AbstractChronology

AI-generated Key Takeaways

• AbstractChronology is a foundational class for implementing various calendar systems, with IsoChronology as its primary subclass, representing the ISO calendar.

• This class provides a framework for comparing chronologies and managing their equality, utilizing both ID-based and state-based comparisons via the compareTo, equals, and hashCode methods.

• The resolveDate method within AbstractChronology is crucial for translating temporal field values, like year, month, and day, into a concrete date, with customizable validation rules for date fields being applied.

• AbstractChronology handles the combination of various temporal fields to form a date, including the management of fields like YEAR, ALIGNED_WEEK_OF_YEAR, and DAY_OF_WEEK, with the resolution style impacting the validation and adjustment of these values.

• The toString() method will output the chronology as a string, relying on the chronology ID to do so.

public abstract class AbstractChronology extends Object
implements Chronology

Known Direct Subclasses IsoChronology IsoChronology The ISO calendar system.

An abstract implementation of a calendar system, used to organize and identify dates.

The main date and time API is built on the ISO calendar system. The chronology operates behind the scenes to represent the general concept of a calendar system.

See Chronology for more details.

Protected Constructor Summary

AbstractChronology() Creates an instance.

Public Method Summary

int	compareTo(Chronology other) Compares this chronology to another chronology.
boolean	equals(Object obj) Checks if this chronology is equal to another chronology.
int	hashCode() A hash code for this chronology.
ChronoLocalDate	resolveDate(Map<TemporalField, Long> fieldValues, ResolverStyle resolverStyle) Resolves parsed ChronoField values into a date during parsing.
String	toString() Outputs this chronology as a String, using the chronology ID.

Inherited Method Summary

From class java.lang.Object

Object	clone() Creates and returns a copy of this Object.
boolean	equals(Object obj) Compares this instance with the specified object and indicates if they are equal.
void	finalize() Invoked when the garbage collector has detected that this instance is no longer reachable.
final Class<?>	getClass() Returns the unique instance of Class that represents this object's class.
int	hashCode() Returns an integer hash code for this object.
final void	notify() Causes a thread which is waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
final void	notifyAll() Causes all threads which are waiting on this object's monitor (by means of calling one of the wait() methods) to be woken up.
String	toString() Returns a string containing a concise, human-readable description of this object.
final void	wait(long timeout, int nanos) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait(long timeout) Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object or until the specified timeout expires.
final void	wait() Causes the calling thread to wait until another thread calls the notify() or notifyAll() method of this object.

From interface java.time.chrono.Chronology

abstract int	compareTo(Chronology other) Compares this chronology to another chronology.
ChronoLocalDate	date(Era era, int yearOfEra, int month, int dayOfMonth) Obtains a local date in this chronology from the era, year-of-era, month-of-year and day-of-month fields.
abstract ChronoLocalDate	date(int prolepticYear, int month, int dayOfMonth) Obtains a local date in this chronology from the proleptic-year, month-of-year and day-of-month fields.
abstract ChronoLocalDate	date(TemporalAccessor temporal) Obtains a local date in this chronology from another temporal object.
abstract ChronoLocalDate	dateEpochDay(long epochDay) Obtains a local date in this chronology from the epoch-day.
ChronoLocalDate	dateNow(Clock clock) Obtains the current local date in this chronology from the specified clock.
ChronoLocalDate	dateNow(ZoneId zone) Obtains the current local date in this chronology from the system clock in the specified time-zone.
ChronoLocalDate	dateNow() Obtains the current local date in this chronology from the system clock in the default time-zone.
ChronoLocalDate	dateYearDay(Era era, int yearOfEra, int dayOfYear) Obtains a local date in this chronology from the era, year-of-era and day-of-year fields.
abstract ChronoLocalDate	dateYearDay(int prolepticYear, int dayOfYear) Obtains a local date in this chronology from the proleptic-year and day-of-year fields.
abstract boolean	equals(Object obj) Checks if this chronology is equal to another chronology.
abstract Era	eraOf(int eraValue) Creates the chronology era object from the numeric value.
abstract List<Era>	eras() Gets the list of eras for the chronology.
static Chronology	from(TemporalAccessor temporal) Obtains an instance of Chronology from a temporal object.
static Set<Chronology>	getAvailableChronologies() Returns the available chronologies.
abstract String	getCalendarType() Gets the calendar type of the calendar system.
String	getDisplayName(TextStyle style, Locale locale) Gets the textual representation of this chronology.
abstract String	getId() Gets the ID of the chronology.
abstract int	hashCode() A hash code for this chronology.
abstract boolean	isLeapYear(long prolepticYear) Checks if the specified year is a leap year.
ChronoLocalDateTime<? extends ChronoLocalDate>	localDateTime(TemporalAccessor temporal) Obtains a local date-time in this chronology from another temporal object.
static Chronology	of(String id) Obtains an instance of Chronology from a chronology ID or calendar system type.
static Chronology	ofLocale(Locale locale) Obtains an instance of Chronology from a locale.
ChronoPeriod	period(int years, int months, int days) Obtains a period for this chronology based on years, months and days.
abstract int	prolepticYear(Era era, int yearOfEra) Calculates the proleptic-year given the era and year-of-era.
abstract ValueRange	range(ChronoField field) Gets the range of valid values for the specified field.
abstract ChronoLocalDate	resolveDate(Map<TemporalField, Long> fieldValues, ResolverStyle resolverStyle) Resolves parsed ChronoField values into a date during parsing.
abstract String	toString() Outputs this chronology as a String.
ChronoZonedDateTime<? extends ChronoLocalDate>	zonedDateTime(Instant instant, ZoneId zone) Obtains a ChronoZonedDateTime in this chronology from an Instant.
ChronoZonedDateTime<? extends ChronoLocalDate>	zonedDateTime(TemporalAccessor temporal) Obtains a ChronoZonedDateTime in this chronology from another temporal object.

From interface java.lang.Comparable

abstract int

compareTo(Chronology o) Compares this object with the specified object for order.

Protected Constructors

protected AbstractChronology ()

Creates an instance.

Public Methods

public int compareTo (Chronology other)

Compares this chronology to another chronology.

The comparison order first by the chronology ID string, then by any additional information specific to the subclass. It is "consistent with equals", as defined by Comparable.

Parameters

other	the other chronology to compare to, not null

Returns

• the comparator value, negative if less, positive if greater

public boolean equals (Object obj)

Checks if this chronology is equal to another chronology.

The comparison is based on the entire state of the object.

Parameters

obj	the object to check, null returns false

Returns

• true if this is equal to the other chronology

public int hashCode ()

A hash code for this chronology.

The hash code should be based on the entire state of the object.

Returns

• a suitable hash code

public ChronoLocalDate resolveDate (Map<TemporalField, Long> fieldValues, ResolverStyle resolverStyle)

Resolves parsed ChronoField values into a date during parsing.

Most TemporalField implementations are resolved using the resolve method on the field. By contrast, the ChronoField class defines fields that only have meaning relative to the chronology. As such, ChronoField date fields are resolved here in the context of a specific chronology.

ChronoField instances are resolved by this method, which may be overridden in subclasses.

• EPOCH_DAY - If present, this is converted to a date and all other date fields are then cross-checked against the date.
• PROLEPTIC_MONTH - If present, then it is split into the YEAR and MONTH_OF_YEAR. If the mode is strict or smart then the field is validated.
• YEAR_OF_ERA and ERA - If both are present, then they are combined to form a YEAR. In lenient mode, the YEAR_OF_ERA range is not validated, in smart and strict mode it is. The ERA is validated for range in all three modes. If only the YEAR_OF_ERA is present, and the mode is smart or lenient, then the last available era is assumed. In strict mode, no era is assumed and the YEAR_OF_ERA is left untouched. If only the ERA is present, then it is left untouched.
• YEAR, MONTH_OF_YEAR and DAY_OF_MONTH - If all three are present, then they are combined to form a date. In all three modes, the YEAR is validated. If the mode is smart or strict, then the month and day are validated. If the mode is lenient, then the date is combined in a manner equivalent to creating a date on the first day of the first month 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.
• YEAR and DAY_OF_YEAR - If both are present, then they are combined to form a date. In all three modes, the YEAR is validated. If the mode is lenient, then the date is combined in a manner equivalent to creating a date on the first day of 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.
• YEAR, MONTH_OF_YEAR, ALIGNED_WEEK_OF_MONTH and ALIGNED_DAY_OF_WEEK_IN_MONTH - If all four are present, then they are combined to form a date. In all three modes, the YEAR is validated. If the mode is lenient, then the date is combined in a manner equivalent to creating a date on the first day of the first month 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.
• YEAR, MONTH_OF_YEAR, ALIGNED_WEEK_OF_MONTH and DAY_OF_WEEK - If all four are present, then they are combined to form a date. The approach is the same as described above for years, months and weeks in 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.
• YEAR, ALIGNED_WEEK_OF_YEAR and ALIGNED_DAY_OF_WEEK_IN_YEAR - If all three are present, then they are combined to form a date. In all three modes, the YEAR is validated. If the mode is lenient, then the date is combined in a manner equivalent to creating a date on the first day of 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.
• YEAR, ALIGNED_WEEK_OF_YEAR and DAY_OF_WEEK - If all three are present, then they are combined to form a date. The approach is the same as described above for years and weeks in 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.

The default implementation is suitable for most calendar systems. If ChronoField.YEAR_OF_ERA is found without an ChronoField.ERA then the last era in Chronology.eras() is used. The implementation assumes a 7 day week, that the first day-of-month has the value 1, that first day-of-year has the value 1, and that the first of the month and year always exists.

Parameters

fieldValues	the map of fields to values, which can be updated, not null
resolverStyle	the requested type of resolve, not null

Returns

• 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

public String toString ()

Outputs this chronology as a String, using the chronology ID.

Returns

• a string representation of this chronology, not null