Class Date

java.lang.Object
org.javagi.base.ProxyInstance
org.gnome.glib.Date
All Implemented Interfaces:
Proxy
@Generated("org.javagi.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(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(DateDay, DateMonth, 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(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 ProxyInstance

    equals, handle, hashCode

    Methods inherited from class 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