GregorianCalendar
is a concrete subclass of
Calendar
and provides the standard calendar system
used by most of the world.
GregorianCalendar
is a hybrid calendar that
supports both the Julian and Gregorian calendar systems with the
support of a single discontinuity, which corresponds by default to
the Gregorian date when the Gregorian calendar was instituted
(October 15, 1582 in some countries, later in others). The cutover
date may be changed by the caller by calling setGregorianChange()
.
Historically, in those countries which adopted the Gregorian calendar first,
October 4, 1582 (Julian) was thus followed by October 15, 1582 (Gregorian). This calendar models
this correctly. Before the Gregorian cutover, GregorianCalendar
implements the Julian calendar. The only difference between the Gregorian
and the Julian calendar is the leap year rule. The Julian calendar specifies
leap years every four years, whereas the Gregorian calendar omits century
years which are not divisible by 400.
GregorianCalendar
implements proleptic Gregorian and
Julian calendars. That is, dates are computed by extrapolating the current
rules indefinitely far backward and forward in time. As a result,
GregorianCalendar
may be used for all years to generate
meaningful and consistent results. However, dates obtained using
GregorianCalendar
are historically accurate only from March 1, 4
AD onward, when modern Julian calendar rules were adopted. Before this date,
leap year rules were applied irregularly, and before 45 BC the Julian
calendar did not even exist.
Prior to the institution of the Gregorian calendar, New Year's Day was March 25. To avoid confusion, this calendar always uses January 1. A manual adjustment may be made if desired for dates that are prior to the Gregorian changeover and which fall between January 1 and March 24.
Week Of Year and Week Year
Values calculated for the WEEK_OF_YEAR
field range from 1 to 53. The first week of a
calendar year is the earliest seven day period starting on getFirstDayOfWeek()
that contains at
least getMinimalDaysInFirstWeek()
days from that year. It thus depends
on the values of getMinimalDaysInFirstWeek()
, getFirstDayOfWeek()
, and the day of the week of January 1. Weeks
between week 1 of one year and week 1 of the following year
(exclusive) are numbered sequentially from 2 to 52 or 53 (except
for year(s) involved in the Julian-Gregorian transition).
The getFirstDayOfWeek()
and getMinimalDaysInFirstWeek()
values are initialized using
locale-dependent resources when constructing a GregorianCalendar
. The week
determination is compatible with the ISO 8601 standard when getFirstDayOfWeek()
is MONDAY
and getMinimalDaysInFirstWeek()
is 4, which values are used in locales
where the standard is preferred. These values can explicitly be set by
calling setFirstDayOfWeek()
and
setMinimalDaysInFirstWeek()
.
A week year is in sync with a
WEEK_OF_YEAR
cycle. All weeks between the first and last
weeks (inclusive) have the same week year value.
Therefore, the first and last days of a week year may have
different calendar year values.
For example, January 1, 1998 is a Thursday. If getFirstDayOfWeek()
is MONDAY
and getMinimalDaysInFirstWeek()
is 4 (ISO 8601 standard compatible
setting), then week 1 of 1998 starts on December 29, 1997, and ends
on January 4, 1998. The week year is 1998 for the last three days
of calendar year 1997. If, however, getFirstDayOfWeek()
is
SUNDAY
, then week 1 of 1998 starts on January 4, 1998, and
ends on January 10, 1998; the first three days of 1998 then are
part of week 53 of 1997 and their week year is 1997.
Week Of Month
Values calculated for the WEEK_OF_MONTH
field range from 0
to 6. Week 1 of a month (the days with WEEK_OF_MONTH =
1
) is the earliest set of at least
getMinimalDaysInFirstWeek()
contiguous days in that month,
ending on the day before getFirstDayOfWeek()
. Unlike
week 1 of a year, week 1 of a month may be shorter than 7 days, need
not start on getFirstDayOfWeek()
, and will not include days of
the previous month. Days of a month before week 1 have a
WEEK_OF_MONTH
of 0.
For example, if getFirstDayOfWeek()
is SUNDAY
and getMinimalDaysInFirstWeek()
is 4, then the first week of
January 1998 is Sunday, January 4 through Saturday, January 10. These days
have a WEEK_OF_MONTH
of 1. Thursday, January 1 through
Saturday, January 3 have a WEEK_OF_MONTH
of 0. If
getMinimalDaysInFirstWeek()
is changed to 3, then January 1
through January 3 have a WEEK_OF_MONTH
of 1.
Default Fields Values
The clear
method sets calendar field(s)
undefined. GregorianCalendar
uses the following
default value for each calendar field if its value is undefined.
Field |
Default Value |
---|---|
ERA
|
AD
|
YEAR
|
1970
|
MONTH
|
JANUARY
|
DAY_OF_MONTH
|
1
|
DAY_OF_WEEK
|
the first day of week
|
WEEK_OF_MONTH
|
0
|
DAY_OF_WEEK_IN_MONTH
|
1
|
AM_PM
|
AM
|
HOUR, HOUR_OF_DAY, MINUTE, SECOND, MILLISECOND
|
0
|
Default values are not applicable for the fields not listed above.
Example:
// get the supported ids for GMT-08:00 (Pacific Standard Time) String[] ids = TimeZone.getAvailableIDs(-8 * 60 * 60 * 1000); // if no ids were returned, something is wrong. get out. if (ids.length == 0) System.exit(0); // begin output System.out.println("Current Time"); // create a Pacific Standard Time time zone SimpleTimeZone pdt = new SimpleTimeZone(-8 * 60 * 60 * 1000, ids[0]); // set up rules for Daylight Saving Time pdt.setStartRule(Calendar.APRIL, 1, Calendar.SUNDAY, 2 * 60 * 60 * 1000); pdt.setEndRule(Calendar.OCTOBER, -1, Calendar.SUNDAY, 2 * 60 * 60 * 1000); // create a GregorianCalendar with the Pacific Daylight time zone // and the current date and time Calendar calendar = new GregorianCalendar(pdt); Date trialTime = new Date(); calendar.setTime(trialTime); // print out a bunch of interesting things System.out.println("ERA: " + calendar.get(Calendar.ERA)); System.out.println("YEAR: " + calendar.get(Calendar.YEAR)); System.out.println("MONTH: " + calendar.get(Calendar.MONTH)); System.out.println("WEEK_OF_YEAR: " + calendar.get(Calendar.WEEK_OF_YEAR)); System.out.println("WEEK_OF_MONTH: " + calendar.get(Calendar.WEEK_OF_MONTH)); System.out.println("DATE: " + calendar.get(Calendar.DATE)); System.out.println("DAY_OF_MONTH: " + calendar.get(Calendar.DAY_OF_MONTH)); System.out.println("DAY_OF_YEAR: " + calendar.get(Calendar.DAY_OF_YEAR)); System.out.println("DAY_OF_WEEK: " + calendar.get(Calendar.DAY_OF_WEEK)); System.out.println("DAY_OF_WEEK_IN_MONTH: " + calendar.get(Calendar.DAY_OF_WEEK_IN_MONTH)); System.out.println("AM_PM: " + calendar.get(Calendar.AM_PM)); System.out.println("HOUR: " + calendar.get(Calendar.HOUR)); System.out.println("HOUR_OF_DAY: " + calendar.get(Calendar.HOUR_OF_DAY)); System.out.println("MINUTE: " + calendar.get(Calendar.MINUTE)); System.out.println("SECOND: " + calendar.get(Calendar.SECOND)); System.out.println("MILLISECOND: " + calendar.get(Calendar.MILLISECOND)); System.out.println("ZONE_OFFSET: " + (calendar.get(Calendar.ZONE_OFFSET)/(60*60*1000))); System.out.println("DST_OFFSET: " + (calendar.get(Calendar.DST_OFFSET)/(60*60*1000))); System.out.println("Current Time, with hour reset to 3"); calendar.clear(Calendar.HOUR_OF_DAY); // so doesn't override calendar.set(Calendar.HOUR, 3); System.out.println("ERA: " + calendar.get(Calendar.ERA)); System.out.println("YEAR: " + calendar.get(Calendar.YEAR)); System.out.println("MONTH: " + calendar.get(Calendar.MONTH)); System.out.println("WEEK_OF_YEAR: " + calendar.get(Calendar.WEEK_OF_YEAR)); System.out.println("WEEK_OF_MONTH: " + calendar.get(Calendar.WEEK_OF_MONTH)); System.out.println("DATE: " + calendar.get(Calendar.DATE)); System.out.println("DAY_OF_MONTH: " + calendar.get(Calendar.DAY_OF_MONTH)); System.out.println("DAY_OF_YEAR: " + calendar.get(Calendar.DAY_OF_YEAR)); System.out.println("DAY_OF_WEEK: " + calendar.get(Calendar.DAY_OF_WEEK)); System.out.println("DAY_OF_WEEK_IN_MONTH: " + calendar.get(Calendar.DAY_OF_WEEK_IN_MONTH)); System.out.println("AM_PM: " + calendar.get(Calendar.AM_PM)); System.out.println("HOUR: " + calendar.get(Calendar.HOUR)); System.out.println("HOUR_OF_DAY: " + calendar.get(Calendar.HOUR_OF_DAY)); System.out.println("MINUTE: " + calendar.get(Calendar.MINUTE)); System.out.println("SECOND: " + calendar.get(Calendar.SECOND)); System.out.println("MILLISECOND: " + calendar.get(Calendar.MILLISECOND)); System.out.println("ZONE_OFFSET: " + (calendar.get(Calendar.ZONE_OFFSET)/(60*60*1000))); // in hours System.out.println("DST_OFFSET: " + (calendar.get(Calendar.DST_OFFSET)/(60*60*1000))); // in hours
See Also
Constant Summary
int | AD | Value of the ERA field indicating
the common era (Anno Domini), also known as CE. |
int | BC | Value of the ERA field indicating
the period before the common era (before Christ), also known as BCE. |
Inherited Constant Summary
Inherited Field Summary
Public Constructor Summary
GregorianCalendar()
Constructs a default
GregorianCalendar using the current time
in the default time zone with the default
FORMAT locale. |
|
GregorianCalendar(TimeZone zone)
Constructs a
GregorianCalendar based on the current time
in the given time zone with the default
FORMAT locale. |
|
GregorianCalendar(Locale aLocale)
Constructs a
GregorianCalendar based on the current time
in the default time zone with the given locale. |
|
GregorianCalendar(TimeZone zone, Locale aLocale)
Constructs a
GregorianCalendar based on the current time
in the given time zone with the given locale. |
|
GregorianCalendar(int year, int month, int dayOfMonth)
Constructs a
GregorianCalendar with the given date set
in the default time zone with the default locale. |
|
GregorianCalendar(int year, int month, int dayOfMonth, int hourOfDay, int minute)
Constructs a
GregorianCalendar with the given date
and time set for the default time zone with the default locale. |
|
GregorianCalendar(int year, int month, int dayOfMonth, int hourOfDay, int minute, int second)
Constructs a GregorianCalendar with the given date
and time set for the default time zone with the default locale.
|
Public Method Summary
void |
add(int field, int amount)
Adds the specified (signed) amount of time to the given calendar field,
based on the calendar's rules.
|
Object |
clone()
Creates and returns a copy of this object.
|
boolean | |
int |
getActualMaximum(int field)
Returns the maximum value that this calendar field could have,
taking into consideration the given time value and the current
values of the
getFirstDayOfWeek ,
getMinimalDaysInFirstWeek ,
getGregorianChange and
getTimeZone methods. |
int |
getActualMinimum(int field)
Returns the minimum value that this calendar field could have,
taking into consideration the given time value and the current
values of the
getFirstDayOfWeek ,
getMinimalDaysInFirstWeek ,
getGregorianChange and
getTimeZone methods. |
String |
getCalendarType()
Returns
"gregory" as the calendar type. |
int |
getGreatestMinimum(int field)
Returns the highest minimum value for the given calendar field
of this
GregorianCalendar instance. |
final Date |
getGregorianChange()
Gets the Gregorian Calendar change date.
|
int |
getLeastMaximum(int field)
Returns the lowest maximum value for the given calendar field
of this
GregorianCalendar instance. |
int |
getMaximum(int field)
Returns the maximum value for the given calendar field of this
GregorianCalendar instance. |
int |
getMinimum(int field)
Returns the minimum value for the given calendar field of this
GregorianCalendar instance. |
TimeZone |
getTimeZone()
Gets the time zone.
|
int |
getWeekYear()
Returns the week year represented by this
GregorianCalendar . |
int |
getWeeksInWeekYear()
Returns the number of weeks in the week year
represented by this
GregorianCalendar . |
int |
hashCode()
Generates the hash code for this
GregorianCalendar object. |
boolean |
isLeapYear(int year)
Determines if the given year is a leap year.
|
final boolean |
isWeekDateSupported()
Returns
true indicating this GregorianCalendar
supports week dates. |
void |
roll(int field, boolean up)
Adds or subtracts (up/down) a single unit of time on the given time
field without changing larger fields.
|
void |
roll(int field, int amount)
Adds a signed amount to the specified calendar field without changing larger fields.
|
void | |
void | |
void |
setWeekDate(int weekYear, int weekOfYear, int dayOfWeek)
Sets this
GregorianCalendar to the date given by the
date specifiers - weekYear ,
weekOfYear , and dayOfWeek . |
Protected Method Summary
void |
computeFields()
Converts the time value (millisecond offset from the Epoch) to calendar field values.
|
void |
computeTime()
Converts calendar field values to the time value (millisecond
offset from the Epoch).
|
Inherited Method Summary
Constants
public static final int AD
Value of the ERA
field indicating
the common era (Anno Domini), also known as CE.
The sequence of years at the transition from BC
to AD
is
..., 2 BC, 1 BC, 1 AD, 2 AD,...
See Also
public static final int BC
Value of the ERA
field indicating
the period before the common era (before Christ), also known as BCE.
The sequence of years at the transition from BC
to AD
is
..., 2 BC, 1 BC, 1 AD, 2 AD,...
See Also
Public Constructors
public GregorianCalendar ()
Constructs a default GregorianCalendar
using the current time
in the default time zone with the default
FORMAT
locale.
public GregorianCalendar (TimeZone zone)
Constructs a GregorianCalendar
based on the current time
in the given time zone with the default
FORMAT
locale.
Parameters
zone | the given time zone. |
---|
public GregorianCalendar (Locale aLocale)
Constructs a GregorianCalendar
based on the current time
in the default time zone with the given locale.
Parameters
aLocale | the given locale. |
---|
public GregorianCalendar (TimeZone zone, Locale aLocale)
Constructs a GregorianCalendar
based on the current time
in the given time zone with the given locale.
Parameters
zone | the given time zone. |
---|---|
aLocale | the given locale. |
public GregorianCalendar (int year, int month, int dayOfMonth)
Constructs a GregorianCalendar
with the given date set
in the default time zone with the default locale.
Parameters
year | the value used to set the YEAR calendar field in the calendar. |
---|---|
month | the value used to set the MONTH calendar field in the calendar.
Month value is 0-based. e.g., 0 for January. |
dayOfMonth | the value used to set the DAY_OF_MONTH calendar field in the calendar.
|
public GregorianCalendar (int year, int month, int dayOfMonth, int hourOfDay, int minute)
Constructs a GregorianCalendar
with the given date
and time set for the default time zone with the default locale.
Parameters
year | the value used to set the YEAR calendar field in the calendar. |
---|---|
month | the value used to set the MONTH calendar field in the calendar.
Month value is 0-based. e.g., 0 for January. |
dayOfMonth | the value used to set the DAY_OF_MONTH calendar field in the calendar. |
hourOfDay | the value used to set the HOUR_OF_DAY calendar field
in the calendar. |
minute | the value used to set the MINUTE calendar field
in the calendar.
|
public GregorianCalendar (int year, int month, int dayOfMonth, int hourOfDay, int minute, int second)
Constructs a GregorianCalendar with the given date and time set for the default time zone with the default locale.
Parameters
year | the value used to set the YEAR calendar field in the calendar. |
---|---|
month | the value used to set the MONTH calendar field in the calendar.
Month value is 0-based. e.g., 0 for January. |
dayOfMonth | the value used to set the DAY_OF_MONTH calendar field in the calendar. |
hourOfDay | the value used to set the HOUR_OF_DAY calendar field
in the calendar. |
minute | the value used to set the MINUTE calendar field
in the calendar. |
second | the value used to set the SECOND calendar field
in the calendar.
|
Public Methods
public void add (int field, int amount)
Adds the specified (signed) amount of time to the given calendar field, based on the calendar's rules.
Add rule 1. The value of field
after the call minus the value of field
before the
call is amount
, modulo any overflow that has occurred in
field
. Overflow occurs when a field value exceeds its
range and, as a result, the next larger field is incremented or
decremented and the field value is adjusted back into its range.
Add rule 2. If a smaller field is expected to be
invariant, but it is impossible for it to be equal to its
prior value because of changes in its minimum or maximum after
field
is changed, then its value is adjusted to be as close
as possible to its expected value. A smaller field represents a
smaller unit of time. HOUR
is a smaller field than
DAY_OF_MONTH
. No adjustment is made to smaller fields
that are not expected to be invariant. The calendar system
determines what fields are expected to be invariant.
Parameters
field | the calendar field. |
---|---|
amount | the amount of date or time to be added to the field. |
Throws
IllegalArgumentException | if field is
ZONE_OFFSET , DST_OFFSET , or unknown,
or if any calendar fields have out-of-range values in
non-lenient mode.
|
---|
public boolean equals (Object obj)
Compares this GregorianCalendar
to the specified
Object
. The result is true
if and
only if the argument is a GregorianCalendar
object
that represents the same time value (millisecond offset from
the Epoch) under the same
Calendar
parameters and Gregorian change date as
this object.
Parameters
obj | the object to compare with. |
---|
Returns
true
if this object is equal toobj
;false
otherwise.
See Also
public int getActualMaximum (int field)
Returns the maximum value that this calendar field could have,
taking into consideration the given time value and the current
values of the
getFirstDayOfWeek
,
getMinimalDaysInFirstWeek
,
getGregorianChange
and
getTimeZone
methods.
For example, if the date of this instance is February 1, 2004,
the actual maximum value of the DAY_OF_MONTH
field
is 29 because 2004 is a leap year, and if the date of this
instance is February 1, 2005, it's 28.
This method calculates the maximum value of WEEK_OF_YEAR
based on the YEAR
(calendar year) value, not the week year. Call getWeeksInWeekYear()
to get the maximum value of WEEK_OF_YEAR
in the week year of this GregorianCalendar
.
Parameters
field | the calendar field |
---|
Returns
- the maximum of the given field for the time value of
this
GregorianCalendar
public int getActualMinimum (int field)
Returns the minimum value that this calendar field could have,
taking into consideration the given time value and the current
values of the
getFirstDayOfWeek
,
getMinimalDaysInFirstWeek
,
getGregorianChange
and
getTimeZone
methods.
For example, if the Gregorian change date is January 10,
1970 and the date of this GregorianCalendar
is
January 20, 1970, the actual minimum value of the
DAY_OF_MONTH
field is 10 because the previous date
of January 10, 1970 is December 27, 1996 (in the Julian
calendar). Therefore, December 28, 1969 to January 9, 1970
don't exist.
Parameters
field | the calendar field |
---|
Returns
- the minimum of the given field for the time value of
this
GregorianCalendar
public int getGreatestMinimum (int field)
Returns the highest minimum value for the given calendar field
of this GregorianCalendar
instance. The highest
minimum value is defined as the largest value returned by
getActualMinimum(int)
for any possible time value,
taking into consideration the current values of the
getFirstDayOfWeek
,
getMinimalDaysInFirstWeek
,
getGregorianChange
and
getTimeZone
methods.
Parameters
field | the calendar field. |
---|
Returns
- the highest minimum value for the given calendar field.
public final Date getGregorianChange ()
Gets the Gregorian Calendar change date. This is the point when the switch from Julian dates to Gregorian dates occurred. Default is October 15, 1582 (Gregorian). Previous to this, dates will be in the Julian calendar.
Returns
- the Gregorian cutover date for this
GregorianCalendar
object.
public int getLeastMaximum (int field)
Returns the lowest maximum value for the given calendar field
of this GregorianCalendar
instance. The lowest
maximum value is defined as the smallest value returned by
getActualMaximum(int)
for any possible time value,
taking into consideration the current values of the
getFirstDayOfWeek
,
getMinimalDaysInFirstWeek
,
getGregorianChange
and
getTimeZone
methods.
Parameters
field | the calendar field |
---|
Returns
- the lowest maximum value for the given calendar field.
public int getMaximum (int field)
Returns the maximum value for the given calendar field of this
GregorianCalendar
instance. The maximum value is
defined as the largest value returned by the get
method for any possible time value,
taking into consideration the current values of the
getFirstDayOfWeek
,
getMinimalDaysInFirstWeek
,
getGregorianChange
and
getTimeZone
methods.
Parameters
field | the calendar field. |
---|
Returns
- the maximum value for the given calendar field.
public int getMinimum (int field)
Returns the minimum value for the given calendar field of this
GregorianCalendar
instance. The minimum value is
defined as the smallest value returned by the get
method for any possible time value,
taking into consideration the current values of the
getFirstDayOfWeek
,
getMinimalDaysInFirstWeek
,
getGregorianChange
and
getTimeZone
methods.
Parameters
field | the calendar field. |
---|
Returns
- the minimum value for the given calendar field.
public TimeZone getTimeZone ()
Gets the time zone.
Returns
- the time zone object associated with this calendar.
public int getWeekYear ()
Returns the week year represented by this
GregorianCalendar
. The dates in the weeks between 1 and the
maximum week number of the week year have the same week year value
that may be one year before or after the YEAR
(calendar year) value.
This method calls Calendar.complete()
before
calculating the week year.
Returns
Throws
IllegalArgumentException | if any of the calendar fields is invalid in non-lenient mode. |
---|
public int getWeeksInWeekYear ()
Returns the number of weeks in the week year
represented by this GregorianCalendar
.
For example, if this GregorianCalendar
's date is
December 31, 2008 with the ISO
8601 compatible setting, this method will return 53 for the
period: December 29, 2008 to January 3, 2010 while getActualMaximum(WEEK_OF_YEAR)
will return
52 for the period: December 31, 2007 to December 28, 2008.
Returns
- the number of weeks in the week year.
public int hashCode ()
Generates the hash code for this GregorianCalendar
object.
Returns
- a hash code value for this object.
public boolean isLeapYear (int year)
Determines if the given year is a leap year. Returns true
if
the given year is a leap year. To specify BC year numbers,
1 - year number
must be given. For example, year BC 4 is
specified as -3.
Parameters
year | the given year. |
---|
Returns
true
if the given year is a leap year;false
otherwise.
public final boolean isWeekDateSupported ()
Returns true
indicating this GregorianCalendar
supports week dates.
Returns
true
(always)
public void roll (int field, boolean up)
Adds or subtracts (up/down) a single unit of time on the given time field without changing larger fields.
Example: Consider a GregorianCalendar
originally set to December 31, 1999. Calling roll(Calendar.MONTH, true)
sets the calendar to January 31, 1999. The YEAR
field is unchanged
because it is a larger field than MONTH
.
Parameters
field | the time field. |
---|---|
up | indicates if the value of the specified calendar field is to be
rolled up or rolled down. Use true if rolling up, false otherwise. |
Throws
IllegalArgumentException | if field is
ZONE_OFFSET , DST_OFFSET , or unknown,
or if any calendar fields have out-of-range values in
non-lenient mode. |
---|
See Also
public void roll (int field, int amount)
Adds a signed amount to the specified calendar field without changing larger fields. A negative roll amount means to subtract from field without changing larger fields. If the specified amount is 0, this method performs nothing.
This method calls Calendar.complete()
before adding the
amount so that all the calendar fields are normalized. If there
is any calendar field having an out-of-range value in non-lenient mode, then an
IllegalArgumentException
is thrown.
Example: Consider a GregorianCalendar
originally set to August 31, 1999. Calling roll(Calendar.MONTH,
8)
sets the calendar to April 30, 1999. Using a
GregorianCalendar
, the DAY_OF_MONTH
field cannot
be 31 in the month April. DAY_OF_MONTH
is set to the closest possible
value, 30. The YEAR
field maintains the value of 1999 because it
is a larger field than MONTH
.
Example: Consider a GregorianCalendar
originally set to Sunday June 6, 1999. Calling
roll(Calendar.WEEK_OF_MONTH, -1)
sets the calendar to
Tuesday June 1, 1999, whereas calling
add(Calendar.WEEK_OF_MONTH, -1)
sets the calendar to
Sunday May 30, 1999. This is because the roll rule imposes an
additional constraint: The MONTH
must not change when the
WEEK_OF_MONTH
is rolled. Taken together with add rule 1,
the resultant date must be between Tuesday June 1 and Saturday June
5. According to add rule 2, the DAY_OF_WEEK
, an invariant
when changing the WEEK_OF_MONTH
, is set to Tuesday, the
closest possible value to Sunday (where Sunday is the first day of the
week).
Parameters
field | the calendar field. |
---|---|
amount | the signed amount to add to field . |
Throws
IllegalArgumentException | if field is
ZONE_OFFSET , DST_OFFSET , or unknown,
or if any calendar fields have out-of-range values in
non-lenient mode. |
---|
public void setGregorianChange (Date date)
Sets the GregorianCalendar
change date. This is the point when the switch
from Julian dates to Gregorian dates occurred. Default is October 15,
1582 (Gregorian). Previous to this, dates will be in the Julian calendar.
To obtain a pure Julian calendar, set the change date to
Date(Long.MAX_VALUE)
. To obtain a pure Gregorian calendar,
set the change date to Date(Long.MIN_VALUE)
.
Parameters
date | the given Gregorian cutover date. |
---|
public void setTimeZone (TimeZone zone)
Sets the time zone with the given time zone value.
Parameters
zone | the given time zone. |
---|
public void setWeekDate (int weekYear, int weekOfYear, int dayOfWeek)
Sets this GregorianCalendar
to the date given by the
date specifiers - weekYear
,
weekOfYear
, and dayOfWeek
. weekOfYear
follows the WEEK_OF_YEAR
numbering. The dayOfWeek
value must be one of the
DAY_OF_WEEK
values: SUNDAY
to SATURDAY
.
Note that the numeric day-of-week representation differs from
the ISO 8601 standard, and that the weekOfYear
numbering is compatible with the standard when getFirstDayOfWeek()
is MONDAY
and getMinimalDaysInFirstWeek()
is 4.
Unlike the set
method, all of the calendar fields
and the instant of time value are calculated upon return.
If weekOfYear
is out of the valid week-of-year
range in weekYear
, the weekYear
and weekOfYear
values are adjusted in lenient
mode, or an IllegalArgumentException
is thrown in
non-lenient mode.
Parameters
weekYear | the week year |
---|---|
weekOfYear | the week number based on weekYear |
dayOfWeek | the day of week value: one of the constants
for the DAY_OF_WEEK field:
SUNDAY , ...,
SATURDAY . |
Throws
IllegalArgumentException | if any of the given date specifiers is invalid, or if any of the calendar fields are inconsistent with the given date specifiers in non-lenient mode |
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Protected Methods
protected void computeFields ()
Converts the time value (millisecond offset from the Epoch) to calendar field values.
The time is not
recomputed first; to recompute the time, then the fields, call the
complete
method.
See Also
protected void computeTime ()
Converts calendar field values to the time value (millisecond offset from the Epoch).
Throws
IllegalArgumentException | if any calendar fields are invalid. |
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