https://source.android.com/ 
/*
 * Copyright (C) 2006 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.text.format;

import android.util.TimeFormatException;

import libcore.util.ZoneInfo;
import libcore.util.ZoneInfoDB;

import java.io.IOException;
import java.util.Locale;
import java.util.TimeZone;


An alternative to the Calendar and GregorianCalendar classes. An instance of the Time class represents a moment in time, specified with second precision. It is modelled after struct tm. This class is not thread-safe and does not consider leap seconds. 
This class has a number of issues and it is recommended that GregorianCalendar is used instead. 
Known issues:

    
    
  • For historical reasons when performing time calculations all arithmetic currently takes
    place using 32-bit integers. This limits the reliable time range representable from 1902
    until 2037.See the wikipedia article on the
    Year 2038 problem for details.
    Do not rely on this behavior; it may change in the future.
    
    • 
    
  • Calling switchTimezone(String) on a date that cannot exist, such as a wall time that was skipped due to a DST transition, will result in a date in 1969 (i.e. -1, or 1 second before 1st Jan 1970 UTC).
    • 
    
  • Much of the formatting / parsing assumes ASCII text and is therefore not suitable for
    use with non-ASCII scripts.
    • 
    
  • No support for pseudo-zones like "GMT-07:00".
    • 



Deprecated:Use GregorianCalendar instead.
/**
 * An alternative to the {@link java.util.Calendar} and
 * {@link java.util.GregorianCalendar} classes. An instance of the Time class represents
 * a moment in time, specified with second precision. It is modelled after
 * struct tm. This class is not thread-safe and does not consider leap seconds.
 *
 * <p>This class has a number of issues and it is recommended that
 * {@link java.util.GregorianCalendar} is used instead.
 *
 * <p>Known issues:
 * <ul>
 *     <li>For historical reasons when performing time calculations all arithmetic currently takes
 *     place using 32-bit integers. This limits the reliable time range representable from 1902
 *     until 2037.See the wikipedia article on the
 *     <a href="http://en.wikipedia.org/wiki/Year_2038_problem">Year 2038 problem</a> for details.
 *     Do not rely on this behavior; it may change in the future.
 *     </li>
 *     <li>Calling {@link #switchTimezone(String)} on a date that cannot exist, such as a wall time
 *     that was skipped due to a DST transition, will result in a date in 1969 (i.e. -1, or 1 second
 *     before 1st Jan 1970 UTC).</li>
 *     <li>Much of the formatting / parsing assumes ASCII text and is therefore not suitable for
 *     use with non-ASCII scripts.</li>
 *     <li>No support for pseudo-zones like "GMT-07:00".</li>
 * </ul>
 *
 * @deprecated Use {@link java.util.GregorianCalendar} instead.
 */
@Deprecated
public class Time {
    private static final String Y_M_D_T_H_M_S_000 = "%Y-%m-%dT%H:%M:%S.000";
    private static final String Y_M_D_T_H_M_S_000_Z = "%Y-%m-%dT%H:%M:%S.000Z";
    private static final String Y_M_D = "%Y-%m-%d";

    public static final String TIMEZONE_UTC = "UTC";

    
The Julian day of the epoch, that is, January 1, 1970 on the Gregorian
calendar.

/**
     * The Julian day of the epoch, that is, January 1, 1970 on the Gregorian
     * calendar.
     */
    public static final int EPOCH_JULIAN_DAY = 2440588;

    
The Julian day of the Monday in the week of the epoch, December 29, 1969
on the Gregorian calendar.

/**
     * The Julian day of the Monday in the week of the epoch, December 29, 1969
     * on the Gregorian calendar.
     */
    public static final int MONDAY_BEFORE_JULIAN_EPOCH = EPOCH_JULIAN_DAY - 3;

    
True if this is an allDay event. The hour, minute, second fields are
all zero, and the date is displayed the same in all time zones.

/**
     * True if this is an allDay event. The hour, minute, second fields are
     * all zero, and the date is displayed the same in all time zones.
     */
    public boolean allDay;

    
Seconds [0-61] (2 leap seconds allowed)

/**
     * Seconds [0-61] (2 leap seconds allowed)
     */
    public int second;

    
Minute [0-59]

/**
     * Minute [0-59]
     */
    public int minute;

    
Hour of day [0-23]

/**
     * Hour of day [0-23]
     */
    public int hour;

    
Day of month [1-31]

/**
     * Day of month [1-31]
     */
    public int monthDay;

    
Month [0-11]

/**
     * Month [0-11]
     */
    public int month;

    
Year. For example, 1970.

/**
     * Year. For example, 1970.
     */
    public int year;

    
Day of week [0-6]

/**
     * Day of week [0-6]
     */
    public int weekDay;

    
Day of year [0-365]

/**
     * Day of year [0-365]
     */
    public int yearDay;

    
This time is in daylight savings time. One of:

    

  • positive - in dst
    • 

  • 0 - not in dst
    • 

  • negative - unknown
    • 



/**
     * This time is in daylight savings time. One of:
     * <ul>
     * <li><b>positive</b> - in dst</li>
     * <li><b>0</b> - not in dst</li>
     * <li><b>negative</b> - unknown</li>
     * </ul>
     */
    public int isDst;

    
Offset in seconds from UTC including any DST offset.

/**
     * Offset in seconds from UTC including any DST offset.
     */
    public long gmtoff;

    
The timezone for this Time.  Should not be null.

/**
     * The timezone for this Time.  Should not be null.
     */
    public String timezone;

    /*
     * Define symbolic constants for accessing the fields in this class. Used in
     * getActualMaximum().
     */
    public static final int SECOND = 1;
    public static final int MINUTE = 2;
    public static final int HOUR = 3;
    public static final int MONTH_DAY = 4;
    public static final int MONTH = 5;
    public static final int YEAR = 6;
    public static final int WEEK_DAY = 7;
    public static final int YEAR_DAY = 8;
    public static final int WEEK_NUM = 9;

    public static final int SUNDAY = 0;
    public static final int MONDAY = 1;
    public static final int TUESDAY = 2;
    public static final int WEDNESDAY = 3;
    public static final int THURSDAY = 4;
    public static final int FRIDAY = 5;
    public static final int SATURDAY = 6;

    // An object that is reused for date calculations.
    private TimeCalculator calculator;

    
Construct a Time object in the timezone named by the string
argument "timezone". The time is initialized to Jan 1, 1970.

Params:
  • timezoneId – string containing the timezone to use.
See Also:
/**
     * Construct a Time object in the timezone named by the string
     * argument "timezone". The time is initialized to Jan 1, 1970.
     * @param timezoneId string containing the timezone to use.
     * @see TimeZone
     */
    public Time(String timezoneId) {
        if (timezoneId == null) {
            throw new NullPointerException("timezoneId is null!");
        }
        initialize(timezoneId);
    }

    
Construct a Time object in the default timezone. The time is initialized to
Jan 1, 1970.

/**
     * Construct a Time object in the default timezone. The time is initialized to
     * Jan 1, 1970.
     */
    public Time() {
        initialize(TimeZone.getDefault().getID());
    }

    
A copy constructor.  Construct a Time object by copying the given
Time object.  No normalization occurs.

Params:
  • other – 
/**
     * A copy constructor.  Construct a Time object by copying the given
     * Time object.  No normalization occurs.
     *
     * @param other
     */
    public Time(Time other) {
        initialize(other.timezone);
        set(other);
    }

    
Initialize the Time to 00:00:00 1/1/1970 in the specified timezone. 
/** Initialize the Time to 00:00:00 1/1/1970 in the specified timezone. */
    private void initialize(String timezoneId) {
        this.timezone = timezoneId;
        this.year = 1970;
        this.monthDay = 1;
        // Set the daylight-saving indicator to the unknown value -1 so that
        // it will be recomputed.
        this.isDst = -1;

        // A reusable object that performs the date/time calculations.
        calculator = new TimeCalculator(timezoneId);
    }

    
Ensures the values in each field are in range. For example if the
current value of this calendar is March 32, normalize() will convert it
to April 1. It also fills in weekDay, yearDay, isDst and gmtoff.


If "ignoreDst" is true, then this method sets the "isDst" field to -1
(the "unknown" value) before normalizing.  It then computes the
time in milliseconds and sets the correct value for "isDst" if the
fields resolve to a valid date / time.

 See toMillis(boolean) for more information about when to use true or false for "ignoreDst" and when -1 might be returned. 
Returns:the UTC milliseconds since the epoch, or -1
/**
     * Ensures the values in each field are in range. For example if the
     * current value of this calendar is March 32, normalize() will convert it
     * to April 1. It also fills in weekDay, yearDay, isDst and gmtoff.
     *
     * <p>
     * If "ignoreDst" is true, then this method sets the "isDst" field to -1
     * (the "unknown" value) before normalizing.  It then computes the
     * time in milliseconds and sets the correct value for "isDst" if the
     * fields resolve to a valid date / time.
     *
     * <p>
     * See {@link #toMillis(boolean)} for more information about when to
     * use <tt>true</tt> or <tt>false</tt> for "ignoreDst" and when {@code -1}
     * might be returned.
     *
     * @return the UTC milliseconds since the epoch, or {@code -1}
     */
    public long normalize(boolean ignoreDst) {
        calculator.copyFieldsFromTime(this);
        long timeInMillis = calculator.toMillis(ignoreDst);
        calculator.copyFieldsToTime(this);
        return timeInMillis;
    }

    
Convert this time object so the time represented remains the same, but is
instead located in a different timezone. This method automatically calls
normalize() in some cases.

This method can return incorrect results if the date / time cannot be normalized.

/**
     * Convert this time object so the time represented remains the same, but is
     * instead located in a different timezone. This method automatically calls
     * normalize() in some cases.
     *
     * <p>This method can return incorrect results if the date / time cannot be normalized.
     */
    public void switchTimezone(String timezone) {
        calculator.copyFieldsFromTime(this);
        calculator.switchTimeZone(timezone);
        calculator.copyFieldsToTime(this);
        this.timezone = timezone;
    }

    private static final int[] DAYS_PER_MONTH = { 31, 28, 31, 30, 31, 30, 31,
            31, 30, 31, 30, 31 };

    
Return the maximum possible value for the given field given the value of
the other fields. Requires that it be normalized for MONTH_DAY and
YEAR_DAY.

Params:
  • field – one of the constants for HOUR, MINUTE, SECOND, etc.
Returns:the maximum value for the field.
/**
     * Return the maximum possible value for the given field given the value of
     * the other fields. Requires that it be normalized for MONTH_DAY and
     * YEAR_DAY.
     * @param field one of the constants for HOUR, MINUTE, SECOND, etc.
     * @return the maximum value for the field.
     */
    public int getActualMaximum(int field) {
        switch (field) {
        case SECOND:
            return 59; // leap seconds, bah humbug
        case MINUTE:
            return 59;
        case HOUR:
            return 23;
        case MONTH_DAY: {
            int n = DAYS_PER_MONTH[this.month];
            if (n != 28) {
                return n;
            } else {
                int y = this.year;
                return ((y % 4) == 0 && ((y % 100) != 0 || (y % 400) == 0)) ? 29 : 28;
            }
        }
        case MONTH:
            return 11;
        case YEAR:
            return 2037;
        case WEEK_DAY:
            return 6;
        case YEAR_DAY: {
            int y = this.year;
            // Year days are numbered from 0, so the last one is usually 364.
            return ((y % 4) == 0 && ((y % 100) != 0 || (y % 400) == 0)) ? 365 : 364;
        }
        case WEEK_NUM:
            throw new RuntimeException("WEEK_NUM not implemented");
        default:
            throw new RuntimeException("bad field=" + field);
        }
    }

    
Clears all values, setting the timezone to the given timezone. Sets isDst
to a negative value to mean "unknown".

Params:
  • timezoneId – the timezone to use.
/**
     * Clears all values, setting the timezone to the given timezone. Sets isDst
     * to a negative value to mean "unknown".
     * @param timezoneId the timezone to use.
     */
    public void clear(String timezoneId) {
        if (timezoneId == null) {
            throw new NullPointerException("timezone is null!");
        }
        this.timezone = timezoneId;
        this.allDay = false;
        this.second = 0;
        this.minute = 0;
        this.hour = 0;
        this.monthDay = 0;
        this.month = 0;
        this.year = 0;
        this.weekDay = 0;
        this.yearDay = 0;
        this.gmtoff = 0;
        this.isDst = -1;
    }

    
Compare two Time objects and return a negative number if 
a is less than b, a positive number if a is greater than b, or 0 if they are equal. 
 This method can return an incorrect answer when the date / time fields of either Time have been set to a local time that contradicts the available timezone information. 
Params:
  • a – first Time instance to compare
  • b – second Time instance to compare
Throws:
Returns:a negative result if a is earlier, a positive result if b is earlier, or 0 if they are equal.
/**
     * Compare two {@code Time} objects and return a negative number if {@code
     * a} is less than {@code b}, a positive number if {@code a} is greater than
     * {@code b}, or 0 if they are equal.
     *
     * <p>
     * This method can return an incorrect answer when the date / time fields of
     * either {@code Time} have been set to a local time that contradicts the
     * available timezone information.
     *
     * @param a first {@code Time} instance to compare
     * @param b second {@code Time} instance to compare
     * @throws NullPointerException if either argument is {@code null}
     * @throws IllegalArgumentException if {@link #allDay} is true but {@code
     *             hour}, {@code minute}, and {@code second} are not 0.
     * @return a negative result if {@code a} is earlier, a positive result if
     *         {@code b} is earlier, or 0 if they are equal.
     */
    public static int compare(Time a, Time b) {
        if (a == null) {
            throw new NullPointerException("a == null");
        } else if (b == null) {
            throw new NullPointerException("b == null");
        }
        a.calculator.copyFieldsFromTime(a);
        b.calculator.copyFieldsFromTime(b);

        return TimeCalculator.compare(a.calculator, b.calculator);
    }

    
Print the current value given the format string provided. See man
strftime for what means what. The final string must be less than 256
characters.

Params:
  • format – a string containing the desired format.
Returns:a String containing the current time expressed in the current locale.
/**
     * Print the current value given the format string provided. See man
     * strftime for what means what. The final string must be less than 256
     * characters.
     * @param format a string containing the desired format.
     * @return a String containing the current time expressed in the current locale.
     */
    public String format(String format) {
        calculator.copyFieldsFromTime(this);
        return calculator.format(format);
    }

    
Return the current time in YYYYMMDDTHHMMSS<tz> format

/**
     * Return the current time in YYYYMMDDTHHMMSS&lt;tz&gt; format
     */
    @Override
    public String toString() {
        // toString() uses its own TimeCalculator rather than the shared one. Otherwise crazy stuff
        // happens during debugging when the debugger calls toString().
        TimeCalculator calculator = new TimeCalculator(this.timezone);
        calculator.copyFieldsFromTime(this);
        return calculator.toStringInternal();
    }

    
Parses a date-time string in either the RFC 2445 format or an abbreviated
format that does not include the "time" field.  For example, all of the
following strings are valid:

    
  
  • "20081013T160000Z"
    • 
  
  • "20081013T160000"
    • 
  
  • "20081013"
    • 


Returns whether or not the time is in UTC (ends with Z).  If the string
ends with "Z" then the timezone is set to UTC.  If the date-time string
included only a date and no time field, then the allDay
field of this Time class is set to true and the hour,
minute, and second fields are set to zero;
otherwise (a time field was included in the date-time string)
allDay is set to false. The fields weekDay,
yearDay, and gmtoff are always set to zero,
and the field isDst is set to -1 (unknown). To set those fields, call normalize(boolean) after parsing. To parse a date-time string and convert it to UTC milliseconds, do something like this: 
  Time time = new Time();
  String date = "20081013T160000Z";
  time.parse(date);
  long millis = time.normalize(false);



Params:
  • s – the string to parse
Throws:
Returns:true if the resulting time value is in UTC time
/**
     * Parses a date-time string in either the RFC 2445 format or an abbreviated
     * format that does not include the "time" field.  For example, all of the
     * following strings are valid:
     *
     * <ul>
     *   <li>"20081013T160000Z"</li>
     *   <li>"20081013T160000"</li>
     *   <li>"20081013"</li>
     * </ul>
     *
     * Returns whether or not the time is in UTC (ends with Z).  If the string
     * ends with "Z" then the timezone is set to UTC.  If the date-time string
     * included only a date and no time field, then the <code>allDay</code>
     * field of this Time class is set to true and the <code>hour</code>,
     * <code>minute</code>, and <code>second</code> fields are set to zero;
     * otherwise (a time field was included in the date-time string)
     * <code>allDay</code> is set to false. The fields <code>weekDay</code>,
     * <code>yearDay</code>, and <code>gmtoff</code> are always set to zero,
     * and the field <code>isDst</code> is set to -1 (unknown).  To set those
     * fields, call {@link #normalize(boolean)} after parsing.
     *
     * To parse a date-time string and convert it to UTC milliseconds, do
     * something like this:
     *
     * <pre>
     *   Time time = new Time();
     *   String date = "20081013T160000Z";
     *   time.parse(date);
     *   long millis = time.normalize(false);
     * </pre>
     *
     * @param s the string to parse
     * @return true if the resulting time value is in UTC time
     * @throws android.util.TimeFormatException if s cannot be parsed.
     */
    public boolean parse(String s) {
        if (s == null) {
            throw new NullPointerException("time string is null");
        }
        if (parseInternal(s)) {
            timezone = TIMEZONE_UTC;
            return true;
        }
        return false;
    }

    
Parse a time in the current zone in YYYYMMDDTHHMMSS format.

/**
     * Parse a time in the current zone in YYYYMMDDTHHMMSS format.
     */
    private boolean parseInternal(String s) {
        int len = s.length();
        if (len < 8) {
            throw new TimeFormatException("String is too short: \"" + s +
                    "\" Expected at least 8 characters.");
        }

        boolean inUtc = false;

        // year
        int n = getChar(s, 0, 1000);
        n += getChar(s, 1, 100);
        n += getChar(s, 2, 10);
        n += getChar(s, 3, 1);
        year = n;

        // month
        n = getChar(s, 4, 10);
        n += getChar(s, 5, 1);
        n--;
        month = n;

        // day of month
        n = getChar(s, 6, 10);
        n += getChar(s, 7, 1);
        monthDay = n;

        if (len > 8) {
            if (len < 15) {
                throw new TimeFormatException(
                        "String is too short: \"" + s
                                + "\" If there are more than 8 characters there must be at least"
                                + " 15.");
            }
            checkChar(s, 8, 'T');
            allDay = false;

            // hour
            n = getChar(s, 9, 10);
            n += getChar(s, 10, 1);
            hour = n;

            // min
            n = getChar(s, 11, 10);
            n += getChar(s, 12, 1);
            minute = n;

            // sec
            n = getChar(s, 13, 10);
            n += getChar(s, 14, 1);
            second = n;

            if (len > 15) {
                // Z
                checkChar(s, 15, 'Z');
                inUtc = true;
            }
        } else {
            allDay = true;
            hour = 0;
            minute = 0;
            second = 0;
        }

        weekDay = 0;
        yearDay = 0;
        isDst = -1;
        gmtoff = 0;
        return inUtc;
    }

    private void checkChar(String s, int spos, char expected) {
        char c = s.charAt(spos);
        if (c != expected) {
            throw new TimeFormatException(String.format(
                    "Unexpected character 0x%02d at pos=%d.  Expected 0x%02d (\'%c\').",
                    (int) c, spos, (int) expected, expected));
        }
    }

    private static int getChar(String s, int spos, int mul) {
        char c = s.charAt(spos);
        if (Character.isDigit(c)) {
            return Character.getNumericValue(c) * mul;
        } else {
            throw new TimeFormatException("Parse error at pos=" + spos);
        }
    }

    
Parse a time in RFC 3339 format.  This method also parses simple dates
(that is, strings that contain no time or time offset).  For example,
all of the following strings are valid:

    
  
  • "2008-10-13T16:00:00.000Z"
    • 
  
  • "2008-10-13T16:00:00.000+07:00"
    • 
  
  • "2008-10-13T16:00:00.000-07:00"
    • 
  
  • "2008-10-13"
    • 




If the string contains a time and time offset, then the time offset will
be used to convert the time value to UTC.



 If the given string contains just a date (with no time field), then the allDay field is set to true and the hour, minute, and second fields are set to zero. 



Returns true if the resulting time value is in UTC time.



Params:
  • s – the string to parse
Throws:
Returns:true if the resulting time value is in UTC time
/**
     * Parse a time in RFC 3339 format.  This method also parses simple dates
     * (that is, strings that contain no time or time offset).  For example,
     * all of the following strings are valid:
     *
     * <ul>
     *   <li>"2008-10-13T16:00:00.000Z"</li>
     *   <li>"2008-10-13T16:00:00.000+07:00"</li>
     *   <li>"2008-10-13T16:00:00.000-07:00"</li>
     *   <li>"2008-10-13"</li>
     * </ul>
     *
     * <p>
     * If the string contains a time and time offset, then the time offset will
     * be used to convert the time value to UTC.
     * </p>
     *
     * <p>
     * If the given string contains just a date (with no time field), then
     * the {@link #allDay} field is set to true and the {@link #hour},
     * {@link #minute}, and  {@link #second} fields are set to zero.
     * </p>
     *
     * <p>
     * Returns true if the resulting time value is in UTC time.
     * </p>
     *
     * @param s the string to parse
     * @return true if the resulting time value is in UTC time
     * @throws android.util.TimeFormatException if s cannot be parsed.
     */
     public boolean parse3339(String s) {
         if (s == null) {
             throw new NullPointerException("time string is null");
         }
         if (parse3339Internal(s)) {
             timezone = TIMEZONE_UTC;
             return true;
         }
         return false;
     }

     private boolean parse3339Internal(String s) {
         int len = s.length();
         if (len < 10) {
             throw new TimeFormatException("String too short --- expected at least 10 characters.");
         }
         boolean inUtc = false;

         // year
         int n = getChar(s, 0, 1000);
         n += getChar(s, 1, 100);
         n += getChar(s, 2, 10);
         n += getChar(s, 3, 1);
         year = n;

         checkChar(s, 4, '-');

         // month
         n = getChar(s, 5, 10);
         n += getChar(s, 6, 1);
         --n;
         month = n;

         checkChar(s, 7, '-');

         // day
         n = getChar(s, 8, 10);
         n += getChar(s, 9, 1);
         monthDay = n;

         if (len >= 19) {
             // T
             checkChar(s, 10, 'T');
             allDay = false;

             // hour
             n = getChar(s, 11, 10);
             n += getChar(s, 12, 1);

             // Note that this.hour is not set here. It is set later.
             int hour = n;

             checkChar(s, 13, ':');

             // minute
             n = getChar(s, 14, 10);
             n += getChar(s, 15, 1);
             // Note that this.minute is not set here. It is set later.
             int minute = n;

             checkChar(s, 16, ':');

             // second
             n = getChar(s, 17, 10);
             n += getChar(s, 18, 1);
             second = n;

             // skip the '.XYZ' -- we don't care about subsecond precision.

             int tzIndex = 19;
             if (tzIndex < len && s.charAt(tzIndex) == '.') {
                 do {
                     tzIndex++;
                 } while (tzIndex < len && Character.isDigit(s.charAt(tzIndex)));
             }

             int offset = 0;
             if (len > tzIndex) {
                 char c = s.charAt(tzIndex);
                 // NOTE: the offset is meant to be subtracted to get from local time
                 // to UTC.  we therefore use 1 for '-' and -1 for '+'.
                 switch (c) {
                     case 'Z':
                         // Zulu time -- UTC
                         offset = 0;
                         break;
                     case '-':
                         offset = 1;
                         break;
                     case '+':
                         offset = -1;
                         break;
                     default:
                         throw new TimeFormatException(String.format(
                                 "Unexpected character 0x%02d at position %d.  Expected + or -",
                                 (int) c, tzIndex));
                 }
                 inUtc = true;

                 if (offset != 0) {
                     if (len < tzIndex + 6) {
                         throw new TimeFormatException(
                                 String.format("Unexpected length; should be %d characters",
                                         tzIndex + 6));
                     }

                     // hour
                     n = getChar(s, tzIndex + 1, 10);
                     n += getChar(s, tzIndex + 2, 1);
                     n *= offset;
                     hour += n;

                     // minute
                     n = getChar(s, tzIndex + 4, 10);
                     n += getChar(s, tzIndex + 5, 1);
                     n *= offset;
                     minute += n;
                 }
             }
             this.hour = hour;
             this.minute = minute;

             if (offset != 0) {
                 normalize(false);
             }
         } else {
             allDay = true;
             this.hour = 0;
             this.minute = 0;
             this.second = 0;
         }

         this.weekDay = 0;
         this.yearDay = 0;
         this.isDst = -1;
         this.gmtoff = 0;
         return inUtc;
     }

    
Returns the timezone string that is currently set for the device.

/**
     * Returns the timezone string that is currently set for the device.
     */
    public static String getCurrentTimezone() {
        return TimeZone.getDefault().getID();
    }

    
Sets the time of the given Time object to the current time.

/**
     * Sets the time of the given Time object to the current time.
     */
    public void setToNow() {
        set(System.currentTimeMillis());
    }

    
Converts this time to milliseconds. Suitable for interacting with the
standard java libraries. The time is in UTC milliseconds since the epoch.
This does an implicit normalization to compute the milliseconds but does
not change any of the fields in this Time object. If you want to normalize the fields in this Time object and also get the milliseconds then use normalize(boolean). 

If "ignoreDst" is false, then this method uses the current setting of the
"isDst" field and will adjust the returned time if the "isDst" field is
wrong for the given time.  See the sample code below for an example of
this.


If "ignoreDst" is true, then this method ignores the current setting of
the "isDst" field in this Time object and will instead figure out the
correct value of "isDst" (as best it can) from the fields in this
Time object.  The only case where this method cannot figure out the
correct value of the "isDst" field is when the time is inherently
ambiguous because it falls in the hour that is repeated when switching
from Daylight-Saving Time to Standard Time.


Here is an example where toMillis(true) adjusts the time,
assuming that DST changes at 2am on Sunday, Nov 4, 2007.

Time time = new Time();
time.set(4, 10, 2007);  // set the date to Nov 4, 2007, 12am
time.normalize(false);       // this sets isDst = 1
time.monthDay += 1;     // changes the date to Nov 5, 2007, 12am
millis = time.toMillis(false);   // millis is Nov 4, 2007, 11pm
millis = time.toMillis(true);    // millis is Nov 5, 2007, 12am




To avoid this problem, use toMillis(true)
after adding or subtracting days or explicitly setting the "monthDay"
field.  On the other hand, if you are adding
or subtracting hours or minutes, then you should use
toMillis(false).


You should also use toMillis(false) if you want to read back the same milliseconds that you set with set(long) or set(Time) or after parsing a date string. 
 This method can return -1 when the date / time fields have been set to a local time that conflicts with available timezone information. For example, when daylight savings transitions cause an hour to be skipped: times within that hour will return -1 if isDst = -1. 
/**
     * Converts this time to milliseconds. Suitable for interacting with the
     * standard java libraries. The time is in UTC milliseconds since the epoch.
     * This does an implicit normalization to compute the milliseconds but does
     * <em>not</em> change any of the fields in this Time object.  If you want
     * to normalize the fields in this Time object and also get the milliseconds
     * then use {@link #normalize(boolean)}.
     *
     * <p>
     * If "ignoreDst" is false, then this method uses the current setting of the
     * "isDst" field and will adjust the returned time if the "isDst" field is
     * wrong for the given time.  See the sample code below for an example of
     * this.
     *
     * <p>
     * If "ignoreDst" is true, then this method ignores the current setting of
     * the "isDst" field in this Time object and will instead figure out the
     * correct value of "isDst" (as best it can) from the fields in this
     * Time object.  The only case where this method cannot figure out the
     * correct value of the "isDst" field is when the time is inherently
     * ambiguous because it falls in the hour that is repeated when switching
     * from Daylight-Saving Time to Standard Time.
     *
     * <p>
     * Here is an example where <tt>toMillis(true)</tt> adjusts the time,
     * assuming that DST changes at 2am on Sunday, Nov 4, 2007.
     *
     * <pre>
     * Time time = new Time();
     * time.set(4, 10, 2007);  // set the date to Nov 4, 2007, 12am
     * time.normalize(false);       // this sets isDst = 1
     * time.monthDay += 1;     // changes the date to Nov 5, 2007, 12am
     * millis = time.toMillis(false);   // millis is Nov 4, 2007, 11pm
     * millis = time.toMillis(true);    // millis is Nov 5, 2007, 12am
     * </pre>
     *
     * <p>
     * To avoid this problem, use <tt>toMillis(true)</tt>
     * after adding or subtracting days or explicitly setting the "monthDay"
     * field.  On the other hand, if you are adding
     * or subtracting hours or minutes, then you should use
     * <tt>toMillis(false)</tt>.
     *
     * <p>
     * You should also use <tt>toMillis(false)</tt> if you want
     * to read back the same milliseconds that you set with {@link #set(long)}
     * or {@link #set(Time)} or after parsing a date string.
     *
     * <p>
     * This method can return {@code -1} when the date / time fields have been
     * set to a local time that conflicts with available timezone information.
     * For example, when daylight savings transitions cause an hour to be
     * skipped: times within that hour will return {@code -1} if isDst =
     * {@code -1}.
     */
    public long toMillis(boolean ignoreDst) {
        calculator.copyFieldsFromTime(this);
        return calculator.toMillis(ignoreDst);
    }

    
Sets the fields in this Time object given the UTC milliseconds.  After
this method returns, all the fields are normalized.
This also sets the "isDst" field to the correct value.

Params:
  • millis – the time in UTC milliseconds since the epoch.
/**
     * Sets the fields in this Time object given the UTC milliseconds.  After
     * this method returns, all the fields are normalized.
     * This also sets the "isDst" field to the correct value.
     *
     * @param millis the time in UTC milliseconds since the epoch.
     */
    public void set(long millis) {
        allDay = false;
        calculator.timezone = timezone;
        calculator.setTimeInMillis(millis);
        calculator.copyFieldsToTime(this);
    }

    
Format according to RFC 2445 DATE-TIME type.

The same as format("%Y%m%dT%H%M%S"), or format("%Y%m%dT%H%M%SZ") for a Time with a
timezone set to "UTC".

/**
     * Format according to RFC 2445 DATE-TIME type.
     *
     * <p>The same as format("%Y%m%dT%H%M%S"), or format("%Y%m%dT%H%M%SZ") for a Time with a
     * timezone set to "UTC".
     */
    public String format2445() {
        calculator.copyFieldsFromTime(this);
        return calculator.format2445(!allDay);
    }

    
Copy the value of that to this Time object. No normalization happens.

/**
     * Copy the value of that to this Time object. No normalization happens.
     */
    public void set(Time that) {
        this.timezone = that.timezone;
        this.allDay = that.allDay;
        this.second = that.second;
        this.minute = that.minute;
        this.hour = that.hour;
        this.monthDay = that.monthDay;
        this.month = that.month;
        this.year = that.year;
        this.weekDay = that.weekDay;
        this.yearDay = that.yearDay;
        this.isDst = that.isDst;
        this.gmtoff = that.gmtoff;
    }

    
Sets the fields. Sets weekDay, yearDay and gmtoff to 0, and isDst to -1. Call normalize(boolean) if you need those. 
/**
     * Sets the fields. Sets weekDay, yearDay and gmtoff to 0, and isDst to -1.
     * Call {@link #normalize(boolean)} if you need those.
     */
    public void set(int second, int minute, int hour, int monthDay, int month, int year) {
        this.allDay = false;
        this.second = second;
        this.minute = minute;
        this.hour = hour;
        this.monthDay = monthDay;
        this.month = month;
        this.year = year;
        this.weekDay = 0;
        this.yearDay = 0;
        this.isDst = -1;
        this.gmtoff = 0;
    }

    
Sets the date from the given fields. Also sets allDay to true. Sets weekDay, yearDay and gmtoff to 0, and isDst to -1. Call normalize(boolean) if you need those. 
Params:
  • monthDay – the day of the month (in the range [1,31])
  • month – the zero-based month number (in the range [0,11])
  • year – the year
/**
     * Sets the date from the given fields.  Also sets allDay to true.
     * Sets weekDay, yearDay and gmtoff to 0, and isDst to -1.
     * Call {@link #normalize(boolean)} if you need those.
     *
     * @param monthDay the day of the month (in the range [1,31])
     * @param month the zero-based month number (in the range [0,11])
     * @param year the year
     */
    public void set(int monthDay, int month, int year) {
        this.allDay = true;
        this.second = 0;
        this.minute = 0;
        this.hour = 0;
        this.monthDay = monthDay;
        this.month = month;
        this.year = year;
        this.weekDay = 0;
        this.yearDay = 0;
        this.isDst = -1;
        this.gmtoff = 0;
    }

    
Returns true if the time represented by this Time object occurs before
the given time.

 Equivalent to Time.compare(this, that) < 0. See compare(Time, Time) for details. 
Params:
  • that – a given Time object to compare against
Returns:true if this time is less than the given time
/**
     * Returns true if the time represented by this Time object occurs before
     * the given time.
     *
     * <p>
     * Equivalent to {@code Time.compare(this, that) < 0}. See
     * {@link #compare(Time, Time)} for details.
     *
     * @param that a given Time object to compare against
     * @return true if this time is less than the given time
     */
    public boolean before(Time that) {
        return Time.compare(this, that) < 0;
    }


    
Returns true if the time represented by this Time object occurs after
the given time.

 Equivalent to Time.compare(this, that) > 0. See compare(Time, Time) for details. 
Params:
  • that – a given Time object to compare against
Returns:true if this time is greater than the given time
/**
     * Returns true if the time represented by this Time object occurs after
     * the given time.
     *
     * <p>
     * Equivalent to {@code Time.compare(this, that) > 0}. See
     * {@link #compare(Time, Time)} for details.
     *
     * @param that a given Time object to compare against
     * @return true if this time is greater than the given time
     */
    public boolean after(Time that) {
        return Time.compare(this, that) > 0;
    }

    
This array is indexed by the weekDay field (SUNDAY=0, MONDAY=1, etc.)
and gives a number that can be added to the yearDay to give the
closest Thursday yearDay.

/**
     * This array is indexed by the weekDay field (SUNDAY=0, MONDAY=1, etc.)
     * and gives a number that can be added to the yearDay to give the
     * closest Thursday yearDay.
     */
    private static final int[] sThursdayOffset = { -3, 3, 2, 1, 0, -1, -2 };

    
Computes the week number according to ISO 8601.  The current Time
object must already be normalized because this method uses the
yearDay and weekDay fields.


In IS0 8601, weeks start on Monday.
The first week of the year (week 1) is defined by ISO 8601 as the
first week with four or more of its days in the starting year.
Or equivalently, the week containing January 4.  Or equivalently,
the week with the year's first Thursday in it.




The week number can be calculated by counting Thursdays.  Week N
contains the Nth Thursday of the year.



Returns:the ISO week number.
/**
     * Computes the week number according to ISO 8601.  The current Time
     * object must already be normalized because this method uses the
     * yearDay and weekDay fields.
     *
     * <p>
     * In IS0 8601, weeks start on Monday.
     * The first week of the year (week 1) is defined by ISO 8601 as the
     * first week with four or more of its days in the starting year.
     * Or equivalently, the week containing January 4.  Or equivalently,
     * the week with the year's first Thursday in it.
     * </p>
     *
     * <p>
     * The week number can be calculated by counting Thursdays.  Week N
     * contains the Nth Thursday of the year.
     * </p>
     *
     * @return the ISO week number.
     */
    public int getWeekNumber() {
        // Get the year day for the closest Thursday
        int closestThursday = yearDay + sThursdayOffset[weekDay];

        // Year days start at 0
        if (closestThursday >= 0 && closestThursday <= 364) {
            return closestThursday / 7 + 1;
        }

        // The week crosses a year boundary.
        Time temp = new Time(this);
        temp.monthDay += sThursdayOffset[weekDay];
        temp.normalize(true /* ignore isDst */);
        return temp.yearDay / 7 + 1;
    }

    
Return a string in the RFC 3339 format.


If allDay is true, expresses the time as Y-M-D



Otherwise, if the timezone is UTC, expresses the time as Y-M-D-T-H-M-S UTC



Otherwise the time is expressed the time as Y-M-D-T-H-M-S +- GMT


Returns:string in the RFC 3339 format.
/**
     * Return a string in the RFC 3339 format.
     * <p>
     * If allDay is true, expresses the time as Y-M-D</p>
     * <p>
     * Otherwise, if the timezone is UTC, expresses the time as Y-M-D-T-H-M-S UTC</p>
     * <p>
     * Otherwise the time is expressed the time as Y-M-D-T-H-M-S +- GMT</p>
     * @return string in the RFC 3339 format.
     */
    public String format3339(boolean allDay) {
        if (allDay) {
            return format(Y_M_D);
        } else if (TIMEZONE_UTC.equals(timezone)) {
            return format(Y_M_D_T_H_M_S_000_Z);
        } else {
            String base = format(Y_M_D_T_H_M_S_000);
            String sign = (gmtoff < 0) ? "-" : "+";
            int offset = (int) Math.abs(gmtoff);
            int minutes = (offset % 3600) / 60;
            int hours = offset / 3600;

            return String.format(Locale.US, "%s%s%02d:%02d", base, sign, hours, minutes);
        }
    }

    
Returns true if the day of the given time is the epoch on the Julian Calendar
(January 1, 1970 on the Gregorian calendar).


This method can return an incorrect answer when the date / time fields have
been set to a local time that contradicts the available timezone information.

Params:
  • time – the time to test
Returns:true if epoch.
/**
     * Returns true if the day of the given time is the epoch on the Julian Calendar
     * (January 1, 1970 on the Gregorian calendar).
     *
     * <p>
     * This method can return an incorrect answer when the date / time fields have
     * been set to a local time that contradicts the available timezone information.
     *
     * @param time the time to test
     * @return true if epoch.
     */
    public static boolean isEpoch(Time time) {
        long millis = time.toMillis(true);
        return getJulianDay(millis, 0) == EPOCH_JULIAN_DAY;
    }

    
Computes the Julian day number for a point in time in a particular
timezone. The Julian day for a given date is the same for every
timezone. For example, the Julian day for July 1, 2008 is 2454649.

Callers must pass the time in UTC millisecond (as can be returned by toMillis(boolean) or normalize(boolean)) and the offset from UTC of the timezone in seconds (as might be in gmtoff). 
The Julian day is useful for testing if two events occur on the
same calendar date and for determining the relative time of an event
from the present ("yesterday", "3 days ago", etc.).

Params:
  • millis – the time in UTC milliseconds
  • gmtoff – the offset from UTC in seconds
Returns:the Julian day
/**
     * Computes the Julian day number for a point in time in a particular
     * timezone. The Julian day for a given date is the same for every
     * timezone. For example, the Julian day for July 1, 2008 is 2454649.
     *
     * <p>Callers must pass the time in UTC millisecond (as can be returned
     * by {@link #toMillis(boolean)} or {@link #normalize(boolean)})
     * and the offset from UTC of the timezone in seconds (as might be in
     * {@link #gmtoff}).
     *
     * <p>The Julian day is useful for testing if two events occur on the
     * same calendar date and for determining the relative time of an event
     * from the present ("yesterday", "3 days ago", etc.).
     *
     * @param millis the time in UTC milliseconds
     * @param gmtoff the offset from UTC in seconds
     * @return the Julian day
     */
    public static int getJulianDay(long millis, long gmtoff) {
        long offsetMillis = gmtoff * 1000;
        long julianDay = (millis + offsetMillis) / DateUtils.DAY_IN_MILLIS;
        return (int) julianDay + EPOCH_JULIAN_DAY;
    }

    
Sets the time from the given Julian day number, which must be based on
the same timezone that is set in this Time object.  The "gmtoff" field
need not be initialized because the given Julian day may have a different
GMT offset than whatever is currently stored in this Time object anyway.
After this method returns all the fields will be normalized and the time
will be set to 12am at the beginning of the given Julian day.




The only exception to this is if 12am does not exist for that day because
of daylight saving time.  For example, Cairo, Eqypt moves time ahead one
hour at 12am on April 25, 2008 and there are a few other places that
also change daylight saving time at 12am.  In those cases, the time
will be set to 1am.



Params:
  • julianDay – the Julian day in the timezone for this Time object
Returns:the UTC milliseconds for the beginning of the Julian day
/**
     * <p>Sets the time from the given Julian day number, which must be based on
     * the same timezone that is set in this Time object.  The "gmtoff" field
     * need not be initialized because the given Julian day may have a different
     * GMT offset than whatever is currently stored in this Time object anyway.
     * After this method returns all the fields will be normalized and the time
     * will be set to 12am at the beginning of the given Julian day.
     * </p>
     *
     * <p>
     * The only exception to this is if 12am does not exist for that day because
     * of daylight saving time.  For example, Cairo, Eqypt moves time ahead one
     * hour at 12am on April 25, 2008 and there are a few other places that
     * also change daylight saving time at 12am.  In those cases, the time
     * will be set to 1am.
     * </p>
     *
     * @param julianDay the Julian day in the timezone for this Time object
     * @return the UTC milliseconds for the beginning of the Julian day
     */
    public long setJulianDay(int julianDay) {
        // Don't bother with the GMT offset since we don't know the correct
        // value for the given Julian day.  Just get close and then adjust
        // the day.
        long millis = (julianDay - EPOCH_JULIAN_DAY) * DateUtils.DAY_IN_MILLIS;
        set(millis);

        // Figure out how close we are to the requested Julian day.
        // We can't be off by more than a day.
        int approximateDay = getJulianDay(millis, gmtoff);
        int diff = julianDay - approximateDay;
        monthDay += diff;

        // Set the time to 12am and re-normalize.
        hour = 0;
        minute = 0;
        second = 0;
        millis = normalize(true);
        return millis;
    }

    
Returns the week since EPOCH_JULIAN_DAY (Jan 1, 1970) adjusted for first day of week. This takes a julian day and the week start day and calculates which week since EPOCH_JULIAN_DAY that day occurs in, starting at 0. *Do not* use this to compute the ISO week number for the year. 
Params:
  • julianDay – The julian day to calculate the week number for
  • firstDayOfWeek – Which week day is the first day of the week, see SUNDAY
Returns:Weeks since the epoch
/**
     * Returns the week since {@link #EPOCH_JULIAN_DAY} (Jan 1, 1970) adjusted
     * for first day of week. This takes a julian day and the week start day and
     * calculates which week since {@link #EPOCH_JULIAN_DAY} that day occurs in,
     * starting at 0. *Do not* use this to compute the ISO week number for the
     * year.
     *
     * @param julianDay The julian day to calculate the week number for
     * @param firstDayOfWeek Which week day is the first day of the week, see
     *            {@link #SUNDAY}
     * @return Weeks since the epoch
     */
    public static int getWeeksSinceEpochFromJulianDay(int julianDay, int firstDayOfWeek) {
        int diff = THURSDAY - firstDayOfWeek;
        if (diff < 0) {
            diff += 7;
        }
        int refDay = EPOCH_JULIAN_DAY - diff;
        return (julianDay - refDay) / 7;
    }

    
Takes a number of weeks since the epoch and calculates the Julian day of the Monday for that week. This assumes that the week containing the EPOCH_JULIAN_DAY is considered week 0. It returns the Julian day for the Monday week weeks after the Monday of the week containing the epoch. 
Params:
  • week – Number of weeks since the epoch
Returns:The julian day for the Monday of the given week since the epoch
/**
     * Takes a number of weeks since the epoch and calculates the Julian day of
     * the Monday for that week. This assumes that the week containing the
     * {@link #EPOCH_JULIAN_DAY} is considered week 0. It returns the Julian day
     * for the Monday week weeks after the Monday of the week containing the
     * epoch.
     *
     * @param week Number of weeks since the epoch
     * @return The julian day for the Monday of the given week since the epoch
     */
    public static int getJulianMondayFromWeeksSinceEpoch(int week) {
        return MONDAY_BEFORE_JULIAN_EPOCH + week * 7;
    }

    
A class that handles date/time calculations.
This class originated as a port of a native C++ class ("android.Time") to pure Java. It is
separate from the enclosing class because some methods copy the result of calculations back
to the enclosing object, but others do not: thus separate state is retained.

/**
     * A class that handles date/time calculations.
     *
     * This class originated as a port of a native C++ class ("android.Time") to pure Java. It is
     * separate from the enclosing class because some methods copy the result of calculations back
     * to the enclosing object, but others do not: thus separate state is retained.
     */
    private static class TimeCalculator {
        public final ZoneInfo.WallTime wallTime;
        public String timezone;

        // Information about the current timezone.
        private ZoneInfo zoneInfo;

        public TimeCalculator(String timezoneId) {
            this.zoneInfo = lookupZoneInfo(timezoneId);
            this.wallTime = new ZoneInfo.WallTime();
        }

        public long toMillis(boolean ignoreDst) {
            if (ignoreDst) {
                wallTime.setIsDst(-1);
            }

            int r = wallTime.mktime(zoneInfo);
            if (r == -1) {
                return -1;
            }
            return r * 1000L;
        }

        public void setTimeInMillis(long millis) {
            // Preserve old 32-bit Android behavior.
            int intSeconds = (int) (millis / 1000);

            updateZoneInfoFromTimeZone();
            wallTime.localtime(intSeconds, zoneInfo);
        }

        public String format(String format) {
            if (format == null) {
                format = "%c";
            }
            TimeFormatter formatter = new TimeFormatter();
            return formatter.format(format, wallTime, zoneInfo);
        }

        private void updateZoneInfoFromTimeZone() {
            if (!zoneInfo.getID().equals(timezone)) {
                this.zoneInfo = lookupZoneInfo(timezone);
            }
        }

        private static ZoneInfo lookupZoneInfo(String timezoneId) {
            try {
                ZoneInfo zoneInfo = ZoneInfoDB.getInstance().makeTimeZone(timezoneId);
                if (zoneInfo == null) {
                    zoneInfo = ZoneInfoDB.getInstance().makeTimeZone("GMT");
                }
                if (zoneInfo == null) {
                    throw new AssertionError("GMT not found: \"" + timezoneId + "\"");
                }
                return zoneInfo;
            } catch (IOException e) {
                // This should not ever be thrown.
                throw new AssertionError("Error loading timezone: \"" + timezoneId + "\"", e);
            }
        }

        public void switchTimeZone(String timezone) {
            int seconds = wallTime.mktime(zoneInfo);
            this.timezone = timezone;
            updateZoneInfoFromTimeZone();
            wallTime.localtime(seconds, zoneInfo);
        }

        public String format2445(boolean hasTime) {
            char[] buf = new char[hasTime ? 16 : 8];
            int n = wallTime.getYear();

            buf[0] = toChar(n / 1000);
            n %= 1000;
            buf[1] = toChar(n / 100);
            n %= 100;
            buf[2] = toChar(n / 10);
            n %= 10;
            buf[3] = toChar(n);

            n = wallTime.getMonth() + 1;
            buf[4] = toChar(n / 10);
            buf[5] = toChar(n % 10);

            n = wallTime.getMonthDay();
            buf[6] = toChar(n / 10);
            buf[7] = toChar(n % 10);

            if (!hasTime) {
                return new String(buf, 0, 8);
            }

            buf[8] = 'T';

            n = wallTime.getHour();
            buf[9] = toChar(n / 10);
            buf[10] = toChar(n % 10);

            n = wallTime.getMinute();
            buf[11] = toChar(n / 10);
            buf[12] = toChar(n % 10);

            n = wallTime.getSecond();
            buf[13] = toChar(n / 10);
            buf[14] = toChar(n % 10);

            if (TIMEZONE_UTC.equals(timezone)) {
                // The letter 'Z' is appended to the end.
                buf[15] = 'Z';
                return new String(buf, 0, 16);
            } else {
                return new String(buf, 0, 15);
            }
        }

        private char toChar(int n) {
            return (n >= 0 && n <= 9) ? (char) (n + '0') : ' ';
        }

        
A method that will return the state of this object in string form. Note: it has side effects and so has deliberately not been made the default Object.toString(). 
/**
         * A method that will return the state of this object in string form. Note: it has side
         * effects and so has deliberately not been made the default {@link #toString()}.
         */
        public String toStringInternal() {
            // This implementation possibly displays the un-normalized fields because that is
            // what it has always done.
            return String.format("%04d%02d%02dT%02d%02d%02d%s(%d,%d,%d,%d,%d)",
                    wallTime.getYear(),
                    wallTime.getMonth() + 1,
                    wallTime.getMonthDay(),
                    wallTime.getHour(),
                    wallTime.getMinute(),
                    wallTime.getSecond(),
                    timezone,
                    wallTime.getWeekDay(),
                    wallTime.getYearDay(),
                    wallTime.getGmtOffset(),
                    wallTime.getIsDst(),
                    toMillis(false /* use isDst */) / 1000
            );

        }

        public static int compare(TimeCalculator aObject, TimeCalculator bObject) {
            if (aObject.timezone.equals(bObject.timezone)) {
                // If the timezones are the same, we can easily compare the two times.
                int diff = aObject.wallTime.getYear() - bObject.wallTime.getYear();
                if (diff != 0) {
                    return diff;
                }

                diff = aObject.wallTime.getMonth() - bObject.wallTime.getMonth();
                if (diff != 0) {
                    return diff;
                }

                diff = aObject.wallTime.getMonthDay() - bObject.wallTime.getMonthDay();
                if (diff != 0) {
                    return diff;
                }

                diff = aObject.wallTime.getHour() - bObject.wallTime.getHour();
                if (diff != 0) {
                    return diff;
                }

                diff = aObject.wallTime.getMinute() - bObject.wallTime.getMinute();
                if (diff != 0) {
                    return diff;
                }

                diff = aObject.wallTime.getSecond() - bObject.wallTime.getSecond();
                if (diff != 0) {
                    return diff;
                }

                return 0;
            } else {
                // Otherwise, convert to milliseconds and compare that. This requires that object be
                // normalized. Note: For dates that do not exist: toMillis() can return -1, which
                // can be confused with a valid time.
                long am = aObject.toMillis(false /* use isDst */);
                long bm = bObject.toMillis(false /* use isDst */);
                long diff = am - bm;
                return (diff < 0) ? -1 : ((diff > 0) ? 1 : 0);
            }

        }

        public void copyFieldsToTime(Time time) {
            time.second = wallTime.getSecond();
            time.minute = wallTime.getMinute();
            time.hour = wallTime.getHour();
            time.monthDay = wallTime.getMonthDay();
            time.month = wallTime.getMonth();
            time.year = wallTime.getYear();

            // Read-only fields that are derived from other information above.
            time.weekDay = wallTime.getWeekDay();
            time.yearDay = wallTime.getYearDay();

            // < 0: DST status unknown, 0: is not in DST, 1: is in DST
            time.isDst = wallTime.getIsDst();
            // This is in seconds and includes any DST offset too.
            time.gmtoff = wallTime.getGmtOffset();
        }

        public void copyFieldsFromTime(Time time) {
            wallTime.setSecond(time.second);
            wallTime.setMinute(time.minute);
            wallTime.setHour(time.hour);
            wallTime.setMonthDay(time.monthDay);
            wallTime.setMonth(time.month);
            wallTime.setYear(time.year);
            wallTime.setWeekDay(time.weekDay);
            wallTime.setYearDay(time.yearDay);
            wallTime.setIsDst(time.isDst);
            wallTime.setGmtOffset((int) time.gmtoff);

            if (time.allDay && (time.second != 0 || time.minute != 0 || time.hour != 0)) {
                throw new IllegalArgumentException("allDay is true but sec, min, hour are not 0.");
            }

            timezone = time.timezone;
            updateZoneInfoFromTimeZone();
        }
    }
}