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/*
* This file is available under and governed by the GNU General Public
* License version 2 only, as published by the Free Software Foundation.
* However, the following notice accompanied the original version of this
* file:
*
* Copyright (c) 2012, 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
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*/
package java.time.chrono;
import java.io.InvalidObjectException;
import static java.time.temporal.ChronoField.DAY_OF_MONTH;
import static java.time.temporal.ChronoField.ERA;
import static java.time.temporal.ChronoField.MONTH_OF_YEAR;
import static java.time.temporal.ChronoField.PROLEPTIC_MONTH;
import static java.time.temporal.ChronoField.YEAR;
import static java.time.temporal.ChronoField.YEAR_OF_ERA;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.time.Clock;
import java.time.DateTimeException;
import java.time.Instant;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.Month;
import java.time.Period;
import java.time.Year;
import java.time.ZoneId;
import java.time.ZonedDateTime;
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.Locale;
import java.util.Map;
import java.util.Objects;
/**
* The ISO calendar system.
* <p>
* This chronology defines the rules of the ISO calendar system.
* This calendar system is based on the ISO-8601 standard, which is the
* <i>de facto</i> world calendar.
* <p>
* The fields are defined as follows:
* <ul>
* <li>era - There are two eras, 'Current Era' (CE) and 'Before Current Era' (BCE).
* <li>year-of-era - The year-of-era is the same as the proleptic-year for the current CE era.
* For the BCE era before the ISO epoch the year increases from 1 upwards 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 an ISO year, numbered from 1 to 12.
* <li>day-of-month - There are between 28 and 31 days in each of the ISO 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.
* <li>day-of-year - There are 365 days in a standard ISO year and 366 in a leap year.
* The days are numbered from 1 to 365 or 1 to 366.
* <li>leap-year - Leap years occur every 4 years, except where the year is divisble by 100 and not divisble by 400.
* </ul>
*
* @implSpec
* This class is immutable and thread-safe.
*
* @since 1.8
*/
public final class IsoChronology extends AbstractChronology implements Serializable {
/**
* Singleton instance of the ISO chronology.
*/
public static final IsoChronology INSTANCE = new IsoChronology();
/**
* Serialization version.
*/
private static final long serialVersionUID = -1440403870442975015L;
/**
* Restricted constructor.
*/
private IsoChronology() {
}
//-----------------------------------------------------------------------
/**
* Gets the ID of the chronology - 'ISO'.
* <p>
* The ID uniquely identifies the {@code Chronology}.
* It can be used to lookup the {@code Chronology} using {@link #of(String)}.
*
* @return the chronology ID - 'ISO'
* @see #getCalendarType()
*/
@Override
public String getId() {
return "ISO";
}
/**
* Gets the calendar type of the underlying calendar system - 'iso8601'.
* <p>
* The calendar type is an identifier defined by the
* <em>Unicode Locale Data Markup Language (LDML)</em> specification.
* It can be used to lookup the {@code Chronology} using {@link #of(String)}.
* It can also be used as part of a locale, accessible via
* {@link Locale#getUnicodeLocaleType(String)} with the key 'ca'.
*
* @return the calendar system type - 'iso8601'
* @see #getId()
*/
@Override
public String getCalendarType() {
return "iso8601";
}
//-----------------------------------------------------------------------
/**
* Obtains an ISO local date from the era, year-of-era, month-of-year
* and day-of-month fields.
*
* @param era the ISO era, not null
* @param yearOfEra the ISO year-of-era
* @param month the ISO month-of-year
* @param dayOfMonth the ISO day-of-month
* @return the ISO local date, not null
* @throws DateTimeException if unable to create the date
* @throws ClassCastException if the type of {@code era} is not {@code IsoEra}
*/
@Override // override with covariant return type
public LocalDate date(Era era, int yearOfEra, int month, int dayOfMonth) {
return date(prolepticYear(era, yearOfEra), month, dayOfMonth);
}
/**
* Obtains an ISO local date from the proleptic-year, month-of-year
* and day-of-month fields.
* <p>
* This is equivalent to {@link LocalDate#of(int, int, int)}.
*
* @param prolepticYear the ISO proleptic-year
* @param month the ISO month-of-year
* @param dayOfMonth the ISO day-of-month
* @return the ISO local date, not null
* @throws DateTimeException if unable to create the date
*/
@Override // override with covariant return type
public LocalDate date(int prolepticYear, int month, int dayOfMonth) {
return LocalDate.of(prolepticYear, month, dayOfMonth);
}
/**
* Obtains an ISO local date from the era, year-of-era and day-of-year fields.
*
* @param era the ISO era, not null
* @param yearOfEra the ISO year-of-era
* @param dayOfYear the ISO day-of-year
* @return the ISO local date, not null
* @throws DateTimeException if unable to create the date
*/
@Override // override with covariant return type
public LocalDate dateYearDay(Era era, int yearOfEra, int dayOfYear) {
return dateYearDay(prolepticYear(era, yearOfEra), dayOfYear);
}
/**
* Obtains an ISO local date from the proleptic-year and day-of-year fields.
* <p>
* This is equivalent to {@link LocalDate#ofYearDay(int, int)}.
*
* @param prolepticYear the ISO proleptic-year
* @param dayOfYear the ISO day-of-year
* @return the ISO local date, not null
* @throws DateTimeException if unable to create the date
*/
@Override // override with covariant return type
public LocalDate dateYearDay(int prolepticYear, int dayOfYear) {
return LocalDate.ofYearDay(prolepticYear, dayOfYear);
}
/**
* Obtains an ISO local date from the epoch-day.
* <p>
* This is equivalent to {@link LocalDate#ofEpochDay(long)}.
*
* @param epochDay the epoch day
* @return the ISO local date, not null
* @throws DateTimeException if unable to create the date
*/
@Override // override with covariant return type
public LocalDate dateEpochDay(long epochDay) {
return LocalDate.ofEpochDay(epochDay);
}
//-----------------------------------------------------------------------
/**
* Obtains an ISO local date from another date-time object.
* <p>
* This is equivalent to {@link LocalDate#from(TemporalAccessor)}.
*
* @param temporal the date-time object to convert, not null
* @return the ISO local date, not null
* @throws DateTimeException if unable to create the date
*/
@Override // override with covariant return type
public LocalDate date(TemporalAccessor temporal) {
return LocalDate.from(temporal);
}
/**
* Obtains an ISO local date-time from another date-time object.
* <p>
* This is equivalent to {@link LocalDateTime#from(TemporalAccessor)}.
*
* @param temporal the date-time object to convert, not null
* @return the ISO local date-time, not null
* @throws DateTimeException if unable to create the date-time
*/
@Override // override with covariant return type
public LocalDateTime localDateTime(TemporalAccessor temporal) {
return LocalDateTime.from(temporal);
}
/**
* Obtains an ISO zoned date-time from another date-time object.
* <p>
* This is equivalent to {@link ZonedDateTime#from(TemporalAccessor)}.
*
* @param temporal the date-time object to convert, not null
* @return the ISO zoned date-time, not null
* @throws DateTimeException if unable to create the date-time
*/
@Override // override with covariant return type
public ZonedDateTime zonedDateTime(TemporalAccessor temporal) {
return ZonedDateTime.from(temporal);
}
/**
* Obtains an ISO zoned date-time in this chronology from an {@code Instant}.
* <p>
* This is equivalent to {@link ZonedDateTime#ofInstant(Instant, ZoneId)}.
*
* @param instant the instant to create the date-time from, not null
* @param zone the time-zone, not null
* @return the zoned date-time, not null
* @throws DateTimeException if the result exceeds the supported range
*/
@Override
public ZonedDateTime zonedDateTime(Instant instant, ZoneId zone) {
return ZonedDateTime.ofInstant(instant, zone);
}
//-----------------------------------------------------------------------
/**
* Obtains the current ISO 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 ISO 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 LocalDate dateNow() {
return dateNow(Clock.systemDefaultZone());
}
/**
* Obtains the current ISO 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.
*
* @return the current ISO local date using the system clock, not null
* @throws DateTimeException if unable to create the date
*/
@Override // override with covariant return type
public LocalDate dateNow(ZoneId zone) {
return dateNow(Clock.system(zone));
}
/**
* Obtains the current ISO 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 ISO local date, not null
* @throws DateTimeException if unable to create the date
*/
@Override // override with covariant return type
public LocalDate dateNow(Clock clock) {
Objects.requireNonNull(clock, "clock");
return date(LocalDate.now(clock));
}
//-----------------------------------------------------------------------
/**
* Checks if the year is a leap year, according to the ISO proleptic
* calendar system rules.
* <p>
* This method applies the current rules for leap years across the whole time-line.
* In general, a year is a leap year if it is divisible by four without
* remainder. However, years divisible by 100, are not leap years, with
* the exception of years divisible by 400 which are.
* <p>
* For example, 1904 is a leap year it is divisible by 4.
* 1900 was not a leap year as it is divisible by 100, however 2000 was a
* leap year as it is divisible by 400.
* <p>
* The calculation is proleptic - applying the same rules into the far future and far past.
* This is historically inaccurate, but is correct for the ISO-8601 standard.
*
* @param prolepticYear the ISO proleptic year to check
* @return true if the year is leap, false otherwise
*/
@Override
public boolean isLeapYear(long prolepticYear) {
return ((prolepticYear & 3) == 0) && ((prolepticYear % 100) != 0 || (prolepticYear % 400) == 0);
}
@Override
public int prolepticYear(Era era, int yearOfEra) {
if (era instanceof IsoEra == false) {
throw new ClassCastException("Era must be IsoEra");
}
return (era == IsoEra.CE ? yearOfEra : 1 - yearOfEra);
}
@Override
public IsoEra eraOf(int eraValue) {
return IsoEra.of(eraValue);
}
@Override
public List<Era> eras() {
return Arrays.<Era>asList(IsoEra.values());
}
//-----------------------------------------------------------------------
/**
* Resolves parsed {@code ChronoField} values into a date during parsing.
* <p>
* Most {@code TemporalField} implementations are resolved using the
* resolve method on the field. By contrast, the {@code ChronoField} class
* defines fields that only have meaning relative to the chronology.
* As such, {@code ChronoField} date fields are resolved here in the
* context of a specific chronology.
* <p>
* {@code ChronoField} instances on the ISO calendar system are resolved
* as follows.
* <ul>
* <li>{@code EPOCH_DAY} - If present, this is converted to a {@code LocalDate}
* and all other date fields are then cross-checked against the date.
* <li>{@code PROLEPTIC_MONTH} - If present, then it is split into the
* {@code YEAR} and {@code MONTH_OF_YEAR}. If the mode is strict or smart
* then the field is validated.
* <li>{@code YEAR_OF_ERA} and {@code ERA} - If both are present, then they
* are combined to form a {@code YEAR}. In lenient mode, the {@code YEAR_OF_ERA}
* range is not validated, in smart and strict mode it is. The {@code ERA} is
* validated for range in all three modes. If only the {@code YEAR_OF_ERA} is
* present, and the mode is smart or lenient, then the current era (CE/AD)
* is assumed. In strict mode, no era is assumed and the {@code YEAR_OF_ERA} is
* left untouched. If only the {@code ERA} is present, then it is left untouched.
* <li>{@code YEAR}, {@code MONTH_OF_YEAR} and {@code DAY_OF_MONTH} -
* If all three are present, then they are combined to form a {@code LocalDate}.
* In all three modes, the {@code YEAR} is validated. If the mode is smart or strict,
* then the month and day are validated, with the day validated from 1 to 31.
* If the mode is lenient, then the date is combined in a manner equivalent to
* creating a date on the first of January in the requested year, then adding
* the difference in months, then the difference in days.
* If the mode is smart, and the day-of-month is greater than the maximum for
* the year-month, then the day-of-month is adjusted to the last day-of-month.
* If the mode is strict, then the three fields must form a valid date.
* <li>{@code YEAR} and {@code DAY_OF_YEAR} -
* If both are present, then they are combined to form a {@code LocalDate}.
* In all three modes, the {@code YEAR} is validated.
* If the mode is lenient, then the date is combined in a manner equivalent to
* creating a date on the first of January in the requested year, then adding
* the difference in days.
* If the mode is smart or strict, then the two fields must form a valid date.
* <li>{@code YEAR}, {@code MONTH_OF_YEAR}, {@code ALIGNED_WEEK_OF_MONTH} and
* {@code ALIGNED_DAY_OF_WEEK_IN_MONTH} -
* If all four are present, then they are combined to form a {@code LocalDate}.
* In all three modes, the {@code YEAR} is validated.
* If the mode is lenient, then the date is combined in a manner equivalent to
* creating a date on the first of January in the requested year, then adding
* the difference in months, then the difference in weeks, then in days.
* If the mode is smart or strict, then the all four fields are validated to
* their outer ranges. The date is then combined in a manner equivalent to
* creating a date on the first day of the requested year and month, then adding
* the amount in weeks and days to reach their values. If the mode is strict,
* the date is additionally validated to check that the day and week adjustment
* did not change the month.
* <li>{@code YEAR}, {@code MONTH_OF_YEAR}, {@code ALIGNED_WEEK_OF_MONTH} and
* {@code DAY_OF_WEEK} - If all four are present, then they are combined to
* form a {@code LocalDate}. The approach is the same as described above for
* years, months and weeks in {@code ALIGNED_DAY_OF_WEEK_IN_MONTH}.
* The day-of-week is adjusted as the next or same matching day-of-week once
* the years, months and weeks have been handled.
* <li>{@code YEAR}, {@code ALIGNED_WEEK_OF_YEAR} and {@code ALIGNED_DAY_OF_WEEK_IN_YEAR} -
* If all three are present, then they are combined to form a {@code LocalDate}.
* In all three modes, the {@code YEAR} is validated.
* If the mode is lenient, then the date is combined in a manner equivalent to
* creating a date on the first of January in the requested year, then adding
* the difference in weeks, then in days.
* If the mode is smart or strict, then the all three fields are validated to
* their outer ranges. The date is then combined in a manner equivalent to
* creating a date on the first day of the requested year, then adding
* the amount in weeks and days to reach their values. If the mode is strict,
* the date is additionally validated to check that the day and week adjustment
* did not change the year.
* <li>{@code YEAR}, {@code ALIGNED_WEEK_OF_YEAR} and {@code DAY_OF_WEEK} -
* If all three are present, then they are combined to form a {@code LocalDate}.
* The approach is the same as described above for years and weeks in
* {@code ALIGNED_DAY_OF_WEEK_IN_YEAR}. The day-of-week is adjusted as the
* next or same matching day-of-week once the years and weeks have been handled.
* </ul>
*
* @param fieldValues the map of fields to values, which can be updated, not null
* @param resolverStyle the requested type of resolve, not null
* @return the resolved date, null if insufficient information to create a date
* @throws DateTimeException if the date cannot be resolved, typically
* because of a conflict in the input data
*/
@Override // override for performance
public LocalDate resolveDate(Map<TemporalField, Long> fieldValues, ResolverStyle resolverStyle) {
return (LocalDate) super.resolveDate(fieldValues, resolverStyle);
}
@Override // override for better proleptic algorithm
void resolveProlepticMonth(Map<TemporalField, Long> fieldValues, ResolverStyle resolverStyle) {
Long pMonth = fieldValues.remove(PROLEPTIC_MONTH);
if (pMonth != null) {
if (resolverStyle != ResolverStyle.LENIENT) {
PROLEPTIC_MONTH.checkValidValue(pMonth);
}
addFieldValue(fieldValues, MONTH_OF_YEAR, Math.floorMod(pMonth, 12) + 1);
addFieldValue(fieldValues, YEAR, Math.floorDiv(pMonth, 12));
}
}
@Override // override for enhanced behaviour
LocalDate resolveYearOfEra(Map<TemporalField, Long> fieldValues, ResolverStyle resolverStyle) {
Long yoeLong = fieldValues.remove(YEAR_OF_ERA);
if (yoeLong != null) {
if (resolverStyle != ResolverStyle.LENIENT) {
YEAR_OF_ERA.checkValidValue(yoeLong);
}
Long era = fieldValues.remove(ERA);
if (era == null) {
Long year = fieldValues.get(YEAR);
if (resolverStyle == ResolverStyle.STRICT) {
// do not invent era if strict, but do cross-check with year
if (year != null) {
addFieldValue(fieldValues, YEAR, (year > 0 ? yoeLong: Math.subtractExact(1, yoeLong)));
} else {
// reinstate the field removed earlier, no cross-check issues
fieldValues.put(YEAR_OF_ERA, yoeLong);
}
} else {
// invent era
addFieldValue(fieldValues, YEAR, (year == null || year > 0 ? yoeLong: Math.subtractExact(1, yoeLong)));
}
} else if (era.longValue() == 1L) {
addFieldValue(fieldValues, YEAR, yoeLong);
} else if (era.longValue() == 0L) {
addFieldValue(fieldValues, YEAR, Math.subtractExact(1, yoeLong));
} else {
throw new DateTimeException("Invalid value for era: " + era);
}
} else if (fieldValues.containsKey(ERA)) {
ERA.checkValidValue(fieldValues.get(ERA)); // always validated
}
return null;
}
@Override // override for performance
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