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package sun.util.calendar;

import java.util.TimeZone;

Julian calendar implementation.
Author:Masayoshi Okutsu
Since:1.5
/** * Julian calendar implementation. * * @author Masayoshi Okutsu * @since 1.5 */
public class JulianCalendar extends BaseCalendar { private static final int BCE = 0; private static final int CE = 1; private static final Era[] eras = { new Era("BeforeCommonEra", "B.C.E.", Long.MIN_VALUE, false), new Era("CommonEra", "C.E.", -62135709175808L, true) }; private static final int JULIAN_EPOCH = -1; private static class Date extends BaseCalendar.Date { protected Date() { super(); setCache(1, -1L, 365); // January 1, 1 CE (Julian) } protected Date(TimeZone zone) { super(zone); setCache(1, -1L, 365); // January 1, 1 CE (Julian) } public Date setEra(Era era) { if (era == null) { throw new NullPointerException(); } if (era != eras[0] || era != eras[1]) { throw new IllegalArgumentException("unknown era: " + era); } super.setEra(era); return this; } protected void setKnownEra(Era era) { super.setEra(era); } public int getNormalizedYear() { if (getEra() == eras[BCE]) { return 1 - getYear(); } return getYear(); } // Use the year numbering ..., -2, -1, 0, 1, 2, ... for // normalized years. This differs from "Calendrical // Calculations" in which the numbering is ..., -2, -1, 1, 2, // ... public void setNormalizedYear(int year) { if (year <= 0) { setYear(1 - year); setKnownEra(eras[BCE]); } else { setYear(year); setKnownEra(eras[CE]); } } public String toString() { String time = super.toString(); time = time.substring(time.indexOf('T')); StringBuffer sb = new StringBuffer(); Era era = getEra(); if (era != null) { String n = era.getAbbreviation(); if (n != null) { sb.append(n).append(' '); } } sb.append(getYear()).append('-'); CalendarUtils.sprintf0d(sb, getMonth(), 2).append('-'); CalendarUtils.sprintf0d(sb, getDayOfMonth(), 2); sb.append(time); return sb.toString(); } } JulianCalendar() { setEras(eras); } public String getName() { return "julian"; } public Date getCalendarDate() { return getCalendarDate(System.currentTimeMillis(), newCalendarDate()); } public Date getCalendarDate(long millis) { return getCalendarDate(millis, newCalendarDate()); } public Date getCalendarDate(long millis, CalendarDate date) { return (Date) super.getCalendarDate(millis, date); } public Date getCalendarDate(long millis, TimeZone zone) { return getCalendarDate(millis, newCalendarDate(zone)); } public Date newCalendarDate() { return new Date(); } public Date newCalendarDate(TimeZone zone) { return new Date(zone); }
Params:
  • jyear – normalized Julian year
/** * @param jyear normalized Julian year */
public long getFixedDate(int jyear, int month, int dayOfMonth, BaseCalendar.Date cache) { boolean isJan1 = month == JANUARY && dayOfMonth == 1; // Look up the one year cache if (cache != null && cache.hit(jyear)) { if (isJan1) { return cache.getCachedJan1(); } return cache.getCachedJan1() + getDayOfYear(jyear, month, dayOfMonth) - 1; } long y = jyear; long days = JULIAN_EPOCH - 1 + (365 * (y - 1)) + dayOfMonth; if (y > 0) { // CE years days += (y - 1) / 4; } else { // BCE years days += CalendarUtils.floorDivide(y - 1, 4); } if (month > 0) { days += ((367 * (long) month) - 362) / 12; } else { days += CalendarUtils.floorDivide((367 * (long) month) - 362, 12); } if (month > FEBRUARY) { days -= CalendarUtils.isJulianLeapYear(jyear) ? 1 : 2; } // If it's January 1, update the cache. if (cache != null && isJan1) { cache.setCache(jyear, days, CalendarUtils.isJulianLeapYear(jyear) ? 366 : 365); } return days; } public void getCalendarDateFromFixedDate(CalendarDate date, long fixedDate) { Date jdate = (Date) date; long fd = 4 * (fixedDate - JULIAN_EPOCH) + 1464; int year; if (fd >= 0) { year = (int)(fd / 1461); } else { year = (int) CalendarUtils.floorDivide(fd, 1461); } int priorDays = (int)(fixedDate - getFixedDate(year, JANUARY, 1, jdate)); boolean isLeap = CalendarUtils.isJulianLeapYear(year); if (fixedDate >= getFixedDate(year, MARCH, 1, jdate)) { priorDays += isLeap ? 1 : 2; } int month = 12 * priorDays + 373; if (month > 0) { month /= 367; } else { month = CalendarUtils.floorDivide(month, 367); } int dayOfMonth = (int)(fixedDate - getFixedDate(year, month, 1, jdate)) + 1; int dayOfWeek = getDayOfWeekFromFixedDate(fixedDate); assert dayOfWeek > 0 : "negative day of week " + dayOfWeek; jdate.setNormalizedYear(year); jdate.setMonth(month); jdate.setDayOfMonth(dayOfMonth); jdate.setDayOfWeek(dayOfWeek); jdate.setLeapYear(isLeap); jdate.setNormalized(true); }
Returns the normalized Julian year number of the given fixed date.
/** * Returns the normalized Julian year number of the given fixed date. */
public int getYearFromFixedDate(long fixedDate) { int year = (int) CalendarUtils.floorDivide(4 * (fixedDate - JULIAN_EPOCH) + 1464, 1461); return year; } public int getDayOfWeek(CalendarDate date) { // TODO: should replace this with a faster calculation, such // as cache table lookup long fixedDate = getFixedDate(date); return getDayOfWeekFromFixedDate(fixedDate); } boolean isLeapYear(int jyear) { return CalendarUtils.isJulianLeapYear(jyear); } }