BritishCutoverChronology.java
/*
* Copyright (c) 2007-present, Stephen Colebourne & Michael Nascimento Santos
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* * Neither the name of JSR-310 nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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package org.threeten.extra.chrono;
import java.io.Serializable;
import java.time.Clock;
import java.time.DateTimeException;
import java.time.Instant;
import java.time.LocalDate;
import java.time.ZoneId;
import java.time.chrono.AbstractChronology;
import java.time.chrono.ChronoLocalDateTime;
import java.time.chrono.ChronoZonedDateTime;
import java.time.chrono.Chronology;
import java.time.chrono.Era;
import java.time.chrono.IsoChronology;
import java.time.format.ResolverStyle;
import java.time.temporal.ChronoField;
import java.time.temporal.TemporalAccessor;
import java.time.temporal.TemporalField;
import java.time.temporal.ValueRange;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
/**
* The British Julian-Gregorian cutover calendar system.
* <p>
* The British calendar system follows the rules of the Julian calendar
* until 1752 and the rules of the Gregorian (ISO) calendar since then.
* The Julian differs from the Gregorian only in terms of the leap year rule.
* <p>
* The Julian and Gregorian calendar systems are linked to Rome and the Vatican
* with the Julian preceding the Gregorian. The Gregorian was introduced to
* handle the drift of the seasons through the year due to the inaccurate
* Julian leap year rules. When first introduced by the Vatican in 1582,
* the cutover resulted in a "gap" of 10 days.
* <p>
* While the calendar was introduced in 1582, it was not adopted everywhere.
* Britain did not adopt it until the 1752, when Wednesday 2nd September 1752
* was followed by Thursday 14th September 1752.
* <p>
* This chronology implements the proleptic Julian calendar system followed by
* the proleptic Gregorian calendar system (identical to the ISO calendar system).
* Dates are aligned such that {@code 0001-01-01 (British)} is {@code 0000-12-30 (ISO)}.
* <p>
* This class implements a calendar where January 1st is the start of the year.
* The history of the start of the year is complex and using the current standard
* is the most consistent.
* <p>
* The eras of this calendar system are defined by {@link JulianEra} to avoid unnecessary duplication.
* <p>
* The fields are defined as follows:
* <ul>
* <li>era - There are two eras, the current 'Anno Domini' (AD) and the previous era 'Before Christ' (BC).
* <li>year-of-era - The year-of-era for the current era increases uniformly from the epoch at year one.
* For the previous era the year increases from one as time goes backwards.
* <li>proleptic-year - The proleptic year is the same as the year-of-era for the
* current era. For the previous era, years have zero, then negative values.
* <li>month-of-year - There are 12 months in a year, numbered from 1 to 12.
* <li>day-of-month - There are between 28 and 31 days in each month, numbered from 1 to 31.
* Months 4, 6, 9 and 11 have 30 days, Months 1, 3, 5, 7, 8, 10 and 12 have 31 days.
* Month 2 has 28 days, or 29 in a leap year.
* The cutover month, September 1752, has a value range from 1 to 30, but a length of 19.
* <li>day-of-year - There are 365 days in a standard year and 366 in a leap year.
* The days are numbered from 1 to 365 or 1 to 366.
* The cutover year 1752 has values from 1 to 355 and a length of 355 days.
* </ul>
*
* <h3>Implementation Requirements</h3>
* This class is immutable and thread-safe.
*/
public final class BritishCutoverChronology
extends AbstractChronology
implements Serializable {
/**
* Singleton instance for the Coptic chronology.
*/
public static final BritishCutoverChronology INSTANCE = new BritishCutoverChronology();
/**
* The cutover date, Thursday 14th September 1752.
*/
public static final LocalDate CUTOVER = LocalDate.of(1752, 9, 14);
/**
* The number of cutover days.
*/
static final int CUTOVER_DAYS = 11;
/**
* The cutover year.
*/
static final int CUTOVER_YEAR = 1752;
/**
* Serialization version.
*/
private static final long serialVersionUID = 87235724675472657L;
/**
* Range of day-of-year.
*/
static final ValueRange DOY_RANGE = ValueRange.of(1, 355, 366);
/**
* Range of aligned-week-of-month.
*/
static final ValueRange ALIGNED_WOM_RANGE = ValueRange.of(1, 3, 5);
/**
* Range of aligned-week-of-year.
*/
static final ValueRange ALIGNED_WOY_RANGE = ValueRange.of(1, 51, 53);
/**
* Range of proleptic-year.
*/
static final ValueRange YEAR_RANGE = ValueRange.of(-999_998, 999_999);
/**
* Range of year.
*/
static final ValueRange YOE_RANGE = ValueRange.of(1, 999_999);
/**
* Range of proleptic month.
*/
static final ValueRange PROLEPTIC_MONTH_RANGE = ValueRange.of(-999_998 * 12L, 999_999 * 12L + 11);
/**
* Private constructor, that is public to satisfy the {@code ServiceLoader}.
* @deprecated Use the singleton {@link #INSTANCE} instead.
*/
@Deprecated
public BritishCutoverChronology() {
}
/**
* Resolve singleton.
*
* @return the singleton instance, not null
*/
private Object readResolve() {
return INSTANCE;
}
//-------------------------------------------------------------------------
/**
* Gets the cutover date between the Julian and Gregorian calendar.
* <p>
* The date returned is the first date that the Gregorian (ISO) calendar applies,
* which is Thursday 14th September 1752.
*
* @return the first date after the cutover, not null
*/
public LocalDate getCutover() {
return CUTOVER;
}
//-----------------------------------------------------------------------
/**
* Gets the ID of the chronology - 'BritishCutover'.
* <p>
* The ID uniquely identifies the {@code Chronology}.
* It can be used to lookup the {@code Chronology} using {@link Chronology#of(String)}.
*
* @return the chronology ID - 'BritishCutover'
* @see #getCalendarType()
*/
@Override
public String getId() {
return "BritishCutover";
}
/**
* Gets the calendar type of the underlying calendar system, which returns null.
* <p>
* The <em>Unicode Locale Data Markup Language (LDML)</em> specification
* does not define an identifier for this calendar system, thus null is returned.
*
* @return the calendar system type, null
* @see #getId()
*/
@Override
public String getCalendarType() {
return null;
}
//-----------------------------------------------------------------------
/**
* Obtains a local date in British Cutover calendar system from the
* era, year-of-era, month-of-year and day-of-month fields.
* <p>
* Dates in the middle of the cutover gap, such as the 10th September 1752,
* will not throw an exception. Instead, the date will be treated as a Julian date
* and converted to an ISO date, with the day of month shifted by 11 days.
*
* @param era the British Cutover era, not null
* @param yearOfEra the year-of-era
* @param month the month-of-year
* @param dayOfMonth the day-of-month
* @return the British Cutover local date, not null
* @throws DateTimeException if unable to create the date
* @throws ClassCastException if the {@code era} is not a {@code JulianEra}
*/
@Override
public BritishCutoverDate date(Era era, int yearOfEra, int month, int dayOfMonth) {
return date(prolepticYear(era, yearOfEra), month, dayOfMonth);
}
/**
* Obtains a local date in British Cutover calendar system from the
* proleptic-year, month-of-year and day-of-month fields.
* <p>
* Dates in the middle of the cutover gap, such as the 10th September 1752,
* will not throw an exception. Instead, the date will be treated as a Julian date
* and converted to an ISO date, with the day of month shifted by 11 days.
*
* @param prolepticYear the proleptic-year
* @param month the month-of-year
* @param dayOfMonth the day-of-month
* @return the British Cutover local date, not null
* @throws DateTimeException if unable to create the date
*/
@Override
public BritishCutoverDate date(int prolepticYear, int month, int dayOfMonth) {
return BritishCutoverDate.of(prolepticYear, month, dayOfMonth);
}
/**
* Obtains a local date in British Cutover calendar system from the
* era, year-of-era and day-of-year fields.
* <p>
* The day-of-year takes into account the cutover, thus there are only 355 days in 1752.
*
* @param era the British Cutover era, not null
* @param yearOfEra the year-of-era
* @param dayOfYear the day-of-year
* @return the British Cutover local date, not null
* @throws DateTimeException if unable to create the date
* @throws ClassCastException if the {@code era} is not a {@code JulianEra}
*/
@Override
public BritishCutoverDate dateYearDay(Era era, int yearOfEra, int dayOfYear) {
return dateYearDay(prolepticYear(era, yearOfEra), dayOfYear);
}
/**
* Obtains a local date in British Cutover calendar system from the
* proleptic-year and day-of-year fields.
* <p>
* The day-of-year takes into account the cutover, thus there are only 355 days in 1752.
*
* @param prolepticYear the proleptic-year
* @param dayOfYear the day-of-year
* @return the British Cutover local date, not null
* @throws DateTimeException if unable to create the date
*/
@Override
public BritishCutoverDate dateYearDay(int prolepticYear, int dayOfYear) {
return BritishCutoverDate.ofYearDay(prolepticYear, dayOfYear);
}
/**
* Obtains a local date in the British Cutover calendar system from the epoch-day.
*
* @param epochDay the epoch day
* @return the British Cutover local date, not null
* @throws DateTimeException if unable to create the date
*/
@Override // override with covariant return type
public BritishCutoverDate dateEpochDay(long epochDay) {
return BritishCutoverDate.ofEpochDay(epochDay);
}
//-------------------------------------------------------------------------
/**
* Obtains the current British Cutover local date from the system clock in the default time-zone.
* <p>
* This will query the {@link Clock#systemDefaultZone() system clock} in the default
* time-zone to obtain the current date.
* <p>
* Using this method will prevent the ability to use an alternate clock for testing
* because the clock is hard-coded.
*
* @return the current British Cutover local date using the system clock and default time-zone, not null
* @throws DateTimeException if unable to create the date
*/
@Override // override with covariant return type
public BritishCutoverDate dateNow() {
return BritishCutoverDate.now();
}
/**
* Obtains the current British Cutover local date from the system clock in the specified time-zone.
* <p>
* This will query the {@link Clock#system(ZoneId) system clock} to obtain the current date.
* Specifying the time-zone avoids dependence on the default time-zone.
* <p>
* Using this method will prevent the ability to use an alternate clock for testing
* because the clock is hard-coded.
*
* @param zone the zone ID to use, not null
* @return the current British Cutover local date using the system clock, not null
* @throws DateTimeException if unable to create the date
*/
@Override // override with covariant return type
public BritishCutoverDate dateNow(ZoneId zone) {
return BritishCutoverDate.now(zone);
}
/**
* Obtains the current British Cutover local date from the specified clock.
* <p>
* This will query the specified clock to obtain the current date - today.
* Using this method allows the use of an alternate clock for testing.
* The alternate clock may be introduced using {@link Clock dependency injection}.
*
* @param clock the clock to use, not null
* @return the current British Cutover local date, not null
* @throws DateTimeException if unable to create the date
*/
@Override // override with covariant return type
public BritishCutoverDate dateNow(Clock clock) {
return BritishCutoverDate.now(clock);
}
//-------------------------------------------------------------------------
/**
* Obtains a British Cutover local date from another date-time object.
*
* @param temporal the date-time object to convert, not null
* @return the British Cutover local date, not null
* @throws DateTimeException if unable to create the date
*/
@Override
public BritishCutoverDate date(TemporalAccessor temporal) {
return BritishCutoverDate.from(temporal);
}
/**
* Obtains a British Cutover local date-time from another date-time object.
*
* @param temporal the date-time object to convert, not null
* @return the British Cutover local date-time, not null
* @throws DateTimeException if unable to create the date-time
*/
@Override
@SuppressWarnings("unchecked")
public ChronoLocalDateTime<BritishCutoverDate> localDateTime(TemporalAccessor temporal) {
return (ChronoLocalDateTime<BritishCutoverDate>) super.localDateTime(temporal);
}
/**
* Obtains a British Cutover zoned date-time from another date-time object.
*
* @param temporal the date-time object to convert, not null
* @return the British Cutover zoned date-time, not null
* @throws DateTimeException if unable to create the date-time
*/
@Override
@SuppressWarnings("unchecked")
public ChronoZonedDateTime<BritishCutoverDate> zonedDateTime(TemporalAccessor temporal) {
return (ChronoZonedDateTime<BritishCutoverDate>) super.zonedDateTime(temporal);
}
/**
* Obtains a British Cutover zoned date-time in this chronology from an {@code Instant}.
*
* @param instant the instant to create the date-time from, not null
* @param zone the time-zone, not null
* @return the British Cutover zoned date-time, not null
* @throws DateTimeException if the result exceeds the supported range
*/
@Override
@SuppressWarnings("unchecked")
public ChronoZonedDateTime<BritishCutoverDate> zonedDateTime(Instant instant, ZoneId zone) {
return (ChronoZonedDateTime<BritishCutoverDate>) super.zonedDateTime(instant, zone);
}
//-----------------------------------------------------------------------
/**
* Checks if the specified year is a leap year.
* <p>
* The result will return the same as {@link JulianChronology#isLeapYear(long)} for
* year 1752 and earlier, and {@link IsoChronology#isLeapYear(long)} otherwise.
* This method does not validate the year passed in, and only has a
* well-defined result for years in the supported range.
*
* @param prolepticYear the proleptic-year to check, not validated for range
* @return true if the year is a leap year
*/
@Override
public boolean isLeapYear(long prolepticYear) {
if (prolepticYear <= CUTOVER_YEAR) {
return JulianChronology.INSTANCE.isLeapYear(prolepticYear);
}
return IsoChronology.INSTANCE.isLeapYear(prolepticYear);
}
@Override
public int prolepticYear(Era era, int yearOfEra) {
if (era instanceof JulianEra == false) {
throw new ClassCastException("Era must be JulianEra");
}
return (era == JulianEra.AD ? yearOfEra : 1 - yearOfEra);
}
@Override
public JulianEra eraOf(int eraValue) {
return JulianEra.of(eraValue);
}
@Override
public List<Era> eras() {
return Arrays.<Era>asList(JulianEra.values());
}
//-----------------------------------------------------------------------
@Override
public ValueRange range(ChronoField field) {
switch (field) {
case DAY_OF_YEAR:
return DOY_RANGE;
case ALIGNED_WEEK_OF_MONTH:
return ALIGNED_WOM_RANGE;
case ALIGNED_WEEK_OF_YEAR:
return ALIGNED_WOY_RANGE;
case PROLEPTIC_MONTH:
return PROLEPTIC_MONTH_RANGE;
case YEAR_OF_ERA:
return YOE_RANGE;
case YEAR:
return YEAR_RANGE;
default:
break;
}
return field.range();
}
//-----------------------------------------------------------------------
@Override // override for return type
public BritishCutoverDate resolveDate(Map<TemporalField, Long> fieldValues, ResolverStyle resolverStyle) {
return (BritishCutoverDate) super.resolveDate(fieldValues, resolverStyle);
}
}