com.trolltech.qt.core
Class QDate

java.lang.Object
  extended by com.trolltech.qt.internal.QSignalEmitterInternal
      extended by com.trolltech.qt.QSignalEmitter
          extended by com.trolltech.qt.QtJambiObject
              extended by com.trolltech.qt.core.QDate
All Implemented Interfaces:
QtJambiInterface, java.lang.Cloneable, java.lang.Comparable

public class QDate
extends QtJambiObject
implements java.lang.Comparable, java.lang.Cloneable

The QDate class provides date functions. A QDate object contains a calendar date, i.e. year, month, and day numbers, in the Gregorian calendar. (see Use of Gregorian and Julian Calendars for dates prior to 15 October 1582). It can read the current date from the system clock. It provides functions for comparing dates, and for manipulating dates. For example, it is possible to add and subtract days, months, and years to dates.

A QDate object is typically created either by giving the year, month, and day numbers explicitly. Note that QDate interprets two digit years as is, i.e., years 0 - 99. A QDate can also be constructed with the static function currentDate(), which creates a QDate object containing the system clock's date. An explicit date can also be set using setDate(). The fromString() function returns a QDate given a string and a date format which is used to interpret the date within the string.

The year(), month(), and day() functions provide access to the year, month, and day numbers. Also, dayOfWeek() and dayOfYear() functions are provided. The same information is provided in textual format by the toString(), shortDayName(), longDayName(), shortMonthName(), and longMonthName() functions.

QDate provides a full set of operators to compare two QDate objects where smaller means earlier, and larger means later.

You can increment (or decrement) a date by a given number of days using addDays(). Similarly you can use addMonths() and addYears(). The daysTo() function returns the number of days between two dates.

The daysInMonth() and daysInYear() functions return how many days there are in this date's month and year, respectively. The isLeapYear() function indicates whether a date is in a leap year.

Use of Gregorian and Julian Calendars

QDate uses the Gregorian calendar in all locales, beginning on the date 15 October 1582. For dates up to and including 4 October 1582, the Julian calendar is used. This means there is a 10-day gap in the internal calendar between the 4th and the 15th of October 1582. When you use QDateTime for dates in that epoch, the day after 4 October 1582 is 15 October 1582, and the dates in the gap are invalid.

The Julian to Gregorian changeover date used here is the date when the Gregorian calendar was first introduced, by Pope Gregory XIII. That change was not universally accepted and some localities only executed it at a later date (if at all). QDateTime doesn't take any of these historical facts into account. If an application must support a locale-specific dating system, it must do so on its own, remembering to convert the dates using the Julian day.

No Year 0

There is no year 0. Dates in that year are considered invalid. The year -1 is the year "1 before Christ" or "1 before current era." The day before 0001-01-01 is December 31st, 1 BCE.

Range of Valid Dates

The range of valid dates is from January 2nd, 4713 BCE, to sometime in the year 11 million CE. The Julian Day returned by
QDate::toJulianDay() is a number in the contiguous range from 1 to overflow, even across QDateTime's "date holes". It is suitable for use in applications that must convert a QDateTime to a date in another calendar system, e.g., Hebrew, Islamic or Chinese.

See also:
QTime, QDateTime, QDateEdit, QDateTimeEdit, and QCalendarWidget.


Nested Class Summary
static class QDate.MonthNameType
          This enum describes the types of the string representation used for the month name.
 
Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter
QSignalEmitter.AbstractSignal, QSignalEmitter.PrivateSignal0, QSignalEmitter.PrivateSignal1, QSignalEmitter.PrivateSignal2, QSignalEmitter.PrivateSignal3, QSignalEmitter.PrivateSignal4, QSignalEmitter.PrivateSignal5, QSignalEmitter.PrivateSignal6, QSignalEmitter.PrivateSignal7, QSignalEmitter.PrivateSignal8, QSignalEmitter.PrivateSignal9, QSignalEmitter.Signal0, QSignalEmitter.Signal1, QSignalEmitter.Signal2, QSignalEmitter.Signal3, QSignalEmitter.Signal4, QSignalEmitter.Signal5, QSignalEmitter.Signal6, QSignalEmitter.Signal7, QSignalEmitter.Signal8, QSignalEmitter.Signal9
 
Nested classes/interfaces inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
com.trolltech.qt.internal.QSignalEmitterInternal.AbstractSignalInternal
 
Field Summary
 
Fields inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
currentSender
 
Constructor Summary
QDate()
          Constructs a null date.
QDate(int y, int m, int d)
          Constructs a date with year y, month m and day d.
 
Method Summary
 QDate addDays(int days)
          Returns a QDate object containing a date ndays later than the date of this object (or earlier if ndays is negative).
 QDate addMonths(int months)
          Returns a QDate object containing a date nmonths later than the date of this object (or earlier if nmonths is negative).
 QDate addYears(int years)
          Returns a QDate object containing a date nyears later than the date of this object (or earlier if nyears is negative).
 QDate clone()
          This method is reimplemented for internal reasons
static QDate currentDate()
          This is an overloaded member function, provided for convenience.
 int day()
          Returns the day of the month (1 to 31) of this date.
 int dayOfWeek()
          Returns the weekday (1 to 7) for this date.
 int dayOfYear()
          Returns the day of the year (1 to 365 or 366 on leap years) for this date.
 int daysInMonth()
          Returns the number of days in the month (28 to 31) for this date.
 int daysInYear()
          Returns the number of days in the year (365 or 366) for this date.
 int daysTo(QDate arg__1)
          Returns the number of days from this date to d (which is negative if d is earlier than this date).
static QDate fromJulianDay(int jd)
          Converts the Julian day jd to a QDate.
static QDate fromString(java.lang.String s)
          Returns the QDate represented by the string, using the format given, or an invalid date if the string cannot be parsed.
static QDate fromString(java.lang.String s, Qt.DateFormat f)
          Returns the QDate represented by the string, using the format given, or an invalid date if the string cannot be parsed.
static QDate fromString(java.lang.String s, java.lang.String format)
          Returns the QDate represented by the string, using the format given, or an invalid date if the string cannot be parsed.
static boolean isLeapYear(int year)
          Returns true if the specified year is a leap year; otherwise returns false.
 boolean isNull()
          Returns true if the date is null; otherwise returns false.
 boolean isValid()
          Returns true if this date is valid; otherwise returns false.
static boolean isValid(int y, int m, int d)
          This is an overloaded member function, provided for convenience.
static java.lang.String longDayName(int weekday)
          Returns the long version of the name of the weekday.
static java.lang.String longDayName(int weekday, QDate.MonthNameType type)
          Returns the long name of the weekday for the representation specified by type.
static java.lang.String longMonthName(int month)
          Returns the long version of the name of the month.
static java.lang.String longMonthName(int month, QDate.MonthNameType type)
          Returns the long name of the month for the representation specified by type.
 int month()
          Returns the number corresponding to the month of this date, using the following convention.
 void readFrom(QDataStream arg__1)
          Reads a QDate
 boolean setDate(int year, int month, int day)
          Sets the date's year, month, and day.
static java.lang.String shortDayName(int weekday)
          Returns the short version of the name of the weekday.
static java.lang.String shortDayName(int weekday, QDate.MonthNameType type)
          Returns the short name of the weekday for the representation specified by type.
static java.lang.String shortMonthName(int month)
          Returns the short version of the name of the month.
static java.lang.String shortMonthName(int month, QDate.MonthNameType type)
          Returns the short name of the month for the representation specified by type.
 int toJulianDay()
          Converts the date to a Julian day.
 java.lang.String toString()
          Returns a string representation of the this QDate.
 java.lang.String toString(Qt.DateFormat f)
          Returns a string representation of the com.trolltech.qt.core.Qt$DateFormat argument.
 java.lang.String toString(java.lang.String format)
          Returns a string representation of the java.lang.String argument.
 int weekNumber()
          Returns the week number (1 to 53).
 void writeTo(QDataStream arg__1)
          Writes thisQDate
 int year()
          Returns the year of this date.
 int yearOfWeekNumber()
          This function returns the year number of the QDate's current week.
 
Methods inherited from class com.trolltech.qt.QtJambiObject
dispose, disposed, equals, finalize, reassignNativeResources, tr, tr, tr
 
Methods inherited from class com.trolltech.qt.QSignalEmitter
blockSignals, disconnect, disconnect, signalsBlocked, signalSender, thread
 
Methods inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
__qt_signalInitialization
 
Methods inherited from class java.lang.Object
getClass, hashCode, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface java.lang.Comparable
compareTo
 
Methods inherited from interface com.trolltech.qt.QtJambiInterface
disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership
 

Constructor Detail

QDate

public QDate()
Constructs a null date. Null dates are invalid.

See also:
isNull(), and isValid().


QDate

public QDate(int y,
             int m,
             int d)
Constructs a date with year y, month m and day d.

If the specified date is invalid, the date is not set and isValid() returns false. A date before 2 January 4713 B.C. is considered invalid.

Warning: Years 0 to 99 are interpreted as is, i.e., years 0-99.

See also:
isValid().

Method Detail

addDays

public final QDate addDays(int days)
Returns a QDate object containing a date ndays later than the date of this object (or earlier if ndays is negative).

See also:
addMonths(), addYears(), and daysTo().


addMonths

public final QDate addMonths(int months)
Returns a QDate object containing a date nmonths later than the date of this object (or earlier if nmonths is negative).

Note: If the ending day/month combination does not exist in the resulting month/year, this function will return a date that is the latest valid date.

Warning:QDate has a date hole around the days introducing the Gregorian calendar (the days 5 to 14 October 1582, inclusive, do not exist). If the calculation ends in one of those days, QDate will return either October 4 or October 15.

See also:
addDays(), and addYears().


addYears

public final QDate addYears(int years)
Returns a QDate object containing a date nyears later than the date of this object (or earlier if nyears is negative).

Note: If the ending day/month combination does not exist in the resulting year (i.e., if the date was Feb 29 and the final year is not a leap year), this function will return a date that is the latest valid date (that is, Feb 28).

See also:
addDays(), and addMonths().


day

public final int day()
Returns the day of the month (1 to 31) of this date.

See also:
year(), month(), and dayOfWeek().


dayOfWeek

public final int dayOfWeek()
Returns the weekday (1 to 7) for this date.

See also:
day(), dayOfYear(), and Qt::DayOfWeek .


dayOfYear

public final int dayOfYear()
Returns the day of the year (1 to 365 or 366 on leap years) for this date.

See also:
day(), and dayOfWeek().


daysInMonth

public final int daysInMonth()
Returns the number of days in the month (28 to 31) for this date.

See also:
day(), and daysInYear().


daysInYear

public final int daysInYear()
Returns the number of days in the year (365 or 366) for this date.

See also:
day(), and daysInMonth().


daysTo

public final int daysTo(QDate arg__1)
Returns the number of days from this date to d (which is negative if d is earlier than this date).

Example:

        QDate d1 = new QDate(1995, 5, 17);  // May 17, 1995
        QDate d2 = new QDate(1995, 5, 20);  // May 20, 1995
        d1.daysTo(d2);          // returns 3
        d2.daysTo(d1);          // returns -3

See also:
addDays().


isNull

public final boolean isNull()
Returns true if the date is null; otherwise returns false. A null date is invalid.

Note: The behavior of this function is identical to isValid().

See also:
isValid().


isValid

public final boolean isValid()
Returns true if this date is valid; otherwise returns false.

See also:
isNull().


month

public final int month()
Returns the number corresponding to the month of this date, using the following convention.

See also:
year(), and day().


writeTo

public final void writeTo(QDataStream arg__1)
Writes thisQDate


readFrom

public final void readFrom(QDataStream arg__1)
Reads a QDate


setDate

public final boolean setDate(int year,
                             int month,
                             int day)
Sets the date's year, month, and day. Returns true if the date is valid; otherwise returns false.

If the specified date is invalid, the QDate object is set to be invalid. Any date before 2 January 4713 B.C. is considered invalid.

See also:
isValid().


toJulianDay

public final int toJulianDay()
Converts the date to a Julian day.

See also:
fromJulianDay().


toString

public final java.lang.String toString()
Returns a string representation of the this QDate.

Overrides:
toString in class java.lang.Object

toString

public final java.lang.String toString(Qt.DateFormat f)
Returns a string representation of the com.trolltech.qt.core.Qt$DateFormat argument.


toString

public final java.lang.String toString(java.lang.String format)
Returns a string representation of the java.lang.String argument.


year

public final int year()
Returns the year of this date. Negative numbers indicate years before 1 A.D. = 1 C.E., such that year -44 is 44 B.C.

See also:
month(), and day().


currentDate

public static QDate currentDate()
This is an overloaded member function, provided for convenience.

Returns the current date, as reported by the system clock.

See also:
QTime::currentTime(), and QDateTime::currentDateTime().


fromJulianDay

public static QDate fromJulianDay(int jd)
Converts the Julian day jd to a QDate.

See also:
toJulianDay().


fromString

public static QDate fromString(java.lang.String s)
Returns the QDate represented by the string, using the format given, or an invalid date if the string cannot be parsed.

Note for Qt::TextDate : It is recommended that you use the English short month names (e.g. "Jan"). Although localized month names can also be used, they depend on the user's locale settings.


fromString

public static QDate fromString(java.lang.String s,
                               Qt.DateFormat f)
Returns the QDate represented by the string, using the format given, or an invalid date if the string cannot be parsed.

Note for Qt::TextDate : It is recommended that you use the English short month names (e.g. "Jan"). Although localized month names can also be used, they depend on the user's locale settings.


fromString

public static QDate fromString(java.lang.String s,
                               java.lang.String format)
Returns the QDate represented by the string, using the format given, or an invalid date if the string cannot be parsed.

These expressions may be used for the format:

Expression
Output
d The day as a number without a leading zero (1 to 31)
dd The day as a number with a leading zero (01 to 31)
ddd The abbreviated localized day name (e.g. 'Mon' to 'Sun'). Uses QDate::shortDayName().
dddd The long localized day name (e.g. 'Monday' to 'Sunday'). Uses QDate::longDayName().
M The month as a number without a leading zero (1 to 12)
MM The month as a number with a leading zero (01 to 12)
MMM The abbreviated localized month name (e.g. 'Jan' to 'Dec'). Uses QDate::shortMonthName().
MMMM The long localized month name (e.g. 'January' to 'December'). Uses QDate::longMonthName().
yy The year as two digit number (00 to 99)
yyyy The year as four digit number. If the year is negative, a minus sign is prepended in addition.
All other input characters will be treated as text. Any sequence of characters that are enclosed in single quotes will also be treated as text and will not be used as an expression. For example:
        QDate date = QDate.fromString("1MM12car2003", "d'MM'MMcaryyyy");
        // date is 1 December 2003
If the format is not satisfied, an invalid QDate is returned. The expressions that don't expect leading zeroes (d, M) will be greedy. This means that they will use two digits even if this will put them outside the accepted range of values and leaves too few digits for other sections. For example, the following format string could have meant January 30 but the M will grab two digits, resulting in an invalid date:
        QDate date = QDate.fromString("130", "Md"); // invalid
For any field that is not represented in the format the following defaults are used:
Field
Default value
Year 1900
Month 1
Day 1
The following examples demonstrate the default values:
        QDate.fromString("1.30", "M.d");           // January 30 1900
        QDate.fromString("20000110", "yyyyMMdd");  // January 10, 2000
        QDate.fromString("20000110", "yyyyMd");    // January 10, 2000

See also:
QDateTime::fromString(), QTime::fromString(), QDate::toString(), QDateTime::toString(), and QTime::toString().


isLeapYear

public static boolean isLeapYear(int year)
Returns true if the specified year is a leap year; otherwise returns false.


isValid

public static boolean isValid(int y,
                              int m,
                              int d)
This is an overloaded member function, provided for convenience.

Returns true if the specified date (year, month, and day) is valid; otherwise returns false.

Example:

        QDate.isValid(2002, 5, 17);  // true
        QDate.isValid(2002, 2, 30);  // false (Feb 30 does not exist)
        QDate.isValid(2004, 2, 29);  // true (2004 is a leap year)
        QDate.isValid(2000, 2, 29);  // true (2000 is a leap year)
        QDate.isValid(2006, 2, 29);  // false (2006 is not a leap year)
        QDate.isValid(2100, 2, 29);  // false (2100 is not a leap year)
        QDate.isValid(1202, 6, 6);   // true (even though 1202 is pre-Gregorian)

See also:
isNull(), and setDate().


longDayName

public static java.lang.String longDayName(int weekday)
Returns the long version of the name of the weekday. The returned name is in normal type which can be used for date formatting.

See also:
toString(), shortDayName(), shortMonthName(), and longMonthName().


longDayName

public static java.lang.String longDayName(int weekday,
                                           QDate.MonthNameType type)
Returns the long name of the weekday for the representation specified by type.

The days are enumerated using the following convention:

The day names will be localized according to the system's locale settings.

See also:
toString(), shortDayName(), shortMonthName(), and longMonthName().


longMonthName

public static java.lang.String longMonthName(int month)
Returns the long version of the name of the month. The returned name is in normal type which can be used for date formatting.

See also:
toString(), shortMonthName(), shortDayName(), and longDayName().


longMonthName

public static java.lang.String longMonthName(int month,
                                             QDate.MonthNameType type)
Returns the long name of the month for the representation specified by type.

The months are enumerated using the following convention:

The month names will be localized according to the system's locale settings.

See also:
toString(), shortMonthName(), shortDayName(), and longDayName().


shortDayName

public static java.lang.String shortDayName(int weekday)
Returns the short version of the name of the weekday. The returned name is in normal type which can be used for date formatting.

See also:
toString(), longDayName(), shortMonthName(), and longMonthName().


shortDayName

public static java.lang.String shortDayName(int weekday,
                                            QDate.MonthNameType type)
Returns the short name of the weekday for the representation specified by type.

The days are enumerated using the following convention:

The day names will be localized according to the system's locale settings.

See also:
toString(), shortMonthName(), longMonthName(), and longDayName().


shortMonthName

public static java.lang.String shortMonthName(int month)
Returns the short version of the name of the month. The returned name is in normal type which can be used for date formatting.

See also:
toString(), longMonthName(), shortDayName(), and longDayName().


shortMonthName

public static java.lang.String shortMonthName(int month,
                                              QDate.MonthNameType type)
Returns the short name of the month for the representation specified by type.

The months are enumerated using the following convention:

The month names will be localized according to the system's locale settings.

See also:
toString(), longMonthName(), shortDayName(), and longDayName().


weekNumber

public final int weekNumber()
Returns the week number (1 to 53).

Returns null if the date is invalid.

In accordance with ISO 8601, weeks start on Qt.DayOfWeek.Monday and the first Qt.DayOfWeek.Thursday of a year is always in week 1 of that year. Most years have 52 weeks, but some have 53.

Copyright (c) 1989 The Regents of the University of California. All rights reserved.

Redistribution and use in source and binary forms are permitted provided that the above copyright notice and this paragraph are duplicated in all such forms and that any documentation, advertising materials, and other materials related to such distribution and use acknowledge that the software was developed by the University of California, Berkeley. The name of the University may not be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.


yearOfWeekNumber

public final int yearOfWeekNumber()
This function returns the year number of the QDate's current week.


clone

public QDate clone()
This method is reimplemented for internal reasons

Overrides:
clone in class java.lang.Object