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/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You 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 java.util;

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

/**
 * {@code GregorianCalendar} is a concrete subclass of {@link Calendar}
 * and provides the standard calendar used by most of the world.
 * 

*

* The standard (Gregorian) calendar has 2 eras, BC and AD. *

*

* This implementation handles a single discontinuity, which corresponds by * default to the date the Gregorian calendar was instituted (October 15, 1582 * in some countries, later in others). The cutover date may be changed by the * caller by calling {@code setGregorianChange()}. *

*

* Historically, in those countries which adopted the Gregorian calendar first, * October 4, 1582 was thus followed by October 15, 1582. This calendar models * this correctly. Before the Gregorian cutover, {@code GregorianCalendar} * implements the Julian calendar. The only difference between the Gregorian and * the Julian calendar is the leap year rule. The Julian calendar specifies leap * years every four years, whereas the Gregorian calendar omits century years * which are not divisible by 400. *

*

* {@code GregorianCalendar} implements proleptic Gregorian * and Julian calendars. That is, dates are computed by extrapolating the * current rules indefinitely far backward and forward in time. As a result, * {@code GregorianCalendar} may be used for all years to generate * meaningful and consistent results. However, dates obtained using * {@code GregorianCalendar} are historically accurate only from March 1, * 4 AD onward, when modern Julian calendar rules were adopted. Before this * date, leap year rules were applied irregularly, and before 45 BC the Julian * calendar did not even exist. *

*

* Prior to the institution of the Gregorian calendar, New Year's Day was March * 25. To avoid confusion, this calendar always uses January 1. A manual * adjustment may be made if desired for dates that are prior to the Gregorian * changeover and which fall between January 1 and March 24. *

*

* Values calculated for the {@code WEEK_OF_YEAR} field range from 1 to * 53. Week 1 for a year is the earliest seven day period starting on * {@code getFirstDayOfWeek()} that contains at least * {@code getMinimalDaysInFirstWeek()} days from that year. It thus * depends on the values of {@code getMinimalDaysInFirstWeek()}, * {@code getFirstDayOfWeek()}, and the day of the week of January 1. * Weeks between week 1 of one year and week 1 of the following year are * numbered sequentially from 2 to 52 or 53 (as needed). *

*

* For example, January 1, 1998 was a Thursday. If * {@code getFirstDayOfWeek()} is {@code MONDAY} and * {@code getMinimalDaysInFirstWeek()} is 4 (these are the values * reflecting ISO 8601 and many national standards), then week 1 of 1998 starts * on December 29, 1997, and ends on January 4, 1998. If, however, * {@code getFirstDayOfWeek()} is {@code SUNDAY}, then week 1 of * 1998 starts on January 4, 1998, and ends on January 10, 1998; the first three * days of 1998 then are part of week 53 of 1997. *

*

* Values calculated for the {@code WEEK_OF_MONTH} field range from 0 or * 1 to 4 or 5. Week 1 of a month (the days with WEEK_OF_MONTH = * 1) * is the earliest set of at least {@code getMinimalDaysInFirstWeek()} * contiguous days in that month, ending on the day before * {@code getFirstDayOfWeek()}. Unlike week 1 of a year, week 1 of a * month may be shorter than 7 days, need not start on * {@code getFirstDayOfWeek()}, and will not include days of the * previous month. Days of a month before week 1 have a * {@code WEEK_OF_MONTH} of 0. *

*

* For example, if {@code getFirstDayOfWeek()} is {@code SUNDAY} * and {@code getMinimalDaysInFirstWeek()} is 4, then the first week of * January 1998 is Sunday, January 4 through Saturday, January 10. These days * have a {@code WEEK_OF_MONTH} of 1. Thursday, January 1 through * Saturday, January 3 have a {@code WEEK_OF_MONTH} of 0. If * {@code getMinimalDaysInFirstWeek()} is changed to 3, then January 1 * through January 3 have a {@code WEEK_OF_MONTH} of 1. *

*

* Example:

*

*

 * // get the supported ids for GMT-08:00 (Pacific Standard Time)
 * String[] ids = TimeZone.getAvailableIDs(-8 * 60 * 60 * 1000);
 * // if no ids were returned, something is wrong. get out.
 * if (ids.length == 0)
 *     System.exit(0);
 *
 *  // begin output
 * System.out.println("Current Time");
 *
 * // create a Pacific Standard Time time zone
 * SimpleTimeZone pdt = new SimpleTimeZone(-8 * 60 * 60 * 1000, ids[0]);
 *
 * // set up rules for daylight savings time
 * pdt.setStartRule(Calendar.APRIL, 1, Calendar.SUNDAY, 2 * 60 * 60 * 1000);
 * pdt.setEndRule(Calendar.OCTOBER, -1, Calendar.SUNDAY, 2 * 60 * 60 * 1000);
 *
 * // create a GregorianCalendar with the Pacific Daylight time zone
 * // and the current date and time
 * Calendar calendar = new GregorianCalendar(pdt);
 * Date trialTime = new Date();
 * calendar.setTime(trialTime);
 *
 * // print out a bunch of interesting things
 * System.out.println("ERA: " + calendar.get(Calendar.ERA));
 * System.out.println("YEAR: " + calendar.get(Calendar.YEAR));
 * System.out.println("MONTH: " + calendar.get(Calendar.MONTH));
 * System.out.println("WEEK_OF_YEAR: " + calendar.get(Calendar.WEEK_OF_YEAR));
 * System.out.println("WEEK_OF_MONTH: " + calendar.get(Calendar.WEEK_OF_MONTH));
 * System.out.println("DATE: " + calendar.get(Calendar.DATE));
 * System.out.println("DAY_OF_MONTH: " + calendar.get(Calendar.DAY_OF_MONTH));
 * System.out.println("DAY_OF_YEAR: " + calendar.get(Calendar.DAY_OF_YEAR));
 * System.out.println("DAY_OF_WEEK: " + calendar.get(Calendar.DAY_OF_WEEK));
 * System.out.println("DAY_OF_WEEK_IN_MONTH: "
 *                    + calendar.get(Calendar.DAY_OF_WEEK_IN_MONTH));
 * System.out.println("AM_PM: " + calendar.get(Calendar.AM_PM));
 * System.out.println("HOUR: " + calendar.get(Calendar.HOUR));
 * System.out.println("HOUR_OF_DAY: " + calendar.get(Calendar.HOUR_OF_DAY));
 * System.out.println("MINUTE: " + calendar.get(Calendar.MINUTE));
 * System.out.println("SECOND: " + calendar.get(Calendar.SECOND));
 * System.out.println("MILLISECOND: " + calendar.get(Calendar.MILLISECOND));
 * System.out.println("ZONE_OFFSET: "
 *                    + (calendar.get(Calendar.ZONE_OFFSET)/(60*60*1000)));
 * System.out.println("DST_OFFSET: "
 *                    + (calendar.get(Calendar.DST_OFFSET)/(60*60*1000)));
 *
 * System.out.println("Current Time, with hour reset to 3");
 * calendar.clear(Calendar.HOUR_OF_DAY); // so doesn't override
 * calendar.set(Calendar.HOUR, 3);
 * System.out.println("ERA: " + calendar.get(Calendar.ERA));
 * System.out.println("YEAR: " + calendar.get(Calendar.YEAR));
 * System.out.println("MONTH: " + calendar.get(Calendar.MONTH));
 * System.out.println("WEEK_OF_YEAR: " + calendar.get(Calendar.WEEK_OF_YEAR));
 * System.out.println("WEEK_OF_MONTH: " + calendar.get(Calendar.WEEK_OF_MONTH));
 * System.out.println("DATE: " + calendar.get(Calendar.DATE));
 * System.out.println("DAY_OF_MONTH: " + calendar.get(Calendar.DAY_OF_MONTH));
 * System.out.println("DAY_OF_YEAR: " + calendar.get(Calendar.DAY_OF_YEAR));
 * System.out.println("DAY_OF_WEEK: " + calendar.get(Calendar.DAY_OF_WEEK));
 * System.out.println("DAY_OF_WEEK_IN_MONTH: "
 *                    + calendar.get(Calendar.DAY_OF_WEEK_IN_MONTH));
 * System.out.println("AM_PM: " + calendar.get(Calendar.AM_PM));
 * System.out.println("HOUR: " + calendar.get(Calendar.HOUR));
 * System.out.println("HOUR_OF_DAY: " + calendar.get(Calendar.HOUR_OF_DAY));
 * System.out.println("MINUTE: " + calendar.get(Calendar.MINUTE));
 * System.out.println("SECOND: " + calendar.get(Calendar.SECOND));
 * System.out.println("MILLISECOND: " + calendar.get(Calendar.MILLISECOND));
 * System.out.println("ZONE_OFFSET: "
 *        + (calendar.get(Calendar.ZONE_OFFSET)/(60*60*1000))); // in hours
 * System.out.println("DST_OFFSET: "
 *        + (calendar.get(Calendar.DST_OFFSET)/(60*60*1000))); // in hours
 * 
*

*

* * @see Calendar * @see TimeZone */ public class GregorianCalendar extends Calendar { /** * Value for the BC era. */ public static final int BC = 0; /** * Value for the AD era. */ public static final int AD = 1; private static final long defaultGregorianCutover = -12219292800000l; private long gregorianCutover = defaultGregorianCutover; private transient int changeYear = 1582; private transient int julianSkew = ((changeYear - 2000) / 400) + julianError() - ((changeYear - 2000) / 100); static byte[] DaysInMonth = new byte[]{31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; private static int[] DaysInYear = new int[]{0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334}; private static int[] maximums = new int[]{1, 292278994, 11, 53, 6, 31, 366, 7, 6, 1, 11, 23, 59, 59, 999, 14 * 3600 * 1000, 7200000}; private static int[] minimums = new int[]{0, 1, 0, 1, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, -13 * 3600 * 1000, 0}; private static int[] leastMaximums = new int[]{1, 292269054, 11, 50, 3, 28, 355, 7, 3, 1, 11, 23, 59, 59, 999, 50400000, 1200000}; private int currentYearSkew = 10; private int lastYearSkew = 0; /** * Constructs a new {@code GregorianCalendar} initialized to the current date and * time with the default {@code Locale} and {@code TimeZone}. */ public GregorianCalendar() { this(TimeZone.getDefault(), Locale.getDefault()); } /** * Constructs a new {@code GregorianCalendar} initialized to midnight in the default * {@code TimeZone} and {@code Locale} on the specified date. * * @param year the year. * @param month the month. * @param day the day of the month. */ public GregorianCalendar(int year, int month, int day) { super(TimeZone.getDefault(), Locale.getDefault()); set(year, month, day); } /** * Constructs a new {@code GregorianCalendar} initialized to the specified date and * time in the default {@code TimeZone} and {@code Locale}. * * @param year the year. * @param month the month. * @param day the day of the month. * @param hour the hour. * @param minute the minute. */ public GregorianCalendar(int year, int month, int day, int hour, int minute) { super(TimeZone.getDefault(), Locale.getDefault()); set(year, month, day, hour, minute); } /** * Constructs a new {@code GregorianCalendar} initialized to the specified date and * time in the default {@code TimeZone} and {@code Locale}. * * @param year the year. * @param month the month. * @param day the day of the month. * @param hour the hour. * @param minute the minute. * @param second the second. */ public GregorianCalendar(int year, int month, int day, int hour, int minute, int second) { super(TimeZone.getDefault(), Locale.getDefault()); set(year, month, day, hour, minute, second); } GregorianCalendar(long milliseconds) { this(false); setTimeInMillis(milliseconds); } /** * Constructs a new {@code GregorianCalendar} initialized to the current date and * time and using the specified {@code Locale} and the default {@code TimeZone}. * * @param locale the {@code Locale}. */ public GregorianCalendar(Locale locale) { this(TimeZone.getDefault(), locale); } /** * Constructs a new {@code GregorianCalendar} initialized to the current date and * time and using the specified {@code TimeZone} and the default {@code Locale}. * * @param timezone the {@code TimeZone}. */ public GregorianCalendar(TimeZone timezone) { this(timezone, Locale.getDefault()); } /** * Constructs a new {@code GregorianCalendar} initialized to the current date and * time and using the specified {@code TimeZone} and {@code Locale}. * * @param timezone the {@code TimeZone}. * @param locale the {@code Locale}. */ public GregorianCalendar(TimeZone timezone, Locale locale) { super(timezone, locale); setTimeInMillis(System.currentTimeMillis()); } GregorianCalendar(boolean ignored) { super(TimeZone.getDefault()); setFirstDayOfWeek(SUNDAY); setMinimalDaysInFirstWeek(1); } /** * Adds the specified amount to a {@code Calendar} field. * * @param field the {@code Calendar} field to modify. * @param value the amount to add to the field. * @throws IllegalArgumentException if the specified field is DST_OFFSET or ZONE_OFFSET. */ @Override public void add(int field, int value) { if (value == 0) { return; } if (field < 0 || field >= ZONE_OFFSET) { throw new IllegalArgumentException(); } if (field == ERA) { complete(); if (fields[ERA] == AD) { if (value >= 0) { return; } set(ERA, BC); } else { if (value <= 0) { return; } set(ERA, AD); } complete(); return; } if (field == YEAR || field == MONTH) { complete(); if (field == MONTH) { int month = fields[MONTH] + value; if (month < 0) { value = (month - 11) / 12; month = 12 + (month % 12); } else { value = month / 12; } set(MONTH, month % 12); } set(YEAR, fields[YEAR] + value); int days = daysInMonth(isLeapYear(fields[YEAR]), fields[MONTH]); if (fields[DATE] > days) { set(DATE, days); } complete(); return; } long multiplier = 0; getTimeInMillis(); // Update the time switch (field) { case MILLISECOND: time += value; break; case SECOND: time += value * 1000L; break; case MINUTE: time += value * 60000L; break; case HOUR: case HOUR_OF_DAY: time += value * 3600000L; break; case AM_PM: multiplier = 43200000L; break; case DATE: case DAY_OF_YEAR: case DAY_OF_WEEK: multiplier = 86400000L; break; case WEEK_OF_YEAR: case WEEK_OF_MONTH: case DAY_OF_WEEK_IN_MONTH: multiplier = 604800000L; break; } if (multiplier == 0) { areFieldsSet = false; complete(); return; } long delta = value * multiplier; /* * Attempt to keep the hour and minute constant when we've crossed a DST * boundary and the user's units are AM_PM or larger. The typical * consequence is that calls to add(DATE, 1) will add 23, 24 or 25 hours * depending on whether the DST goes forward, constant, or backward. * * We know we've crossed a DST boundary if the new time will have a * different timezone offset. Adjust by adding the difference of the two * offsets. We don't adjust when doing so prevents the change from * crossing the boundary. */ int zoneOffset = getTimeZone().getRawOffset(); int offsetBefore = getOffset(time + zoneOffset); int offsetAfter = getOffset(time + zoneOffset + delta); int dstDelta = offsetBefore - offsetAfter; if (getOffset(time + zoneOffset + delta + dstDelta) == offsetAfter) { delta += dstDelta; } time += delta; areFieldsSet = false; complete(); } private void fullFieldsCalc(long timeVal, int zoneOffset) { int millis = (int) (time % 86400000); long days = timeVal / 86400000; if (millis < 0) { millis += 86400000; days--; } // Cannot add ZONE_OFFSET to time as it might overflow millis += zoneOffset; while (millis < 0) { millis += 86400000; days--; } while (millis >= 86400000) { millis -= 86400000; days++; } int dayOfYear = computeYearAndDay(days, timeVal + zoneOffset); fields[DAY_OF_YEAR] = dayOfYear; if (fields[YEAR] == changeYear && gregorianCutover <= timeVal + zoneOffset) { dayOfYear += currentYearSkew; } int month = dayOfYear / 32; boolean leapYear = isLeapYear(fields[YEAR]); int date = dayOfYear - daysInYear(leapYear, month); if (date > daysInMonth(leapYear, month)) { date -= daysInMonth(leapYear, month); month++; } fields[DAY_OF_WEEK] = mod7(days - 3) + 1; int dstOffset = fields[YEAR] <= 0 ? 0 : getTimeZone().getOffset(AD, fields[YEAR], month, date, fields[DAY_OF_WEEK], millis); if (fields[YEAR] > 0) { dstOffset -= zoneOffset; } fields[DST_OFFSET] = dstOffset; if (dstOffset != 0) { long oldDays = days; millis += dstOffset; if (millis < 0) { millis += 86400000; days--; } else if (millis >= 86400000) { millis -= 86400000; days++; } if (oldDays != days) { dayOfYear = computeYearAndDay(days, timeVal - zoneOffset + dstOffset); fields[DAY_OF_YEAR] = dayOfYear; if (fields[YEAR] == changeYear && gregorianCutover <= timeVal - zoneOffset + dstOffset) { dayOfYear += currentYearSkew; } month = dayOfYear / 32; leapYear = isLeapYear(fields[YEAR]); date = dayOfYear - daysInYear(leapYear, month); if (date > daysInMonth(leapYear, month)) { date -= daysInMonth(leapYear, month); month++; } fields[DAY_OF_WEEK] = mod7(days - 3) + 1; } } fields[MILLISECOND] = (millis % 1000); millis /= 1000; fields[SECOND] = (millis % 60); millis /= 60; fields[MINUTE] = (millis % 60); millis /= 60; fields[HOUR_OF_DAY] = (millis % 24); fields[AM_PM] = fields[HOUR_OF_DAY] > 11 ? 1 : 0; fields[HOUR] = fields[HOUR_OF_DAY] % 12; if (fields[YEAR] <= 0) { fields[ERA] = BC; fields[YEAR] = -fields[YEAR] + 1; } else { fields[ERA] = AD; } fields[MONTH] = month; fields[DATE] = date; fields[DAY_OF_WEEK_IN_MONTH] = (date - 1) / 7 + 1; fields[WEEK_OF_MONTH] = (date - 1 + mod7(days - date - 2 - (getFirstDayOfWeek() - 1))) / 7 + 1; int daysFromStart = mod7(days - 3 - (fields[DAY_OF_YEAR] - 1) - (getFirstDayOfWeek() - 1)); int week = (fields[DAY_OF_YEAR] - 1 + daysFromStart) / 7 + (7 - daysFromStart >= getMinimalDaysInFirstWeek() ? 1 : 0); if (week == 0) { fields[WEEK_OF_YEAR] = 7 - mod7(daysFromStart - (isLeapYear(fields[YEAR] - 1) ? 2 : 1)) >= getMinimalDaysInFirstWeek() ? 53 : 52; } else if (fields[DAY_OF_YEAR] >= (leapYear ? 367 : 366) - mod7(daysFromStart + (leapYear ? 2 : 1))) { fields[WEEK_OF_YEAR] = 7 - mod7(daysFromStart + (leapYear ? 2 : 1)) >= getMinimalDaysInFirstWeek() ? 1 : week; } else { fields[WEEK_OF_YEAR] = week; } } @Override protected void computeFields() { TimeZone timeZone = getTimeZone(); int dstOffset = timeZone.inDaylightTime(new Date(time)) ? timeZone.getDSTSavings() : 0; int zoneOffset = timeZone.getRawOffset(); fields[DST_OFFSET] = dstOffset; fields[ZONE_OFFSET] = zoneOffset; fullFieldsCalc(time, zoneOffset); for (int i = 0; i < FIELD_COUNT; i++) { isSet[i] = true; } } @Override protected void computeTime() { if (!isLenient()) { if (isSet[HOUR_OF_DAY]) { if (fields[HOUR_OF_DAY] < 0 || fields[HOUR_OF_DAY] > 23) { throw new IllegalArgumentException(); } } else if (isSet[HOUR] && (fields[HOUR] < 0 || fields[HOUR] > 11)) { throw new IllegalArgumentException(); } if (isSet[MINUTE] && (fields[MINUTE] < 0 || fields[MINUTE] > 59)) { throw new IllegalArgumentException(); } if (isSet[SECOND] && (fields[SECOND] < 0 || fields[SECOND] > 59)) { throw new IllegalArgumentException(); } if (isSet[MILLISECOND] && (fields[MILLISECOND] < 0 || fields[MILLISECOND] > 999)) { throw new IllegalArgumentException(); } if (isSet[WEEK_OF_YEAR] && (fields[WEEK_OF_YEAR] < 1 || fields[WEEK_OF_YEAR] > 53)) { throw new IllegalArgumentException(); } if (isSet[DAY_OF_WEEK] && (fields[DAY_OF_WEEK] < 1 || fields[DAY_OF_WEEK] > 7)) { throw new IllegalArgumentException(); } if (isSet[DAY_OF_WEEK_IN_MONTH] && (fields[DAY_OF_WEEK_IN_MONTH] < 1 || fields[DAY_OF_WEEK_IN_MONTH] > 6)) { throw new IllegalArgumentException(); } if (isSet[WEEK_OF_MONTH] && (fields[WEEK_OF_MONTH] < 1 || fields[WEEK_OF_MONTH] > 6)) { throw new IllegalArgumentException(); } if (isSet[AM_PM] && fields[AM_PM] != AM && fields[AM_PM] != PM) { throw new IllegalArgumentException(); } if (isSet[HOUR] && (fields[HOUR] < 0 || fields[HOUR] > 11)) { throw new IllegalArgumentException(); } if (isSet[YEAR]) { if (isSet[ERA] && fields[ERA] == BC && (fields[YEAR] < 1 || fields[YEAR] > 292269054)) { throw new IllegalArgumentException(); } else if (fields[YEAR] < 1 || fields[YEAR] > 292278994) { throw new IllegalArgumentException(); } } if (isSet[MONTH] && (fields[MONTH] < 0 || fields[MONTH] > 11)) { throw new IllegalArgumentException(); } } long timeVal; long hour = 0; if (isSet[HOUR_OF_DAY] && lastTimeFieldSet != HOUR) { hour = fields[HOUR_OF_DAY]; } else if (isSet[HOUR]) { hour = (fields[AM_PM] * 12) + fields[HOUR]; } timeVal = hour * 3600000; if (isSet[MINUTE]) { timeVal += ((long) fields[MINUTE]) * 60000; } if (isSet[SECOND]) { timeVal += ((long) fields[SECOND]) * 1000; } if (isSet[MILLISECOND]) { timeVal += fields[MILLISECOND]; } long days; int year = isSet[YEAR] ? fields[YEAR] : 1970; if (isSet[ERA]) { // Always test for valid ERA, even if the Calendar is lenient if (fields[ERA] != BC && fields[ERA] != AD) { throw new IllegalArgumentException(); } if (fields[ERA] == BC) { year = 1 - year; } } boolean weekMonthSet = isSet[WEEK_OF_MONTH] || isSet[DAY_OF_WEEK_IN_MONTH]; boolean useMonth = (isSet[DATE] || isSet[MONTH] || weekMonthSet) && lastDateFieldSet != DAY_OF_YEAR; if (useMonth && (lastDateFieldSet == DAY_OF_WEEK || lastDateFieldSet == WEEK_OF_YEAR)) { if (isSet[WEEK_OF_YEAR] && isSet[DAY_OF_WEEK]) { useMonth = lastDateFieldSet != WEEK_OF_YEAR && weekMonthSet && isSet[DAY_OF_WEEK]; } else if (isSet[DAY_OF_YEAR]) { useMonth = isSet[DATE] && isSet[MONTH]; } } if (useMonth) { int month = fields[MONTH]; year += month / 12; month %= 12; if (month < 0) { year--; month += 12; } boolean leapYear = isLeapYear(year); days = daysFromBaseYear(year) + daysInYear(leapYear, month); boolean useDate = isSet[DATE]; if (useDate && (lastDateFieldSet == DAY_OF_WEEK || lastDateFieldSet == WEEK_OF_MONTH || lastDateFieldSet == DAY_OF_WEEK_IN_MONTH)) { useDate = !(isSet[DAY_OF_WEEK] && weekMonthSet); } if (useDate) { if (!isLenient() && (fields[DATE] < 1 || fields[DATE] > daysInMonth( leapYear, month))) { throw new IllegalArgumentException(); } days += fields[DATE] - 1; } else { int dayOfWeek; if (isSet[DAY_OF_WEEK]) { dayOfWeek = fields[DAY_OF_WEEK] - 1; } else { dayOfWeek = getFirstDayOfWeek() - 1; } if (isSet[WEEK_OF_MONTH] && lastDateFieldSet != DAY_OF_WEEK_IN_MONTH) { int skew = mod7(days - 3 - (getFirstDayOfWeek() - 1)); days += (fields[WEEK_OF_MONTH] - 1) * 7 + mod7(skew + dayOfWeek - (days - 3)) - skew; } else if (isSet[DAY_OF_WEEK_IN_MONTH]) { if (fields[DAY_OF_WEEK_IN_MONTH] >= 0) { days += mod7(dayOfWeek - (days - 3)) + (fields[DAY_OF_WEEK_IN_MONTH] - 1) * 7; } else { days += daysInMonth(leapYear, month) + mod7(dayOfWeek - (days + daysInMonth(leapYear, month) - 3)) + fields[DAY_OF_WEEK_IN_MONTH] * 7; } } else if (isSet[DAY_OF_WEEK]) { int skew = mod7(days - 3 - (getFirstDayOfWeek() - 1)); days += mod7(mod7(skew + dayOfWeek - (days - 3)) - skew); } } } else { boolean useWeekYear = isSet[WEEK_OF_YEAR] && lastDateFieldSet != DAY_OF_YEAR; if (useWeekYear && isSet[DAY_OF_YEAR]) { useWeekYear = isSet[DAY_OF_WEEK]; } days = daysFromBaseYear(year); if (useWeekYear) { int dayOfWeek; if (isSet[DAY_OF_WEEK]) { dayOfWeek = fields[DAY_OF_WEEK] - 1; } else { dayOfWeek = getFirstDayOfWeek() - 1; } int skew = mod7(days - 3 - (getFirstDayOfWeek() - 1)); days += (fields[WEEK_OF_YEAR] - 1) * 7 + mod7(skew + dayOfWeek - (days - 3)) - skew; if (7 - skew < getMinimalDaysInFirstWeek()) { days += 7; } } else if (isSet[DAY_OF_YEAR]) { if (!isLenient() && (fields[DAY_OF_YEAR] < 1 || fields[DAY_OF_YEAR] > (365 + (isLeapYear(year) ? 1 : 0)))) { throw new IllegalArgumentException(); } days += fields[DAY_OF_YEAR] - 1; } else if (isSet[DAY_OF_WEEK]) { days += mod7(fields[DAY_OF_WEEK] - 1 - (days - 3)); } } lastDateFieldSet = 0; timeVal += days * 86400000; // Use local time to compare with the gregorian change if (year == changeYear && timeVal >= gregorianCutover + julianError() * 86400000L) { timeVal -= julianError() * 86400000L; } // It is not possible to simply subtract getOffset(timeVal) from timeVal // to get UTC. // The trick is needed for the moment when DST transition occurs, // say 1:00 is a transition time when DST offset becomes +1 hour, // then wall time in the interval 1:00 - 2:00 is invalid and is // treated as UTC time. long timeValWithoutDST = timeVal - getOffset(timeVal) + getTimeZone().getRawOffset(); timeVal -= getOffset(timeValWithoutDST); // Need to update wall time in fields, since it was invalid due to DST // transition this.time = timeVal; if (timeValWithoutDST != timeVal) { computeFields(); areFieldsSet = true; } } private int computeYearAndDay(long dayCount, long localTime) { int year = 1970; long days = dayCount; if (localTime < gregorianCutover) { days -= julianSkew; } int approxYears; while ((approxYears = (int) (days / 365)) != 0) { year = year + approxYears; days = dayCount - daysFromBaseYear(year); } if (days < 0) { year = year - 1; days = days + daysInYear(year); } fields[YEAR] = year; return (int) days + 1; } private long daysFromBaseYear(long year) { if (year >= 1970) { long days = (year - 1970) * 365 + ((year - 1969) / 4); if (year > changeYear) { days -= ((year - 1901) / 100) - ((year - 1601) / 400); } else { if (year == changeYear) { days += currentYearSkew; } else if (year == changeYear - 1) { days += lastYearSkew; } else { days += julianSkew; } } return days; } else if (year <= changeYear) { return (year - 1970) * 365 + ((year - 1972) / 4) + julianSkew; } return (year - 1970) * 365 + ((year - 1972) / 4) - ((year - 2000) / 100) + ((year - 2000) / 400); } private int daysInMonth() { return daysInMonth(isLeapYear(fields[YEAR]), fields[MONTH]); } private int daysInMonth(boolean leapYear, int month) { if (leapYear && month == FEBRUARY) { return DaysInMonth[month] + 1; } return DaysInMonth[month]; } private int daysInYear(int year) { int daysInYear = isLeapYear(year) ? 366 : 365; if (year == changeYear) { daysInYear -= currentYearSkew; } if (year == changeYear - 1) { daysInYear -= lastYearSkew; } return daysInYear; } private int daysInYear(boolean leapYear, int month) { if (leapYear && month > FEBRUARY) { return DaysInYear[month] + 1; } return DaysInYear[month]; } /** * Returns true if {@code object} is a GregorianCalendar with the same * properties. */ @Override public boolean equals(Object object) { if (!(object instanceof GregorianCalendar)) { return false; } if (object == this) { return true; } return super.equals(object) && gregorianCutover == ((GregorianCalendar) object).gregorianCutover; } @Override public int getActualMaximum(int field) { int value; if ((value = maximums[field]) == leastMaximums[field]) { return value; } complete(); long orgTime = time; int result = 0; switch (field) { case WEEK_OF_YEAR: set(DATE, 31); set(MONTH, DECEMBER); result = get(WEEK_OF_YEAR); if (result == 1) { set(DATE, 31 - 7); result = get(WEEK_OF_YEAR); } areFieldsSet = false; break; case WEEK_OF_MONTH: set(DATE, daysInMonth()); result = get(WEEK_OF_MONTH); areFieldsSet = false; break; case DATE: return daysInMonth(); case DAY_OF_YEAR: return daysInYear(fields[YEAR]); case DAY_OF_WEEK_IN_MONTH: result = get(DAY_OF_WEEK_IN_MONTH) + ((daysInMonth() - get(DATE)) / 7); break; case YEAR: GregorianCalendar clone = (GregorianCalendar) clone(); if (get(ERA) == AD) { clone.setTimeInMillis(Long.MAX_VALUE); } else { clone.setTimeInMillis(Long.MIN_VALUE); } result = clone.get(YEAR); clone.set(YEAR, get(YEAR)); if (clone.before(this)) { result--; } break; case DST_OFFSET: result = getMaximum(DST_OFFSET); break; } time = orgTime; return result; } /** * Gets the minimum value of the specified field for the current date. For * the gregorian calendar, this value is the same as * {@code getMinimum()}. * * @param field the field. * @return the minimum value of the specified field. */ @Override public int getActualMinimum(int field) { return getMinimum(field); } /** * Gets the greatest minimum value of the specified field. For the gregorian * calendar, this value is the same as {@code getMinimum()}. * * @param field the field. * @return the greatest minimum value of the specified field. */ @Override public int getGreatestMinimum(int field) { return minimums[field]; } /** * Returns the gregorian change date of this calendar. This is the date on * which the gregorian calendar came into effect. * * @return a {@code Date} which represents the gregorian change date. */ public final Date getGregorianChange() { return new Date(gregorianCutover); } /** * Gets the smallest maximum value of the specified field. For example, 28 * for the day of month field. * * @param field the field. * @return the smallest maximum value of the specified field. */ @Override public int getLeastMaximum(int field) { // return value for WEEK_OF_YEAR should make corresponding changes when // the gregorian change date have been reset. if (gregorianCutover != defaultGregorianCutover && field == WEEK_OF_YEAR) { long currentTimeInMillis = time; setTimeInMillis(gregorianCutover); int actual = getActualMaximum(field); setTimeInMillis(currentTimeInMillis); return actual; } return leastMaximums[field]; } /** * Gets the greatest maximum value of the specified field. For example, 31 * for the day of month field. * * @param field the field. * @return the greatest maximum value of the specified field. */ @Override public int getMaximum(int field) { return maximums[field]; } /** * Gets the smallest minimum value of the specified field. * * @param field the field. * @return the smallest minimum value of the specified field. */ @Override public int getMinimum(int field) { return minimums[field]; } private int getOffset(long localTime) { TimeZone timeZone = getTimeZone(); long dayCount = localTime / 86400000; int millis = (int) (localTime % 86400000); if (millis < 0) { millis += 86400000; dayCount--; } int year = 1970; long days = dayCount; if (localTime < gregorianCutover) { days -= julianSkew; } int approxYears; while ((approxYears = (int) (days / 365)) != 0) { year = year + approxYears; days = dayCount - daysFromBaseYear(year); } if (days < 0) { year = year - 1; days = days + 365 + (isLeapYear(year) ? 1 : 0); if (year == changeYear && localTime < gregorianCutover) { days -= julianError(); } } if (year <= 0) { return timeZone.getRawOffset(); } int dayOfYear = (int) days + 1; int month = dayOfYear / 32; boolean leapYear = isLeapYear(year); int date = dayOfYear - daysInYear(leapYear, month); if (date > daysInMonth(leapYear, month)) { date -= daysInMonth(leapYear, month); month++; } int dayOfWeek = mod7(dayCount - 3) + 1; return timeZone.getOffset(AD, year, month, date, dayOfWeek, millis); } @Override public int hashCode() { return super.hashCode() + ((int) (gregorianCutover >>> 32) ^ (int) gregorianCutover); } /** * Returns true if {@code year} is a leap year. */ public boolean isLeapYear(int year) { if (year > changeYear) { return year % 4 == 0 && (year % 100 != 0 || year % 400 == 0); } return year % 4 == 0; } private int julianError() { return changeYear / 100 - changeYear / 400 - 2; } private int mod(int value, int mod) { int rem = value % mod; if (value < 0 && rem < 0) { return rem + mod; } return rem; } private int mod7(long num1) { int rem = (int) (num1 % 7); if (num1 < 0 && rem < 0) { return rem + 7; } return rem; } /** * Adds the specified amount the specified field and wraps the value of the * field when it goes beyond the maximum or minimum value for the current * date. Other fields will be adjusted as required to maintain a consistent * date. * * @param field the field to roll. * @param value the amount to add. * @throws IllegalArgumentException if an invalid field is specified. */ @Override public void roll(int field, int value) { if (value == 0) { return; } if (field < 0 || field >= ZONE_OFFSET) { throw new IllegalArgumentException(); } complete(); int days, day, mod, maxWeeks, newWeek; int max = -1; switch (field) { case YEAR: max = maximums[field]; break; case WEEK_OF_YEAR: days = daysInYear(fields[YEAR]); day = DAY_OF_YEAR; mod = mod7(fields[DAY_OF_WEEK] - fields[day] - (getFirstDayOfWeek() - 1)); maxWeeks = (days - 1 + mod) / 7 + 1; newWeek = mod(fields[field] - 1 + value, maxWeeks) + 1; if (newWeek == maxWeeks) { int addDays = (newWeek - fields[field]) * 7; if (fields[day] > addDays && fields[day] + addDays > days) { set(field, 1); } else { set(field, newWeek - 1); } } else if (newWeek == 1) { int week = (fields[day] - ((fields[day] - 1) / 7 * 7) - 1 + mod) / 7 + 1; if (week > 1) { set(field, 1); } else { set(field, newWeek); } } else { set(field, newWeek); } break; case WEEK_OF_MONTH: days = daysInMonth(); day = DATE; mod = mod7(fields[DAY_OF_WEEK] - fields[day] - (getFirstDayOfWeek() - 1)); maxWeeks = (days - 1 + mod) / 7 + 1; newWeek = mod(fields[field] - 1 + value, maxWeeks) + 1; if (newWeek == maxWeeks) { if (fields[day] + (newWeek - fields[field]) * 7 > days) { set(day, days); } else { set(field, newWeek); } } else if (newWeek == 1) { int week = (fields[day] - ((fields[day] - 1) / 7 * 7) - 1 + mod) / 7 + 1; if (week > 1) { set(day, 1); } else { set(field, newWeek); } } else { set(field, newWeek); } break; case DATE: max = daysInMonth(); break; case DAY_OF_YEAR: max = daysInYear(fields[YEAR]); break; case DAY_OF_WEEK: max = maximums[field]; lastDateFieldSet = WEEK_OF_MONTH; break; case DAY_OF_WEEK_IN_MONTH: max = (fields[DATE] + ((daysInMonth() - fields[DATE]) / 7 * 7) - 1) / 7 + 1; break; case ERA: case MONTH: case AM_PM: case HOUR: case HOUR_OF_DAY: case MINUTE: case SECOND: case MILLISECOND: set(field, mod(fields[field] + value, maximums[field] + 1)); if (field == MONTH && fields[DATE] > daysInMonth()) { set(DATE, daysInMonth()); } else if (field == AM_PM) { lastTimeFieldSet = HOUR; } break; } if (max != -1) { set(field, mod(fields[field] - 1 + value, max) + 1); } complete(); } /** * Increments or decrements the specified field and wraps the value of the * field when it goes beyond the maximum or minimum value for the current * date. Other fields will be adjusted as required to maintain a consistent * date. For example, March 31 will roll to April 30 when rolling the month * field. * * @param field the field to roll. * @param increment {@code true} to increment the field, {@code false} to * decrement. * @throws IllegalArgumentException if an invalid field is specified. */ @Override public void roll(int field, boolean increment) { roll(field, increment ? 1 : -1); } /** * Sets the gregorian change date of this calendar. */ public void setGregorianChange(Date date) { gregorianCutover = date.getTime(); GregorianCalendar cal = new GregorianCalendar(TimeZone.getTimeZone("GMT")); cal.setTime(date); changeYear = cal.get(YEAR); if (cal.get(ERA) == BC) { changeYear = 1 - changeYear; } julianSkew = ((changeYear - 2000) / 400) + julianError() - ((changeYear - 2000) / 100); int dayOfYear = cal.get(DAY_OF_YEAR); if (dayOfYear < julianSkew) { currentYearSkew = dayOfYear - 1; lastYearSkew = julianSkew - dayOfYear + 1; } else { lastYearSkew = 0; currentYearSkew = julianSkew; } } private void writeObject(ObjectOutputStream stream) throws IOException { stream.defaultWriteObject(); } private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException { stream.defaultReadObject(); setGregorianChange(new Date(gregorianCutover)); } }




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