/*
* Copyright (c) 2007-2010, 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
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package javax.time.calendar;
import java.io.Serializable;
import javax.time.CalendricalException;
import javax.time.MathUtils;
import javax.time.period.Period;
import javax.time.period.PeriodProvider;
/**
* A year in the ISO-8601 calendar system, such as '2007'.
* <p>
* {@code Year} is an immutable calendrical that represents a year.
* Any field that can be derived from a year can be obtained.
* <p>
* <b>Note that years in the ISO chronology only align with years in the
* Gregorian-Julian system for modern years. Parts of Russia did not switch to the
* modern Gregorian/ISO rules until 1920.
* As such, historical years must be treated with caution.</b>
* <p>
* This class does not store or represent a month, day, time or time zone.
* Thus, for example, the value "2007" can be stored in a {@code Year}.
* <p>
* Years represented by this class follow the ISO-8601 standard and use
* the proleptic numbering system. Year 1 is preceded by year 0, then by year -1.
* <p>
* The ISO-8601 calendar system is the modern civil calendar system used today
* in most of the world. It is equivalent to the proleptic Gregorian calendar
* system, in which todays's rules for leap years are applied for all time.
* For most applications written today, the ISO-8601 rules are entirely suitable.
* Any application that uses historical dates should consider using {@code HistoricDate}.
* <p>
* Year is immutable and thread-safe.
*
* @author Michael Nascimento Santos
* @author Stephen Colebourne
*/
public final class Year
implements Calendrical, Comparable<Year>, Serializable, DateAdjuster, CalendricalMatcher {
/**
* Constant for the minimum year on the proleptic ISO calendar system.
*/
public static final int MIN_YEAR = Integer.MIN_VALUE + 2;
/**
* Constant for the maximum year on the proleptic ISO calendar system,
* which is the same as the maximum for year of era.
*/
public static final int MAX_YEAR = Integer.MAX_VALUE;
/**
* A serialization identifier for this class.
*/
private static final long serialVersionUID = 2751581L;
/**
* The year being represented.
*/
private final int year;
//-----------------------------------------------------------------------
/**
* Gets the rule that defines how the year field operates.
* <p>
* The rule provides access to the minimum and maximum values, and a
* generic way to access values within a calendrical.
*
* @return the year rule, never null
*/
public static DateTimeFieldRule<Integer> rule() {
return ISOChronology.yearRule();
}
//-----------------------------------------------------------------------
/**
* Obtains an instance of {@code Year}.
* <p>
* This method accepts a year value from the proleptic ISO calendar system.
* <p>
* The year 2AD/CE is represented by 2.<br />
* The year 1AD/CE is represented by 1.<br />
* The year 1BC/BCE is represented by 0.<br />
* The year 2BC/BCE is represented by -1.<br />
*
* @param isoYear the ISO proleptic year to represent, from MIN_YEAR to MAX_YEAR
* @return the created Year, never null
* @throws IllegalCalendarFieldValueException if the field is invalid
*/
public static Year of(int isoYear) {
rule().checkValue(isoYear);
return new Year(isoYear);
}
/**
* Obtains an instance of {@code Year} from a calendrical.
* <p>
* This can be used extract the year value directly from any implementation
* of {@code Calendrical}, including those in other calendar systems.
*
* @param calendrical the calendrical to extract from, not null
* @return the Year instance, never null
* @throws UnsupportedRuleException if the year cannot be obtained
*/
public static Year from(Calendrical calendrical) {
return Year.of(rule().getInt(calendrical));
}
//-----------------------------------------------------------------------
/**
* Constructor.
*
* @param year the year to represent
*/
private Year(int year) {
this.year = year;
}
//-----------------------------------------------------------------------
/**
* Gets the year value.
*
* @return the year, from MIN_YEAR to MAX_YEAR
*/
public int getValue() {
return year;
}
//-----------------------------------------------------------------------
/**
* Gets the value of the specified calendrical rule.
* <p>
* This method queries the value of the specified calendrical rule.
* If the value cannot be returned for the rule from this instance then
* {@code null} will be returned.
*
* @param rule the rule to use, not null
* @return the value for the rule, null if the value cannot be returned
*/
public <T> T get(CalendricalRule<T> rule) {
return rule().deriveValueFor(rule, year, this);
}
//-----------------------------------------------------------------------
/**
* 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 ISO8601 standard.
*
* @return true if the year is leap, false otherwise
*/
public boolean isLeap() {
return ISOChronology.isLeapYear(year);
}
//-----------------------------------------------------------------------
/**
* Returns the next year.
*
* @return the next year, never null
* @throws CalendricalException if the maximum year is reached
*/
public Year next() {
if (year == MAX_YEAR) {
throw new CalendricalException("Year is already at the maximum value");
}
return of(year + 1);
}
/**
* Returns the next leap year after the current year.
* The definition of a leap year is specified in {@link #isLeap()}.
*
* @return the next leap year after this year
* @throws CalendricalException if the maximum year is reached
*/
public Year nextLeap() {
Year temp = next();
while (!temp.isLeap()) {
temp = temp.next();
}
return temp;
}
/**
* Returns the previous year.
*
* @return the previous year, never null
* @throws CalendricalException if the maximum year is reached
*/
public Year previous() {
if (year == MIN_YEAR) {
throw new CalendricalException("Year is already at the minimum value");
}
return of(year - 1);
}
/**
* Returns the previous leap year before the current year.
* The definition of a leap year is specified in {@link #isLeap()}.
*
* @return the previous leap year after this year
* @throws CalendricalException if the minimum year is reached
*/
public Year previousLeap() {
Year temp = previous();
while (!temp.isLeap()) {
temp = temp.previous();
}
return temp;
}
//-----------------------------------------------------------------------
/**
* Returns a copy of this Year with the specified period added.
* <p>
* This adds the amount in years from the specified period to this year.
* Any other amounts, such as months or hours are ignored.
* <p>
* This instance is immutable and unaffected by this method call.
*
* @param periodProvider the period to add, not null
* @return a new updated Year, never null
* @throws CalendricalException if the result exceeds the supported year range
*/
public Year plus(PeriodProvider periodProvider) {
Period period = Period.from(periodProvider);
return plusYears(period.getYears());
}
/**
* Returns a copy of this Year with the specified number of years added.
* <p>
* This instance is immutable and unaffected by this method call.
*
* @param years the years to add
* @return a new updated Year, never null
* @throws CalendricalException if the result exceeds the supported year range
*/
public Year plusYears(int years) {
if (years == 0) {
return this;
}
int result = year + years;
if (((year ^ result) < 0 && (year ^ years) >= 0) || rule().isValidValue(result) == false) {
throw new CalendricalException("Addition exceeds the supported year range: " + year + " + " + years);
}
return of(result);
}
//-----------------------------------------------------------------------
/**
* Returns a copy of this Year with the specified period subtracted.
* <p>
* This subtracts the amount in years extracted the specified period from this year.
* Any other amounts, such as months or hours are ignored.
* <p>
* This instance is immutable and unaffected by this method call.
*
* @param periodProvider the period to subtract, not null
* @return a new updated Year, never null
* @throws CalendricalException if the result exceeds the supported year range
*/
public Year minus(PeriodProvider periodProvider) {
Period period = Period.from(periodProvider);
return minusYears(period.getYears());
}
/**
* Returns a copy of this Year with the specified number of years subtracted.
* <p>
* This instance is immutable and unaffected by this method call.
*
* @param years the years to subtract
* @return a new updated Year, never null
* @throws CalendricalException if the result exceeds the supported year range
*/
public Year minusYears(int years) {
if (years == 0) {
return this;
}
int result = year - years;
if (((year ^ result) < 0 && (year ^ years) < 0) || rule().isValidValue(result) == false) {
throw new CalendricalException("Subtraction exceeds the supported year range: " + year + " + " + years);
}
return of(result);
}
//-----------------------------------------------------------------------
/**
* Checks if the year extracted from the calendrical matches this.
*
* @param calendrical the calendrical to match, not null
* @return true if the calendrical matches, false otherwise
*/
public boolean matchesCalendrical(Calendrical calendrical) {
Integer calValue = calendrical.get(rule());
return calValue != null && calValue == getValue();
}
/**
* Adjusts a date to have the value of this year, returning a new date.
* <p>
* If the day-of-month is invalid for the new year then the
* {@link DateResolvers#previousValid()} resolver is used.
* This occurs if the input date is 29th February in a leap year, and this
* object represents a non-leap year.
* <p>
* This instance is immutable and unaffected by this method call.
*
* @param date the date to be adjusted, not null
* @return the adjusted date, never null
*/
public LocalDate adjustDate(LocalDate date) {
return adjustDate(date, DateResolvers.previousValid());
}
/**
* Adjusts a date to have the value of this year, using a resolver to
* handle the case when the day-of-month becomes invalid.
* <p>
* This instance is immutable and unaffected by this method call.
*
* @param date the date to be adjusted, not null
* @param resolver the date resolver to use if the day-of-month becomes invalid, not null
* @return the adjusted date, never null
* @throws IllegalCalendarFieldValueException if the date cannot be resolved using the resolver
*/
public LocalDate adjustDate(LocalDate date, DateResolver resolver) {
return date.withYear(year, resolver);
}
//-----------------------------------------------------------------------
/**
* Gets the length of this year in days.
*
* @return the length of this year in days, 365 or 366
*/
public int lengthInDays() {
return isLeap() ? 366 : 365;
}
//-----------------------------------------------------------------------
/**
* Checks if the month-day is valid for this year.
* <p>
* This method checks whether this year and the input month and day form
* a valid date.
*
* @param monthDay the month-day to validate, null returns false
* @return true if the month and day are valid for this year
*/
public boolean isValidMonthDay(MonthDay monthDay) {
return monthDay != null && monthDay.isValidYear(year);
}
// //-----------------------------------------------------------------------
// /**
// * Gets the ISO proleptic year, from MIN_YEAR to MAX_YEAR.
// * <p>
// * The year 2AD/CE is represented by 2.<br />
// * The year 1AD/CE is represented by 1.<br />
// * The year 1BC/BCE is represented by 0.<br />
// * The year 2BC/BCE is represented by -1.<br />
// *
// * @return the ISO proleptic year, from MIN_YEAR to MAX_YEAR
// */
// public int getISOYear() {
// return year;
// }
//
// /**
// * Returns a new {@code Year} instance with a different year.
// * <p>
// * The year 2AD/CE is represented by 2.<br />
// * The year 1AD/CE is represented by 1.<br />
// * The year 1BC/BCE is represented by 0.<br />
// * The year 2BC/BCE is represented by -1.<br />
// * <p>
// * This instance is immutable and unaffected by this method call.
// *
// * @param isoYear the year to represent, from MIN_YEAR to MAX_YEAR
// * @return a new updated Year, never null
// */
// public Year withISOYear(int isoYear) {
// rule().checkValue(isoYear);
// return null;
// }
// /**
// * Gets the year of era, from 1 to MAX_YEAR, which is used in combination
// * with {@link #getEstimatedEra()}.
// * <p>
// * The year 2, estimated as 2AD/CE is represented by 2.<br />
// * The year 1, estimated as 1AD/CE is represented by 1.<br />
// * The year 0, estimated as 1BC/BCE is represented by 1.<br />
// * The year -1, estimated as 2BC/BCE is represented by 2.<br />
// *
// * @return the year of era, from 1 to MAX_YEAR
// */
// public int getYearOfEra() {
// // TODO: ISO Year doesn't have an era
// return (year > 0 ? year : -(year - 1));
// }
// //-----------------------------------------------------------------------
// /**
// * Gets the century of era, from 0 to MAX_YEAR / 100.
// * <p>
// * This method uses a simple definition of century, being the
// * ISO year divided by 100, which is the same as the printed ISO year
// * without the last two digits.
// * <p>
// * The value 20 will be returned from 2000 to 2099.<br/>
// * The value 19 will be returned from 1900 to 1999.<br/>
// * The value 1 will be returned from 100 to 199.<br/>
// * The value 0 will be returned from -99 to 99 (199 years in the century).<br/>
// * The value -1 will be returned from -100 to 199.<br/>
// *
// * @return the century of era, from 0 to MAX_YEAR / 100
// */
// public int getISOCentury() {
// return year / 100;
// }
//
// /**
// * Gets the year of century, from 0 to 99, which is used in combination
// * with {@link #getCenturyOfEra()}.
// * This is the lower two digits of the ISO year.
// *
// * @return the year of era, from 0 to 99
// */
// public int getYearOfISOCentury() {
// int yoc = year % 100;
// return yoc < 0 ? yoc + 100 : yoc;
// }
//-----------------------------------------------------------------------
/**
* Returns a year-month formed from this year at the specified month.
* <p>
* This method merges {@code this} and the specified month to form an
* instance of {@code YearMonth}.
* This method can be used as part of a chain to produce a date:
* <pre>
* LocalDate date = year.atMonth(month).atDay(day);
* </pre>
* <p>
* This instance is immutable and unaffected by this method call.
*
* @param monthOfYear the month-of-year to use, not null
* @return the year-month formed from this year and the specified month, never null
*/
public YearMonth atMonth(MonthOfYear monthOfYear) {
return YearMonth.of(year, monthOfYear);
}
/**
* Returns a year-month formed from this year at the specified month.
* <p>
* This method merges {@code this} and the specified month to form an
* instance of {@code YearMonth}.
* This method can be used as part of a chain to produce a date:
* <pre>
* LocalDate date = year.atMonth(month).atDay(day);
* </pre>
* <p>
* This instance is immutable and unaffected by this method call.
*
* @param monthOfYear the month-of-year to use, from 1 (January) to 12 (December)
* @return the year-month formed from this year and the specified month, never null
*/
public YearMonth atMonth(int monthOfYear) {
return YearMonth.of(year, monthOfYear);
}
/**
* Returns a date formed from this year at the specified month-day.
* <p>
* This merges the two objects - {@code this} and the specified day -
* to form an instance of {@code LocalDate}.
* <pre>
* LocalDate date = year.atMonthDay(monthDay);
* </pre>
* <p>
* This instance is immutable and unaffected by this method call.
*
* @param monthDay the month-day to use, not null
* @return the local date formed from this year and the specified month-day, never null
* @throws InvalidCalendarFieldException if the month-day is February 29th and this is not a leap year
*/
public LocalDate atMonthDay(MonthDay monthDay) {
return LocalDate.of(year, monthDay.getMonthOfYear(), monthDay.getDayOfMonth());
}
/**
* Returns a date formed from this year at the specified day-of-year.
* <p>
* This merges the two objects - {@code this} and the specified day -
* to form an instance of {@code LocalDate}.
* <pre>
* LocalDate date = year.atDay(dayOfYear);
* </pre>
* <p>
* This instance is immutable and unaffected by this method call.
*
* @param dayOfYear the day-of-year to use, not null
* @return the local date formed from this year and the specified date of year, never null
* @throws InvalidCalendarFieldException if the day of year is 366 and this is not a leap year
*/
public LocalDate atDay(int dayOfYear) {
ISOChronology.dayOfYearRule().checkValue(dayOfYear);
if (dayOfYear == 366 && !isLeap()) {
throw new InvalidCalendarFieldException("Day of year 366 is invalid for year " + year, ISOChronology.dayOfYearRule());
}
return LocalDate.of(year, 1, 1).plusDays(dayOfYear - 1);
}
//-----------------------------------------------------------------------
/**
* Compares this year to another year.
*
* @param other the other year to compare to, not null
* @return the comparator value, negative if less, positive if greater
* @throws NullPointerException if {@code other} is null
*/
public int compareTo(Year other) {
return MathUtils.safeCompare(year, other.year);
}
/**
* Is this year after the specified year.
*
* @param other the other year to compare to, not null
* @return true if this is after the specified year
* @throws NullPointerException if {@code other} is null
*/
public boolean isAfter(Year other) {
return year > other.year;
}
/**
* Is this year before the specified year.
*
* @param other the other year to compare to, not null
* @return true if this point is before the specified year
* @throws NullPointerException if {@code other} is null
*/
public boolean isBefore(Year other) {
return year < other.year;
}
//-----------------------------------------------------------------------
/**
* Is this year equal to the specified year.
*
* @param other the other year to compare to, null returns false
* @return true if this point is equal to the specified year
*/
@Override
public boolean equals(Object other) {
if (this == other) {
return true;
}
if (other instanceof Year) {
return year == ((Year) other).year;
}
return false;
}
/**
* A hash code for this year.
*
* @return a suitable hash code
*/
@Override
public int hashCode() {
return year;
}
//-----------------------------------------------------------------------
/**
* Outputs the string form of the year.
*
* @return the string form of the year
*/
@Override
public String toString() {
return "Year=" + Integer.toString(year);
}
}