simpletimezone.java

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/*
 * @(#)SimpleTimeZone.java	1.16 98/01/12
 *
 * (C) Copyright Taligent, Inc. 1996 - All Rights Reserved
 * (C) Copyright IBM Corp. 1996 - All Rights Reserved
 *
 * Portions copyright (c) 1996 Sun Microsystems, Inc. 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.
 *
 * Permission to use, copy, modify, and distribute this software
 * and its documentation for NON-COMMERCIAL purposes and without
 * fee is hereby granted provided that this copyright notice
 * appears in all copies. Please refer to the file "copyright.html"
 * for further important copyright and licensing information.
 *
 * SUN MAKES NO REPRESENTATIONS OR WARRANTIES ABOUT THE SUITABILITY OF
 * THE SOFTWARE, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
 * TO THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE, OR NON-INFRINGEMENT. SUN SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
 *
 */

package java.util;

import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.IOException;

/**
 * <code>SimpleTimeZone</code> is a concrete subclass of <code>TimeZone</code>
 * that represents a time zone for use with a Gregorian calendar. This
 * class does not handle historical changes.
 *
 * <P>
 * Use a negative value for <code>dayOfWeekInMonth</code> to indicate that
 * <code>SimpleTimeZone</code> should count from the end of the month backwards.
 * For example, Daylight Savings Time ends at the last
 * (dayOfWeekInMonth = -1) Sunday in October, at 2 AM in standard time.
 *
 * @see      Calendar
 * @see      GregorianCalendar
 * @see      TimeZone
 * @version  1.16 01/12/98
 * @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. Timezone IDs can be obtained from
     * TimeZone.getAvailableIDs. Normally you should use TimeZone.getDefault to
     * construct a TimeZone.
     *
     * @param rawOffset  The given base time zone offset to GMT.
     * @param ID         The time zone ID which is obtained from
     *                   TimeZone.getAvailableIDs.
     */
    public SimpleTimeZone(int rawOffset, String ID)
    {
        this.rawOffset = rawOffset;
        setID (ID);
    dstSavings = millisPerHour; // In case user sets rules later
    }

    /**
     * Construct a SimpleTimeZone with the given base time zone offset from
     * GMT, time zone ID, time to start and end the daylight time. Timezone IDs
     * can be obtained from TimeZone.getAvailableIDs. Normally you should use
     * TimeZone.getDefault to create a TimeZone. For a time zone that does not
     * use daylight saving time, do not use this constructor; instead you should
     * use SimpleTimeZone(rawOffset, ID).
     *
     * By default, this constructor specifies day-of-week-in-month rules. That
     * is, if the startDay is 1, and the startDayOfWeek is SUNDAY, then this
     * indicates the first Sunday in the startMonth. A startDay of -1 likewise
     * indicates the last Sunday. However, by using negative or zero values for
     * certain parameters, other types of rules can be specified.
     *
     * Day of month. To specify an exact day of the month, such as March 1, set
     * startDayOfWeek to zero.
     *
     * Day of week after day of month. To specify the first day of the week
     * occurring on or after an exact day of the month, make the day of the week
     * negative. For example, if startDay is 5 and startDayOfWeek is -MONDAY,
     * this indicates the first Monday on or after the 5th day of the
     * startMonth.
     *
     * Day of week before day of month. To specify the last day of the week
     * occurring on or before an exact day of the month, make the day of the
     * week and the day of the month negative. For example, if startDay is -21
     * and startDayOfWeek is -WEDNESDAY, this indicates the last Wednesday on or
     * before the 21st of the startMonth.
     *
     * The above examples refer to the startMonth, startDay, and startDayOfWeek;
     * the same applies for the endMonth, endDay, and endDayOfWeek.
     *
     * @param rawOffset       The given base time zone offset to GMT.
     * @param ID              The time zone ID which is obtained from
     *                        TimeZone.getAvailableIDs.
     * @param startMonth      The daylight savings starting month. Month is
     *                        0-based. eg, 0 for January.
     * @param startDay        The daylight savings starting
     *                        day-of-week-in-month. Please see the member
     *                        description for an example.
     * @param startDayOfWeek  The daylight savings starting day-of-week. Please
     *                        see the member description for an example.
     * @param startTime       The daylight savings starting time. Please see the
     *                        member description for an example.
     * @param endMonth        The daylight savings ending month. Month is
     *                        0-based. eg, 0 for January.
     * @param endDay          The daylight savings ending day-of-week-in-month.
     *                        Please see the member description for an example.
     * @param endDayOfWeek    The daylight savings ending day-of-week. Please
     *                        see the member description for an example.
     * @param endTime         The daylight savings ending time. Please see the
     *                        member description for an example.
     */
    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,
             endMonth, endDay, endDayOfWeek, endTime,
             millisPerHour);
    }

    /**
     * Constructor.  This constructor is package private at this point.  It will
     * be made public at the next API change.  It is identical to the 10-argument
     * constructor, but also takes a dstSavings parameter.
     * @param dstSavings   The amount of time in ms saved during DST.
     */
    SimpleTimeZone(int rawOffset, String ID,
                   int startMonth, int startDay, int startDayOfWeek, int startTime,
                   int endMonth, int endDay, int endDayOfWeek, int endTime,
                   int dstSavings)
    {
        setID(ID);
        this.rawOffset      = rawOffset;
        this.startMonth     = startMonth;
        this.startDay       = startDay;
        this.startDayOfWeek = startDayOfWeek;
        this.startTime      = startTime;
        this.endMonth       = endMonth;
        this.endDay         = endDay;
        this.endDayOfWeek   = endDayOfWeek;
        this.endTime        = endTime;
        this.dstSavings     = dstSavings;
        // this.useDaylight    = true; // Set by decodeRules
        decodeRules();
    }

    /**
     * Sets the daylight savings starting year.
     *
     * @param year  The daylight savings starting year.
     */
    public void setStartYear(int year)
    {
        startYear = year;
    }

    /**
     * Sets the daylight savings starting rule. For example, Daylight Savings
     * Time starts at the first Sunday in April, at 2 AM in standard time.
     * Therefore, you can set the start rule by calling:
     * setStartRule(TimeFields.APRIL, 1, TimeFields.SUNDAY, 2*60*60*1000);
     *
     * @param month             The daylight savings starting month. Month is
     *                          0-based. eg, 0 for January.
     * @param dayOfWeekInMonth  The daylight savings starting
     *                          day-of-week-in-month. Please see the member
     *                          description for an example.
     * @param dayOfWeek         The daylight savings starting day-of-week.
     *                          Please see the member description for an
     *                          example.
     * @param time              The daylight savings starting time. Please see
     *                          the member description for an example.
     */
    public void setStartRule(int month, int dayOfWeekInMonth, int dayOfWeek,
                             int time)
    {
        startMonth = month;
        startDay = dayOfWeekInMonth;
        startDayOfWeek = dayOfWeek;
        startTime = time;
        // useDaylight = true; // Set by decodeRules
        decodeRules();
    }

    /**
     * Sets the daylight savings ending rule. For example, Daylight Savings Time
     * ends at the last (-1) Sunday in October, at 2 AM in standard time.
     * Therefore, you can set the end rule by calling:
     * setEndRule(TimeFields.OCTOBER, -1, TimeFields.SUNDAY, 2*60*60*1000);
     *
     * @param month             The daylight savings ending month. Month is
     *                          0-based. eg, 0 for January.
     * @param dayOfWeekInMonth  The daylight savings ending
     *                          day-of-week-in-month. Please see the member
     *                          description for an example.
     * @param dayOfWeek         The daylight savings ending day-of-week. Please
     *                          see the member description for an example.
     * @param time              The daylight savings ending time. Please see the
     *                          member description for an example.
     */
    public void setEndRule(int month, int dayOfWeekInMonth, int dayOfWeek,
                           int time)
    {
        endMonth = month;
        endDay = dayOfWeekInMonth;
        endDayOfWeek = dayOfWeek;
        endTime = time;
        // useDaylight = true; // Set by decodeRules
        decodeRules();
    }

    /**
     * Overrides TimeZone
     * Gets offset, for current date, modified in case of
     * daylight savings. This is the offset to add *to* UTC to get local time.
     * Gets the time zone offset, for current date, modified in case of daylight
     * savings. This is the offset to add *to* UTC to get local time. Assume
     * that the start and end month are distinct, and that no rule refers to the
     * end of February (e.g., last Sunday in February).
     *
     * @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 milliseconds  The millis in day in <em>standard</em> local time.
     * @return              The offset to add *to* GMT to get local time.
     */
    public int getOffset(int era, int year, int month, int day, int dayOfWeek,
                         int millis)
    {
        int result = rawOffset;