Package org.gnome.glib

Class Date

java.lang.Object

org.javagi.base.ProxyInstance

org.gnome.glib.Date

All Implemented Interfaces:

Proxy

@Generated("io.github.jwharm.JavaGI")
public class Date
extends ProxyInstance

GDate is a struct for calendrical calculations.

The GDate data structure represents a day between January 1, Year 1, and sometime a few thousand years in the future (right now it will go to the year 65535 or so, but setParse(java.lang.String) only parses up to the year 8000 or so - just count on "a few thousand"). GDate is meant to represent everyday dates, not astronomical dates or historical dates or ISO timestamps or the like. It extrapolates the current Gregorian calendar forward and backward in time; there is no attempt to change the calendar to match time periods or locations. GDate does not store time information; it represents a day.

The GDate implementation has several nice features; it is only a 64-bit struct, so storing large numbers of dates is very efficient. It can keep both a Julian and day-month-year representation of the date, since some calculations are much easier with one representation or the other. A Julian representation is simply a count of days since some fixed day in the past; for GDate the fixed day is January 1, 1 AD. ("Julian" dates in the GDate API aren't really Julian dates in the technical sense; technically, Julian dates count from the start of the Julian period, Jan 1, 4713 BC).

GDate is simple to use. First you need a "blank" date; you can get a dynamically allocated date from Date(), or you can declare an automatic variable or array and initialize it by calling clear(int). A cleared date is safe; it's safe to call setDmy(org.gnome.glib.DateDay, org.gnome.glib.DateMonth, org.gnome.glib.DateYear) and the other mutator functions to initialize the value of a cleared date. However, a cleared date is initially invalid, meaning that it doesn't represent a day that exists. It is undefined to call any of the date calculation routines on an invalid date. If you obtain a date from a user or other unpredictable source, you should check its validity with the valid() predicate. valid() is also used to check for errors with setParse(java.lang.String) and other functions that can fail. Dates can be invalidated by calling clear(int) again.

It is very important to use the API to access the GDate struct. Often only the day-month-year or only the Julian representation is valid. Sometimes neither is valid. Use the API.

GLib also features GDateTime which represents a precise time.

Constructor Summary

Constructors

Constructor	Description
Date()	Allocates a GDate and initializes it to a safe state.
Date(MemorySegment address)	Create a Date proxy instance for the provided memory address.

Method Summary

Modifier and Type	Method	Description
void	addDays(int nDays)	Increments a date some number of days.
void	addMonths(int nMonths)	Increments a date by some number of months.
void	addYears(int nYears)	Increments a date by some number of years.
void	clamp(Date minDate, Date maxDate)	If this Date is prior to minDate, sets this Date equal to minDate. If this Date falls after maxDate, sets this Date equal to maxDate. Otherwise, this Date is unchanged.
void	clear(int nDates)	Initializes one or more GDate structs to a safe but invalid state.
int	compare(Date rhs)	qsort()-style comparison function for dates.
Date	copy()	Copies a GDate to a newly-allocated GDate.
int	daysBetween(Date date2)	Computes the number of days between two dates.
static Date	dmy(DateDay day, DateMonth month, DateYear year)	Create a new GDate representing the given day-month-year triplet.
void	free()	Frees a GDate returned from g_date_new().
DateDay	getDay()	Returns the day of the month.
int	getDayOfYear()	Returns the day of the year, where Jan 1 is the first day of the year.
static byte	getDaysInMonth(DateMonth month, DateYear year)	Returns the number of days in a month, taking leap years into account.
int	getIso8601WeekOfYear()	Returns the week of the year, where weeks are interpreted according to ISO 8601.
int	getJulian()	Returns the Julian day or "serial number" of the GDate.
static MemoryLayout	getMemoryLayout()	The memory layout of the native struct.
int	getMondayWeekOfYear()	Returns the week of the year, where weeks are understood to start on Monday.
static byte	getMondayWeeksInYear(DateYear year)	Returns the number of weeks in the year, where weeks are taken to start on Monday.
DateMonth	getMonth()	Returns the month of the year.
int	getSundayWeekOfYear()	Returns the week of the year during which this date falls, if weeks are understood to begin on Sunday.
static byte	getSundayWeeksInYear(DateYear year)	Returns the number of weeks in the year, where weeks are taken to start on Sunday.
static @Nullable Type	getType()	Get the GType of the Date class
DateWeekday	getWeekday()	Returns the day of the week for a GDate.
int	getWeekOfYear(DateWeekday firstDayOfWeek)	Calculates the week of the year during which this date falls.
static byte	getWeeksInYear(DateYear year, DateWeekday firstDayOfWeek)	Calculates the number of weeks in the year.
DateYear	getYear()	Returns the year of a GDate.
boolean	isFirstOfMonth()	Returns true if the date is on the first of a month.
boolean	isLastOfMonth()	Returns true if the date is the last day of the month.
static boolean	isLeapYear(DateYear year)	Returns true if the year is a leap year.
static Date	julian(int julianDay)	Create a new GDate representing the given Julian date.
void	order(Date date2)	Checks if this Date is less than or equal to date2, and swap the values if this is not the case.
void	setDay(DateDay day)	Sets the day of the month for a GDate.
void	setDmy(DateDay day, DateMonth month, DateYear y)	Sets the value of a GDate from a day, month, and year.
void	setJulian(int julianDate)	Sets the value of a GDate from a Julian day number.
void	setMonth(DateMonth month)	Sets the month of the year for a GDate.
void	setParse(String str)	Parses a user-inputted string str, and try to figure out what date it represents, taking the current locale into account.
void	setTime(Time time)	Deprecated. Use g_date_set_time_t() instead.
void	setTimeT(long timet)	Sets the value of a date to the date corresponding to a time specified as a time_t.
void	setTimeVal(TimeVal timeval)	Deprecated. GTimeVal is not year-2038-safe.
void	setYear(DateYear year)	Sets the year for a GDate.
static long	strftime(String s, long slen, String format, Date date)	Generates a printed representation of the date, in a locale-specific way.
void	subtractDays(int nDays)	Moves a date some number of days into the past.
void	subtractMonths(int nMonths)	Moves a date some number of months into the past.
void	subtractYears(int nYears)	Moves a date some number of years into the past.
void	toStructTm(MemorySegment tm)	Fills in the date-related bits of a struct tm using the this Date value.
boolean	valid()	Returns true if the GDate represents an existing day.
static boolean	validDay(DateDay day)	Returns true if the day of the month is valid (a day is valid if it's between 1 and 31 inclusive).
static boolean	validDmy(DateDay day, DateMonth month, DateYear year)	Returns true if the day-month-year triplet forms a valid, existing day in the range of days GDate understands (Year 1 or later, no more than a few thousand years in the future).
static boolean	validJulian(int julianDate)	Returns true if the Julian day is valid.
static boolean	validMonth(DateMonth month)	Returns true if the month value is valid.
static boolean	validWeekday(DateWeekday weekday)	Returns true if the weekday is valid.
static boolean	validYear(DateYear year)	Returns true if the year is valid.

Methods inherited from class org.javagi.base.ProxyInstance

equals, handle, hashCode

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Details

Date

public Date(MemorySegment address)

Create a Date proxy instance for the provided memory address.

Parameters:

address - the memory address of the native object

Date

public Date()

Allocates a GDate and initializes it to a safe state. The new date will be cleared (as if you'd called g_date_clear()) but invalid (it won't represent an existing day). Free the return value with g_date_free().

Method Details

getType

public static @Nullable Type getType()

Get the GType of the Date class

Returns:

the GType

getMemoryLayout

public static MemoryLayout getMemoryLayout()

The memory layout of the native struct.

Returns:

the memory layout

dmy

public static Date dmy(DateDay day,
 DateMonth month,
 DateYear year)

Create a new GDate representing the given day-month-year triplet.

The triplet you pass in must represent a valid date. Use g_date_valid_dmy() if needed to validate it. The returned GDate is guaranteed to be non-null and valid.

Parameters:

day - day of the month

month - month of the year

year - year

Returns:

a newly-allocated GDate initialized with day, month, and year

julian

public static Date julian(int julianDay)

Create a new GDate representing the given Julian date.

The julianDay you pass in must be valid. Use g_date_valid_julian() if needed to validate it. The returned GDate is guaranteed to be non-null and valid.

Parameters:

julianDay - days since January 1, Year 1

Returns:

a newly-allocated GDate initialized with julianDay

getDaysInMonth

public static byte getDaysInMonth(DateMonth month,
 DateYear year)

Returns the number of days in a month, taking leap years into account.

Parameters:

month - month

year - year

Returns:

number of days in month during the year

getMondayWeeksInYear

public static byte getMondayWeeksInYear(DateYear year)

Returns the number of weeks in the year, where weeks are taken to start on Monday. Will be 52 or 53. The date must be valid. (Years always have 52 7-day periods, plus 1 or 2 extra days depending on whether it's a leap year. This function is basically telling you how many Mondays are in the year, i.e. there are 53 Mondays if one of the extra days happens to be a Monday.)

Parameters:

year - a year

Returns:

number of Mondays in the year

getSundayWeeksInYear

public static byte getSundayWeeksInYear(DateYear year)

Returns the number of weeks in the year, where weeks are taken to start on Sunday. Will be 52 or 53. The date must be valid. (Years always have 52 7-day periods, plus 1 or 2 extra days depending on whether it's a leap year. This function is basically telling you how many Sundays are in the year, i.e. there are 53 Sundays if one of the extra days happens to be a Sunday.)

Parameters:

year - year to count weeks in

Returns:

the number of weeks in year

getWeeksInYear

public static byte getWeeksInYear(DateYear year,
 DateWeekday firstDayOfWeek)

Calculates the number of weeks in the year.

The result depends on which day is considered the first day of the week, which varies by locale. first_day_of_week must be valid.

The result will be either 52 or 53. Years always have 52 seven-day periods, plus one or two extra days depending on whether it’s a leap year. This function effectively calculates how many firstDayOfWeek days there are in the year.

Parameters:

year - year to count weeks in

firstDayOfWeek - the day which is considered the first day of the week (for example, this would be GLib.DateWeekday.SUNDAY in US locales, GLib.DateWeekday.MONDAY in British locales, and GLib.DateWeekday.SATURDAY in Egyptian locales

Returns:

the number of weeks in year

Since:

2.86

isLeapYear

public static boolean isLeapYear(DateYear year)

Returns true if the year is a leap year.

For the purposes of this function, leap year is every year divisible by 4 unless that year is divisible by 100. If it is divisible by 100 it would be a leap year only if that year is also divisible by 400.

Parameters:

year - year to check

Returns:

true if the year is a leap year

strftime

public static long strftime(String s,
 long slen,
 String format,
 Date date)

Generates a printed representation of the date, in a locale-specific way. Works just like the platform's C library strftime() function, but only accepts date-related formats; time-related formats give undefined results. Date must be valid. Unlike strftime() (which uses the locale encoding), works on a UTF-8 format string and stores a UTF-8 result.

This function does not provide any conversion specifiers in addition to those implemented by the platform's C library. For example, don't expect that using g_date_strftime() would make the \\F provided by the C99 strftime() work on Windows where the C library only complies to C89.

Parameters:

s - destination buffer

slen - buffer size

format - format string

date - valid GDate

Returns:

number of characters written to the buffer, or 0 if the buffer was too small

validDay

public static boolean validDay(DateDay day)

Returns true if the day of the month is valid (a day is valid if it's between 1 and 31 inclusive).

Parameters:

day - day to check

Returns:

true if the day is valid

validDmy

public static boolean validDmy(DateDay day,
 DateMonth month,
 DateYear year)

Returns true if the day-month-year triplet forms a valid, existing day in the range of days GDate understands (Year 1 or later, no more than a few thousand years in the future).

Parameters:

day - day

month - month

year - year

Returns:

true if the date is a valid one

validJulian

public static boolean validJulian(int julianDate)

Returns true if the Julian day is valid. Anything greater than zero is basically a valid Julian, though there is a 32-bit limit.

Parameters:

julianDate - Julian day to check

Returns:

true if the Julian day is valid

validMonth

public static boolean validMonth(DateMonth month)

Returns true if the month value is valid. The 12 GDateMonth enumeration values are the only valid months.

Parameters:

month - month

Returns:

true if the month is valid

validWeekday

public static boolean validWeekday(DateWeekday weekday)

Returns true if the weekday is valid. The seven GDateWeekday enumeration values are the only valid weekdays.

Parameters:

weekday - weekday

Returns:

true if the weekday is valid

validYear

public static boolean validYear(DateYear year)

Returns true if the year is valid. Any year greater than 0 is valid, though there is a 16-bit limit to what GDate will understand.

Parameters:

year - year

Returns:

true if the year is valid

addDays

public void addDays(int nDays)

Increments a date some number of days. To move forward by weeks, add weeks*7 days. The date must be valid.

Parameters:

nDays - number of days to move the date forward

addMonths

public void addMonths(int nMonths)

Increments a date by some number of months. If the day of the month is greater than 28, this routine may change the day of the month (because the destination month may not have the current day in it). The date must be valid.

Parameters:

nMonths - number of months to move forward

addYears

public void addYears(int nYears)

Increments a date by some number of years. If the date is February 29, and the destination year is not a leap year, the date will be changed to February 28. The date must be valid.

Parameters:

nYears - number of years to move forward

clamp

public void clamp(Date minDate,
 Date maxDate)

If this Date is prior to minDate, sets this Date equal to minDate. If this Date falls after maxDate, sets this Date equal to maxDate. Otherwise, this Date is unchanged. Either of minDate and maxDate may be null. All non-null dates must be valid.

Parameters:

minDate - minimum accepted value for this Date

maxDate - maximum accepted value for this Date

clear

public void clear(int nDates)

Initializes one or more GDate structs to a safe but invalid state. The cleared dates will not represent an existing date, but will not contain garbage. Useful to init a date declared on the stack. Validity can be tested with g_date_valid().

Parameters:

nDates - number of dates to clear

compare

public int compare(Date rhs)

qsort()-style comparison function for dates. Both dates must be valid.

Parameters:

rhs - second date to compare

Returns:

0 for equal, less than zero if this Date is less than rhs, greater than zero if this Date is greater than rhs

copy

public Date copy()

Copies a GDate to a newly-allocated GDate. If the input was invalid (as determined by g_date_valid()), the invalid state will be copied as is into the new object.

Returns:

a newly-allocated GDate initialized from this Date

Since:

2.56

daysBetween

public int daysBetween(Date date2)

Computes the number of days between two dates. If date2 is prior to date1, the returned value is negative. Both dates must be valid.

Parameters:

date2 - the second date

Returns:

the number of days between this Date and date2

free

public void free()

Frees a GDate returned from g_date_new().

getDay

public DateDay getDay()

Returns the day of the month. The date must be valid.

Returns:

day of the month

getDayOfYear

public int getDayOfYear()

Returns the day of the year, where Jan 1 is the first day of the year. The date must be valid.

Returns:

day of the year

getIso8601WeekOfYear

public int getIso8601WeekOfYear()

Returns the week of the year, where weeks are interpreted according to ISO 8601.

Returns:

ISO 8601 week number of the year.

Since:

2.6

getJulian

public int getJulian()

Returns the Julian day or "serial number" of the GDate. The Julian day is simply the number of days since January 1, Year 1; i.e., January 1, Year 1 is Julian day 1; January 2, Year 1 is Julian day 2, etc. The date must be valid.

Returns:

Julian day

getMondayWeekOfYear

public int getMondayWeekOfYear()

Returns the week of the year, where weeks are understood to start on Monday. If the date is before the first Monday of the year, return 0. The date must be valid.

Returns:

week of the year

getMonth

public DateMonth getMonth()

Returns the month of the year. The date must be valid.

Returns:

month of the year as a GDateMonth

getSundayWeekOfYear

public int getSundayWeekOfYear()

Returns the week of the year during which this date falls, if weeks are understood to begin on Sunday. The date must be valid. Can return 0 if the day is before the first Sunday of the year.

Returns:

week number

getWeekOfYear

public int getWeekOfYear(DateWeekday firstDayOfWeek)

Calculates the week of the year during which this date falls.

The result depends on which day is considered the first day of the week, which varies by locale. Both date and first_day_of_week must be valid.

If this Date is before the start of the first week of the year (for example, before the first Monday in January if firstDayOfWeek is GLib.DateWeekday.MONDAY) then zero will be returned.

Parameters:

firstDayOfWeek - the day which is considered the first day of the week (for example, this would be GLib.DateWeekday.SUNDAY in US locales, GLib.DateWeekday.MONDAY in British locales, and GLib.DateWeekday.SATURDAY in Egyptian locales

Returns:

week number (starting from 1), or 0 if this Date is before the start of the first week of the year

Since:

2.86

getWeekday

public DateWeekday getWeekday()

Returns the day of the week for a GDate. The date must be valid.

Returns:

day of the week as a GDateWeekday.

getYear

public DateYear getYear()

Returns the year of a GDate. The date must be valid.

Returns:

year in which the date falls

isFirstOfMonth

public boolean isFirstOfMonth()

Returns true if the date is on the first of a month. The date must be valid.

Returns:

true if the date is the first of the month

isLastOfMonth

public boolean isLastOfMonth()

Returns true if the date is the last day of the month. The date must be valid.

Returns:

true if the date is the last day of the month

order

public void order(Date date2)

Checks if this Date is less than or equal to date2, and swap the values if this is not the case.

Parameters:

date2 - the second date

setDay

public void setDay(DateDay day)

Sets the day of the month for a GDate. If the resulting day-month-year triplet is invalid, the date will be invalid.

Parameters:

day - day to set

setDmy

public void setDmy(DateDay day,
 DateMonth month,
 DateYear y)

Sets the value of a GDate from a day, month, and year. The day-month-year triplet must be valid; if you aren't sure it is, call g_date_valid_dmy() to check before you set it.

Parameters:

day - day

month - month

y - year

setJulian

public void setJulian(int julianDate)

Sets the value of a GDate from a Julian day number.

Parameters:

julianDate - Julian day number (days since January 1, Year 1)

setMonth

public void setMonth(DateMonth month)

Sets the month of the year for a GDate. If the resulting day-month-year triplet is invalid, the date will be invalid.

Parameters:

month - month to set

setParse

public void setParse(String str)

Parses a user-inputted string str, and try to figure out what date it represents, taking the current locale into account. If the string is successfully parsed, the date will be valid after the call. Otherwise, it will be invalid. You should check using g_date_valid() to see whether the parsing succeeded.

This function is not appropriate for file formats and the like; it isn't very precise, and its exact behavior varies with the locale. It's intended to be a heuristic routine that guesses what the user means by a given string (and it does work pretty well in that capacity).

Parameters:

str - string to parse

setTime

@Deprecated
public void setTime(Time time)

Deprecated.

Use g_date_set_time_t() instead.

Sets the value of a date from a GTime value. The time to date conversion is done using the user's current timezone.

Parameters:

time - GTime value to set.

setTimeT

public void setTimeT(long timet)

Sets the value of a date to the date corresponding to a time specified as a time_t. The time to date conversion is done using the user's current timezone.

To set the value of a date to the current day, you could write:

 time_t now = time (NULL);
  if (now == (time_t) -1)
    // handle the error
  g_date_set_time_t (date, now);
 

Parameters:

timet - time_t value to set

Since:

2.10

setTimeVal

@Deprecated
public void setTimeVal(TimeVal timeval)

Deprecated.

GTimeVal is not year-2038-safe. Use g_date_set_time_t() instead.

Sets the value of a date from a GTimeVal value. Note that the tvUsec member is ignored, because GDate can't make use of the additional precision.

The time to date conversion is done using the user's current timezone.

Parameters:

timeval - GTimeVal value to set

Since:

2.10

setYear

public void setYear(DateYear year)

Sets the year for a GDate. If the resulting day-month-year triplet is invalid, the date will be invalid.

Parameters:

year - year to set

subtractDays

public void subtractDays(int nDays)

Moves a date some number of days into the past. To move by weeks, just move by weeks*7 days. The date must be valid.

Parameters:

nDays - number of days to move

subtractMonths

public void subtractMonths(int nMonths)

Moves a date some number of months into the past. If the current day of the month doesn't exist in the destination month, the day of the month may change. The date must be valid.

Parameters:

nMonths - number of months to move

subtractYears

public void subtractYears(int nYears)

Moves a date some number of years into the past. If the current day doesn't exist in the destination year (i.e. it's February 29 and you move to a non-leap-year) then the day is changed to February 29. The date must be valid.

Parameters:

nYears - number of years to move

toStructTm

public void toStructTm(MemorySegment tm)

Fills in the date-related bits of a struct tm using the this Date value. Initializes the non-date parts with something safe but meaningless.

Parameters:

tm - struct tm to fill

valid

public boolean valid()

Returns true if the GDate represents an existing day. The date must not contain garbage; it should have been initialized with g_date_clear() if it wasn't allocated by one of the g_date_new() variants.

Returns:

Whether the date is valid