/*

  * Copyright (c) 1996, 2011, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.  Oracle designates this

  * particular file as subject to the "Classpath" exception as provided

  * by Oracle in the LICENSE file that accompanied this code.

  *

  * This code is distributed in the hope that it will be useful, but WITHOUT

  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

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  */

 /*

  * (C) Copyright Taligent, Inc. 1996 - All Rights Reserved

  * (C) Copyright IBM Corp. 1996 - 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.ObjectInputStream;

 import java.io.ObjectOutputStream;

 import java.io.IOException;

 import sun.util.calendar.CalendarSystem;

 import sun.util.calendar.CalendarUtils;

 import sun.util.calendar.BaseCalendar;

 import sun.util.calendar.Gregorian;

 /**

  * <code>SimpleTimeZone</code> is a concrete subclass of <code>TimeZone</code>

  * that represents a time zone for use with a Gregorian calendar.

  * The class holds an offset from GMT, called <em>raw offset</em>, and start

  * and end rules for a daylight saving time schedule.  Since it only holds

  * single values for each, it cannot handle historical changes in the offset

  * from GMT and the daylight saving schedule, except that the {@link

  * #setStartYear setStartYear} method can specify the year when the daylight

  * saving time schedule starts in effect.

  * <p>

  * To construct a <code>SimpleTimeZone</code> with a daylight saving time

  * schedule, the schedule can be described with a set of rules,

  * <em>start-rule</em> and <em>end-rule</em>. A day when daylight saving time

  * starts or ends is specified by a combination of <em>month</em>,

  * <em>day-of-month</em>, and <em>day-of-week</em> values. The <em>month</em>

  * value is represented by a Calendar {@link Calendar#MONTH MONTH} field

  * value, such as {@link Calendar#MARCH}. The <em>day-of-week</em> value is

  * represented by a Calendar {@link Calendar#DAY_OF_WEEK DAY_OF_WEEK} value,

  * such as {@link Calendar#SUNDAY SUNDAY}. The meanings of value combinations

  * are as follows.

  *

  * <ul>

  * <li><b>Exact day of month</b><br>

  * To specify an exact day of month, set the <em>month</em> and

  * <em>day-of-month</em> to an exact value, and <em>day-of-week</em> to zero. For

  * example, to specify March 1, set the <em>month</em> to {@link Calendar#MARCH

  * MARCH}, <em>day-of-month</em> to 1, and <em>day-of-week</em> to 0.</li>

  *

  * <li><b>Day of week on or after day of month</b><br>

  * To specify a day of week on or after an exact day of month, set the

  * <em>month</em> to an exact month value, <em>day-of-month</em> to the day on

  * or after which the rule is applied, and <em>day-of-week</em> to a negative {@link

  * Calendar#DAY_OF_WEEK DAY_OF_WEEK} field value. For example, to specify the

  * second Sunday of April, set <em>month</em> to {@link Calendar#APRIL APRIL},

  * <em>day-of-month</em> to 8, and <em>day-of-week</em> to <code>-</code>{@link

  * Calendar#SUNDAY SUNDAY}.</li>

  *

  * <li><b>Day of week on or before day of month</b><br>

  * To specify a day of the week on or before an exact day of the month, set

  * <em>day-of-month</em> and <em>day-of-week</em> to a negative value. For

  * example, to specify the last Wednesday on or before the 21st of March, set

  * <em>month</em> to {@link Calendar#MARCH MARCH}, <em>day-of-month</em> is -21

  * and <em>day-of-week</em> is <code>-</code>{@link Calendar#WEDNESDAY WEDNESDAY}. </li>

  *

  * <li><b>Last day-of-week of month</b><br>

  * To specify, the last day-of-week of the month, set <em>day-of-week</em> to a

  * {@link Calendar#DAY_OF_WEEK DAY_OF_WEEK} value and <em>day-of-month</em> to

  * -1. For example, to specify the last Sunday of October, set <em>month</em>

  * to {@link Calendar#OCTOBER OCTOBER}, <em>day-of-week</em> to {@link

  * Calendar#SUNDAY SUNDAY} and <em>day-of-month</em> to -1.  </li>

  *

  * </ul>

  * The time of the day at which daylight saving time starts or ends is

  * specified by a millisecond value within the day. There are three kinds of

  * <em>mode</em>s to specify the time: {@link #WALL_TIME}, {@link

  * #STANDARD_TIME} and {@link #UTC_TIME}. For example, if daylight

  * saving time ends

  * at 2:00 am in the wall clock time, it can be specified by 7200000

  * milliseconds in the {@link #WALL_TIME} mode. In this case, the wall clock time

  * for an <em>end-rule</em> means the same thing as the daylight time.

  * <p>

  * The following are examples of parameters for constructing time zone objects.

  * <pre><code>

  *      // Base GMT offset: -8:00

  *      // DST starts:      at 2:00am in standard time

  *      //                  on the first Sunday in April

  *      // DST ends:        at 2:00am in daylight time

  *      //                  on the last Sunday in October

  *      // Save:            1 hour

  *      SimpleTimeZone(-28800000,

  *                     "America/Los_Angeles",

  *                     Calendar.APRIL, 1, -Calendar.SUNDAY,

  *                     7200000,

  *                     Calendar.OCTOBER, -1, Calendar.SUNDAY,

  *                     7200000,

  *                     3600000)

  *

  *      // Base GMT offset: +1:00

  *      // DST starts:      at 1:00am in UTC time

  *      //                  on the last Sunday in March

  *      // DST ends:        at 1:00am in UTC time

  *      //                  on the last Sunday in October

  *      // Save:            1 hour

  *      SimpleTimeZone(3600000,

  *                     "Europe/Paris",

  *                     Calendar.MARCH, -1, Calendar.SUNDAY,

  *                     3600000, SimpleTimeZone.UTC_TIME,

  *                     Calendar.OCTOBER, -1, Calendar.SUNDAY,

  *                     3600000, SimpleTimeZone.UTC_TIME,

  *                     3600000)

  * </code></pre>

  * These parameter rules are also applicable to the set rule methods, such as

  * <code>setStartRule</code>.

  *

  * @since 1.1

  * @see      Calendar

  * @see      GregorianCalendar

  * @see      TimeZone

  * @author   David Goldsmith, Mark Davis, Chen-Lieh Huang, Alan Liu

  */

 public class SimpleTimeZone extends TimeZone {

     /**

      * Constructs a SimpleTimeZone with the given base time zone offset from GMT

      * and time zone ID with no daylight saving time schedule.

      *

      * @param rawOffset  The base time zone offset in milliseconds to GMT.

      * @param ID         The time zone name that is given to this instance.

      */

     public SimpleTimeZone(int rawOffset, String ID)

     {

         this.rawOffset = rawOffset;

         setID (ID);

         dstSavings = millisPerHour; // In case user sets rules later

     }

     /**

      * Constructs a SimpleTimeZone with the given base time zone offset from

      * GMT, time zone ID, and rules for starting and ending the daylight

      * time.

      * Both <code>startTime</code> and <code>endTime</code> are specified to be

      * represented in the wall clock time. The amount of daylight saving is

      * assumed to be 3600000 milliseconds (i.e., one hour). This constructor is

      * equivalent to:

      * <pre><code>

      *     SimpleTimeZone(rawOffset,

      *                    ID,

      *                    startMonth,

      *                    startDay,

      *                    startDayOfWeek,

      *                    startTime,

      *                    SimpleTimeZone.{@link #WALL_TIME},

      *                    endMonth,

      *                    endDay,

      *                    endDayOfWeek,

      *                    endTime,

      *                    SimpleTimeZone.{@link #WALL_TIME},

      *                    3600000)

      * </code></pre>

      *

      * @param rawOffset       The given base time zone offset from GMT.

      * @param ID              The time zone ID which is given to this object.

      * @param startMonth      The daylight saving time starting month. Month is

      *                        a {@link Calendar#MONTH MONTH} field value (0-based. e.g., 0

      *                        for January).

      * @param startDay        The day of the month on which the daylight saving time starts.

      *                        See the class description for the special cases of this parameter.

      * @param startDayOfWeek  The daylight saving time starting day-of-week.

      *                        See the class description for the special cases of this parameter.

      * @param startTime       The daylight saving time starting time in local wall clock

      *                        time (in milliseconds within the day), which is local

      *                        standard time in this case.

      * @param endMonth        The daylight saving time ending month. Month is

      *                        a {@link Calendar#MONTH MONTH} field

      *                        value (0-based. e.g., 9 for October).

      * @param endDay          The day of the month on which the daylight saving time ends.

      *                        See the class description for the special cases of this parameter.

      * @param endDayOfWeek    The daylight saving time ending day-of-week.

      *                        See the class description for the special cases of this parameter.

      * @param endTime         The daylight saving ending time in local wall clock time,

      *                        (in milliseconds within the day) which is local daylight

      *                        time in this case.

      * @exception IllegalArgumentException if the month, day, dayOfWeek, or time

      * parameters are out of range for the start or end rule

      */

     public SimpleTimeZone(int rawOffset, String ID,

                           int startMonth, int startDay, int startDayOfWeek, int startTime,

                           int endMonth, int endDay, int endDayOfWeek, int endTime)

     {

         this(rawOffset, ID,

              startMonth, startDay, startDayOfWeek, startTime, WALL_TIME,

              endMonth, endDay, endDayOfWeek, endTime, WALL_TIME,

              millisPerHour);

     }

     /**

      * Constructs a SimpleTimeZone with the given base time zone offset from

      * GMT, time zone ID, and rules for starting and ending the daylight

      * time.

      * Both <code>startTime</code> and <code>endTime</code> are assumed to be

      * represented in the wall clock time. This constructor is equivalent to:

      * <pre><code>

      *     SimpleTimeZone(rawOffset,

      *                    ID,

      *                    startMonth,

      *                    startDay,

      *                    startDayOfWeek,

      *                    startTime,

      *                    SimpleTimeZone.{@link #WALL_TIME},

      *                    endMonth,

      *                    endDay,

      *                    endDayOfWeek,

      *                    endTime,

      *                    SimpleTimeZone.{@link #WALL_TIME},

      *                    dstSavings)

      * </code></pre>

      *

      * @param rawOffset       The given base time zone offset from GMT.

      * @param ID              The time zone ID which is given to this object.

      * @param startMonth      The daylight saving time starting month. Month is

      *                        a {@link Calendar#MONTH MONTH} field

      *                        value (0-based. e.g., 0 for January).

      * @param startDay        The day of the month on which the daylight saving time starts.

      *                        See the class description for the special cases of this parameter.

      * @param startDayOfWeek  The daylight saving time starting day-of-week.

      *                        See the class description for the special cases of this parameter.

      * @param startTime       The daylight saving time starting time in local wall clock

      *                        time, which is local standard time in this case.

      * @param endMonth        The daylight saving time ending month. Month is

      *                        a {@link Calendar#MONTH MONTH} field

      *                        value (0-based. e.g., 9 for October).

      * @param endDay          The day of the month on which the daylight saving time ends.

      *                        See the class description for the special cases of this parameter.

      * @param endDayOfWeek    The daylight saving time ending day-of-week.

      *                        See the class description for the special cases of this parameter.

      * @param endTime         The daylight saving ending time in local wall clock time,

      *                        which is local daylight time in this case.

      * @param dstSavings      The amount of time in milliseconds saved during

      *                        daylight saving time.

      * @exception IllegalArgumentException if the month, day, dayOfWeek, or time

      * parameters are out of range for the start or end rule

      * @since 1.2

      */

     public SimpleTimeZone(int rawOffset, String ID,

                           int startMonth, int startDay, int startDayOfWeek, int startTime,

                           int endMonth, int endDay, int endDayOfWeek, int endTime,

                           int dstSavings)

     {

         this(rawOffset, ID,

              startMonth, startDay, startDayOfWeek, startTime, WALL_TIME,

              endMonth, endDay, endDayOfWeek, endTime, WALL_TIME,

              dstSavings);

     }

     /**

      * Constructs a SimpleTimeZone with the given base time zone offset from

      * GMT, time zone ID, and rules for starting and ending the daylight

      * time.

      * This constructor takes the full set of the start and end rules

      * parameters, including modes of <code>startTime</code> and

      * <code>endTime</code>. The mode specifies either {@link #WALL_TIME wall

      * time} or {@link #STANDARD_TIME standard time} or {@link #UTC_TIME UTC

      * time}.

      *

      * @param rawOffset       The given base time zone offset from GMT.

      * @param ID              The time zone ID which is given to this object.

      * @param startMonth      The daylight saving time starting month. Month is

      *                        a {@link Calendar#MONTH MONTH} field

      *                        value (0-based. e.g., 0 for January).

      * @param startDay        The day of the month on which the daylight saving time starts.

      *                        See the class description for the special cases of this parameter.

      * @param startDayOfWeek  The daylight saving time starting day-of-week.

      *                        See the class description for the special cases of this parameter.

      * @param startTime       The daylight saving time starting time in the time mode

      *                        specified by <code>startTimeMode</code>.

      * @param startTimeMode   The mode of the start time specified by startTime.

      * @param endMonth        The daylight saving time ending month. Month is

      *                        a {@link Calendar#MONTH MONTH} field

      *                        value (0-based. e.g., 9 for October).

      * @param endDay          The day of the month on which the daylight saving time ends.

      *                        See the class description for the special cases of this parameter.

      * @param endDayOfWeek    The daylight saving time ending day-of-week.

      *                        See the class description for the special cases of this parameter.

      * @param endTime         The daylight saving ending time in time time mode

      *                        specified by <code>endTimeMode</code>.

      * @param endTimeMode     The mode of the end time specified by endTime

      * @param dstSavings      The amount of time in milliseconds saved during

      *                        daylight saving time.

      *

      * @exception IllegalArgumentException if the month, day, dayOfWeek, time more, or

      * time parameters are out of range for the start or end rule, or if a time mode

      * value is invalid.

      *

      * @see #WALL_TIME

      * @see #STANDARD_TIME

      * @see #UTC_TIME

      *

      * @since 1.4

      */

     public SimpleTimeZone(int rawOffset, String ID,

                           int startMonth, int startDay, int startDayOfWeek,

                           int startTime, int startTimeMode,

                           int endMonth, int endDay, int endDayOfWeek,

                           int endTime, int endTimeMode,

                           int dstSavings) {

         setID(ID);

         this.rawOffset      = rawOffset;

         this.startMonth     = startMonth;

         this.startDay       = startDay;

         this.startDayOfWeek = startDayOfWeek;

         this.startTime      = startTime;

         this.startTimeMode  = startTimeMode;

         this.endMonth       = endMonth;

         this.endDay         = endDay;

         this.endDayOfWeek   = endDayOfWeek;

         this.endTime        = endTime;

         this.endTimeMode    = endTimeMode;

         this.dstSavings     = dstSavings;

         // this.useDaylight is set by decodeRules

         decodeRules();

         if (dstSavings <= 0) {

             throw new IllegalArgumentException("Illegal daylight saving value: " + dstSavings);

         }

     }

     /**

      * Sets the daylight saving time starting year.

      *

      * @param year  The daylight saving starting year.

      */

     public void setStartYear(int year)

     {

         startYear = year;

         invalidateCache();

     }

     /**

      * Sets the daylight saving time start rule. For example, if daylight saving

      * time starts on the first Sunday in April at 2 am in local wall clock

      * time, you can set the start rule by calling:

      * <pre><code>setStartRule(Calendar.APRIL, 1, Calendar.SUNDAY, 2*60*60*1000);</code></pre>

      *

      * @param startMonth      The daylight saving time starting month. Month is

      *                        a {@link Calendar#MONTH MONTH} field

      *                        value (0-based. e.g., 0 for January).

      * @param startDay        The day of the month on which the daylight saving time starts.

      *                        See the class description for the special cases of this parameter.

      * @param startDayOfWeek  The daylight saving time starting day-of-week.

      *                        See the class description for the special cases of this parameter.

      * @param startTime       The daylight saving time starting time in local wall clock

      *                        time, which is local standard time in this case.

      * @exception IllegalArgumentException if the <code>startMonth</code>, <code>startDay</code>,

      * <code>startDayOfWeek</code>, or <code>startTime</code> parameters are out of range

      */

     public void setStartRule(int startMonth, int startDay, int startDayOfWeek, int startTime)

     {

         this.startMonth = startMonth;

         this.startDay = startDay;

         this.startDayOfWeek = startDayOfWeek;

         this.startTime = startTime;

         startTimeMode = WALL_TIME;

         decodeStartRule();

         invalidateCache();

     }

     /**

      * Sets the daylight saving time start rule to a fixed date within a month.

      * This method is equivalent to:

      * <pre><code>setStartRule(startMonth, startDay, 0, startTime)</code></pre>

      *

      * @param startMonth      The daylight saving time starting month. Month is

      *                        a {@link Calendar#MONTH MONTH} field

      *                        value (0-based. e.g., 0 for January).

      * @param startDay        The day of the month on which the daylight saving time starts.

      * @param startTime       The daylight saving time starting time in local wall clock

      *                        time, which is local standard time in this case.

      *                        See the class description for the special cases of this parameter.

      * @exception IllegalArgumentException if the <code>startMonth</code>,

      * <code>startDayOfMonth</code>, or <code>startTime</code> parameters are out of range

      * @since 1.2

      */

     public void setStartRule(int startMonth, int startDay, int startTime) {

         setStartRule(startMonth, startDay, 0, startTime);

     }

     /**

      * Sets the daylight saving time start rule to a weekday before or after the given date within

      * a month, e.g., the first Monday on or after the 8th.

      *

      * @param startMonth      The daylight saving time starting month. Month is

      *                        a {@link Calendar#MONTH MONTH} field

      *                        value (0-based. e.g., 0 for January).

      * @param startDay        The day of the month on which the daylight saving time starts.

      * @param startDayOfWeek  The daylight saving time starting day-of-week.

      * @param startTime       The daylight saving time starting time in local wall clock

      *                        time, which is local standard time in this case.

      * @param after           If true, this rule selects the first <code>dayOfWeek</code> on or

      *                        <em>after</em> <code>dayOfMonth</code>.  If false, this rule

      *                        selects the last <code>dayOfWeek</code> on or <em>before</em>

      *                        <code>dayOfMonth</code>.

      * @exception IllegalArgumentException if the <code>startMonth</code>, <code>startDay</code>,

      * <code>startDayOfWeek</code>, or <code>startTime</code> parameters are out of range

      * @since 1.2

      */

     public void setStartRule(int startMonth, int startDay, int startDayOfWeek,

                              int startTime, boolean after)

     {

         // TODO: this method doesn't check the initial values of dayOfMonth or dayOfWeek.

         if (after) {

             setStartRule(startMonth, startDay, -startDayOfWeek, startTime);

         } else {

             setStartRule(startMonth, -startDay, -startDayOfWeek, startTime);

         }

     }

     /**

      * Sets the daylight saving time end rule. For example, if daylight saving time

      * ends on the last Sunday in October at 2 am in wall clock time,

      * you can set the end rule by calling:

      * <code>setEndRule(Calendar.OCTOBER, -1, Calendar.SUNDAY, 2*60*60*1000);</code>

      *

      * @param endMonth        The daylight saving time ending month. Month is

      *                        a {@link Calendar#MONTH MONTH} field

      *                        value (0-based. e.g., 9 for October).

      * @param endDay          The day of the month on which the daylight saving time ends.

      *                        See the class description for the special cases of this parameter.

      * @param endDayOfWeek    The daylight saving time ending day-of-week.

      *                        See the class description for the special cases of this parameter.

      * @param endTime         The daylight saving ending time in local wall clock time,

      *                        (in milliseconds within the day) which is local daylight

      *                        time in this case.

      * @exception IllegalArgumentException if the <code>endMonth</code>, <code>endDay</code>,

      * <code>endDayOfWeek</code>, or <code>endTime</code> parameters are out of range

      */

     public void setEndRule(int endMonth, int endDay, int endDayOfWeek,

                            int endTime)

     {

         this.endMonth = endMonth;

         this.endDay = endDay;

         this.endDayOfWeek = endDayOfWeek;

         this.endTime = endTime;

         this.endTimeMode = WALL_TIME;

         decodeEndRule();

         invalidateCache();

     }

     /**

      * Sets the daylight saving time end rule to a fixed date within a month.

      * This method is equivalent to:

      * <pre><code>setEndRule(endMonth, endDay, 0, endTime)</code></pre>

      *

      * @param endMonth        The daylight saving time ending month. Month is

      *                        a {@link Calendar#MONTH MONTH} field

      *                        value (0-based. e.g., 9 for October).

      * @param endDay          The day of the month on which the daylight saving time ends.

      * @param endTime         The daylight saving ending time in local wall clock time,

      *                        (in milliseconds within the day) which is local daylight

      *                        time in this case.

      * @exception IllegalArgumentException the <code>endMonth</code>, <code>endDay</code>,

      * or <code>endTime</code> parameters are out of range

      * @since 1.2

      */

     public void setEndRule(int endMonth, int endDay, int endTime)

     {

         setEndRule(endMonth, endDay, 0, endTime);

     }

     /**

      * Sets the daylight saving time end rule to a weekday before or after the given date within

      * a month, e.g., the first Monday on or after the 8th.

      *

      * @param endMonth        The daylight saving time ending month. Month is

      *                        a {@link Calendar#MONTH MONTH} field

      *                        value (0-based. e.g., 9 for October).

      * @param endDay          The day of the month on which the daylight saving time ends.

      * @param endDayOfWeek    The daylight saving time ending day-of-week.

      * @param endTime         The daylight saving ending time in local wall clock time,

      *                        (in milliseconds within the day) which is local daylight

      *                        time in this case.

      * @param after           If true, this rule selects the first <code>endDayOfWeek</code> on

      *                        or <em>after</em> <code>endDay</code>.  If false, this rule

      *                        selects the last <code>endDayOfWeek</code> on or before

      *                        <code>endDay</code> of the month.

      * @exception IllegalArgumentException the <code>endMonth</code>, <code>endDay</code>,

      * <code>endDayOfWeek</code>, or <code>endTime</code> parameters are out of range

      * @since 1.2

      */

     public void setEndRule(int endMonth, int endDay, int endDayOfWeek, int endTime, boolean after)

     {

         if (after) {

             setEndRule(endMonth, endDay, -endDayOfWeek, endTime);

         } else {

             setEndRule(endMonth, -endDay, -endDayOfWeek, endTime);

         }

     }

     /**

      * Returns the offset of this time zone from UTC at the given

      * time. If daylight saving time is in effect at the given time,

      * the offset value is adjusted with the amount of daylight

      * saving.

      *

      * @param date the time at which the time zone offset is found

      * @return the amount of time in milliseconds to add to UTC to get

      * local time.

      * @since 1.4

      */

     public int getOffset(long date) {

         return getOffsets(date, null);

     }

     /**

      * @see TimeZone#getOffsets

      */

     int getOffsets(long date, int[] offsets) {

         int offset = rawOffset;

       computeOffset:

         if (useDaylight) {

             synchronized (this) {

                 if (cacheStart != 0) {

                     if (date >= cacheStart && date < cacheEnd) {

                         offset += dstSavings;

                         break computeOffset;

                     }

                 }

             }

             BaseCalendar cal = date >= GregorianCalendar.DEFAULT_GREGORIAN_CUTOVER ?

                 gcal : (BaseCalendar) CalendarSystem.forName("julian");

             BaseCalendar.Date cdate = (BaseCalendar.Date) cal.newCalendarDate(TimeZone.NO_TIMEZONE);

             // Get the year in local time

             cal.getCalendarDate(date + rawOffset, cdate);

             int year = cdate.getNormalizedYear();

             if (year >= startYear) {

                 // Clear time elements for the transition calculations

                 cdate.setTimeOfDay(0, 0, 0, 0);

                 offset = getOffset(cal, cdate, year, date);

             }

         }

         if (offsets != null) {

             offsets[0] = rawOffset;

             offsets[1] = offset - rawOffset;

         }

         return offset;

     }

    /**

      * Returns the difference in milliseconds between local time and

      * UTC, taking into account both the raw offset and the effect of

      * daylight saving, for the specified date and time.  This method

      * assumes that the start and end month are distinct.  It also

      * uses a default {@link GregorianCalendar} object as its

      * underlying calendar, such as for determining leap years.  Do

      * not use the result of this method with a calendar other than a

      * default <code>GregorianCalendar</code>.

      *

      * <p><em>Note:  In general, clients should use

      * <code>Calendar.get(ZONE_OFFSET) + Calendar.get(DST_OFFSET)</code>

      * instead of calling this method.</em>

      *

      * @param era       The era of the given date.

      * @param year      The year in the given date.

      * @param month     The month in the given date. Month is 0-based. e.g.,

      *                  0 for January.

      * @param day       The day-in-month of the given date.

      * @param dayOfWeek The day-of-week of the given date.

      * @param millis    The milliseconds in day in <em>standard</em> local time.

      * @return          The milliseconds to add to UTC to get local time.

      * @exception       IllegalArgumentException the <code>era</code>,

      *                  <code>month</code>, <code>day</code>, <code>dayOfWeek</code>,

      *                  or <code>millis</code> parameters are out of range

      */

     public int getOffset(int era, int year, int month, int day, int dayOfWeek,

                          int millis)

     {

         if (era != GregorianCalendar.AD && era != GregorianCalendar.BC) {

             throw new IllegalArgumentException("Illegal era " + era);

         }

         int y = year;

         if (era == GregorianCalendar.BC) {

             // adjust y with the GregorianCalendar-style year numbering.

             y = 1 - y;

         }

         // If the year isn't representable with the 64-bit long

         // integer in milliseconds, convert the year to an

         // equivalent year. This is required to pass some JCK test cases

         // which are actually useless though because the specified years

         // can't be supported by the Java time system.

         if (y >= 292278994) {

             y = 2800 + y % 2800;

         } else if (y <= -292269054) {

             // y %= 28 also produces an equivalent year, but positive

             // year numbers would be convenient to use the UNIX cal

             // command.

             y = (int) CalendarUtils.mod((long) y, 28);

         }

         // convert year to its 1-based month value

         int m = month + 1;

         // First, calculate time as a Gregorian date.

         BaseCalendar cal = gcal;

         BaseCalendar.Date cdate = (BaseCalendar.Date) cal.newCalendarDate(TimeZone.NO_TIMEZONE);

         cdate.setDate(y, m, day);

         long time = cal.getTime(cdate); // normalize cdate

         time += millis - rawOffset; // UTC time

         // If the time value represents a time before the default

         // Gregorian cutover, recalculate time using the Julian

         // calendar system. For the Julian calendar system, the

         // normalized year numbering is ..., -2 (BCE 2), -1 (BCE 1),

         // 1, 2 ... which is different from the GregorianCalendar

         // style year numbering (..., -1, 0 (BCE 1), 1, 2, ...).

         if (time < GregorianCalendar.DEFAULT_GREGORIAN_CUTOVER) {

             cal = (BaseCalendar) CalendarSystem.forName("julian");

             cdate = (BaseCalendar.Date) cal.newCalendarDate(TimeZone.NO_TIMEZONE);

             cdate.setNormalizedDate(y, m, day);

             time = cal.getTime(cdate) + millis - rawOffset;

         }

         if ((cdate.getNormalizedYear() != y)

             || (cdate.getMonth() != m)

             || (cdate.getDayOfMonth() != day)

             // The validation should be cdate.getDayOfWeek() ==

             // dayOfWeek. However, we don't check dayOfWeek for

             // compatibility.

             || (dayOfWeek < Calendar.SUNDAY || dayOfWeek > Calendar.SATURDAY)

             || (millis < 0 || millis >= (24*60*60*1000))) {

             throw new IllegalArgumentException();

         }

         if (!useDaylight || year < startYear || era != GregorianCalendar.CE) {

             return rawOffset;

         }

         return getOffset(cal, cdate, y, time);

     }

     private int getOffset(BaseCalendar cal, BaseCalendar.Date cdate, int year, long time) {

         synchronized (this) {

             if (cacheStart != 0) {

                 if (time >= cacheStart && time < cacheEnd) {

                     return rawOffset + dstSavings;

                 }

                 if (year == cacheYear) {

                     return rawOffset;

                 }

             }

         }

         long start = getStart(cal, cdate, year);

         long end = getEnd(cal, cdate, year);

         int offset = rawOffset;

         if (start <= end) {

             if (time >= start && time < end) {

                 offset += dstSavings;

             }

             synchronized (this) {

                 cacheYear = year;

                 cacheStart = start;

                 cacheEnd = end;

             }

         } else {

             if (time < end) {

                 // TODO: support Gregorian cutover. The previous year

                 // may be in the other calendar system.

                 start = getStart(cal, cdate, year - 1);

                 if (time >= start) {

                     offset += dstSavings;

                 }

             } else if (time >= start) {

                 // TODO: support Gregorian cutover. The next year

                 // may be in the other calendar system.

                 end = getEnd(cal, cdate, year + 1);

                 if (time < end) {

                     offset += dstSavings;

                 }

             }

             if (start <= end) {

                 synchronized (this) {

                     // The start and end transitions are in multiple years.

                     cacheYear = (long) startYear - 1;

                     cacheStart = start;

                     cacheEnd = end;

                 }

             }

         }

         return offset;

     }

     private long getStart(BaseCalendar cal, BaseCalendar.Date cdate, int year) {

         int time = startTime;

         if (startTimeMode != UTC_TIME) {

             time -= rawOffset;

         }

         return getTransition(cal, cdate, startMode, year, startMonth, startDay,

                              startDayOfWeek, time);

     }

     private long getEnd(BaseCalendar cal, BaseCalendar.Date cdate, int year) {

         int time = endTime;

         if (endTimeMode != UTC_TIME) {

             time -= rawOffset;

         }

         if (endTimeMode == WALL_TIME) {

             time -= dstSavings;

         }

         return getTransition(cal, cdate, endMode, year, endMonth, endDay,

                                         endDayOfWeek, time);

     }

     private long getTransition(BaseCalendar cal, BaseCalendar.Date cdate,

                                int mode, int year, int month, int dayOfMonth,

                                int dayOfWeek, int timeOfDay) {

         cdate.setNormalizedYear(year);

         cdate.setMonth(month + 1);

         switch (mode) {

         case DOM_MODE:

             cdate.setDayOfMonth(dayOfMonth);

             break;

         case DOW_IN_MONTH_MODE:

             cdate.setDayOfMonth(1);

             if (dayOfMonth < 0) {

                 cdate.setDayOfMonth(cal.getMonthLength(cdate));

             }

             cdate = (BaseCalendar.Date) cal.getNthDayOfWeek(dayOfMonth, dayOfWeek, cdate);

             break;

         case DOW_GE_DOM_MODE:

             cdate.setDayOfMonth(dayOfMonth);

             cdate = (BaseCalendar.Date) cal.getNthDayOfWeek(1, dayOfWeek, cdate);

             break;

         case DOW_LE_DOM_MODE:

             cdate.setDayOfMonth(dayOfMonth);

             cdate = (BaseCalendar.Date) cal.getNthDayOfWeek(-1, dayOfWeek, cdate);

             break;

         }

         return cal.getTime(cdate) + timeOfDay;

     }

     /**

      * Gets the GMT offset for this time zone.

      * @return the GMT offset value in milliseconds

      * @see #setRawOffset

      */

     public int getRawOffset()

     {

         // The given date will be taken into account while

         // we have the historical time zone data in place.

         return rawOffset;

     }

     /**

      * Sets the base time zone offset to GMT.

      * This is the offset to add to UTC to get local time.

      * @see #getRawOffset

      */

     public void setRawOffset(int offsetMillis)

     {

         this.rawOffset = offsetMillis;

     }

     /**

      * Sets the amount of time in milliseconds that the clock is advanced

      * during daylight saving time.

      * @param millisSavedDuringDST the number of milliseconds the time is

      * advanced with respect to standard time when the daylight saving time rules

      * are in effect. A positive number, typically one hour (3600000).

      * @see #getDSTSavings

      * @since 1.2

      */

     public void setDSTSavings(int millisSavedDuringDST) {

         if (millisSavedDuringDST <= 0) {

             throw new IllegalArgumentException("Illegal daylight saving value: "

                                                + millisSavedDuringDST);

         }

         dstSavings = millisSavedDuringDST;

     }

     /**

      * Returns the amount of time in milliseconds that the clock is

      * advanced during daylight saving time.

      *

      * @return the number of milliseconds the time is advanced with

      * respect to standard time when the daylight saving rules are in

      * effect, or 0 (zero) if this time zone doesn't observe daylight

      * saving time.

      *

      * @see #setDSTSavings

      * @since 1.2

      */

     public int getDSTSavings() {

         return useDaylight ? dstSavings : 0;

     }

     /**

      * Queries if this time zone uses daylight saving time.

      * @return true if this time zone uses daylight saving time;

      * false otherwise.

      */

     public boolean useDaylightTime()

     {

         return useDaylight;

     }

     /**

      * Returns {@code true} if this {@code SimpleTimeZone} observes

      * Daylight Saving Time. This method is equivalent to {@link

      * #useDaylightTime()}.

      *

      * @return {@code true} if this {@code SimpleTimeZone} observes

      * Daylight Saving Time; {@code false} otherwise.

      * @since 1.7

      */

     @Override

     public boolean observesDaylightTime() {

         return useDaylightTime();

     }

     /**

      * Queries if the given date is in daylight saving time.

      * @return true if daylight saving time is in effective at the

      * given date; false otherwise.

      */

     public boolean inDaylightTime(Date date)

     {

         return (getOffset(date.getTime()) != rawOffset);

     }

     /**

      * Returns a clone of this <code>SimpleTimeZone</code> instance.

      * @return a clone of this instance.

      */

     public Object clone()

     {

         return super.clone();

     }

     /**

      * Generates the hash code for the SimpleDateFormat object.

      * @return the hash code for this object

      */

     public synchronized int hashCode()

     {

         return startMonth ^ startDay ^ startDayOfWeek ^ startTime ^

             endMonth ^ endDay ^ endDayOfWeek ^ endTime ^ rawOffset;

     }

     /**

      * Compares the equality of two <code>SimpleTimeZone</code> objects.

      *

      * @param obj  The <code>SimpleTimeZone</code> object to be compared with.

      * @return     True if the given <code>obj</code> is the same as this

      *             <code>SimpleTimeZone</code> object; false otherwise.

      */

     public boolean equals(Object obj)

     {

         if (this == obj) {

             return true;

         }

         if (!(obj instanceof SimpleTimeZone)) {

             return false;

         }

         SimpleTimeZone that = (SimpleTimeZone) obj;

         return getID().equals(that.getID()) &&

             hasSameRules(that);

     }

     /**

      * Returns <code>true</code> if this zone has the same rules and offset as another zone.

      * @param other the TimeZone object to be compared with

      * @return <code>true</code> if the given zone is a SimpleTimeZone and has the

      * same rules and offset as this one

      * @since 1.2

      */

     public boolean hasSameRules(TimeZone other) {

         if (this == other) {

             return true;

         }

         if (!(other instanceof SimpleTimeZone)) {

             return false;

         }

         SimpleTimeZone that = (SimpleTimeZone) other;

         return rawOffset == that.rawOffset &&

             useDaylight == that.useDaylight &&

             (!useDaylight

              // Only check rules if using DST

              || (dstSavings == that.dstSavings &&

                  startMode == that.startMode &&

                  startMonth == that.startMonth &&

                  startDay == that.startDay &&

                  startDayOfWeek == that.startDayOfWeek &&

                  startTime == that.startTime &&

                  startTimeMode == that.startTimeMode &&

                  endMode == that.endMode &&

                  endMonth == that.endMonth &&

                  endDay == that.endDay &&

                  endDayOfWeek == that.endDayOfWeek &&

                  endTime == that.endTime &&

                  endTimeMode == that.endTimeMode &&

                  startYear == that.startYear));

     }

     /**

      * Returns a string representation of this time zone.

      * @return a string representation of this time zone.

      */

     public String toString() {

         return getClass().getName() +

             "[id=" + getID() +

             ",offset=" + rawOffset +

             ",dstSavings=" + dstSavings +

             ",useDaylight=" + useDaylight +

             ",startYear=" + startYear +

             ",startMode=" + startMode +

             ",startMonth=" + startMonth +

             ",startDay=" + startDay +

             ",startDayOfWeek=" + startDayOfWeek +

             ",startTime=" + startTime +

             ",startTimeMode=" + startTimeMode +

             ",endMode=" + endMode +

             ",endMonth=" + endMonth +

             ",endDay=" + endDay +

             ",endDayOfWeek=" + endDayOfWeek +

             ",endTime=" + endTime +

             ",endTimeMode=" + endTimeMode + ']';

     }

     // =======================privates===============================

     /**

      * The month in which daylight saving time starts.  This value must be

      * between <code>Calendar.JANUARY</code> and

      * <code>Calendar.DECEMBER</code> inclusive.  This value must not equal

      * <code>endMonth</code>.

      * <p>If <code>useDaylight</code> is false, this value is ignored.

      * @serial

      */

     private int startMonth;

     /**

      * This field has two possible interpretations:

      * <dl>

      * <dt><code>startMode == DOW_IN_MONTH</code></dt>

      * <dd>

      * <code>startDay</code> indicates the day of the month of

      * <code>startMonth</code> on which daylight

      * saving time starts, from 1 to 28, 30, or 31, depending on the

      * <code>startMonth</code>.

      * </dd>

      * <dt><code>startMode != DOW_IN_MONTH</code></dt>

      * <dd>

      * <code>startDay</code> indicates which <code>startDayOfWeek</code> in the

      * month <code>startMonth</code> daylight

      * saving time starts on.  For example, a value of +1 and a

      * <code>startDayOfWeek</code> of <code>Calendar.SUNDAY</code> indicates the

      * first Sunday of <code>startMonth</code>.  Likewise, +2 would indicate the

      * second Sunday, and -1 the last Sunday.  A value of 0 is illegal.

      * </dd>

      * </dl>

      * <p>If <code>useDaylight</code> is false, this value is ignored.

      * @serial

      */

     private int startDay;

     /**

      * The day of the week on which daylight saving time starts.  This value

      * must be between <code>Calendar.SUNDAY</code> and

      * <code>Calendar.SATURDAY</code> inclusive.

      * <p>If <code>useDaylight</code> is false or

      * <code>startMode == DAY_OF_MONTH</code>, this value is ignored.

      * @serial

      */

     private int startDayOfWeek;

     /**

      * The time in milliseconds after midnight at which daylight saving

      * time starts.  This value is expressed as wall time, standard time,

      * or UTC time, depending on the setting of <code>startTimeMode</code>.

      * <p>If <code>useDaylight</code> is false, this value is ignored.

      * @serial

      */

     private int startTime;

     /**

      * The format of startTime, either WALL_TIME, STANDARD_TIME, or UTC_TIME.

      * @serial

      * @since 1.3

      */

     private int startTimeMode;

     /**

      * The month in which daylight saving time ends.  This value must be

      * between <code>Calendar.JANUARY</code> and

      * <code>Calendar.UNDECIMBER</code>.  This value must not equal

      * <code>startMonth</code>.

      * <p>If <code>useDaylight</code> is false, this value is ignored.

      * @serial

      */

     private int endMonth;

     /**

      * This field has two possible interpretations:

      * <dl>

      * <dt><code>endMode == DOW_IN_MONTH</code></dt>

      * <dd>

      * <code>endDay</code> indicates the day of the month of

      * <code>endMonth</code> on which daylight

      * saving time ends, from 1 to 28, 30, or 31, depending on the

      * <code>endMonth</code>.

      * </dd>

      * <dt><code>endMode != DOW_IN_MONTH</code></dt>

      * <dd>

      * <code>endDay</code> indicates which <code>endDayOfWeek</code> in th

      * month <code>endMonth</code> daylight

      * saving time ends on.  For example, a value of +1 and a

      * <code>endDayOfWeek</code> of <code>Calendar.SUNDAY</code> indicates the

      * first Sunday of <code>endMonth</code>.  Likewise, +2 would indicate the

      * second Sunday, and -1 the last Sunday.  A value of 0 is illegal.

      * </dd>

      * </dl>

      * <p>If <code>useDaylight</code> is false, this value is ignored.

      * @serial

      */

     private int endDay;

     /**

      * The day of the week on which daylight saving time ends.  This value

      * must be between <code>Calendar.SUNDAY</code> and

      * <code>Calendar.SATURDAY</code> inclusive.

      * <p>If <code>useDaylight</code> is false or

      * <code>endMode == DAY_OF_MONTH</code>, this value is ignored.

      * @serial

      */

     private int endDayOfWeek;

     /**

      * The time in milliseconds after midnight at which daylight saving

      * time ends.  This value is expressed as wall time, standard time,

      * or UTC time, depending on the setting of <code>endTimeMode</code>.

      * <p>If <code>useDaylight</code> is false, this value is ignored.

      * @serial

      */

     private int endTime;

     /**

      * The format of endTime, either <code>WALL_TIME</code>,

      * <code>STANDARD_TIME</code>, or <code>UTC_TIME</code>.

      * @serial

      * @since 1.3

      */

     private int endTimeMode;

     /**

      * The year in which daylight saving time is first observed.  This is an {@link GregorianCalendar#AD AD}

      * value.  If this value is less than 1 then daylight saving time is observed

      * for all <code>AD</code> years.

      * <p>If <code>useDaylight</code> is false, this value is ignored.

      * @serial

      */

     private int startYear;

     /**

      * The offset in milliseconds between this zone and GMT.  Negative offsets

      * are to the west of Greenwich.  To obtain local <em>standard</em> time,

      * add the offset to GMT time.  To obtain local wall time it may also be

      * necessary to add <code>dstSavings</code>.

      * @serial

      */

     private int rawOffset;

     /**

      * A boolean value which is true if and only if this zone uses daylight

      * saving time.  If this value is false, several other fields are ignored.

      * @serial

      */

     private boolean useDaylight=false; // indicate if this time zone uses DST

     private static final int millisPerHour = 60*60*1000;

     private static final int millisPerDay  = 24*millisPerHour;

     /**

      * This field was serialized in JDK 1.1, so we have to keep it that way

      * to maintain serialization compatibility. However, there's no need to

      * recreate the array each time we create a new time zone.

      * @serial An array of bytes containing the values {31, 28, 31, 30, 31, 30,

      * 31, 31, 30, 31, 30, 31}.  This is ignored as of the Java 2 platform v1.2, however, it must

      * be streamed out for compatibility with JDK 1.1.

      */

     private final byte monthLength[] = staticMonthLength;

     private final static byte staticMonthLength[] = {31,28,31,30,31,30,31,31,30,31,30,31};

     private final static byte staticLeapMonthLength[] = {31,29,31,30,31,30,31,31,30,31,30,31};

     /**

      * Variables specifying the mode of the start rule.  Takes the following

      * values:

      * <dl>

      * <dt><code>DOM_MODE</code></dt>

      * <dd>

      * Exact day of week; e.g., March 1.

      * </dd>

      * <dt><code>DOW_IN_MONTH_MODE</code></dt>

      * <dd>

      * Day of week in month; e.g., last Sunday in March.

      * </dd>

      * <dt><code>DOW_GE_DOM_MODE</code></dt>

      * <dd>

      * Day of week after day of month; e.g., Sunday on or after March 15.

      * </dd>

      * <dt><code>DOW_LE_DOM_MODE</code></dt>

      * <dd>

      * Day of week before day of month; e.g., Sunday on or before March 15.

      * </dd>

      * </dl>

      * The setting of this field affects the interpretation of the

      * <code>startDay</code> field.

      * <p>If <code>useDaylight</code> is false, this value is ignored.

      * @serial

      * @since 1.1.4

      */

     private int startMode;

     /**

      * Variables specifying the mode of the end rule.  Takes the following

      * values:

      * <dl>

      * <dt><code>DOM_MODE</code></dt>

      * <dd>

      * Exact day of week; e.g., March 1.

      * </dd>

      * <dt><code>DOW_IN_MONTH_MODE</code></dt>

      * <dd>

      * Day of week in month; e.g., last Sunday in March.

      * </dd>

      * <dt><code>DOW_GE_DOM_MODE</code></dt>

      * <dd>

      * Day of week after day of month; e.g., Sunday on or after March 15.

      * </dd>

      * <dt><code>DOW_LE_DOM_MODE</code></dt>

      * <dd>

      * Day of week before day of month; e.g., Sunday on or before March 15.

      * </dd>

      * </dl>

      * The setting of this field affects the interpretation of the

      * <code>endDay</code> field.

      * <p>If <code>useDaylight</code> is false, this value is ignored.

      * @serial

      * @since 1.1.4

      */

     private int endMode;

     /**

      * A positive value indicating the amount of time saved during DST in

      * milliseconds.

      * Typically one hour (3600000); sometimes 30 minutes (1800000).

      * <p>If <code>useDaylight</code> is false, this value is ignored.

      * @serial

      * @since 1.1.4

      */

     private int dstSavings;

     private static final Gregorian gcal = CalendarSystem.getGregorianCalendar();

     /**

      * Cache values representing a single period of daylight saving

      * time. When the cache values are valid, cacheStart is the start

      * time (inclusive) of daylight saving time and cacheEnd is the

      * end time (exclusive).

      *

      * cacheYear has a year value if both cacheStart and cacheEnd are

      * in the same year. cacheYear is set to startYear - 1 if

      * cacheStart and cacheEnd are in different years. cacheStart is 0

      * if the cache values are void. cacheYear is a long to support

      * Integer.MIN_VALUE - 1 (JCK requirement).

      */

     private transient long cacheYear;

     private transient long cacheStart;

     private transient long cacheEnd;

     /**

      * Constants specifying values of startMode and endMode.

      */

     private static final int DOM_MODE          = 1; // Exact day of month, "Mar 1"

     private static final int DOW_IN_MONTH_MODE = 2; // Day of week in month, "lastSun"

     private static final int DOW_GE_DOM_MODE   = 3; // Day of week after day of month, "Sun>=15"

     private static final int DOW_LE_DOM_MODE   = 4; // Day of week before day of month, "Sun<=21"

     /**

      * Constant for a mode of start or end time specified as wall clock

      * time.  Wall clock time is standard time for the onset rule, and

      * daylight time for the end rule.

      * @since 1.4

      */

     public static final int WALL_TIME = 0; // Zero for backward compatibility

     /**

      * Constant for a mode of start or end time specified as standard time.

      * @since 1.4

      */

     public static final int STANDARD_TIME = 1;

     /**

      * Constant for a mode of start or end time specified as UTC. European

      * Union rules are specified as UTC time, for example.

      * @since 1.4

      */

     public static final int UTC_TIME = 2;

     // Proclaim compatibility with 1.1

     static final long serialVersionUID = -403250971215465050L;

     // the internal serial version which says which version was written

     // - 0 (default) for version up to JDK 1.1.3

     // - 1 for version from JDK 1.1.4, which includes 3 new fields

     // - 2 for JDK 1.3, which includes 2 new fields

     static final int currentSerialVersion = 2;

     /**

      * The version of the serialized data on the stream.  Possible values:

      * <dl>

      * <dt><b>0</b> or not present on stream</dt>

      * <dd>

      * JDK 1.1.3 or earlier.

      * </dd>

      * <dt><b>1</b></dt>

      * <dd>

      * JDK 1.1.4 or later.  Includes three new fields: <code>startMode</code>,

      * <code>endMode</code>, and <code>dstSavings</code>.

      * </dd>

      * <dt><b>2</b></dt>

      * <dd>

      * JDK 1.3 or later.  Includes two new fields: <code>startTimeMode</code>

      * and <code>endTimeMode</code>.

      * </dd>

      * </dl>

      * When streaming out this class, the most recent format

      * and the highest allowable <code>serialVersionOnStream</code>

      * is written.

      * @serial

      * @since 1.1.4

      */

     private int serialVersionOnStream = currentSerialVersion;

     synchronized private void invalidateCache() {

         cacheYear = startYear - 1;

         cacheStart = cacheEnd = 0;

     }

     //----------------------------------------------------------------------

     // Rule representation

     //

     // We represent the following flavors of rules:

     //       5        the fifth of the month

     //       lastSun  the last Sunday in the month

     //       lastMon  the last Monday in the month

     //       Sun>=8   first Sunday on or after the eighth

     //       Sun<=25  last Sunday on or before the 25th

     // This is further complicated by the fact that we need to remain

     // backward compatible with the 1.1 FCS.  Finally, we need to minimize

     // API changes.  In order to satisfy these requirements, we support

     // three representation systems, and we translate between them.

     //

     // INTERNAL REPRESENTATION

     // This is the format SimpleTimeZone objects take after construction or

     // streaming in is complete.  Rules are represented directly, using an

     // unencoded format.  We will discuss the start rule only below; the end

     // rule is analogous.

     //   startMode      Takes on enumerated values DAY_OF_MONTH,

     //                  DOW_IN_MONTH, DOW_AFTER_DOM, or DOW_BEFORE_DOM.

     //   startDay       The day of the month, or for DOW_IN_MONTH mode, a

     //                  value indicating which DOW, such as +1 for first,

     //                  +2 for second, -1 for last, etc.

     //   startDayOfWeek The day of the week.  Ignored for DAY_OF_MONTH.

     //

     // ENCODED REPRESENTATION

     // This is the format accepted by the constructor and by setStartRule()

     // and setEndRule().  It uses various combinations of positive, negative,

     // and zero values to encode the different rules.  This representation

     // allows us to specify all the different rule flavors without altering

     // the API.

     //   MODE              startMonth    startDay    startDayOfWeek

     //   DOW_IN_MONTH_MODE >=0           !=0         >0

     //   DOM_MODE          >=0           >0          ==0

     //   DOW_GE_DOM_MODE   >=0           >0          <0

     //   DOW_LE_DOM_MODE   >=0           <0          <0

     //   (no DST)          don't care    ==0         don't care

     //

     // STREAMED REPRESENTATION

     // We must retain binary compatibility with the 1.1 FCS.  The 1.1 code only

     // handles DOW_IN_MONTH_MODE and non-DST mode, the latter indicated by the

     // flag useDaylight.  When we stream an object out, we translate into an

     // approximate DOW_IN_MONTH_MODE representation so the object can be parsed

     // and used by 1.1 code.  Following that, we write out the full

     // representation separately so that contemporary code can recognize and

     // parse it.  The full representation is written in a "packed" format,

     // consisting of a version number, a length, and an array of bytes.  Future

     // versions of this class may specify different versions.  If they wish to

     // include additional data, they should do so by storing them after the

     // packed representation below.

     //----------------------------------------------------------------------

     /**

      * Given a set of encoded rules in startDay and startDayOfMonth, decode

      * them and set the startMode appropriately.  Do the same for endDay and

      * endDayOfMonth.  Upon entry, the day of week variables may be zero or

      * negative, in order to indicate special modes.  The day of month

      * variables may also be negative.  Upon exit, the mode variables will be

      * set, and the day of week and day of month variables will be positive.

      * This method also recognizes a startDay or endDay of zero as indicating

      * no DST.

      */

     private void decodeRules()

     {

         decodeStartRule();

         decodeEndRule();

     }

     /**

      * Decode the start rule and validate the parameters.  The parameters are

      * expected to be in encoded form, which represents the various rule modes

      * by negating or zeroing certain values.  Representation formats are:

      * <p>

      * <pre>

      *            DOW_IN_MONTH  DOM    DOW>=DOM  DOW<=DOM  no DST

      *            ------------  -----  --------  --------  ----------

      * month       0..11        same    same      same     don't care

      * day        -5..5         1..31   1..31    -1..-31   0

      * dayOfWeek   1..7         0      -1..-7    -1..-7    don't care

      * time        0..ONEDAY    same    same      same     don't care

      * </pre>

      * The range for month does not include UNDECIMBER since this class is

      * really specific to GregorianCalendar, which does not use that month.

      * The range for time includes ONEDAY (vs. ending at ONEDAY-1) because the

      * end rule is an exclusive limit point.  That is, the range of times that

      * are in DST include those >= the start and < the end.  For this reason,

      * it should be possible to specify an end of ONEDAY in order to include the

      * entire day.  Although this is equivalent to time 0 of the following day,

      * it's not always possible to specify that, for example, on December 31.

      * While arguably the start range should still be 0..ONEDAY-1, we keep

      * the start and end ranges the same for consistency.

      */

     private void decodeStartRule() {

         useDaylight = (startDay != 0) && (endDay != 0);

         if (startDay != 0) {

             if (startMonth < Calendar.JANUARY || startMonth > Calendar.DECEMBER) {

                 throw new IllegalArgumentException(

                         "Illegal start month " + startMonth);

             }

             if (startTime < 0 || startTime > millisPerDay) {

                 throw new IllegalArgumentException(

                         "Illegal start time " + startTime);

             }

             if (startDayOfWeek == 0) {

                 startMode = DOM_MODE;

             } else {

                 if (startDayOfWeek > 0) {

                     startMode = DOW_IN_MONTH_MODE;

                 } else {

                     startDayOfWeek = -startDayOfWeek;

                     if (startDay > 0) {

                         startMode = DOW_GE_DOM_MODE;

                     } else {

                         startDay = -startDay;

                         startMode = DOW_LE_DOM_MODE;

                     }

                 }

                 if (startDayOfWeek > Calendar.SATURDAY) {

                     throw new IllegalArgumentException(

                            "Illegal start day of week " + startDayOfWeek);

                 }

             }

             if (startMode == DOW_IN_MONTH_MODE) {

                 if (startDay < -5 || startDay > 5) {

                     throw new IllegalArgumentException(

                             "Illegal start day of week in month " + startDay);

                 }

             } else if (startDay < 1 || startDay > staticMonthLength[startMonth]) {

                 throw new IllegalArgumentException(

                         "Illegal start day " + startDay);

             }

         }

     }

     /**

      * Decode the end rule and validate the parameters.  This method is exactly

      * analogous to decodeStartRule().

      * @see decodeStartRule

      */

     private void decodeEndRule() {

         useDaylight = (startDay != 0) && (endDay != 0);

         if (endDay != 0) {

             if (endMonth < Calendar.JANUARY || endMonth > Calendar.DECEMBER) {

                 throw new IllegalArgumentException(

                         "Illegal end month " + endMonth);

             }

             if (endTime < 0 || endTime > millisPerDay) {

                 throw new IllegalArgumentException(

                         "Illegal end time " + endTime);

             }

             if (endDayOfWeek == 0) {

                 endMode = DOM_MODE;

             } else {

                 if (endDayOfWeek > 0) {

                     endMode = DOW_IN_MONTH_MODE;

                 } else {

                     endDayOfWeek = -endDayOfWeek;

                     if (endDay > 0) {

                         endMode = DOW_GE_DOM_MODE;

                     } else {

                         endDay = -endDay;

                         endMode = DOW_LE_DOM_MODE;

                     }

                 }

                 if (endDayOfWeek > Calendar.SATURDAY) {

                     throw new IllegalArgumentException(

                            "Illegal end day of week " + endDayOfWeek);

                 }

             }

             if (endMode == DOW_IN_MONTH_MODE) {

                 if (endDay < -5 || endDay > 5) {

                     throw new IllegalArgumentException(

                             "Illegal end day of week in month " + endDay);

                 }

             } else if (endDay < 1 || endDay > staticMonthLength[endMonth]) {

                 throw new IllegalArgumentException(

                         "Illegal end day " + endDay);

             }

         }

     }

     /**

      * Make rules compatible to 1.1 FCS code.  Since 1.1 FCS code only understands

      * day-of-week-in-month rules, we must modify other modes of rules to their

      * approximate equivalent in 1.1 FCS terms.  This method is used when streaming

      * out objects of this class.  After it is called, the rules will be modified,

      * with a possible loss of information.  startMode and endMode will NOT be

      * altered, even though semantically they should be set to DOW_IN_MONTH_MODE,

      * since the rule modification is only intended to be temporary.

      */

     private void makeRulesCompatible()

     {

         switch (startMode) {

         case DOM_MODE:

             startDay = 1 + (startDay / 7);

             startDayOfWeek = Calendar.SUNDAY;

             break;

         case DOW_GE_DOM_MODE:

             // A day-of-month of 1 is equivalent to DOW_IN_MONTH_MODE

             // that is, Sun>=1 == firstSun.

             if (startDay != 1) {

                 startDay = 1 + (startDay / 7);

             }

             break;

         case DOW_LE_DOM_MODE:

             if (startDay >= 30) {

                 startDay = -1;

             } else {

                 startDay = 1 + (startDay / 7);

             }

             break;

         }

         switch (endMode) {

         case DOM_MODE:

             endDay = 1 + (endDay / 7);

             endDayOfWeek = Calendar.SUNDAY;

             break;

         case DOW_GE_DOM_MODE:

             // A day-of-month of 1 is equivalent to DOW_IN_MONTH_MODE

             // that is, Sun>=1 == firstSun.

             if (endDay != 1) {

                 endDay = 1 + (endDay / 7);

             }

             break;

         case DOW_LE_DOM_MODE:

             if (endDay >= 30) {

                 endDay = -1;

             } else {

                 endDay = 1 + (endDay / 7);

             }

             break;

         }

         /*

          * Adjust the start and end times to wall time.  This works perfectly

          * well unless it pushes into the next or previous day.  If that

          * happens, we attempt to adjust the day rule somewhat crudely.  The day

          * rules have been forced into DOW_IN_MONTH mode already, so we change

          * the day of week to move forward or back by a day.  It's possible to

          * make a more refined adjustment of the original rules first, but in

          * most cases this extra effort will go to waste once we adjust the day

          * rules anyway.

          */

         switch (startTimeMode) {

         case UTC_TIME:

             startTime += rawOffset;

             break;

         }

         while (startTime < 0) {

             startTime += millisPerDay;

             startDayOfWeek = 1 + ((startDayOfWeek+5) % 7); // Back 1 day

         }

         while (startTime >= millisPerDay) {

             startTime -= millisPerDay;

             startDayOfWeek = 1 + (startDayOfWeek % 7); // Forward 1 day

         }

         switch (endTimeMode) {

         case UTC_TIME:

             endTime += rawOffset + dstSavings;

             break;

         case STANDARD_TIME:

             endTime += dstSavings;

         }

         while (endTime < 0) {

             endTime += millisPerDay;

             endDayOfWeek = 1 + ((endDayOfWeek+5) % 7); // Back 1 day

         }

         while (endTime >= millisPerDay) {

             endTime -= millisPerDay;

             endDayOfWeek = 1 + (endDayOfWeek % 7); // Forward 1 day

         }

     }

     /**

      * Pack the start and end rules into an array of bytes.  Only pack

      * data which is not preserved by makeRulesCompatible.

      */

     private byte[] packRules()

     {

         byte[] rules = new byte[6];

         rules[0] = (byte)startDay;

         rules[1] = (byte)startDayOfWeek;

         rules[2] = (byte)endDay;

         rules[3] = (byte)endDayOfWeek;

         // As of serial version 2, include time modes

         rules[4] = (byte)startTimeMode;

         rules[5] = (byte)endTimeMode;

         return rules;

     }

     /**

      * Given an array of bytes produced by packRules, interpret them

      * as the start and end rules.

      */

     private void unpackRules(byte[] rules)

     {

         startDay       = rules[0];

         startDayOfWeek = rules[1];

         endDay         = rules[2];

         endDayOfWeek   = rules[3];

         // As of serial version 2, include time modes

         if (rules.length >= 6) {

             startTimeMode = rules[4];

             endTimeMode   = rules[5];

         }

     }

     /**

      * Pack the start and end times into an array of bytes.  This is required

      * as of serial version 2.

      */

     private int[] packTimes() {

         int[] times = new int[2];

         times[0] = startTime;

         times[1] = endTime;

         return times;

     }

     /**

      * Unpack the start and end times from an array of bytes.  This is required

      * as of serial version 2.

      */

     private void unpackTimes(int[] times) {

         startTime = times[0];

         endTime = times[1];

     }

     /**

      * Save the state of this object to a stream (i.e., serialize it).

      *

      * @serialData We write out two formats, a JDK 1.1 compatible format, using

      * <code>DOW_IN_MONTH_MODE</code> rules, in the required section, followed

      * by the full rules, in packed format, in the optional section.  The

      * optional section will be ignored by JDK 1.1 code upon stream in.

      * <p> Contents of the optional section: The length of a byte array is

      * emitted (int); this is 4 as of this release. The byte array of the given

      * length is emitted. The contents of the byte array are the true values of

      * the fields <code>startDay</code>, <code>startDayOfWeek</code>,

      * <code>endDay</code>, and <code>endDayOfWeek</code>.  The values of these

      * fields in the required section are approximate values suited to the rule

      * mode <code>DOW_IN_MONTH_MODE</code>, which is the only mode recognized by

      * JDK 1.1.

      */

     private void writeObject(ObjectOutputStream stream)

          throws IOException

     {

         // Construct a binary rule

         byte[] rules = packRules();

         int[] times = packTimes();

         // Convert to 1.1 FCS rules.  This step may cause us to lose information.

         makeRulesCompatible();

         // Write out the 1.1 FCS rules

         stream.defaultWriteObject();

         // Write out the binary rules in the optional data area of the stream.

         stream.writeInt(rules.length);

         stream.write(rules);

         stream.writeObject(times);

         // Recover the original rules.  This recovers the information lost

         // by makeRulesCompatible.

         unpackRules(rules);

         unpackTimes(times);

     }

     /**

      * Reconstitute this object from a stream (i.e., deserialize it).

      *

      * We handle both JDK 1.1

      * binary formats and full formats with a packed byte array.

      */

     private void readObject(ObjectInputStream stream)

          throws IOException, ClassNotFoundException

     {

         stream.defaultReadObject();

         if (serialVersionOnStream < 1) {

             // Fix a bug in the 1.1 SimpleTimeZone code -- namely,

             // startDayOfWeek and endDayOfWeek were usually uninitialized.  We can't do

             // too much, so we assume SUNDAY, which actually works most of the time.

             if (startDayOfWeek == 0) {

                 startDayOfWeek = Calendar.SUNDAY;

             }

             if (endDayOfWeek == 0) {

                 endDayOfWeek = Calendar.SUNDAY;

             }

             // The variables dstSavings, startMode, and endMode are post-1.1, so they

             // won't be present if we're reading from a 1.1 stream.  Fix them up.

             startMode = endMode = DOW_IN_MONTH_MODE;

             dstSavings = millisPerHour;

         } else {

             // For 1.1.4, in addition to the 3 new instance variables, we also

             // store the actual rules (which have not be made compatible with 1.1)

             // in the optional area.  Read them in here and parse them.

             int length = stream.readInt();

             byte[] rules = new byte[length];

             stream.readFully(rules);

             unpackRules(rules);

         }

         if (serialVersionOnStream >= 2) {

             int[] times = (int[]) stream.readObject();

             unpackTimes(times);

         }

         serialVersionOnStream = currentSerialVersion;

     }

 }