amount;
                if (year > 0) {
                    set(YEAR, year);
                } else { // year <= 0
                    set(YEAR, 1 - year);
                    // if year == 0, you get 1 BCE.
                    set(ERA, BCE);
                }
            }
            else { // era == BCE
                year -= amount;
                if (year > 0) {
                    set(YEAR, year);
                } else { // year <= 0
                    set(YEAR, 1 - year);
                    // if year == 0, you get 1 CE
                    set(ERA, CE);
                }
            }
            pinDayOfMonth();
        } else if (field == MONTH) {
            int month = internalGet(MONTH) + amount;
      int year = internalGet(YEAR);
      int y_amount;

      if (month >= 0) {
                y_amount = month/12;
      } else {
                y_amount = (month+1)/12 - 1;
      }
      if (y_amount != 0) {
                if (internalGetEra() == CE) {
                    year += y_amount;
                    if (year > 0) {
                        set(YEAR, year);
                    } else { // year <= 0
                        set(YEAR, 1 - year);
                        // if year == 0, you get 1 BCE
                        set(ERA, BCE);
                    }
                }
                else { // era == BCE
                    year -= y_amount;
                    if (year > 0) {
                        set(YEAR, year);
                    } else { // year <= 0
                        set(YEAR, 1 - year);
                        // if year == 0, you get 1 CE
                        set(ERA, CE);
                    }
                }
            }

            if (month >= 0) {
                set(MONTH, (int) (month % 12));
            } else {
    // month < 0
                month %= 12;
                if (month < 0) {
        month += 12;
    }
                set(MONTH, JANUARY + month);
            }
            pinDayOfMonth();
        } else if (field == ERA) {
            int era = internalGet(ERA) + amount;
            if (era < 0) {
    era = 0;
      }
            if (era > 1) {
    era = 1;
      }
            set(ERA, era);
        } else {
      long delta = amount;
      long timeOfDay = 0;
      switch (field) {
      // Handle the time fields here. Convert the given
      // amount to milliseconds and call setTimeInMillis.
            case HOUR:
            case HOUR_OF_DAY:
                delta *= 60 * 60 * 1000// hours to minutes
                break;

            case MINUTE:
                delta *= 60 * 1000;    // minutes to seconds
                break;

            case SECOND:
                delta *= 1000;      // seconds to milliseconds
                break;

            case MILLISECOND:
                break;

      // Handle week, day and AM_PM fields which involves
      // time zone offset change adjustment. Convert the
      // given amount to the number of days.
            case WEEK_OF_YEAR:
            case WEEK_OF_MONTH:
            case DAY_OF_WEEK_IN_MONTH:
                delta *= 7;
    break;

            case DAY_OF_MONTH: // synonym of DATE
            case DAY_OF_YEAR:
            case DAY_OF_WEEK:
    break;

      case AM_PM:
    // Convert the amount to the number of days (delta)
    // and +12 or -12 hours (timeOfDay).
    delta = amount / 2;
    timeOfDay = 12 * (amount % 2);
    break;
      }

      // The time fields don't require time zone offset change
      // adjustment.
      if (field >= HOUR) {
    setTimeInMillis(time + delta);
    return;
      }

      // The rest of the fields (week, day or AM_PM fields)
      // require time zone offset (both GMT and DST) change
      // adjustment.

      // Translate the current time to the fixed date and time
      // of the day.
      long fd = getCurrentFixedDate();
      timeOfDay += internalGet(HOUR_OF_DAY);
      timeOfDay *= 60;
      timeOfDay += internalGet(MINUTE);
      timeOfDay *= 60;
      timeOfDay += internalGet(SECOND);
      timeOfDay *= 1000;
      timeOfDay += internalGet(MILLISECOND);
      if (timeOfDay >= ONE_DAY) {
    fd++;
    timeOfDay -= ONE_DAY;
      } else if (timeOfDay < 0) {
    fd--;
    timeOfDay += ONE_DAY;
      }

      fd += delta; // fd is the expected fixed date after the calculation
      int zoneOffset = internalGet(ZONE_OFFSET) + internalGet(DST_OFFSET);
      setTimeInMillis((fd - EPOCH_OFFSET) * ONE_DAY + timeOfDay - zoneOffset);
      zoneOffset -= internalGet(ZONE_OFFSET) + internalGet(DST_OFFSET);
      // If the time zone offset has changed, then adjust the difference.
      if (zoneOffset != 0) {
    setTimeInMillis(time + zoneOffset);
    long fd2 = getCurrentFixedDate();
    // If the adjustment has changed the date, then take
    // the previous one.
    if (fd2 != fd) {
        setTimeInMillis(time - zoneOffset);
    }
      }
  }
    }

    /**
     * Adds or subtracts (up/down) a single unit of time on the given time
     * field without changing larger fields.
     * <p>
     * <em>Example</em>: Consider a <code>GregorianCalendar</code>
     * originally set to December 31, 1999. Calling {@link #roll(int,boolean) roll(Calendar.MONTH, true)}
     * sets the calendar to January 31, 1999.  The <code>YEAR</code> field is unchanged
     * because it is a larger field than <code>MONTH</code>.</p>
     *
     * @param up indicates if the value of the specified calendar field is to be
     * rolled up or rolled down. Use <code>true</code> if rolling up, <code>false</code> otherwise.
     * @exception IllegalArgumentException if <code>field</code> is
     * <code>ZONE_OFFSET</code>, <code>DST_OFFSET</code>, or unknown,
     * or if any calendar fields have out-of-range values in
     * non-lenient mode.
     * @see #add(int,int)
     * @see #set(int,int)
     */
    public void roll(int field, boolean up) {
        roll(field, up ? +1 : -1);
    }

    /**
     * Adds a signed amount to the specified calendar field without changing larger fields.
     * A negative roll amount means to subtract from field without changing
     * larger fields. If the specified amount is 0, this method performs nothing.
     *
     * <p>This method calls {@link #complete()} before adding the
     * amount so that all the calendar fields are normalized. If there
     * is any calendar field having an out-of-range value in non-lenient mode, then an
     * <code>IllegalArgumentException</code> is thrown.
     *
     * <p>
     * <em>Example</em>: Consider a <code>GregorianCalendar</code>
     * originally set to August 31, 1999. Calling <code>roll(Calendar.MONTH,
     * 8)</code> sets the calendar to April 30, <strong>1999</strong>. Using a
     * <code>GregorianCalendar</code>, the <code>DAY_OF_MONTH</code> field cannot
     * be 31 in the month April. <code>DAY_OF_MONTH</code> is set to the closest possible
     * value, 30. The <code>YEAR</code> field maintains the value of 1999 because it
     * is a larger field than <code>MONTH</code>.
     * <p>
     * <em>Example</em>: Consider a <code>GregorianCalendar</code>
     * originally set to Sunday June 6, 1999. Calling
     * <code>roll(Calendar.WEEK_OF_MONTH, -1)</code> sets the calendar to
     * Tuesday June 1, 1999, whereas calling
     * <code>add(Calendar.WEEK_OF_MONTH, -1)</code> sets the calendar to
     * Sunday May 30, 1999. This is because the roll rule imposes an
     * additional constraint: The <code>MONTH</code> must not change when the
     * <code>WEEK_OF_MONTH</code> is rolled. Taken together with add rule 1,
     * the resultant date must be between Tuesday June 1 and Saturday June
     * 5. According to add rule 2, the <code>DAY_OF_WEEK</code>, an invariant
     * when changing the <code>WEEK_OF_MONTH</code>, is set to Tuesday, the
     * closest possible value to Sunday (where Sunday is the first day of the
     * week).</p>
     *
     * @param field the calendar field.
     * @param amount the signed amount to add to <code>field</code>.
     * @exception IllegalArgumentException if <code>field</code> is
     * <code>ZONE_OFFSET</code>, <code>DST_OFFSET</code>, or unknown,
     * or if any calendar fields have out-of-range values in
     * non-lenient mode.
     * @see #roll(int,boolean)
     * @see #add(int,int)
     * @see #set(int,int)
     * @since 1.2
     */
    public void roll(int field, int amount) {
  // If amount == 0, do nothing even the given field is out of
  // range. This is tested by JCK.
        if (amount == 0) {
      return;
  }

  if (field < 0 || field >= ZONE_OFFSET) {
      throw new IllegalArgumentException();
  }

  // Sync the time and calendar fields.
  complete();

  int min = getMinimum(field);
  int max = getMaximum(field);

        switch (field) {
        case AM_PM:
        case ERA:
        case YEAR:
        case MINUTE:
        case SECOND:
        case MILLISECOND:
            // These fields are handled simply, since they have fixed minima
            // and maxima.  The field DAY_OF_MONTH is almost as simple.  Other
            // fields are complicated, since the range within they must roll
            // varies depending on the date.
            break;

        case HOUR:
        case HOUR_OF_DAY:
      {
    int unit = max + 1; // 12 or 24 hours
    int h = internalGet(field);
    int nh = (h + amount) % unit;
    if (nh < 0) {
        nh += unit;
    }
    time += ONE_HOUR * (nh - h);

    // The day might have changed, which could happen if
    // the daylight saving time transition brings it to
    // the next day, although it's very unlikely. But we
    // have to make sure not to change the larger fields.
    CalendarDate d = calsys.getCalendarDate(time, getZone());
    if (internalGet(DAY_OF_MONTH) != d.getDayOfMonth()) {
        d.setDate(internalGet(YEAR),
            internalGet(MONTH) + 1,
            internalGet(DAY_OF_MONTH));
        if (field == HOUR) {
      assert (internalGet(AM_PM) == PM);
      d.addHours(+12); // restore PM
        }
        time = calsys.getTime(d);
    }
    int hourOfDay = d.getHours();
    internalSet(field, hourOfDay % unit);
    if (field == HOUR) {
        internalSet(HOUR_OF_DAY, hourOfDay);
    } else {
        internalSet(AM_PM, hourOfDay / 12);
        internalSet(HOUR, hourOfDay % 12);
    }

    // Time zone offset and/or daylight saving might have changed.
    int zoneOffset = d.getZoneOffset();
    int saving = d.getDaylightSaving();
    internalSet(ZONE_OFFSET, zoneOffset - saving);
    internalSet(DST_OFFSET, saving);
    return;
      }

        case MONTH:
            // Rolling the month involves both pinning the final value to [0, 11]
            // and adjusting the DAY_OF_MONTH if necessary.  We only adjust the
            // DAY_OF_MONTH if, after updating the MONTH field, it is illegal.
            // E.g., <jan31>.roll(MONTH, 1) -> <feb28> or <feb29>.
            {
    if (!isCutoverYear(cdate.getNormalizedYear())) {
        int mon = (internalGet(MONTH) + amount) % 12;
        if (mon < 0) {
      mon += 12;
        }
        set(MONTH, mon);
               
        // Keep the day of month in the range.  We don't want to spill over
        // into the next month; e.g., we don't want jan31 + 1 mo -> feb31 ->
        // mar3.
        int monthLen = monthLength(mon);
        if (internalGet(DAY_OF_MONTH) > monthLen) {
      set(DAY_OF_MONTH, monthLen);
        }
    } else {
        // We need to take care of different lengths in
        // year and month due to the cutover.
        int yearLength = getActualMaximum(MONTH) + 1;
        int mon = (internalGet(MONTH) + amount) % yearLength;
        if (mon < 0) {
      mon += yearLength;
        }
        set(MONTH, mon);
        int monthLen = getActualMaximum(DAY_OF_MONTH);
        if (internalGet(DAY_OF_MONTH) > monthLen) {
      set(DAY_OF_MONTH, monthLen);
        }
    }
    return;
            }

        case WEEK_OF_YEAR:
      {
    int y = cdate.getNormalizedYear();
    max = getActualMaximum(WEEK_OF_YEAR);
    set(DAY_OF_WEEK, internalGet(DAY_OF_WEEK));
    int woy = internalGet(WEEK_OF_YEAR);
    int value = woy + amount;
    if (!isCutoverYear(y)) {
        // If the new value is in between min and max
        // (exclusive), then we can use the value.
        if (value > min && value < max) {
      set(WEEK_OF_YEAR, value);
      return;
        }
        long fd = getCurrentFixedDate();
        // Make sure that the min week has the current DAY_OF_WEEK
        long day1 = fd - (7 * (woy - min));
        if (calsys.getYearFromFixedDate(day1) != y) {
      min++;
        }

        // Make sure the same thing for the max week
        fd += 7 * (max - internalGet(WEEK_OF_YEAR));
        if (calsys.getYearFromFixedDate(fd) != y) {
      max--;
        }
        break;
    }

    // Handle cutover here.
    long fd = getCurrentFixedDate();
    BaseCalendar cal;
    if (gregorianCutoverYear == gregorianCutoverYearJulian) {
        cal = getCutoverCalendarSystem();
    } else if (y == gregorianCutoverYear) {
        cal = gcal;
    } else {
        cal = getJulianCalendarSystem();
    }
    long day1 = fd - (7 * (woy - min));
    // Make sure that the min week has the current DAY_OF_WEEK
    if (cal.getYearFromFixedDate(day1) != y) {
        min++;
    }

    // Make sure the same thing for the max week
    fd += 7 * (max - woy);
    cal = (fd >= gregorianCutoverDate) ? gcal : getJulianCalendarSystem();
    if (cal.getYearFromFixedDate(fd) != y) {
        max--;
    }
    // value: the new WEEK_OF_YEAR which must be converted
    // to month and day of month.
    value = getRolledValue(woy, amount, min, max) - 1;
    BaseCalendar.Date d = getCalendarDate(day1 + value * 7);
    set(MONTH, d.getMonth() - 1);
    set(DAY_OF_MONTH, d.getDayOfMonth());
    return;
      }

        case WEEK_OF_MONTH:
      {
    boolean isCutoverYear = isCutoverYear(cdate.getNormalizedYear());
    // dow: relative day of week from first day of week
    int dow = internalGet(DAY_OF_WEEK) - getFirstDayOfWeek();
    if (dow < 0) {
        dow += 7;
    }

    long fd = getCurrentFixedDate();
    long month1;   // fixed date of the first day (usually 1) of the month
    int monthLength; // actual month length
    if (isCutoverYear) {
        month1 = getFixedDateMonth1(cdate, fd);
        monthLength = actualMonthLength();
    } else {
        month1 = fd - internalGet(DAY_OF_MONTH) + 1;
        monthLength = calsys.getMonthLength(cdate);
    }

    // the first day of week of the month.
    long monthDay1st = calsys.getDayOfWeekDateOnOrBefore(month1 + 6,
                     getFirstDayOfWeek());
    // if the week has enough days to form a week, the
    // week starts from the previous month.
    if ((int)(monthDay1st - month1) >= getMinimalDaysInFirstWeek()) {
        monthDay1st -= 7;
    }
    max = getActualMaximum(field);

    // value: the new WEEK_OF_MONTH value
    int value = getRolledValue(internalGet(field), amount, 1, max) - 1;

    // nfd: fixed date of the rolled date
    long nfd = monthDay1st + value * 7 + dow;

    // Unlike WEEK_OF_YEAR, we need to change day of week if the
    // nfd is out of the month.
    if (nfd < month1) {
        nfd = month1;
    } else if (nfd >= (month1 + monthLength)) {
        nfd = month1 + monthLength - 1;
    }
    int dayOfMonth;
    if (isCutoverYear) {
        // If we are in the cutover year, convert nfd to
        // its calendar date and use dayOfMonth.
        BaseCalendar.Date d = getCalendarDate(nfd);
        dayOfMonth = d.getDayOfMonth();
    } else {
        dayOfMonth = (int)(nfd - month1) + 1;
    }
    set(DAY_OF_MONTH, dayOfMonth);
    return;
      }

        case DAY_OF_MONTH:
      {
    if (!isCutoverYear(cdate.getNormalizedYear())) {
        max = calsys.getMonthLength(cdate);
        break;
    }

    // Cutover year handling
    long fd = getCurrentFixedDate();
    long month1 = getFixedDateMonth1(cdate, fd);
    // It may not be a regular month. Convert the date and range to
    // the relative values, perform the roll, and
    // convert the result back to the rolled date.
    int value = getRolledValue((int)(fd - month1), amount, 0, actualMonthLength() - 1);
    BaseCalendar.Date d = getCalendarDate(month1 + value);
    assert d.getMonth()-1 == internalGet(MONTH);
    set(DAY_OF_MONTH, d.getDayOfMonth());
    return;
      }

        case DAY_OF_YEAR:
      {
    max = getActualMaximum(field);
    if (!isCutoverYear(cdate.getNormalizedYear())) {
        break;
    }

    // Handle cutover here.
    long fd = getCurrentFixedDate();
    long jan1 = fd - internalGet(DAY_OF_YEAR) + 1;
    int value = getRolledValue((int)(fd - jan1) + 1, amount, min, max);
    BaseCalendar.Date d = getCalendarDate(jan1 + value - 1);
    set(MONTH, d.getMonth() - 1);
    set(DAY_OF_MONTH, d.getDayOfMonth());
    return;
      }

        case DAY_OF_WEEK:
      {
    if (!isCutoverYear(cdate.getNormalizedYear())) {
        // If the week of year is in the same year, we can
        // just change DAY_OF_WEEK.
        int weekOfYear = internalGet(WEEK_OF_YEAR);
        if (weekOfYear > 1 && weekOfYear < 52) {
      set(WEEK_OF_YEAR, weekOfYear); // update stamp[WEEK_OF_YEAR]
      max = SATURDAY;
      break;
        }
    }

    // We need to handle it in a different way around year
    // boundaries and in the cutover year. Note that
    // changing era and year values violates the roll
    // rule: not changing larger calendar fields...
    amount %= 7;
    if (amount == 0) {
        return;
    }
    long fd = getCurrentFixedDate();
    long dowFirst = calsys.getDayOfWeekDateOnOrBefore(fd, getFirstDayOfWeek());
    fd += amount;
    if (fd < dowFirst) {
        fd += 7;
    } else if (fd >= dowFirst + 7) {
        fd -= 7;
    }
    BaseCalendar.Date d = getCalendarDate(fd);
    set(ERA, (d.getNormalizedYear() <= 0 ? BCE : CE));
    set(d.getYear(), d.getMonth() - 1, d.getDayOfMonth());
    return;
      }

        case DAY_OF_WEEK_IN_MONTH:
            {
    min = 1; // after normalized, min should be 1.
    if (!isCutoverYear(cdate.getNormalizedYear())) {
        int dom = internalGet(DAY_OF_MONTH);
        int monthLength = calsys.getMonthLength(cdate);
        int lastDays = monthLength % 7;
        max = monthLength / 7;
        int x = (dom - 1) % 7;
        if (x < lastDays) {
      max++;
        }
        set(DAY_OF_WEEK, internalGet(DAY_OF_WEEK));
        break;
    }

    // Cutover year handling
    long fd = getCurrentFixedDate();
    long month1 = getFixedDateMonth1(cdate, fd);
    int monthLength = actualMonthLength();
    int lastDays = monthLength % 7;
    max = monthLength / 7;
    int x = (int)(fd - month1) % 7;
    if (x < lastDays) {
        max++;
    }
    int value = getRolledValue(internalGet(field), amount, min, max) - 1;
    fd = month1 + value * 7 + x;
    BaseCalendar cal = (fd >= gregorianCutoverDate) ? gcal : getJulianCalendarSystem();
    BaseCalendar.Date d = (BaseCalendar.Date) cal.newCalendarDate(TimeZone.NO_TIMEZONE);
    cal.getCalendarDateFromFixedDate(d, fd);
    set(DAY_OF_MONTH, d.getDayOfMonth());
    return;
            }
  }

  set(field, getRolledValue(internalGet(field), amount, min, max));
    }

    /**
     * Returns the minimum value for the given calendar field of this
     * <code>GregorianCalendar</code> instance. The minimum value is
     * defined as the smallest value returned by the {@link
     * Calendar#get(int) get} method for any possible time value,
     * taking into consideration the current values of the
     * {@link Calendar#getFirstDayOfWeek() getFirstDayOfWeek},
     * {@link Calendar#getMinimalDaysInFirstWeek() getMinimalDaysInFirstWeek},
     * {@link #getGregorianChange() getGregorianChange} and
     * {@link Calendar#getTimeZone() getTimeZone} methods.
     *
     * @param field the calendar field.
     * @return the minimum value for the given calendar field.
     * @see #getMaximum(int)
     * @see #getGreatestMinimum(int)
     * @see #getLeastMaximum(int)
     * @see #getActualMinimum(int)
     * @see #getActualMaximum(int)
     */
    public int getMinimum(int field) {
        return MIN_VALUES[field];
    }

    /**
     * Returns the maximum value for the given calendar field of this
     * <code>GregorianCalendar</code> instance. The maximum value is
     * defined as the largest value returned by the {@link
     * Calendar#get(int) get} method for any possible time value,
     * taking into consideration the current values of the
     * {@link Calendar#getFirstDayOfWeek() getFirstDayOfWeek},
     * {@link Calendar#getMinimalDaysInFirstWeek() getMinimalDaysInFirstWeek},
     * {@link #getGregorianChange() getGregorianChange} and
     * {@link Calendar#getTimeZone() getTimeZone} methods.
     *
     * @param field the calendar field.
     * @return the maximum value for the given calendar field.
     * @see #getMinimum(int)
     * @see #getGreatestMinimum(int)
     * @see #getLeastMaximum(int)
     * @see #getActualMinimum(int)
     * @see #getActualMaximum(int)
     */
    public int getMaximum(int field) {
  switch (field) {
  case MONTH:
        case DAY_OF_MONTH:
        case DAY_OF_YEAR:
        case WEEK_OF_YEAR:
        case WEEK_OF_MONTH:
        case DAY_OF_WEEK_IN_MONTH:
  case YEAR:
      {
    // On or after Gregorian 200-3-1, Julian and Gregorian
    // calendar dates are the same or Gregorian dates are
    // larger (i.e., there is a "gap") after 300-3-1.
    if (gregorianCutoverYear > 200) {
        break;
    }
    // There might be "overlapping" dates.
    GregorianCalendar gc = (GregorianCalendar) clone();
    gc.setLenient(true);
    gc.setTimeInMillis(gregorianCutover);
    int v1 = gc.getActualMaximum(field);
    gc.setTimeInMillis(gregorianCutover-1);
    int v2 = gc.getActualMaximum(field);
    return Math.max(MAX_VALUES[field], Math.max(v1, v2));
      }
  }
        return MAX_VALUES[field];
    }

    /**
     * Returns the highest minimum value for the given calendar field
     * of this <code>GregorianCalendar</code> instance. The highest
     * minimum value is defined as the largest value returned by
     * {@link #getActualMinimum(int)} for any possible time value,
     * taking into consideration the current values of the
     * {@link Calendar#getFirstDayOfWeek() getFirstDayOfWeek},
     * {@link Calendar#getMinimalDaysInFirstWeek() getMinimalDaysInFirstWeek},
     * {@link #getGregorianChange() getGregorianChange} and
     * {@link Calendar#getTimeZone() getTimeZone} methods.
     *
     * @param field the calendar field.
     * @return the highest minimum value for the given calendar field.
     * @see #getMinimum(int)
     * @see #getMaximum(int)
     * @see #getLeastMaximum(int)
     * @see #getActualMinimum(int)
     * @see #getActualMaximum(int)
     */
    public int getGreatestMinimum(int field) {
  if (field == DAY_OF_MONTH) {
      BaseCalendar.Date d = getGregorianCutoverDate();
      long mon1 = getFixedDateMonth1(d, gregorianCutoverDate);
      d = getCalendarDate(mon1);
      return Math.max(MIN_VALUES[field], d.getDayOfMonth());
  }
        return MIN_VALUES[field];
    }

    /**
     * Returns the lowest maximum value for the given calendar field
     * of this <code>GregorianCalendar</code> instance. The lowest
     * maximum value is defined as the smallest value returned by
     * {@link #getActualMaximum(int)} for any possible time value,
     * taking into consideration the current values of the
     * {@link Calendar#getFirstDayOfWeek() getFirstDayOfWeek},
     * {@link Calendar#getMinimalDaysInFirstWeek() getMinimalDaysInFirstWeek},
     * {@link #getGregorianChange() getGregorianChange} and
     * {@link Calendar#getTimeZone() getTimeZone} methods.
     *
     * @param field the calendar field
     * @return the lowest maximum value for the given calendar field.
     * @see #getMinimum(int)
     * @see #getMaximum(int)
     * @see #getGreatestMinimum(int)
     * @see #getActualMinimum(int)
     * @see #getActualMaximum(int)
     */
    public int getLeastMaximum(int field) {
  switch (field) {
  case MONTH:
        case DAY_OF_MONTH:
        case DAY_OF_YEAR:
        case WEEK_OF_YEAR:
        case WEEK_OF_MONTH:
        case DAY_OF_WEEK_IN_MONTH:
  case YEAR:
      {
    GregorianCalendar gc = (GregorianCalendar) clone();
    gc.setLenient(true);
    gc.setTimeInMillis(gregorianCutover);
    int v1 = gc.getActualMaximum(field);
    gc.setTimeInMillis(gregorianCutover-1);
    int v2 = gc.getActualMaximum(field);
    return Math.min(LEAST_MAX_VALUES[field], Math.min(v1, v2));
      }
  }
        return LEAST_MAX_VALUES[field];
    }

    /**
     * Returns the minimum value that this calendar field could have,
     * taking into consideration the given time value and the current
     * values of the
     * {@link Calendar#getFirstDayOfWeek() getFirstDayOfWeek},
     * {@link Calendar#getMinimalDaysInFirstWeek() getMinimalDaysInFirstWeek},
     * {@link #getGregorianChange() getGregorianChange} and
     * {@link Calendar#getTimeZone() getTimeZone} methods.
     *
     * <p>For example, if the Gregorian change date is January 10,
     * 1970 and the date of this <code>GregorianCalendar</code> is
     * January 20, 1970, the actual minimum value of the
     * <code>DAY_OF_MONTH</code> field is 10 because the previous date
     * of January 10, 1970 is December 27, 1996 (in the Julian
     * calendar). Therefore, December 28, 1969 to January 9, 1970
     * don't exist.
     *
     * @param field the calendar field
     * @return the minimum of the given field for the time value of
     * this <code>GregorianCalendar</code>
     * @see #getMinimum(int)
     * @see #getMaximum(int)
     * @see #getGreatestMinimum(int)
     * @see #getLeastMaximum(int)
     * @see #getActualMaximum(int)
     * @since 1.2
     */
    public int getActualMinimum(int field) {
  if (field == DAY_OF_MONTH) {
      GregorianCalendar gc = getNormalizedCalendar();
      int year = gc.cdate.getNormalizedYear();
      if (year == gregorianCutoverYear || year == gregorianCutoverYearJulian) {
    long month1 = getFixedDateMonth1(gc.cdate, gc.calsys.getFixedDate(gc.cdate));
    BaseCalendar.Date d = getCalendarDate(month1);
    return d.getDayOfMonth();
      }
  }
        return getMinimum(field);
    }

    /**
     * Returns the maximum value that this calendar field could have,
     * taking into consideration the given time value and the current
     * values of the
     * {@link Calendar#getFirstDayOfWeek() getFirstDayOfWeek},
     * {@link Calendar#getMinimalDaysInFirstWeek() getMinimalDaysInFirstWeek},
     * {@link #getGregorianChange() getGregorianChange} and
     * {@link Calendar#getTimeZone() getTimeZone} methods.
     * For example, if the date of this instance is February 1, 2004,
     * the actual maximum value of the <code>DAY_OF_MONTH</code> field
     * is 29 because 2004 is a leap year, and if the date of this
     * instance is February 1, 2005, it's 28.
     *
     * @param field the calendar field
     * @return the maximum of the given field for the time value of
     * this <code>GregorianCalendar</code>
     * @see #getMinimum(int)
     * @see #getMaximum(int)
     * @see #getGreatestMinimum(int)
     * @see #getLeastMaximum(int)
     * @see #getActualMinimum(int)
     * @since 1.2
     */
    public int getActualMaximum(int field) {
  final int fieldsForFixedMax = ERA_MASK|DAY_OF_WEEK_MASK|HOUR_MASK|AM_PM_MASK|
      HOUR_OF_DAY_MASK|MINUTE_MASK|SECOND_MASK|MILLISECOND_MASK|
      ZONE_OFFSET_MASK|DST_OFFSET_MASK;
  if ((fieldsForFixedMax & (1<<field)) != 0) {
      return getMaximum(field);
  }

  GregorianCalendar gc = getNormalizedCalendar();
  BaseCalendar.Date date = gc.cdate;
  BaseCalendar cal = gc.calsys;
  int normalizedYear = date.getNormalizedYear();

  int value = -1;
        switch (field) {
  case MONTH:
      {
    if (!gc.isCutoverYear(normalizedYear)) {
        value = DECEMBER;
        break;
    }

    // January 1 of the next year may or may not exist.
    long nextJan1;
    do {
        nextJan1 = gcal.getFixedDate(++normalizedYear, BaseCalendar.JANUARY, 1, null);
    } while (nextJan1 < gregorianCutoverDate);
    BaseCalendar.Date d = (BaseCalendar.Date) date.clone();
    cal.getCalendarDateFromFixedDate(d, nextJan1 - 1);
    value = d.getMonth() - 1;
      }
      break;

        case DAY_OF_MONTH:
      {
    value = cal.getMonthLength(date);
    if (!gc.isCutoverYear(normalizedYear) || date.getDayOfMonth() == value) {
        break;
    }

    // Handle cutover year.
    long fd = gc.getCurrentFixedDate();
    if (fd >= gregorianCutoverDate) {
        break;
    }
    int monthLength = gc.actualMonthLength();
    long monthEnd = gc.getFixedDateMonth1(gc.cdate, fd) + monthLength - 1;
    // Convert the fixed date to its calendar date.
    BaseCalendar.Date d = gc.getCalendarDate(monthEnd);
    value = d.getDayOfMonth();
      }       
      break;

        case DAY_OF_YEAR:
      {
    if (!gc.isCutoverYear(normalizedYear)) {
        value = cal.getYearLength(date);
        break;
    }

    // Handle cutover year.
    long jan1;
    if (gregorianCutoverYear == gregorianCutoverYearJulian) {
        BaseCalendar cocal = gc.getCutoverCalendarSystem();
        jan1 = cocal.getFixedDate(normalizedYear, 1, 1, null);
    } else if (normalizedYear == gregorianCutoverYearJulian) {
        jan1 = cal.getFixedDate(normalizedYear, 1, 1, null);
    } else {
        jan1 = gregorianCutoverDate;
    }
    // January 1 of the next year may or may not exist.
    long nextJan1 = gcal.getFixedDate(++normalizedYear, 1, 1, null);
    if (nextJan1 < gregorianCutoverDate) {
        nextJan1 = gregorianCutoverDate;
    }
    assert jan1 <= cal.getFixedDate(date.getNormalizedYear(), date.getMonth(),
            date.getDayOfMonth(), date);
    assert nextJan1 >= cal.getFixedDate(date.getNormalizedYear(), date.getMonth(),
            date.getDayOfMonth(), date);
    value = (int)(nextJan1 - jan1);
      }
      break;

        case WEEK_OF_YEAR:
      {
    if (!gc.isCutoverYear(normalizedYear)) {
        // Get the day of week of January 1 of the year
        CalendarDate d = cal.newCalendarDate(TimeZone.NO_TIMEZONE);
        d.setDate(date.getYear(), BaseCalendar.JANUARY, 1);
        int dayOfWeek = cal.getDayOfWeek(d);
        // Normalize the day of week with the firstDayOfWeek value
        dayOfWeek -= getFirstDayOfWeek();
        if (dayOfWeek < 0) {
      dayOfWeek += 7;
        }
        value = 52;
        int magic = dayOfWeek + getMinimalDaysInFirstWeek() - 1;
        if ((magic == 6) ||
      (date.isLeapYear() && (magic == 5 || magic == 12))) {
      value++;
        }
        break;
    }

    if (gc == this) {
        gc = (GregorianCalendar) gc.clone();
    }
    gc.set(DAY_OF_YEAR, getActualMaximum(DAY_OF_YEAR));
    value = gc.get(WEEK_OF_YEAR);
      }
      break;

        case WEEK_OF_MONTH:
      {
    if (!gc.isCutoverYear(normalizedYear)) {
        CalendarDate d = cal.newCalendarDate(null);
        d.setDate(date.getYear(), date.getMonth(), 1);
        int dayOfWeek = cal.getDayOfWeek(d);
        int monthLength = cal.getMonthLength(d);
        dayOfWeek -= getFirstDayOfWeek();
        if (dayOfWeek < 0) {
      dayOfWeek += 7;
        }
        int nDaysFirstWeek = 7 - dayOfWeek; // # of days in the first week
        value = 3;
        if (nDaysFirstWeek >= getMinimalDaysInFirstWeek()) {
      value++;
        }
        monthLength -= nDaysFirstWeek + 7 * 3;
        if (monthLength > 0) {
      value++;
      if (monthLength > 7) {
          value++;
      }
        }
        break;
    }

    // Cutover year handling
    if (gc == this) {
        gc = (GregorianCalendar) gc.clone();
    }
    int y = gc.internalGet(YEAR);
    int m = gc.internalGet(MONTH);
    do {
        value = gc.get(WEEK_OF_MONTH);
        gc.add(WEEK_OF_MONTH, +1);
    } while (gc.get(YEAR) == y && gc.get(MONTH) == m);
      }
      break;

        case DAY_OF_WEEK_IN_MONTH:
      {
    // may be in the Gregorian cutover month
    int ndays, dow1;
    int dow = date.getDayOfWeek();
    if (!gc.isCutoverYear(normalizedYear)) {
        BaseCalendar.Date d = (BaseCalendar.Date) date.clone();
        ndays = cal.getMonthLength(d);
        d.setDayOfMonth(1);
        cal.normalize(d);
        dow1 = d.getDayOfWeek();
    } else {
        // Let a cloned GregorianCalendar take care of the cutover cases.
        if (gc == this) {
      gc = (GregorianCalendar) clone();
        }
        ndays = gc.actualMonthLength();
        gc.set(DAY_OF_MONTH, gc.getActualMinimum(DAY_OF_MONTH));
        dow1 = gc.get(DAY_OF_WEEK);
    }
    int x = dow - dow1;
    if (x < 0) {
        x += 7;
    }
    ndays -= x;
    value = (ndays + 6) / 7;
      }
      break;

  case YEAR:
            /* The year computation is no different, in principle, from the
             * others, however, the range of possible maxima is large.  In
             * addition, the way we know we've exceeded the range is different.
             * For these reasons, we use the special case code below to handle
             * this field.
             *
             * The actual maxima for YEAR depend on the type of calendar:
             *
             *     Gregorian = May 17, 292275056 BCE - Aug 17, 292278994 CE
             *     Julian    = Dec  2, 292269055 BCE - Jan  3, 292272993 CE
             *     Hybrid    = Dec  2, 292269055 BCE - Aug 17, 292278994 CE
             *
             * We know we've exceeded the maximum when either the month, date,
             * time, or era changes in response to setting the year.  We don't
             * check for month, date, and time here because the year and era are
             * sufficient to detect an invalid year setting.  NOTE: If code is
             * added to check the month and date in the future for some reason,
             * Feb 29 must be allowed to shift to Mar 1 when setting the year.
             */
      {
    if (gc == this) {
        gc = (GregorianCalendar) clone();
    }

    // Calculate the millisecond offset from the beginning
    // of the year of this calendar and adjust the max
    // year value if we are beyond the limit in the max
    // year.
    long current = gc.getYearOffsetInMillis();

    if (gc.internalGetEra() == CE) {
        gc.setTimeInMillis(Long.MAX_VALUE);
        value = gc.get(YEAR);
        long maxEnd = gc.getYearOffsetInMillis();
        if (current > maxEnd) {
      value--;
        }
    } else {
        CalendarSystem mincal = gc.getTimeInMillis() >= gregorianCutover ?
      gcal : getJulianCalendarSystem();
        CalendarDate d = mincal.getCalendarDate(Long.MIN_VALUE, getZone());
        long maxEnd = (cal.getDayOfYear(d) - 1) * 24 + d.getHours();
        maxEnd *= 60;
        maxEnd += d.getMinutes();
        maxEnd *= 60;
        maxEnd += d.getSeconds();
        maxEnd *= 1000;
        maxEnd += d.getMillis();
        value = d.getYear();
        if (value <= 0) {
      assert mincal == gcal;
      value = 1 - value;
        }
        if (current < maxEnd) {
      value--;
        }
    }
      }
      break;

  default:
      throw new ArrayIndexOutOfBoundsException(field);
  }
  return value;
    }

    /**
     * Returns the millisecond offset from the beginning of this
     * year. This Calendar object must have been normalized.
     */
    private final long getYearOffsetInMillis() {
  long t = (internalGet(DAY_OF_YEAR) - 1) * 24;
  t += internalGet(HOUR_OF_DAY);
  t *= 60;
  t += internalGet(MINUTE);
  t *= 60;
  t += internalGet(SECOND);
  t *= 1000;
  return t + internalGet(MILLISECOND) -
      (internalGet(ZONE_OFFSET) + internalGet(DST_OFFSET));
    }

    public Object clone()
    {
  GregorianCalendar other = (GregorianCalendar) super.clone();

  other.gdate = (BaseCalendar.Date) gdate.clone();
  if (cdate != null) {
      if (cdate != gdate) {
    other.cdate = (BaseCalendar.Date) cdate.clone();
      } else {
    other.cdate = other.gdate;
      }
  }
  other.originalFields = null;
  other.zoneOffsets = null;
  return other;
    }

    public TimeZone getTimeZone() {
  TimeZone zone = super.getTimeZone();
  // To share the zone by CalendarDates
  gdate.setZone(zone);
  if (cdate != null && cdate != gdate) {
      cdate.setZone(zone);
  }
  return zone;
    }

    public void setTimeZone(TimeZone zone) {
  super.setTimeZone(zone);
  // To share the zone by CalendarDates
  gdate.setZone(zone);
  if (cdate != null && cdate != gdate) {
      cdate.setZone(zone);
  }
    }

//////////////////////
// Proposed public API
//////////////////////

    /**
     * Returns the year that corresponds to the <code>WEEK_OF_YEAR</code> field.
     * This may be one year before or after the Gregorian or Julian year stored
     * in the <code>YEAR</code> field.  For example, January 1, 1999 is considered
     * Friday of week 53 of 1998 (if minimal days in first week is
     * 2 or less, and the first day of the week is Sunday).  Given
     * these same settings, the ISO year of January 1, 1999 is
     * 1998.
     *
     * <p>This method calls {@link Calendar#complete} before
     * calculating the week-based year.
     *
     * @return the year corresponding to the <code>WEEK_OF_YEAR</code> field, which
     * may be one year before or after the <code>YEAR</code> field.
     * @see #YEAR
     * @see #WEEK_OF_YEAR
     */
    /*
    public int getWeekBasedYear() {
        complete();
  // TODO: Below doesn't work for gregorian cutover...
        int weekOfYear = internalGet(WEEK_OF_YEAR);
        int year = internalGet(YEAR);
        if (internalGet(MONTH) == Calendar.JANUARY) {
            if (weekOfYear >= 52) {
                --year;
            }
        } else {
            if (weekOfYear == 1) {
                ++year;
            }
        }
        return year;
    }
    */


/////////////////////////////
// Time => Fields computation
/////////////////////////////

    /**
     * The fixed date corresponding to gdate. If the value is
     * Long.MIN_VALUE, the fixed date value is unknown. Currently,
     * Julian calendar dates are not cached.
     */
    transient private long cachedFixedDate = Long.MIN_VALUE;

    /**
     * Converts the time value (millisecond offset from the <a
     * href="Calendar.html#Epoch">Epoch</a>) to calendar field values.
     * The time is <em>not</em>
     * recomputed first; to recompute the time, then the fields, call the
     * <code>complete</code> method.
     *
     * @see Calendar#complete
     */
    protected void computeFields() {
  int mask = 0;
  if (isPartiallyNormalized()) {
      // Determine which calendar fields need to be computed.
      mask = getSetStateFields();
      int fieldMask = ~mask & ALL_FIELDS;
      // We have to call computTime in case calsys == null in
      // order to set calsys and cdate. (6263644)
      if (fieldMask != 0 || calsys == null) {
    mask |= computeFields(fieldMask,
              mask & (ZONE_OFFSET_MASK|DST_OFFSET_MASK));
    assert mask == ALL_FIELDS;
      }
  } else {
      mask = ALL_FIELDS;
      computeFields(mask, 0);
  }
  // After computing all the fields, set the field state to `COMPUTED'.
  setFieldsComputed(mask);
    }

    /**
     * This computeFields implements the conversion from UTC
     * (millisecond offset from the Epoch) to calendar
     * field values. fieldMask specifies which fields to change the
     * setting state to COMPUTED, although all fields are set to
     * the correct values. This is required to fix 4685354.
     *
     * @param fieldMask a bit mask to specify which fields to change
     * the setting state.
     * @param tzMask a bit mask to specify which time zone offset
     * fields to be used for time calculations
     * @return a new field mask that indicates what field values have
     * actually been set.
     */
    private int computeFields(int fieldMask, int tzMask) {
  int zoneOffset = 0;
  TimeZone tz = getZone();
  if (zoneOffsets == null) {
      zoneOffsets = new int[2];
  }
  if (tzMask != (ZONE_OFFSET_MASK|DST_OFFSET_MASK)) {
      if (tz instanceof ZoneInfo) {
    zoneOffset = ((ZoneInfo)tz).getOffsets(time, zoneOffsets);
      } else {
    zoneOffset = tz.getOffset(time);
    zoneOffsets[0] = tz.getRawOffset();
    zoneOffsets[1] = zoneOffset - zoneOffsets[0];
      }
  }
  if (tzMask != 0) {
      if (isFieldSet(tzMask, ZONE_OFFSET)) {
    zoneOffsets[0] = internalGet(ZONE_OFFSET);
      }
      if (isFieldSet(tzMask, DST_OFFSET)) {
    zoneOffsets[1] = internalGet(DST_OFFSET);
      }
      zoneOffset = zoneOffsets[0] + zoneOffsets[1];
  }

  // By computing time and zoneOffset separately, we can take
  // the wider range of time+zoneOffset than the previous
  // implementation.
  long fixedDate = zoneOffset / ONE_DAY;
  int timeOfDay = zoneOffset % (int)ONE_DAY;
  fixedDate += time / ONE_DAY;
  timeOfDay += (int) (time % ONE_DAY);
  if (timeOfDay >= ONE_DAY) {
      timeOfDay -= ONE_DAY;
      ++fixedDate;
  } else {
      while (timeOfDay < 0) {
    timeOfDay += ONE_DAY;
    --fixedDate;
      }
  }
  fixedDate += EPOCH_OFFSET;

  int era = CE;
  int year;
  if (fixedDate >= gregorianCutoverDate) {
      // Handle Gregorian dates.
      assert cachedFixedDate == Long.MIN_VALUE || gdate.isNormalized()
      : "cache control: not normalized";
      assert cachedFixedDate == Long.MIN_VALUE ||
       gcal.getFixedDate(gdate.getNormalizedYear(),
            gdate.getMonth(),
            gdate.getDayOfMonth(), gdate)
        == cachedFixedDate
      : "cache control: inconsictency" +
        ", cachedFixedDate=" + cachedFixedDate +
        ", computed=" +
              gcal.getFixedDate(gdate.getNormalizedYear(),
             gdate.getMonth(),
             gdate.getDayOfMonth(),
             gdate) +
        ", date=" + gdate;

      // See if we can use gdate to avoid date calculation.
      if (fixedDate != cachedFixedDate) {
    gcal.getCalendarDateFromFixedDate(gdate, fixedDate);
    cachedFixedDate = fixedDate;
      }

      year = gdate.getYear();
      if (year <= 0) {
    year = 1 - year;
    era = BCE;
      }
      calsys = gcal;
      cdate = gdate;
      assert cdate.getDayOfWeek() > 0 : "dow="+cdate.getDayOfWeek()+", date="+cdate;
  } else {
      // Handle Julian calendar dates.
      calsys = getJulianCalendarSystem();
      cdate = (BaseCalendar.Date) jcal.newCalendarDate(getZone());
      jcal.getCalendarDateFromFixedDate(cdate, fixedDate);
      Era e = cdate.getEra();
      if (e == jeras[0]) {
    era = BCE;
      }
      year = cdate.getYear();
  }

  // Always set the ERA and YEAR values.
        internalSet(ERA, era);
  internalSet(YEAR, year);
  int mask = fieldMask | (ERA_MASK|YEAR_MASK);

  int month =  cdate.getMonth() - 1; // 0-based
  int dayOfMonth = cdate.getDayOfMonth();

  // Set the basic date fields.
  if ((fieldMask & (MONTH_MASK|DAY_OF_MONTH_MASK|DAY_OF_WEEK_MASK))
      != 0) {
      internalSet(MONTH, month);
      internalSet(DAY_OF_MONTH, dayOfMonth);
      internalSet(DAY_OF_WEEK, cdate.getDayOfWeek());
      mask |= MONTH_MASK|DAY_OF_MONTH_MASK|DAY_OF_WEEK_MASK;
  }

  if ((fieldMask & (HOUR_OF_DAY_MASK|AM_PM_MASK|HOUR_MASK
        |MINUTE_MASK|SECOND_MASK|MILLISECOND_MASK)) != 0) {
      if (timeOfDay != 0) {
    int hours = timeOfDay / ONE_HOUR;
    internalSet(HOUR_OF_DAY, hours);
    internalSet(AM_PM, hours / 12); // Assume AM == 0
    internalSet(HOUR, hours % 12);
    int r = timeOfDay % ONE_HOUR;
    internalSet(MINUTE, r / ONE_MINUTE);
    r %= ONE_MINUTE;
    internalSet(SECOND, r / ONE_SECOND);
    internalSet(MILLISECOND, r % ONE_SECOND);
      } else {
    internalSet(HOUR_OF_DAY, 0);
    internalSet(AM_PM, AM);
    internalSet(HOUR, 0);
    internalSet(MINUTE, 0);
    internalSet(SECOND, 0);
    internalSet(MILLISECOND, 0);
      }
      mask |= (HOUR_OF_DAY_MASK|AM_PM_MASK|HOUR_MASK
         |MINUTE_MASK|SECOND_MASK|MILLISECOND_MASK);
  }

  if ((fieldMask & (ZONE_OFFSET_MASK|DST_OFFSET_MASK)) != 0) {
      internalSet(ZONE_OFFSET, zoneOffsets[0]);
      internalSet(DST_OFFSET, zoneOffsets[1]);
      mask |= (ZONE_OFFSET_MASK|DST_OFFSET_MASK);
  }

  if ((fieldMask & (DAY_OF_YEAR_MASK|WEEK_OF_YEAR_MASK|WEEK_OF_MONTH_MASK|DAY_OF_WEEK_IN_MONTH_MASK)) != 0) {
      int normalizedYear = cdate.getNormalizedYear();
      long fixedDateJan1 = calsys.getFixedDate(normalizedYear, 1, 1, cdate);
      int dayOfYear = (int)(fixedDate - fixedDateJan1) + 1;
      long fixedDateMonth1 = fixedDate - dayOfMonth + 1;
      int cutoverGap = 0;
      int cutoverYear = (calsys == gcal) ? gregorianCutoverYear : gregorianCutoverYearJulian;
      int relativeDayOfMonth = dayOfMonth - 1;

      // If we are in the cutover year, we need some special handling.
      if (normalizedYear == cutoverYear) {
    // Need to take care of the "missing" days.
    if (getCutoverCalendarSystem() == jcal) {
        // We need to find out where we are. The cutover
        // gap could even be more than one year.  (One
        // year difference in ~48667 years.)
        fixedDateJan1 = getFixedDateJan1(cdate, fixedDate);
        if (fixedDate >= gregorianCutoverDate) {
      fixedDateMonth1 = getFixedDateMonth1(cdate, fixedDate);
        }
    }
    int realDayOfYear = (int)(fixedDate - fixedDateJan1) + 1;
    cutoverGap = dayOfYear - realDayOfYear;
    dayOfYear = realDayOfYear;
    relativeDayOfMonth = (int)(fixedDate - fixedDateMonth1);
      }
      internalSet(DAY_OF_YEAR, dayOfYear);
      internalSet(DAY_OF_WEEK_IN_MONTH, relativeDayOfMonth / 7 + 1);

      int weekOfYear = getWeekNumber(fixedDateJan1, fixedDate);

      // The spec is to calculate WEEK_OF_YEAR in the
      // ISO8601-style. This creates problems, though.
      if (weekOfYear == 0) {
    // If the date belongs to the last week of the
    // previous year, use the week number of "12/31" of
    // the "previous" year. Again, if the previous year is
    // the Gregorian cutover year, we need to take care of
    // it.  Usually the previous day of January 1 is
    // December 31, which is not always true in
    // GregorianCalendar.
    long fixedDec31 = fixedDateJan1 - 1;
    long prevJan1;
    if (normalizedYear > (cutoverYear + 1)) {
        prevJan1 = fixedDateJan1 - 365;
        if (CalendarUtils.isGregorianLeapYear(normalizedYear - 1)) {
      --prevJan1;
        }
    } else {
        BaseCalendar calForJan1 = calsys;
        int prevYear = normalizedYear - 1;
        if (prevYear == cutoverYear) {
      calForJan1 = getCutoverCalendarSystem();
        }
        prevJan1 = calForJan1.getFixedDate(prevYear,
                   BaseCalendar.JANUARY,
                   1,
                   null);
        while (prevJan1 > fixedDec31) {
      prevJan1 = getJulianCalendarSystem().getFixedDate(--prevYear,
                    BaseCalendar.JANUARY,
                    1,
                    null);
        }
    }
    weekOfYear = getWeekNumber(prevJan1, fixedDec31);
      } else {
    if (normalizedYear > gregorianCutoverYear ||
        normalizedYear < (gregorianCutoverYearJulian - 1)) {
        // Regular years
        if (weekOfYear >= 52) {
      long nextJan1 = fixedDateJan1 + 365;
      if (cdate.isLeapYear()) {
          nextJan1++;
      }
      long nextJan1st = calsys.getDayOfWeekDateOnOrBefore(nextJan1 + 6,
                      getFirstDayOfWeek());
      int ndays = (int)(nextJan1st - nextJan1);
      if (ndays >= getMinimalDaysInFirstWeek() && fixedDate >= (nextJan1st - 7)) {
          // The first days forms a week in which the date is included.
          weekOfYear = 1;
      }
        }
    } else {
        BaseCalendar calForJan1 = calsys;
        int nextYear = normalizedYear + 1;
        if (nextYear == (gregorianCutoverYearJulian + 1) &&
      nextYear < gregorianCutoverYear) {
      // In case the gap is more than one year.
      nextYear = gregorianCutoverYear;
        }
        if (nextYear == gregorianCutoverYear) {
      calForJan1 = getCutoverCalendarSystem();
        }
        long nextJan1 = calForJan1.getFixedDate(nextYear,
                  BaseCalendar.JANUARY,
                  1,
                  null);
        if (nextJan1 < fixedDate) {
      nextJan1 = gregorianCutoverDate;
      calForJan1 = gcal;
        }
        long nextJan1st = calForJan1.getDayOfWeekDateOnOrBefore(nextJan1 + 6,
                      getFirstDayOfWeek());
        int ndays = (int)(nextJan1st - nextJan1);
        if (ndays >= getMinimalDaysInFirstWeek() && fixedDate >= (nextJan1st - 7)) {
      // The first days forms a week in which the date is included.
      weekOfYear = 1;
        }
    }
      }
      internalSet(WEEK_OF_YEAR, weekOfYear);
      internalSet(WEEK_OF_MONTH, getWeekNumber(fixedDateMonth1, fixedDate));
      mask |= (DAY_OF_YEAR_MASK|WEEK_OF_YEAR_MASK|WEEK_OF_MONTH_MASK|DAY_OF_WEEK_IN_MONTH_MASK);
  }
  return mask;
    }

    /**
     * Returns the number of weeks in a period between fixedDay1 and
     * fixedDate. The getFirstDayOfWeek-getMinimalDaysInFirstWeek rule
     * is applied to calculate the number of weeks.
     *
     * @param fixedDay1 the fixed date of the first day of the period
     * @param fixedDate the fixed date of the last day of the period
     * @return the number of weeks of the given period
     */
    private final int getWeekNumber(long fixedDay1, long fixedDate) {
  // We can always use `gcal' since Julian and Gregorian are the
  // same thing for this calculation.
  long fixedDay1st = gcal.getDayOfWeekDateOnOrBefore(fixedDay1 + 6,
                 getFirstDayOfWeek());
  int ndays = (int)(fixedDay1st - fixedDay1);
  assert ndays <= 7;
  if (ndays >= getMinimalDaysInFirstWeek()) {
      fixedDay1st -= 7;
  }
  int normalizedDayOfPeriod = (int)(fixedDate - fixedDay1st);
  if (normalizedDayOfPeriod >= 0) {
      return normalizedDayOfPeriod / 7 + 1;
  }
  return CalendarUtils.floorDivide(normalizedDayOfPeriod, 7) + 1;
    }

    /**
     * Converts calendar field values to the time value (millisecond
     * offset from the <a href="Calendar.html#Epoch">Epoch</a>).
     *
     * @exception IllegalArgumentException if any calendar fields are invalid.
     */
    protected void computeTime() {
  // In non-lenient mode, perform brief checking of calendar
  // fields which have been set externally. Through this
  // checking, the field values are stored in originalFields[]
  // to see if any of them are normalized later.
        if (!isLenient()) {
      if (originalFields == null) {
    originalFields = new int[FIELD_COUNT];
      }
      for (int field = 0; field < FIELD_COUNT; field++) {
    int value = internalGet(field);
    if (isExternallySet(field)) {
        // Quick validation for any out of range values
        if (value < getMinimum(field) || value > getMaximum(field)) {
      throw new IllegalArgumentException(getFieldName(field));
        }
    }
    originalFields[field] = value;
      }
  }

  // Let the super class determine which calendar fields to be
  // used to calculate the time.
  int fieldMask = selectFields();

        // The year defaults to the epoch start. We don't check
        // fieldMask for YEAR because YEAR is a mandatory field to
        // determine the date.
        int year = isSet(YEAR) ? internalGet(YEAR) : EPOCH_YEAR;

        int era = internalGetEra();
  if (era == BCE) {
      year = 1 - year;
  } else if (era != CE) {
      // Even in lenient mode we disallow ERA values other than CE & BCE.
      // (The same normalization rule as add()/roll() could be
      // applied here in lenient mode. But this checking is kept
      // unchanged for compatibility as of 1.5.)
      throw new IllegalArgumentException("Invalid era");
  }
     
  // If year is 0 or negative, we need to set the ERA value later.
  if (year <= 0 && !isSet(ERA)) {
      fieldMask |= ERA_MASK;
      setFieldsComputed(ERA_MASK);
  }

        // Calculate the time of day. We rely on the convention that
        // an UNSET field has 0.
        long timeOfDay = 0;
  if (isFieldSet(fieldMask, HOUR_OF_DAY)) {
      timeOfDay += (long) internalGet(HOUR_OF_DAY);
  } else {
      timeOfDay += internalGet(HOUR);
      // The default value of AM_PM is 0 which designates AM.
      if (isFieldSet(fieldMask, AM_PM)) {
    timeOfDay += 12 * internalGet(AM_PM);
      }
        }
        timeOfDay *= 60;
  timeOfDay += internalGet(MINUTE);
        timeOfDay *= 60;
  timeOfDay += internalGet(SECOND);
        timeOfDay *= 1000;
  timeOfDay += internalGet(MILLISECOND);

  // Convert the time of day to the number of days and the
  // millisecond offset from midnight.
  long fixedDate = timeOfDay / ONE_DAY;
  timeOfDay %= ONE_DAY;
  while (timeOfDay < 0) {
      timeOfDay += ONE_DAY;
      --fixedDate;
  }

  // Calculate the fixed date since January 1, 1 (Gregorian).
  calculateFixedDate: {
      long gfd, jfd;
      if (year > gregorianCutoverYear && year > gregorianCutoverYearJulian) {
    gfd = fixedDate + getFixedDate(gcal, year, fieldMask);
    if (gfd >= gregorianCutoverDate) {
        fixedDate = gfd;
        break calculateFixedDate;
    }
    jfd = fixedDate + getFixedDate(getJulianCalendarSystem(), year, fieldMask);
      } else if (year < gregorianCutoverYear && year < gregorianCutoverYearJulian) {
    jfd = fixedDate + getFixedDate(getJulianCalendarSystem(), year, fieldMask);
    if (jfd < gregorianCutoverDate) {
        fixedDate = jfd;
        break calculateFixedDate;
    }
    gfd = fixedDate + getFixedDate(gcal, year, fieldMask);
      } else {
    gfd = fixedDate + getFixedDate(gcal, year, fieldMask);
    jfd = fixedDate + getFixedDate(getJulianCalendarSystem(), year, fieldMask);
      }
      // Now we have to determine which calendar date it is.
      if (gfd >= gregorianCutoverDate) {
    if (jfd >= gregorianCutoverDate) {
        fixedDate = gfd;
    } else {
        // The date is in an "overlapping" period. No way
        // to disambiguate it. Determine it using the
        // previous date calculation.
        if (calsys == gcal || calsys == null) {
      fixedDate = gfd;
        } else {
      fixedDate = jfd;
        }
    }
      } else {
    if (jfd < gregorianCutoverDate) {
        fixedDate = jfd;
    } else {
        // The date is in a "missing" period.
        if (!isLenient()) {
      throw new IllegalArgumentException("the specified date doesn't exist");
        }
        // Take the Julian date for compatibility, which
        // will produce a Gregorian date.
        fixedDate = jfd;
    }
      }
  }

        // millis represents local wall-clock time in milliseconds.
        long millis = (fixedDate - EPOCH_OFFSET) * ONE_DAY + timeOfDay;

        // Compute the time zone offset and DST offset.  There are two potential
        // ambiguities here.  We'll assume a 2:00 am (wall time) switchover time
        // for discussion purposes here.
        // 1. The transition into DST.  Here, a designated time of 2:00 am - 2:59 am
        //    can be in standard or in DST depending.  However, 2:00 am is an invalid
        //    representation (the representation jumps from 1:59:59 am Std to 3:00:00 am DST).
        //    We assume standard time.
        // 2. The transition out of DST.  Here, a designated time of 1:00 am - 1:59 am
        //    can be in standard or DST.  Both are valid representations (the rep
        //    jumps from 1:59:59 DST to 1:00:00 Std).
        //    Again, we assume standard time.
        // We use the TimeZone object, unless the user has explicitly set the ZONE_OFFSET
        // or DST_OFFSET fields; then we use those fields.
        TimeZone zone = getZone();
  if (zoneOffsets == null) {
      zoneOffsets = new int[2];
  }
  int tzMask = fieldMask & (ZONE_OFFSET_MASK|DST_OFFSET_MASK);
  if (tzMask != (ZONE_OFFSET_MASK|DST_OFFSET_MASK)) {
      if (zone instanceof ZoneInfo) {
    ((ZoneInfo)zone).getOffsetsByWall(millis, zoneOffsets);
      } else {
    int gmtOffset = isFieldSet(fieldMask, ZONE_OFFSET) ?
            internalGet(ZONE_OFFSET) : zone.getRawOffset();
    zone.getOffsets(millis - gmtOffset, zoneOffsets);
      }
  }
  if (tzMask != 0) {
      if (isFieldSet(tzMask, ZONE_OFFSET)) {
    zoneOffsets[0] = internalGet(ZONE_OFFSET);
      }
      if (isFieldSet(tzMask, DST_OFFSET)) {
    zoneOffsets[1] = internalGet(DST_OFFSET);
      }
  }

  // Adjust the time zone offset values to get the UTC time.
  millis -= zoneOffsets[0] + zoneOffsets[1];

  // Set this calendar's time in milliseconds
  time = millis;

  int mask = computeFields(fieldMask | getSetStateFields(), tzMask);

  if (!isLenient()) {
      for (int field = 0; field < FIELD_COUNT; field++) {
    if (!isExternallySet(field)) {
        continue;
    }
    if (originalFields[field] != internalGet(field)) {
        // Restore the original field values
        System.arraycopy(originalFields, 0, fields, 0, fields.length);
        throw new IllegalArgumentException(getFieldName(field));
    }
      }
  }
  setFieldsNormalized(mask);
    }

    /**
     * Computes the fixed date under either the Gregorian or the
     * Julian calendar, using the given year and the specified calendar fields.
     *
     * @param cal the CalendarSystem to be used for the date calculation
     * @param year the normalized year number, with 0 indicating the
     * year 1 BCE, -1 indicating 2 BCE, etc.
     * @param fieldMask the calendar fields to be used for the date calculation
     * @return the fixed date
     * @see Calendar#selectFields
     */
    private long getFixedDate(BaseCalendar cal, int year, int fieldMask) {
  int month = JANUARY;
  if (isFieldSet(fieldMask, MONTH)) {
            // No need to check if MONTH has been set (no isSet(MONTH)
            // call) since its unset value happens to be JANUARY (0).
      month = internalGet(MONTH);

            // If the month is out of range, adjust it into range
      if (month > DECEMBER) {
    year += month / 12;
    month %= 12;
      } else if (month < JANUARY) {
                int[] rem = new int[1];
                year += CalendarUtils.floorDivide(month, 12, rem);
                month = rem[0];
            }
  }

  // Get the fixed date since Jan 1, 1 (Gregorian). We are on
  // the first day of either `month' or January in 'year'.
  long fixedDate = cal.getFixedDate(year, month + 1, 1,
            cal == gcal ? gdate : null);
  if (isFieldSet(fieldMask, MONTH)) {
      // Month-based calculations
            if (isFieldSet(fieldMask, DAY_OF_MONTH)) {
    // We are on the first day of the month. Just add the
    // offset if DAY_OF_MONTH is set. If the isSet call
    // returns false, that means DAY_OF_MONTH has been
    // selected just because of the selected
    // combination. We don't need to add any since the
    // default value is the 1st.
    if (isSet(DAY_OF_MONTH)) {
        // To avoid underflow with DAY_OF_MONTH-1, add
        // DAY_OF_MONTH, then subtract 1.
        fixedDate += internalGet(DAY_OF_MONTH);
        fixedDate--;
    }
            } else {
                if (isFieldSet(fieldMask, WEEK_OF_MONTH)) {
        long firstDayOfWeek = cal.getDayOfWeekDateOnOrBefore(fixedDate + 6,
                   getFirstDayOfWeek());
                    // If we have enough days in the first week, then
                    // move to the previous week.
                    if ((firstDayOfWeek - fixedDate) >= getMinimalDaysInFirstWeek()) {
      firstDayOfWeek -= 7;
        }
        if (isFieldSet(fieldMask, DAY_OF_WEEK)) {
      firstDayOfWeek = cal.getDayOfWeekDateOnOrBefore(firstDayOfWeek + 6,
                  internalGet(DAY_OF_WEEK));
        }
        // In lenient mode, we treat days of the previous
        // months as a part of the specified
        // WEEK_OF_MONTH. See 4633646.
        fixedDate = firstDayOfWeek + 7 * (internalGet(WEEK_OF_MONTH) - 1);
                } else {
        int dayOfWeek;
        if (isFieldSet(fieldMask, DAY_OF_WEEK)) {
      dayOfWeek = internalGet(DAY_OF_WEEK);
        } else {
      dayOfWeek = getFirstDayOfWeek();
        }
                    // We are basing this on the day-of-week-in-month.  The only
                    // trickiness occurs if the day-of-week-in-month is
                    // negative.
        int dowim;
        if (isFieldSet(fieldMask, DAY_OF_WEEK_IN_MONTH)) {
      dowim = internalGet(DAY_OF_WEEK_IN_MONTH);
        } else {
      dowim = 1;
        }
        if (dowim >= 0) {
      fixedDate = cal.getDayOfWeekDateOnOrBefore(fixedDate + (7 * dowim) - 1,
                   dayOfWeek);
        } else {
      // Go to the first day of the next week of
      // the specified week boundary.
      int lastDate = monthLength(month, year) + (7 * (dowim + 1));
      // Then, get the day of week date on or before the last date.
      fixedDate = cal.getDayOfWeekDateOnOrBefore(fixedDate + lastDate - 1,
                   dayOfWeek);
                    }
                }
            }
        } else {
      if (year == gregorianCutoverYear && cal == gcal
    && fixedDate < gregorianCutoverDate
    && gregorianCutoverYear != gregorianCutoverYearJulian) {
    // January 1 of the year doesn't exist.  Use
    // gregorianCutoverDate as the first day of the
    // year.
    fixedDate = gregorianCutoverDate;
      }
      // We are on the first day of the year.
            if (isFieldSet(fieldMask, DAY_OF_YEAR)) {
    // Add the offset, then subtract 1. (Make sure to avoid underflow.)
                fixedDate += internalGet(DAY_OF_YEAR);
    fixedDate--;
            } else {
    long firstDayOfWeek = cal.getDayOfWeekDateOnOrBefore(fixedDate + 6,
                     getFirstDayOfWeek());
    // If we have enough days in the first week, then move
    // to the previous week.
    if ((firstDayOfWeek - fixedDate) >= getMinimalDaysInFirstWeek()) {
        firstDayOfWeek -= 7;
    }
    if (isFieldSet(fieldMask, DAY_OF_WEEK)) {
        int dayOfWeek = internalGet(DAY_OF_WEEK);
        if (dayOfWeek != getFirstDayOfWeek()) {
      firstDayOfWeek = cal.getDayOfWeekDateOnOrBefore(firstDayOfWeek + 6,
                  dayOfWeek);
        }
    }
    fixedDate = firstDayOfWeek + 7 * ((long)internalGet(WEEK_OF_YEAR) - 1);
            }
        }

        return fixedDate;
    }

    /**
     * Returns this object if it's normalized (all fields and time are
     * in sync). Otherwise, a cloned object is returned after calling
     * complete() in lenient mode.
     */
    private final GregorianCalendar getNormalizedCalendar() {
  GregorianCalendar gc;
  if (isFullyNormalized()) {
      gc = this;
  } else {
      // Create a clone and normalize the calendar fields
      gc = (GregorianCalendar) this.clone();
      gc.setLenient(true);
      gc.complete();
  }
  return gc;
    }

    /**
     * Returns the Julian calendar system instance (singleton). 'jcal'
     * and 'jeras' are set upon the return.
     */
    synchronized private static final BaseCalendar getJulianCalendarSystem() {
  if (jcal == null) {
      jcal = (JulianCalendar) CalendarSystem.forName("julian");
      jeras = jcal.getEras();
  }
  return jcal;
    }

    /**
     * Returns the calendar system for dates before the cutover date
     * in the cutover year. If the cutover date is January 1, the
     * method returns Gregorian. Otherwise, Julian.
     */
    private BaseCalendar getCutoverCalendarSystem() {
  CalendarDate date = getGregorianCutoverDate();
  if (date.getMonth() == BaseCalendar.JANUARY
      && date.getDayOfMonth() == 1) {
      return gcal;
  }
  return getJulianCalendarSystem();
    }

    /**
     * Determines if the specified year (normalized) is the Gregorian
     * cutover year. This object must have been normalized.
     */
    private final boolean isCutoverYear(int normalizedYear) {
  int cutoverYear = (calsys == gcal) ? gregorianCutoverYear : gregorianCutoverYearJulian;
  return normalizedYear == cutoverYear;
    }

    /**
     * Returns the fixed date of the first day of the year (usually
     * January 1) before the specified date.
     *
     * @param date the date for which the first day of the year is
     * calculated. The date has to be in the cut-over year (Gregorian
     * or Julian).
     * @param fixedDate the fixed date representation of the date
     */
    private final long getFixedDateJan1(BaseCalendar.Date date, long fixedDate) {
  assert date.getNormalizedYear() == gregorianCutoverYear ||
      date.getNormalizedYear() == gregorianCutoverYearJulian;
  if (gregorianCutoverYear != gregorianCutoverYearJulian) {
      if (fixedDate >= gregorianCutoverDate) {
    // Dates before the cutover date don't exist
    // in the same (Gregorian) year. So, no
    // January 1 exists in the year. Use the
    // cutover date as the first day of the year.
    return gregorianCutoverDate;
      }
  }
  // January 1 of the normalized year should exist.
  BaseCalendar jcal = getJulianCalendarSystem();
  return jcal.getFixedDate(date.getNormalizedYear(), BaseCalendar.JANUARY, 1, null);
    }

    /**
     * Returns the fixed date of the first date of the month (usually
     * the 1st of the month) before the specified date.
     *
     * @param date the date for which the first day of the month is
     * calculated. The date has to be in the cut-over year (Gregorian
     * or Julian).
     * @param fixedDate the fixed date representation of the date
     */
    private final long getFixedDateMonth1(BaseCalendar.Date date, long fixedDate) {
  assert date.getNormalizedYear() == gregorianCutoverYear ||
      date.getNormalizedYear() == gregorianCutoverYearJulian;
  BaseCalendar.Date gCutover = getGregorianCutoverDate();
  if (gCutover.getMonth() == BaseCalendar.JANUARY
      && gCutover.getDayOfMonth() == 1) {
      // The cutover happened on January 1.
      return fixedDate - date.getDayOfMonth() + 1;
  }

  long fixedDateMonth1;
  // The cutover happened sometime during the year.
  if (date.getMonth() == gCutover.getMonth()) {
      // The cutover happened in the month.
      BaseCalendar.Date jLastDate = getLastJulianDate();
      if (gregorianCutoverYear == gregorianCutoverYearJulian
    && gCutover.getMonth() == jLastDate.getMonth()) {
    // The "gap" fits in the same month.
    fixedDateMonth1 = jcal.getFixedDate(date.getNormalizedYear(),
                date.getMonth(),
                1,
                null);
      } else {
    // Use the cutover date as the first day of the month.
    fixedDateMonth1 = gregorianCutoverDate;
      }
  } else {
      // The cutover happened before the month.
      fixedDateMonth1 = fixedDate - date.getDayOfMonth() + 1;
  }

  return fixedDateMonth1;
    }

    /**
     * Returns a CalendarDate produced from the specified fixed date.
     *
     * @param fd the fixed date
     */
    private final BaseCalendar.Date getCalendarDate(long fd) {
  BaseCalendar cal = (fd >= gregorianCutoverDate) ? gcal : getJulianCalendarSystem();
  BaseCalendar.Date d = (BaseCalendar.Date) cal.newCalendarDate(TimeZone.NO_TIMEZONE);
  cal.getCalendarDateFromFixedDate(d, fd);
  return d;
    }

    /**
     * Returns the Gregorian cutover date as a BaseCalendar.Date. The
     * date is a Gregorian date.
     */
    private final BaseCalendar.Date getGregorianCutoverDate() {
  return getCalendarDate(gregorianCutoverDate);
    }

    /**
     * Returns the day before the Gregorian cutover date as a
     * BaseCalendar.Date. The date is a Julian date.
     */
    private final BaseCalendar.Date getLastJulianDate() {
  return getCalendarDate(gregorianCutoverDate - 1);
    }

    /**
     * Returns the length of the specified month in the specified
     * year. The year number must be normalized.
     *
     * @see #isLeapYear(int)
     */
    private final int monthLength(int month, int year) {
        return isLeapYear(year) ? LEAP_MONTH_LENGTH[month] : MONTH_LENGTH[month];
    }

    /**
     * Returns the length of the specified month in the year provided
     * by internalGet(YEAR).
     *
     * @see #isLeapYear(int)
     */
    private final int monthLength(int month) {
        int year = internalGet(YEAR);
        if (internalGetEra() == BCE) {
            year = 1 - year;
        }
        return monthLength(month, year);
    }

    private final int actualMonthLength() {
        int year = cdate.getNormalizedYear();
  if (year != gregorianCutoverYear && year != gregorianCutoverYearJulian) {
      return calsys.getMonthLength(cdate);
  }
  BaseCalendar.Date date = (BaseCalendar.Date) cdate.clone();
  long fd = calsys.getFixedDate(date);
  long month1 = getFixedDateMonth1(date, fd);
  long next1 = month1 + calsys.getMonthLength(date);
  if (next1 < gregorianCutoverDate) {
      return (int)(next1 - month1);
  }
  if (cdate != gdate) {
      date = (BaseCalendar.Date) gcal.newCalendarDate(TimeZone.NO_TIMEZONE);
  }
  gcal.getCalendarDateFromFixedDate(date, next1);
  next1 = getFixedDateMonth1(date, next1);
  return (int)(next1 - month1);
    }

    /**
     * Returns the length (in days) of the specified year. The year
     * must be normalized.
     */
    private final int yearLength(int year) {
        return isLeapYear(year) ? 366 : 365;
    }

    /**
     * Returns the length (in days) of the year provided by
     * internalGet(YEAR).
     */
    private final int yearLength() {
        int year = internalGet(YEAR);
        if (internalGetEra() == BCE) {
            year = 1 - year;
        }
        return yearLength(year);
    }

    /**
     * After adjustments such as add(MONTH), add(YEAR), we don't want the
     * month to jump around.  E.g., we don't want Jan 31 + 1 month to go to Mar
     * 3, we want it to go to Feb 28.  Adjustments which might run into this
     * problem call this method to retain the proper month.
     */
    private final void pinDayOfMonth() {
  int year = internalGet(YEAR);
  int monthLen;
  if (year > gregorianCutoverYear || year < gregorianCutoverYearJulian) {
      monthLen = monthLength(internalGet(MONTH));
  } else {
      GregorianCalendar gc = getNormalizedCalendar();
      monthLen = gc.getActualMaximum(DAY_OF_MONTH);
  }
  int dom = internalGet(DAY_OF_MONTH);
  if (dom > monthLen) {
      set(DAY_OF_MONTH, monthLen);
  }
    }

    /**
     * Returns the fixed date value of this object. The time value and
     * calendar fields must be in synch.
     */
    private final long getCurrentFixedDate() {
  return (calsys == gcal) ? cachedFixedDate : calsys.getFixedDate(cdate);
    }

    /**
     * Returns the new value after 'roll'ing the specified value and amount.
     */
    private static final int getRolledValue(int value, int amount, int min, int max) {
  assert value >= min && value <= max;
  int range = max - min + 1;
  amount %= range;
  int n = value + amount;
  if (n > max) {
      n -= range;
  } else if (n < min) {
      n += range;
  }
  assert n >= min && n <= max;
  return n;
    }

    /**
     * Returns the ERA.  We need a special method for this because the
     * default ERA is CE, but a zero (unset) ERA is BCE.
     */
    private final int internalGetEra() {
        return isSet(ERA) ? internalGet(ERA) : CE;
    }

    /**
     * Updates internal state.
     */
    private void readObject(ObjectInputStream stream)
      throws IOException, ClassNotFoundException {
  stream.defaultReadObject();
  if (gdate == null) {
      gdate = (BaseCalendar.Date) gcal.newCalendarDate(getZone());
      cachedFixedDate = Long.MIN_VALUE;
  }
  setGregorianChange(gregorianCutover);
    }
}
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