public
abstract
class
Calendar
extends Object
implements
Serializable,
Cloneable,
Comparable<Calendar>
| java.lang.Object | |
| ↳ | android.icu.util.Calendar |
 Known Direct Subclasses
|
|
Known Indirect Subclasses
|
[icu enhancement] ICU's replacement for Calendar. Methods, fields, and other functionality specific to ICU are labeled '[icu]'.
Calendar is an abstract base class for converting between
a Date object and a set of integer fields such as
YEAR, MONTH, DAY, HOUR,
and so on. (A Date object represents a specific instant in
time with millisecond precision. See
Date
for information about the Date class.)
Subclasses of Calendar interpret a Date
according to the rules of a specific calendar system. ICU4J contains
several subclasses implementing different international calendar systems.
Like other locale-sensitive classes, Calendar provides a
class method, getInstance, for getting a generally useful
object of this type. Calendar's getInstance method
returns a calendar of a type appropriate to the locale, whose
time fields have been initialized with the current date and time:
Calendar rightNow = Calendar.getInstance()
When a ULocale is used by getInstance, its
'calendar' tag and value are retrieved if present. If a recognized
value is supplied, a calendar is provided and configured as appropriate.
Currently recognized tags are "buddhist", "chinese", "coptic", "ethiopic",
"gregorian", "hebrew", "islamic", "islamic-civil", "japanese", and "roc". For
example:
Developers
Calendar cal = Calendar.getInstance(new ULocale("en_US@calendar=japanese"));
will return an instance of JapaneseCalendar (using en_US conventions for
minimum days in first week, start day of week, et cetera).
A Calendar object can produce all the time field values
needed to implement the date-time formatting for a particular language and
calendar style (for example, Japanese-Gregorian, Japanese-Traditional).
Calendar defines the range of values returned by certain fields,
as well as their meaning. For example, the first month of the year has value
MONTH == JANUARY for all calendars. Other values
are defined by the concrete subclass, such as ERA and
YEAR. See individual field documentation and subclass
documentation for details.
When a Calendar is lenient, it accepts a wider range
of field values than it produces. For example, a lenient
GregorianCalendar interprets MONTH ==
JANUARY, DAY_OF_MONTH == 32 as February 1. A
non-lenient GregorianCalendar throws an exception when given
out-of-range field settings. When calendars recompute field values for
return by get(), they normalize them. For example, a
GregorianCalendar always produces DAY_OF_MONTH
values between 1 and the length of the month.
Calendar defines a locale-specific seven day week using two
parameters: the first day of the week and the minimal days in first week
(from 1 to 7). These numbers are taken from the locale resource data when a
Calendar is constructed. They may also be specified explicitly
through the API.
When setting or getting the WEEK_OF_MONTH or
WEEK_OF_YEAR fields, Calendar must determine the
first week of the month or year as a reference point. The first week of a
month or year is defined as the earliest seven day period beginning on
getFirstDayOfWeek() and containing at least
getMinimalDaysInFirstWeek() days of that month or year. Weeks
numbered ..., -1, 0 precede the first week; weeks numbered 2, 3,... follow
it. Note that the normalized numbering returned by get() may be
different. For example, a specific Calendar subclass may
designate the week before week 1 of a year as week n of the previous
year.
When computing a Date from time fields, some special
circumstances may arise: there may be insufficient information to compute the
Date (such as only year and month but no day in the month),
there may be inconsistent information (such as "Tuesday, July 15, 1996" --
July 15, 1996 is actually a Monday), or the input time might be ambiguous
because of time zone transition.
Insufficient information. The calendar will use default information to specify the missing fields. This may vary by calendar; for the Gregorian calendar, the default for a field is the same as that of the start of the epoch: i.e., YEAR = 1970, MONTH = JANUARY, DATE = 1, etc.
Inconsistent information. If fields conflict, the calendar will give preference to fields set more recently. For example, when determining the day, the calendar will look for one of the following combinations of fields. The most recent combination, as determined by the most recently set single field, will be used.
For the time of day:MONTH + DAY_OF_MONTH MONTH + WEEK_OF_MONTH + DAY_OF_WEEK MONTH + DAY_OF_WEEK_IN_MONTH + DAY_OF_WEEK DAY_OF_YEAR DAY_OF_WEEK + WEEK_OF_YEAR
HOUR_OF_DAY AM_PM + HOUR
Ambiguous Wall Clock Time. When time offset from UTC has changed, it produces an ambiguous time slot around the transition. For example, many US locations observe daylight saving time. On the date switching to daylight saving time in US, wall clock time jumps from 12:59 AM (standard) to 2:00 AM (daylight). Therefore, wall clock time from 1:00 AM to 1:59 AM do not exist on the date. When the input wall time fall into this missing time slot, the ICU Calendar resolves the time using the UTC offset before the transition by default. In this example, 1:30 AM is interpreted as 1:30 AM standard time (non-exist), so the final result will be 2:30 AM daylight time.
On the date switching back to standard time, wall clock time is moved back one hour at 2:00 AM. So wall clock time from 1:00 AM to 1:59 AM occur twice. In this case, the ICU Calendar resolves the time using the UTC offset after the transition by default. For example, 1:30 AM on the date is resolved as 1:30 AM standard time.
Ambiguous wall clock time resolution behaviors can be customized by Calendar APIs
setRepeatedWallTimeOption(int) and setSkippedWallTimeOption(int).
These methods are available in ICU 49 or later versions.
Note: for some non-Gregorian calendars, different fields may be necessary for complete disambiguation. For example, a full specification of the historial Arabic astronomical calendar requires year, month, day-of-month and day-of-week in some cases.
Note: There are certain possible ambiguities in interpretation of certain singular times, which are resolved in the following ways:
The date or time format strings are not part of the definition of a
calendar, as those must be modifiable or overridable by the user at
runtime. Use DateFormat
to format dates.
Field manipulation methods
Calendar fields can be changed using three methods:
set(), add(), and roll().
set(f, value) changes field
f to value. In addition, it sets an
internal member variable to indicate that field f has
been changed. Although field f is changed immediately,
the calendar's milliseconds is not recomputed until the next call to
get(), getTime(), or
getTimeInMillis() is made. Thus, multiple calls to
set() do not trigger multiple, unnecessary
computations. As a result of changing a field using
set(), other fields may also change, depending on the
field, the field value, and the calendar system. In addition,
get(f) will not necessarily return value
after the fields have been recomputed. The specifics are determined by
the concrete calendar class.
Example: Consider a GregorianCalendar
originally set to August 31, 1999. Calling set(Calendar.MONTH,
Calendar.SEPTEMBER) sets the calendar to September 31,
1999. This is a temporary internal representation that resolves to
October 1, 1999 if getTime()is then called. However, a
call to set(Calendar.DAY_OF_MONTH, 30) before the call to
getTime() sets the calendar to September 30, 1999, since
no recomputation occurs after set() itself.
add(f, delta) adds delta
to field f. This is equivalent to calling set(f,
get(f) + delta) with two adjustments:
Add rule 1. The value of field
fafter the call minus the value of fieldfbefore the call isdelta, modulo any overflow that has occurred in fieldf. 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
fis 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.HOURis a smaller field thanDAY_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.
In addition, unlike set(), add() forces
an immediate recomputation of the calendar's milliseconds and all
fields.
Example: Consider a GregorianCalendar
originally set to August 31, 1999. Calling add(Calendar.MONTH,
13) sets the calendar to September 30, 2000. Add rule
1 sets the MONTH field to September, since
adding 13 months to August gives September of the next year. Since
DAY_OF_MONTH cannot be 31 in September in a
GregorianCalendar, add rule 2 sets the
DAY_OF_MONTH to 30, the closest possible value. Although
it is a smaller field, DAY_OF_WEEK is not adjusted by
rule 2, since it is expected to change when the month changes in a
GregorianCalendar.
roll(f, delta) adds
delta to field f without changing larger
fields. This is equivalent to calling add(f, delta) with
the following adjustment:
Roll rule. Larger fields are unchanged after the call. A larger field represents a larger unit of time.
DAY_OF_MONTHis a larger field thanHOUR.
Example: Consider a GregorianCalendar
originally set to August 31, 1999. Calling roll(Calendar.MONTH,
8) sets the calendar to April 30, 1999. Add
rule 1 sets the MONTH field to April. Using a
GregorianCalendar, the DAY_OF_MONTH cannot
be 31 in the month April. Add rule 2 sets it to the closest possible
value, 30. Finally, the roll rule maintains the
YEAR field value of 1999.
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).
Usage model. To motivate the behavior of
add() and roll(), consider a user interface
component with increment and decrement buttons for the month, day, and
year, and an underlying GregorianCalendar. If the
interface reads January 31, 1999 and the user presses the month
increment button, what should it read? If the underlying
implementation uses set(), it might read March 3, 1999. A
better result would be February 28, 1999. Furthermore, if the user
presses the month increment button again, it should read March 31,
1999, not March 28, 1999. By saving the original date and using either
add() or roll(), depending on whether larger
fields should be affected, the user interface can behave as most users
will intuitively expect.
Note: You should always use roll and add rather
than attempting to perform arithmetic operations directly on the fields
of a Calendar. It is quite possible for Calendar subclasses
to have fields with non-linear behavior, for example missing months
or days during non-leap years. The subclasses' add and roll
methods will take this into account, while simple arithmetic manipulations
may give invalid results.
Calendar Architecture in ICU4J
Recently the implementation of Calendar has changed
significantly in order to better support subclassing. The original
Calendar class was designed to support subclassing, but
it had only one implemented subclass, GregorianCalendar.
With the implementation of several new calendar subclasses, including
the BuddhistCalendar, ChineseCalendar,
HebrewCalendar, IslamicCalendar, and
JapaneseCalendar, the subclassing API has been reworked
thoroughly. This section details the new subclassing API and other
ways in which android.icu.util.Calendar differs from
java.util.Calendar.
Changes
Overview of changes between the classic Calendar
architecture and the new architecture.
fields[] array is private now
instead of protected. Subclasses must access it
using the methods internalSet(int, int) and
internalGet(int). Motivation: Subclasses should
not directly access data members.time long word is private now
instead of protected. Subclasses may access it using
the method internalGetTimeInMillis(), which does not
provoke an update. Motivation: Subclasses should not
directly access data members.Calendar base class. As a result, it is much easier
to subclass Calendar. Motivation: Subclasses
should not have to reimplement common code. Certain behaviors are
common across calendar systems: The definition and behavior of
week-related fields and time fields, the arithmetic
(add and roll) behavior of many
fields, and the field validation system.Calendar base class contains some Gregorian
calendar algorithmic support that subclasses can use (specifically
in handleComputeFields(int)). Subclasses can use the
methods getGregorianXxx() to obtain precomputed
values. Motivation: This is required by all
Calendar subclasses in order to implement consistent
time zone behavior, and Gregorian-derived systems can use the
already computed data.FIELD_COUNT constant has been removed. Use
getFieldCount(). In addition, framework API has been
added to allow subclasses to define additional fields.
Motivation: The number of fields is not constant across
calendar systems.Date(Long.MIN_VALUE) or
Date(Long.MAX_VALUE). Instead, the
Calendar protected constants should be used.
Motivation: With
the addition of the JULIAN_DAY field, Julian day
numbers must be restricted to a 32-bit int. This
restricts the overall supported range. Furthermore, restricting
the supported range simplifies the computations by removing
special case code that was used to accomodate arithmetic overflow
at millis near Long.MIN_VALUE and
Long.MAX_VALUE.JULIAN_DAY defines
single-field specification of the
date. MILLISECONDS_IN_DAY defines a single-field
specification of the wall time. DOW_LOCAL and
YEAR_WOY implement localized day-of-week and
week-of-year behavior.Calendar.DateFormat.Subclass API
The original Calendar API was based on the experience
of implementing a only a single subclass,
GregorianCalendar. As a result, all of the subclassing
kinks had not been worked out. The new subclassing API has been
refined based on several implemented subclasses. This includes methods
that must be overridden and methods for subclasses to call. Subclasses
no longer have direct access to fields and
stamp. Instead, they have new API to access
these. Subclasses are able to allocate the fields array
through a protected framework method; this allows subclasses to
specify additional fields.
More functionality has been moved into the base class. The base class now contains much of the computational machinery to support the Gregorian calendar. This is based on two things: (1) Many calendars are based on the Gregorian calendar (such as the Buddhist and Japanese imperial calendars). (2) All calendars require basic Gregorian support in order to handle timezone computations.
Common computations have been moved into
Calendar. Subclasses no longer compute the week related
fields and the time related fields. These are commonly handled for all
calendars by the base class.
Subclass computation of time => fields
The ERA, YEAR,
EXTENDED_YEAR, MONTH,
DAY_OF_MONTH, and DAY_OF_YEAR fields are
computed by the subclass, based on the Julian day. All other fields
are computed by Calendar.
handleComputeFields(int)
to compute the ERA, YEAR,
EXTENDED_YEAR, MONTH,
DAY_OF_MONTH, and DAY_OF_YEAR fields,
based on the value of the JULIAN_DAY field. If there
are calendar-specific fields not defined by Calendar,
they must also be computed. These are the only fields that the
subclass should compute. All other fields are computed by the base
class, so time and week fields behave in a consistent way across
all calendars. The default version of this method in
Calendar implements a proleptic Gregorian
calendar. Within this method, subclasses may call
getGregorianXxx() to obtain the Gregorian calendar
month, day of month, and extended year for the given date.Subclass computation of fields => time
The interpretation of most field values is handled entirely by
Calendar. Calendar determines which fields
are set, which are not, which are set more recently, and so on. In
addition, Calendar handles the computation of the time
from the time fields and handles the week-related fields. The only
thing the subclass must do is determine the extended year, based on
the year fields, and then, given an extended year and a month, it must
return a Julian day number.
handleGetExtendedYear()
to return the extended year for this calendar system, based on the
YEAR, EXTENDED_YEAR, and any fields that
the calendar system uses that are larger than a year, such as
ERA.handleComputeMonthStart(int, int, boolean)
to return the Julian day number
associated with a month and extended year. This is the Julian day
number of the day before the first day of the month. The month
number is zero-based. This computation should not depend on any
field values.Other methods
handleGetMonthLength(int, int)
to return the number of days in a
given month of a given extended year. The month number, as always,
is zero-based.handleGetYearLength(int)
to return the number of days in the given
extended year. This method is used by
computeWeekFields to compute the
WEEK_OF_YEAR and YEAR_WOY fields.handleGetLimit(int, int)
to return the protected values of a field, depending on the value of
limitType. This method only needs to handle the
fields ERA, YEAR, MONTH,
WEEK_OF_YEAR, WEEK_OF_MONTH,
DAY_OF_MONTH, DAY_OF_YEAR,
DAY_OF_WEEK_IN_MONTH, YEAR_WOY, and
EXTENDED_YEAR. Other fields are invariant (with
respect to calendar system) and are handled by the base
class.validateField(int)
to check any subclass-specific fields. If the
field's value is out of range, the method should throw an
IllegalArgumentException. The method may call
super.validateField(field) to handle fields in a
generic way, that is, to compare them to the range
getMinimum(field)..getMaximum(field).handleCreateFields() to create an int[]
array large enough to hold the calendar's fields. This is only
necessary if the calendar defines additional fields beyond those
defined by Calendar. The length of the result must be
be between the base and maximum field counts.handleGetDateFormat(String, ULocale) to create a
DateFormat appropriate to this calendar. This is only
required if a calendar subclass redefines the use of a field (for
example, changes the ERA field from a symbolic field
to a numeric one) or defines an additional field.roll and
add to handle fields that are discontinuous. For
example, in the Hebrew calendar the month "Adar I" only
occurs in leap years; in other years the calendar jumps from
Shevat (month #4) to Adar (month #6). The HebrewCalendar.add and HebrewCalendar.roll methods take this into
account, so that adding 1 month to Shevat gives the proper result
(Adar) in a non-leap year. The protected utility method pinField is often useful when implementing these two
methods. Normalized behavior
The behavior of certain fields has been made consistent across all
calendar systems and implemented in Calendar.
Calendar and to maintain basic correpsondences
between calendar systems. Affected fields: AM_PM,
HOUR, HOUR_OF_DAY, MINUTE,
SECOND, MILLISECOND,
ZONE_OFFSET, and DST_OFFSET.GregorianCalendar fields: the
YEAR, MONTH, and
DAY_OF_MONTH. As a result, Calendar
always computes these fields, even for non-Gregorian calendar
systems. These fields are available to subclasses.DAY_OF_WEEK, WEEK_OF_YEAR,
WEEK_OF_MONTH, DAY_OF_WEEK_IN_MONTH,
DOW_LOCAL, YEAR_WOY are all computed in
a consistent way in the base class, based on the
EXTENDED_YEAR, DAY_OF_YEAR,
MONTH, and DAY_OF_MONTH, which are
computed by the subclass.Supported range
The allowable range of Calendar has been
narrowed. GregorianCalendar used to attempt to support
the range of dates with millisecond values from
Long.MIN_VALUE to Long.MAX_VALUE. This
introduced awkward constructions (hacks) which slowed down
performance. It also introduced non-uniform behavior at the
boundaries. The new Calendar protocol specifies the
maximum range of supportable dates as those having Julian day numbers
of -0x7F000000 to +0x7F000000. This
corresponds to years from ~5,800,000 BCE to ~5,800,000 CE. Programmers
should use the protected constants in Calendar to
specify an extremely early or extremely late date.
General notes
GregorianCalendar class supports
dates before the historical onset of the calendar by extending the
calendar system backward in time. Similarly, the
HebrewCalendar extends backward before the start of
its epoch into zero and negative years. Subclasses do not throw
exceptions because a date precedes the historical start of a
calendar system. Instead, they implement
handleGetLimit(int, int) to return appropriate limits on
YEAR, ERA, etc. fields. Then, if the
calendar is set to not be lenient, out-of-range field values will
trigger an exception.YEAR field in that
it ranges over all integer values, including zero and negative
values, and it encapsulates the information of the
YEAR field and all larger fields. Thus, for the
Gregorian calendar, the EXTENDED_YEAR is computed as
ERA==AD ? YEAR : 1-YEAR. Another example is the Mayan
long count, which has years (KUN) and nested cycles
of years (KATUN and BAKTUN). The Mayan
EXTENDED_YEAR is computed as TUN + 20 * (KATUN
+ 20 * BAKTUN). The Calendar base class uses
the EXTENDED_YEAR field to compute the week-related
fields.See also:
Nested classes | |
|---|---|
class |
Calendar.WeekData
Simple, immutable struct-like class for access to the CLDR weekend data. |
Constants | |
|---|---|
int |
AM
Value of the |
int |
AM_PM
Field number for |
int |
APRIL
Value of the |
int |
AUGUST
Value of the |
int |
BASE_FIELD_COUNT
The number of fields defined by this class. |
int |
DATE
Field number for |
int |
DAY_OF_MONTH
Field number for |
int |
DAY_OF_WEEK
Field number for |
int |
DAY_OF_WEEK_IN_MONTH
Field number for |
int |
DAY_OF_YEAR
Field number for |
int |
DECEMBER
Value of the |
int |
DOW_LOCAL
[icu] Field number for |
int |
DST_OFFSET
Field number for |
int |
EPOCH_JULIAN_DAY
The Julian day of the epoch, that is, January 1, 1970 on the Gregorian calendar. |
int |
ERA
Field number for |
int |
EXTENDED_YEAR
[icu] Field number for |
int |
FEBRUARY
Value of the |
int |
FRIDAY
Value of the |
int |
GREATEST_MINIMUM
Limit type for |
int |
HOUR
Field number for |
int |
HOUR_OF_DAY
Field number for |
int |
INTERNALLY_SET
Value of the time stamp |
int |
IS_LEAP_MONTH
[icu] Field indicating whether or not the current month is a leap month. |
int |
JANUARY
Value of the |
int |
JAN_1_1_JULIAN_DAY
The Julian day of the Gregorian epoch, that is, January 1, 1 on the Gregorian calendar. |
int |
JULIAN_DAY
[icu] Field number for |
int |
JULY
Value of the |
int |
JUNE
Value of the |
int |
LEAST_MAXIMUM
Limit type for |
int |
MARCH
Value of the |
int |
MAXIMUM
Limit type for |
int |
MAX_FIELD_COUNT
The maximum number of fields possible. |
int |
MAX_JULIAN
The maximum supported Julian day. |
long |
MAX_MILLIS
The maximum supported epoch milliseconds. |
int |
MAY
Value of the |
int |
MILLISECOND
Field number for |
int |
MILLISECONDS_IN_DAY
[icu] Field number for |
int |
MINIMUM
Limit type for |
int |
MINIMUM_USER_STAMP
If the time stamp |
int |
MINUTE
Field number for |
int |
MIN_JULIAN
The minimum supported Julian day. |
long |
MIN_MILLIS
The minimum supported epoch milliseconds. |
int |
MONDAY
Value of the |
int |
MONTH
Field number for |
int |
NOVEMBER
Value of the |
int |
OCTOBER
Value of the |
long |
ONE_DAY
The number of milliseconds in one day. |
int |
ONE_HOUR
The number of milliseconds in one hour. |
int |
ONE_MINUTE
The number of milliseconds in one minute. |
int |
ONE_SECOND
The number of milliseconds in one second. |
long |
ONE_WEEK
The number of milliseconds in one week. |
int |
PM
Value of the |
int |
RESOLVE_REMAP
Value to OR against resolve table field values for remapping. |
int |
SATURDAY
Value of the |
int |
SECOND
Field number for |
int |
SEPTEMBER
Value of the |
int |
SUNDAY
Value of the |
int |
THURSDAY
Value of the |
int |
TUESDAY
Value of the |
int |
UNDECIMBER
Value of the |
int |
UNSET
Value of the time stamp |
int |
WALLTIME_FIRST
[icu]Option used by |
int |
WALLTIME_LAST
[icu]Option used by |
int |
WALLTIME_NEXT_VALID
[icu]Option used by |
int |
WEDNESDAY
Value of the |
int |
WEEK_OF_MONTH
Field number for |
int |
WEEK_OF_YEAR
Field number for |
int |
YEAR
Field number for |
int |
YEAR_WOY
[icu] Field number for |
int |
ZONE_OFFSET
Field number for |
Fields | |
|---|---|
protected
static
final
Date |
MAX_DATE
The maximum supported |
protected
static
final
Date |
MIN_DATE
The minimum supported |
Protected constructors | |
|---|---|
Calendar()
Constructs a Calendar with the default time zone
and the default |
|
Calendar(TimeZone zone, Locale aLocale)
Constructs a calendar with the specified time zone and locale. |
|
Calendar(TimeZone zone, ULocale locale)
Constructs a calendar with the specified time zone and locale. |
|
Public methods | |
|---|---|
void
|
add(int field, int amount)
Add a signed amount to a specified field, using this calendar's rules. |
boolean
|
after(Object when)
Compares the time field records. |
boolean
|
before(Object when)
Compares the time field records. |
final
void
|
clear()
Clears the values of all the time fields. |
final
void
|
clear(int field)
Clears the value in the given time field. |
Object
|
clone()
Overrides Cloneable |
int
|
compareTo(Calendar that)
Compares the times (in millis) represented by two
|
boolean
|
equals(Object obj)
Compares this calendar to the specified object. |
int
|
fieldDifference(Date when, int field)
[icu] Returns the difference between the given time and the time this calendar object is set to. |
final
int
|
get(int field)
Returns the value for a given time field. |
int
|
getActualMaximum(int field)
Returns the maximum value that this field could have, given the current date. |
int
|
getActualMinimum(int field)
Returns the minimum value that this field could have, given the current date. |
static
Locale[]
|
getAvailableLocales()
Returns the list of locales for which Calendars are installed. |
DateFormat
|
getDateTimeFormat(int dateStyle, int timeStyle, ULocale loc)
[icu] Returns a |
DateFormat
|
getDateTimeFormat(int dateStyle, int timeStyle, Locale loc)
[icu] Returns a |
String
|
getDisplayName(ULocale loc)
Returns the name of this calendar in the language of the given locale. |
String
|
getDisplayName(Locale loc)
Returns the name of this calendar in the language of the given locale. |
final
int
|
getFieldCount()
[icu] Returns the number of fields defined by this calendar. |
int
|
getFirstDayOfWeek()
Returns what the first day of the week is,
where 1 = |
final
int
|
getGreatestMinimum(int field)
Returns the highest minimum value for the given field if varies. |
static
Calendar
|
getInstance()
Returns a calendar using the default time zone and locale. |
static
Calendar
|
getInstance(Locale aLocale)
Returns a calendar using the default time zone and specified locale. |
static
Calendar
|
getInstance(TimeZone zone, Locale aLocale)
Returns a calendar with the specified time zone and locale. |
static
Calendar
|
getInstance(TimeZone zone, ULocale locale)
Returns a calendar with the specified time zone and locale. |
static
Calendar
|
getInstance(TimeZone zone)
Returns a calendar using the specified time zone and default locale. |
static
Calendar
|
getInstance(ULocale locale)
Returns a calendar using the default time zone and specified locale. |
static
final
String[]
|
getKeywordValuesForLocale(String key, ULocale locale, boolean commonlyUsed)
[icu] Given a key and a locale, returns an array of string values in a preferred order that would make a difference. |
final
int
|
getLeastMaximum(int field)
Returns the lowest maximum value for the given field if varies. |
final
int
|
getMaximum(int field)
Returns the maximum value for the given time field. |
int
|
getMinimalDaysInFirstWeek()
Returns what the minimal days required in the first week of the year are. |
final
int
|
getMinimum(int field)
Returns the minimum value for the given time field. |
int
|
getRepeatedWallTimeOption()
[icu]Gets the behavior for handling wall time repeating multiple times at negative time zone offset transitions. |
int
|
getSkippedWallTimeOption()
[icu]Gets the behavior for handling skipped wall time at positive time zone offset transitions. |
final
Date
|
getTime()
Returns this Calendar's current time. |
long
|
getTimeInMillis()
Returns this Calendar's current time as a long. |
TimeZone
|
getTimeZone()
Returns the time zone. |
String
|
getType()
[icu] Returns the calendar type name string for this Calendar object. |
Calendar.WeekData
|
getWeekData()
[icu] Return simple, immutable struct-like class for access to the weekend data in this calendar. |
static
Calendar.WeekData
|
getWeekDataForRegion(String region)
[icu] Return simple, immutable struct-like class for access to the CLDR weekend data. |
int
|
hashCode()
Returns a hash code for this calendar. |
boolean
|
isEquivalentTo(Calendar other)
[icu] Returns true if the given Calendar object is equivalent to this one. |
boolean
|
isLenient()
Tell whether date/time interpretation is to be lenient. |
final
boolean
|
isSet(int field)
Determines if the given time field has a value set. |
boolean
|
isWeekend(Date date)
[icu] Returns true if the given date and time is in the weekend in this calendar system. |
boolean
|
isWeekend()
[icu] Returns true if this Calendar's current date and time is in the weekend in this calendar system. |
final
void
|
roll(int field, boolean up)
Rolls (up/down) a single unit of time on the given field. |
void
|
roll(int field, int amount)
Rolls (up/down) a specified amount time on the given field. |
final
void
|
set(int year, int month, int date, int hour, int minute, int second)
Sets the values for the fields year, month, date, hour, minute, and second. |
final
void
|
set(int year, int month, int date, int hour, int minute)
Sets the values for the fields year, month, date, hour, and minute. |
final
void
|
set(int field, int value)
Sets the time field with the given value. |
final
void
|
set(int year, int month, int date)
Sets the values for the fields year, month, and date. |
void
|
setFirstDayOfWeek(int value)
Sets what the first day of the week is,
where 1 = |
void
|
setLenient(boolean lenient)
Specify whether or not date/time interpretation is to be lenient. |
void
|
setMinimalDaysInFirstWeek(int value)
Sets what the minimal days required in the first week of the year are. |
void
|
setRepeatedWallTimeOption(int option)
[icu]Sets the behavior for handling wall time repeating multiple times at negative time zone offset transitions. |
void
|
setSkippedWallTimeOption(int option)
[icu]Sets the behavior for handling skipped wall time at positive time zone offset transitions. |
final
void
|
setTime(Date date)
Sets this Calendar's current time with the given Date. |
void
|
setTimeInMillis(long millis)
Sets this Calendar's current time from the given long value. |
void
|
setTimeZone(TimeZone value)
Sets the time zone with the given time zone value. |
Calendar
|
setWeekData(Calendar.WeekData wdata)
[icu] Set data in this calendar based on the WeekData input. |
String
|
toString()
Returns a string representation of this calendar. |
Protected methods | |
|---|---|
void
|
complete()
Fills in any unset fields in the time field list. |
void
|
computeFields()
Converts the current millisecond time value |
final
void
|
computeGregorianFields(int julianDay)
Compute the Gregorian calendar year, month, and day of month from the Julian day. |
int
|
computeGregorianMonthStart(int year, int month)
Compute the Julian day of a month of the Gregorian calendar. |
int
|
computeJulianDay()
Compute the Julian day number as specified by this calendar's fields. |
int
|
computeMillisInDay()
Compute the milliseconds in the day from the fields. |
void
|
computeTime()
Converts the current field values in |
int
|
computeZoneOffset(long millis, int millisInDay)
This method can assume EXTENDED_YEAR has been set. |
String
|
fieldName(int field)
Returns a string name for a field, for debugging and exceptions. |
static
final
int
|
floorDivide(int numerator, int denominator, int[] remainder)
Divide two integers, returning the floor of the quotient, and the modulus remainder. |
static
final
int
|
floorDivide(int numerator, int denominator)
Divide two integers, returning the floor of the quotient. |
static
final
long
|
floorDivide(long numerator, long denominator)
Divide two long integers, returning the floor of the quotient. |
static
final
int
|
floorDivide(long numerator, int denominator, int[] remainder)
Divide two integers, returning the floor of the quotient, and the modulus remainder. |
int[][][]
|
getFieldResolutionTable()
Returns the field resolution array for this calendar. |
final
int
|
getGregorianDayOfMonth()
Returns the day of month (1-based) on the Gregorian calendar as
computed by |
final
int
|
getGregorianDayOfYear()
Returns the day of year (1-based) on the Gregorian calendar as
computed by |
final
int
|
getGregorianMonth()
Returns the month (0-based) on the Gregorian calendar as computed by
|
final
int
|
getGregorianYear()
Returns the extended year on the Gregorian calendar as computed by
|
int
|
getLimit(int field, int limitType)
Returns a limit for a field. |
final
int
|
getStamp(int field)
Returns the timestamp of a field. |
static
final
int
|
gregorianMonthLength(int y, int m)
Returns the length of a month of the Gregorian calendar. |
static
final
int
|
gregorianPreviousMonthLength(int y, int m)
Returns the length of a previous month of the Gregorian calendar. |
void
|
handleComputeFields(int julianDay)
Subclasses may override this method to compute several fields specific to each calendar system. |
int
|
handleComputeJulianDay(int bestField)
Subclasses may override this. |
abstract
int
|
handleComputeMonthStart(int eyear, int month, boolean useMonth)
Returns the Julian day number of day before the first day of the given month in the given extended year. |
int[]
|
handleCreateFields()
Subclasses that use additional fields beyond those defined in
|
DateFormat
|
handleGetDateFormat(String pattern, String override, Locale locale)
Creates a |
DateFormat
|
handleGetDateFormat(String pattern, ULocale locale)
Creates a |
DateFormat
|
handleGetDateFormat(String pattern, Locale locale)
Creates a |
abstract
int
|
handleGetExtendedYear()
Returns the extended year defined by the current fields. |
abstract
int
|
handleGetLimit(int field, int limitType)
Subclass API for defining limits of different types. |
int
|
handleGetMonthLength(int extendedYear, int month)
Returns the number of days in the given month of the given extended year of this calendar system. |
int
|
handleGetYearLength(int eyear)
Returns the number of days in the given extended year of this calendar system. |
final
int
|
internalGet(int field)
Returns the value for a given time field. |
final
int
|
internalGet(int field, int defaultValue)
Returns the value for a given time field, or return the given default value if the field is not set. |
final
long
|
internalGetTimeInMillis()
Returns the current milliseconds without recomputing. |
final
void
|
internalSet(int field, int value)
Set a field to a value. |
static
final
boolean
|
isGregorianLeapYear(int year)
Determines if the given year is a leap year. |
static
final
int
|
julianDayToDayOfWeek(int julian)
Returns the day of week, from SUNDAY to SATURDAY, given a Julian day. |
static
final
long
|
julianDayToMillis(int julian)
Converts Julian day to time as milliseconds. |
static
final
int
|
millisToJulianDay(long millis)
Converts time as milliseconds to Julian day. |
int
|
newerField(int defaultField, int alternateField)
Returns the field that is newer, either defaultField, or alternateField. |
int
|
newestStamp(int first, int last, int bestStampSoFar)
Returns the newest stamp of a given range of fields. |
void
|
pinField(int field)
Adjust the specified field so that it is within the allowable range for the date to which this calendar is set. |
void
|
prepareGetActual(int field, boolean isMinimum)
Prepare this calendar for computing the actual minimum or maximum. |
int
|
resolveFields(int[][][] precedenceTable)
Given a precedence table, return the newest field combination in the table, or -1 if none is found. |
void
|
validateField(int field)
Validate a single field of this calendar. |
final
void
|
validateField(int field, int min, int max)
Validate a single field of this calendar given its minimum and maximum allowed value. |
void
|
validateFields()
Ensure that each field is within its valid range by calling |
int
|
weekNumber(int desiredDay, int dayOfPeriod, int dayOfWeek)
Returns the week number of a day, within a period. |
final
int
|
weekNumber(int dayOfPeriod, int dayOfWeek)
Returns the week number of a day, within a period. |
Inherited methods | |
|---|---|
From
class
java.lang.Object
| |
From
interface
java.lang.Comparable
| |
int AM
Value of the AM_PM field indicating the
period of the day from midnight to just before noon.
Constant Value: 0 (0x00000000)
int AM_PM
Field number for get and set indicating
whether the HOUR is before or after noon.
E.g., at 10:04:15.250 PM the AM_PM is PM.
Constant Value: 9 (0x00000009)
int APRIL
Value of the MONTH field indicating the
fourth month of the year.
Constant Value: 3 (0x00000003)
int AUGUST
Value of the MONTH field indicating the
eighth month of the year.
Constant Value: 7 (0x00000007)
int BASE_FIELD_COUNT
The number of fields defined by this class. Subclasses may define addition fields starting with this number.
Constant Value: 23 (0x00000017)
int DATE
Field number for get and set indicating the
day of the month. This is a synonym for DAY_OF_MONTH.
The first day of the month has value 1.
See also:
Constant Value: 5 (0x00000005)
int DAY_OF_MONTH
Field number for get and set indicating the
day of the month. This is a synonym for DATE.
The first day of the month has value 1.
See also:
Constant Value: 5 (0x00000005)
int DAY_OF_WEEK
Field number for get and set indicating the day
of the week. This field takes values SUNDAY,
MONDAY, TUESDAY, WEDNESDAY,
THURSDAY, FRIDAY, and SATURDAY.
Constant Value: 7 (0x00000007)
int DAY_OF_WEEK_IN_MONTH
Field number for get and set indicating the
ordinal number of the day of the week within the current month. Together
with the DAY_OF_WEEK field, this uniquely specifies a day
within a month. Unlike WEEK_OF_MONTH and
WEEK_OF_YEAR, this field's value does not depend on
getFirstDayOfWeek() or
getMinimalDaysInFirstWeek(). DAY_OF_MONTH 1
through 7 always correspond to DAY_OF_WEEK_IN_MONTH
1; 8 through 15 correspond to
DAY_OF_WEEK_IN_MONTH 2, and so on.
DAY_OF_WEEK_IN_MONTH 0 indicates the week before
DAY_OF_WEEK_IN_MONTH 1. Negative values count back from the
end of the month, so the last Sunday of a month is specified as
DAY_OF_WEEK = SUNDAY, DAY_OF_WEEK_IN_MONTH = -1. Because
negative values count backward they will usually be aligned differently
within the month than positive values. For example, if a month has 31
days, DAY_OF_WEEK_IN_MONTH -1 will overlap
DAY_OF_WEEK_IN_MONTH 5 and the end of 4.
See also:
Constant Value: 8 (0x00000008)
int DAY_OF_YEAR
Field number for get and set indicating the day
number within the current year. The first day of the year has value 1.
Constant Value: 6 (0x00000006)
int DECEMBER
Value of the MONTH field indicating the
twelfth month of the year.
Constant Value: 11 (0x0000000b)
int DOW_LOCAL
[icu] Field number for get() and set()
indicating the localized day of week. This will be a value from 1
to 7 inclusive, with 1 being the localized first day of the week.
Constant Value: 18 (0x00000012)
int DST_OFFSET
Field number for get and set indicating the
daylight savings offset in milliseconds.
Constant Value: 16 (0x00000010)
int EPOCH_JULIAN_DAY
The Julian day of the epoch, that is, January 1, 1970 on the Gregorian calendar.
Constant Value: 2440588 (0x00253d8c)
int ERA
Field number for get and set indicating the
era, e.g., AD or BC in the Julian calendar. This is a calendar-specific
value; see subclass documentation.
Constant Value: 0 (0x00000000)
int EXTENDED_YEAR
[icu] Field number for get() and set()
indicating the extended year. This is a single number designating
the year of this calendar system, encompassing all supra-year
fields. For example, for the Julian calendar system, year numbers
are positive, with an era of BCE or CE. An extended year value for
the Julian calendar system assigns positive values to CE years and
negative values to BCE years, with 1 BCE being year 0.
Constant Value: 19 (0x00000013)
int FEBRUARY
Value of the MONTH field indicating the
second month of the year.
Constant Value: 1 (0x00000001)
int FRIDAY
Value of the DAY_OF_WEEK field indicating
Friday.
Constant Value: 6 (0x00000006)
int GREATEST_MINIMUM
Limit type for getLimit() and handleGetLimit()
indicating the greatest minimum value that a field can take.
Constant Value: 1 (0x00000001)
int HOUR
Field number for get and set indicating the
hour of the morning or afternoon. HOUR is used for the 12-hour
clock.
E.g., at 10:04:15.250 PM the HOUR is 10.
See also:
Constant Value: 10 (0x0000000a)
int HOUR_OF_DAY
Field number for get and set indicating the
hour of the day. HOUR_OF_DAY is used for the 24-hour clock.
E.g., at 10:04:15.250 PM the HOUR_OF_DAY is 22.
See also:
Constant Value: 11 (0x0000000b)
int INTERNALLY_SET
Value of the time stamp stamp[] indicating that a field
has been set via computations from the time or from other fields.
See also:
Constant Value: 1 (0x00000001)
int IS_LEAP_MONTH
[icu] Field indicating whether or not the current month is a leap month. Should have a value of 0 for non-leap months, and 1 for leap months.
Constant Value: 22 (0x00000016)
int JANUARY
Value of the MONTH field indicating the
first month of the year.
Constant Value: 0 (0x00000000)
int JAN_1_1_JULIAN_DAY
The Julian day of the Gregorian epoch, that is, January 1, 1 on the Gregorian calendar.
Constant Value: 1721426 (0x001a4452)
int JULIAN_DAY
[icu] Field number for get() and set()
indicating the modified Julian day number. This is different from
the conventional Julian day number in two regards. First, it
demarcates days at local zone midnight, rather than noon GMT.
Second, it is a local number; that is, it depends on the local time
zone. It can be thought of as a single number that encompasses all
the date-related fields.
Constant Value: 20 (0x00000014)
int JULY
Value of the MONTH field indicating the
seventh month of the year.
Constant Value: 6 (0x00000006)
int JUNE
Value of the MONTH field indicating the
sixth month of the year.
Constant Value: 5 (0x00000005)
int LEAST_MAXIMUM
Limit type for getLimit() and handleGetLimit()
indicating the least maximum value that a field can take.
Constant Value: 2 (0x00000002)
int MARCH
Value of the MONTH field indicating the
third month of the year.
Constant Value: 2 (0x00000002)
int MAXIMUM
Limit type for getLimit() and handleGetLimit()
indicating the maximum value that a field can take (greatest maximum).
Constant Value: 3 (0x00000003)
int MAX_FIELD_COUNT
The maximum number of fields possible. Subclasses must not define more total fields than this number.
Constant Value: 32 (0x00000020)
int MAX_JULIAN
The maximum supported Julian day. This value is equivalent to
MAX_MILLIS and MAX_DATE.
See also:
Constant Value: 2130706432 (0x7f000000)
long MAX_MILLIS
The maximum supported epoch milliseconds. This value is equivalent
to MAX_JULIAN and MAX_DATE.
Constant Value: 183882168921600000 (0x028d47dbbf19b000)
int MAY
Value of the MONTH field indicating the
fifth month of the year.
Constant Value: 4 (0x00000004)
int MILLISECOND
Field number for get and set indicating the
millisecond within the second.
E.g., at 10:04:15.250 PM the MILLISECOND is 250.
Constant Value: 14 (0x0000000e)
int MILLISECONDS_IN_DAY
[icu] Field number for get() and set()
indicating the milliseconds in the day. This ranges from 0 to
23:59:59.999 (regardless of DST). This field behaves
exactly like a composite of all time-related fields, not
including the zone fields. As such, it also reflects
discontinuities of those fields on DST transition days. On a day of
DST onset, it will jump forward. On a day of DST cessation, it will
jump backward. This reflects the fact that is must be combined with
the DST_OFFSET field to obtain a unique local time value.
Constant Value: 21 (0x00000015)
int MINIMUM
Limit type for getLimit() and handleGetLimit()
indicating the minimum value that a field can take (least minimum).
Constant Value: 0 (0x00000000)
int MINIMUM_USER_STAMP
If the time stamp stamp[] has a value greater than or
equal to MINIMUM_USER_SET then it has been set by the
user via a call to set().
See also:
Constant Value: 2 (0x00000002)
int MINUTE
Field number for get and set indicating the
minute within the hour.
E.g., at 10:04:15.250 PM the MINUTE is 4.
Constant Value: 12 (0x0000000c)
int MIN_JULIAN
The minimum supported Julian day. This value is equivalent to
MIN_MILLIS and MIN_DATE.
See also:
Constant Value: -2130706432 (0x81000000)
long MIN_MILLIS
The minimum supported epoch milliseconds. This value is equivalent
to MIN_JULIAN and MIN_DATE.
Constant Value: -184303902528000000 (0xfd713893bf19b000)
int MONDAY
Value of the DAY_OF_WEEK field indicating
Monday.
Constant Value: 2 (0x00000002)
int MONTH
Field number for get and set indicating the
month. This is a calendar-specific value. The first month of the year is
JANUARY; the last depends on the number of months in a year.
Constant Value: 2 (0x00000002)
int NOVEMBER
Value of the MONTH field indicating the
eleventh month of the year.
Constant Value: 10 (0x0000000a)
int OCTOBER
Value of the MONTH field indicating the
tenth month of the year.
Constant Value: 9 (0x00000009)
long ONE_DAY
The number of milliseconds in one day. Although ONE_DAY and ONE_WEEK can fit into ints, they must be longs in order to prevent arithmetic overflow when performing (bug 4173516).
Constant Value: 86400000 (0x0000000005265c00)
int ONE_HOUR
The number of milliseconds in one hour.
Constant Value: 3600000 (0x0036ee80)
int ONE_MINUTE
The number of milliseconds in one minute.
Constant Value: 60000 (0x0000ea60)
int ONE_SECOND
The number of milliseconds in one second.
Constant Value: 1000 (0x000003e8)
long ONE_WEEK
The number of milliseconds in one week. Although ONE_DAY and ONE_WEEK can fit into ints, they must be longs in order to prevent arithmetic overflow when performing (bug 4173516).
Constant Value: 604800000 (0x00000000240c8400)
int PM
Value of the AM_PM field indicating the
period of the day from noon to just before midnight.
Constant Value: 1 (0x00000001)
int RESOLVE_REMAP
Value to OR against resolve table field values for remapping.
See also:
Constant Value: 32 (0x00000020)
int SATURDAY
Value of the DAY_OF_WEEK field indicating
Saturday.
Constant Value: 7 (0x00000007)
int SECOND
Field number for get and set indicating the
second within the minute.
E.g., at 10:04:15.250 PM the SECOND is 15.
Constant Value: 13 (0x0000000d)
int SEPTEMBER
Value of the MONTH field indicating the
ninth month of the year.
Constant Value: 8 (0x00000008)
int SUNDAY
Value of the DAY_OF_WEEK field indicating
Sunday.
Constant Value: 1 (0x00000001)
int THURSDAY
Value of the DAY_OF_WEEK field indicating
Thursday.
Constant Value: 5 (0x00000005)
int TUESDAY
Value of the DAY_OF_WEEK field indicating
Tuesday.
Constant Value: 3 (0x00000003)
int UNDECIMBER
Value of the MONTH field indicating the
thirteenth month of the year. Although GregorianCalendar
does not use this value, lunar calendars do.
Constant Value: 12 (0x0000000c)
int UNSET
Value of the time stamp stamp[] indicating that
a field has not been set since the last call to clear().
See also:
Constant Value: 0 (0x00000000)
int WALLTIME_FIRST
[icu]Option used by setRepeatedWallTimeOption(int) and
setSkippedWallTimeOption(int) specifying an ambiguous wall time
to be interpreted as the earliest.
See also:
Constant Value: 1 (0x00000001)
int WALLTIME_LAST
[icu]Option used by setRepeatedWallTimeOption(int) and
setSkippedWallTimeOption(int) specifying an ambiguous wall time
to be interpreted as the latest.
See also:
Constant Value: 0 (0x00000000)
int WALLTIME_NEXT_VALID
[icu]Option used by setSkippedWallTimeOption(int) specifying an
ambiguous wall time to be interpreted as the next valid wall time.
Constant Value: 2 (0x00000002)
int WEDNESDAY
Value of the DAY_OF_WEEK field indicating
Wednesday.
Constant Value: 4 (0x00000004)
int WEEK_OF_MONTH
Field number for get and set indicating the
week number within the current month. The first week of the month, as
defined by getFirstDayOfWeek() and
getMinimalDaysInFirstWeek(), has value 1. Subclasses define
the value of WEEK_OF_MONTH for days before the first week of
the month.
Constant Value: 4 (0x00000004)
int WEEK_OF_YEAR
Field number for get and set indicating the
week number within the current year. The first week of the year, as
defined by getFirstDayOfWeek() and
getMinimalDaysInFirstWeek(), has value 1. Subclasses define
the value of WEEK_OF_YEAR for days before the first week of
the year.
Constant Value: 3 (0x00000003)
int YEAR
Field number for get and set indicating the
year. This is a calendar-specific value; see subclass documentation.
Constant Value: 1 (0x00000001)
int YEAR_WOY
[icu] Field number for get() and set()
indicating the extended year corresponding to the
WEEK_OF_YEAR field. This may be one greater or less
than the value of EXTENDED_YEAR.
Constant Value: 17 (0x00000011)
int ZONE_OFFSET
Field number for get and set indicating the
raw offset from GMT in milliseconds.
Constant Value: 15 (0x0000000f)
Date MAX_DATE
The maximum supported Date. This value is equivalent
to MAX_JULIAN and MAX_MILLIS.
Date MIN_DATE
The minimum supported Date. This value is equivalent
to MIN_JULIAN and MIN_MILLIS.
Calendar ()
Constructs a Calendar with the default time zone
and the default FORMAT locale.
See also:
Calendar (TimeZone zone, Locale aLocale)
Constructs a calendar with the specified time zone and locale.
| Parameters | |
|---|---|
zone |
TimeZone:
the time zone to use |
aLocale |
Locale:
the locale for the week data
|
Calendar (TimeZone zone, ULocale locale)
Constructs a calendar with the specified time zone and locale.
| Parameters | |
|---|---|
zone |
TimeZone:
the time zone to use |
locale |
ULocale:
the ulocale for the week data
|
void add (int field,
int amount)
Add a signed amount to a specified field, using this calendar's rules.
For example, to add three days to the current date, you can call
add(Calendar.DATE, 3).
When adding to certain fields, the values of other fields may conflict and
need to be changed. For example, when adding one to the MONTH field
for the Gregorian date 1/31/96, the DAY_OF_MONTH field
must be adjusted so that the result is 2/29/96 rather than the invalid
2/31/96.
Adding a positive value always means moving forward in time, so for the Gregorian calendar, starting with 100 BC and adding +1 to year results in 99 BC (even though this actually reduces the numeric value of the field itself).
[icu] Note: The ICU implementation of this method is able to add to
all fields except for ERA, DST_OFFSET,
and ZONE_OFFSET. Subclasses may, of course, add support for
additional fields in their overrides of add.
Note: You should always use roll and add rather than attempting to perform arithmetic operations directly on the fields of a Calendar. It is quite possible for Calendar subclasses to have fields with non-linear behavior, for example missing months or days during non-leap years. The subclasses' add and roll methods will take this into account, while simple arithmetic manipulations may give invalid results.
Subclassing:
This implementation of add assumes that the behavior of the
field is continuous between its minimum and maximum, which are found by
calling getActualMinimum and
getActualMaximum.
For such fields, simple arithmetic operations are sufficient to
perform the add.
Subclasses that have fields for which this assumption of continuity breaks
down must overide add to handle those fields specially.
For example, in the Hebrew calendar the month "Adar I"
only occurs in leap years; in other years the calendar jumps from
Shevat (month #4) to Adar (month #6). The
HebrewCalendar.add method takes this into account,
so that adding one month
to a date in Shevat gives the proper result (Adar) in a non-leap year.
| Parameters | |
|---|---|
field |
int:
the time field. |
amount |
int:
the amount to add to the field. |
| Throws | |
|---|---|
IllegalArgumentException |
if the field is invalid or refers to a field that cannot be handled by this method. |
See also:
boolean after (Object when)
Compares the time field records. Equivalent to comparing result of conversion to UTC.
| Parameters | |
|---|---|
when |
Object:
the Calendar to be compared with this Calendar. |
| Returns | |
|---|---|
boolean |
true if the current time of this Calendar is after the time of Calendar when; false otherwise. |
boolean before (Object when)
Compares the time field records. Equivalent to comparing result of conversion to UTC.
| Parameters | |
|---|---|
when |
Object:
the Calendar to be compared with this Calendar. |
| Returns | |
|---|---|
boolean |
true if the current time of this Calendar is before the time of Calendar when; false otherwise. |
void clear (int field)
Clears the value in the given time field.
| Parameters | |
|---|---|
field |
int:
the time field to be cleared.
|
Object clone ()
Overrides Cloneable
| Returns | |
|---|---|
Object |
a clone of this instance. |
int compareTo (Calendar that)
Compares the times (in millis) represented by two
Calendar objects.
| Parameters | |
|---|---|
that |
Calendar:
the Calendar to compare to this. |
| Returns | |
|---|---|
int |
0 if the time represented by
this Calendar is equal to the time represented
by that Calendar, a value less than
0 if the time represented by this is before
the time represented by that, and a value greater than
0 if the time represented by this
is after the time represented by that. |
| Throws | |
|---|---|
NullPointerException |
if that
Calendar is null. |
IllegalArgumentException |
if the time of that
Calendar can't be obtained because of invalid
calendar values.
|
boolean equals (Object obj)
Compares this calendar to the specified object.
The result is true if and only if the argument is
not null and is a Calendar object that
represents the same calendar as this object.
| Parameters | |
|---|---|
obj |
Object:
the object to compare with. |
| Returns | |
|---|---|
boolean |
true if the objects are the same;
false otherwise.
|
int fieldDifference (Date when, int field)
[icu] Returns the difference between the given time and the time this
calendar object is set to. If this calendar is set
before the given time, the returned value will be
positive. If this calendar is set after the given
time, the returned value will be negative. The
field parameter specifies the units of the return
value. For example, if fieldDifference(when,
Calendar.MONTH) returns 3, then this calendar is set to
3 months before when, and possibly some additional
time less than one month.
As a side effect of this call, this calendar is advanced
toward when by the given amount. That is, calling
this method has the side effect of calling add(field,
n), where n is the return value.
Usage: To use this method, call it first with the largest field of interest, then with progressively smaller fields. For example:
int y = cal.fieldDifference(when, Calendar.YEAR); int m = cal.fieldDifference(when, Calendar.MONTH); int d = cal.fieldDifference(when, Calendar.DATE);computes the difference between
cal and
when in years, months, and days.
Note: fieldDifference() is
asymmetrical. That is, in the following code:
cal.setTime(date1); int m1 = cal.fieldDifference(date2, Calendar.MONTH); int d1 = cal.fieldDifference(date2, Calendar.DATE); cal.setTime(date2); int m2 = cal.fieldDifference(date1, Calendar.MONTH); int d2 = cal.fieldDifference(date1, Calendar.DATE);one might expect that
m1 == -m2 && d1 == -d2.
However, this is not generally the case, because of
irregularities in the underlying calendar system (e.g., the
Gregorian calendar has a varying number of days per month).
| Parameters | |
|---|---|
when |
Date:
the date to compare this calendar's time to |
field |
int:
the field in which to compute the result |
| Returns | |
|---|---|
int |
the difference, either positive or negative, between
this calendar's time and when, in terms of
field.
|
int get (int field)
Returns the value for a given time field.
| Parameters | |
|---|---|
field |
int:
the given time field. |
| Returns | |
|---|---|
int |
the value for the given time field. |
int getActualMaximum (int field)
Returns the maximum value that this field could have, given the
current date. For example, with the Gregorian date February 3, 1997
and the DAY_OF_MONTH field, the actual maximum
is 28; for February 3, 1996 it is 29.
The actual maximum computation ignores smaller fields and the current value of like-sized fields. For example, the actual maximum of the DAY_OF_YEAR or MONTH depends only on the year and supra-year fields. The actual maximum of the DAY_OF_MONTH depends, in addition, on the MONTH field and any other fields at that granularity (such as IS_LEAP_MONTH). The DAY_OF_WEEK_IN_MONTH field does not depend on the current DAY_OF_WEEK; it returns the maximum for any day of week in the current month. Likewise for the WEEK_OF_MONTH and WEEK_OF_YEAR fields.
| Parameters | |
|---|---|
field |
int:
the field whose maximum is desired |
| Returns | |
|---|---|
int |
the maximum of the given field for the current date of this calendar |
See also:
int getActualMinimum (int field)
Returns the minimum value that this field could have, given the current date.
For most fields, this is the same as getMinimum
and getGreatestMinimum. However, some fields,
especially those related to week number, are more complicated.
For example, assume getMinimalDaysInFirstWeek
returns 4 and getFirstDayOfWeek returns SUNDAY.
If the first day of the month is Sunday, Monday, Tuesday, or Wednesday
there will be four or more days in the first week, so it will be week number 1,
and getActualMinimum(WEEK_OF_MONTH) will return 1. However,
if the first of the month is a Thursday, Friday, or Saturday, there are
not four days in that week, so it is week number 0, and
getActualMinimum(WEEK_OF_MONTH) will return 0.
| Parameters | |
|---|---|
field |
int:
the field whose actual minimum value is desired. |
| Returns | |
|---|---|
int |
the minimum of the given field for the current date of this calendar |
See also:
Locale[] getAvailableLocales ()
Returns the list of locales for which Calendars are installed.
| Returns | |
|---|---|
Locale[] |
the list of locales for which Calendars are installed. |
DateFormat getDateTimeFormat (int dateStyle, int timeStyle, ULocale loc)
[icu] Returns a DateFormat appropriate to this calendar.
Subclasses wishing to specialize this behavior should override
handleGetDateFormat(String, ULocale).
| Parameters | |
|---|---|
dateStyle |
int
|
timeStyle |
int
|
loc |
ULocale
|
| Returns | |
|---|---|
DateFormat |
|
DateFormat getDateTimeFormat (int dateStyle, int timeStyle, Locale loc)
[icu] Returns a DateFormat appropriate to this calendar.
Subclasses wishing to specialize this behavior should override
handleGetDateFormat(String, ULocale).
| Parameters | |
|---|---|
dateStyle |
int
|
timeStyle |
int
|
loc |
Locale
|
| Returns | |
|---|---|
DateFormat |
|
String getDisplayName (ULocale loc)
Returns the name of this calendar in the language of the given locale.
| Parameters | |
|---|---|
loc |
ULocale
|
| Returns | |
|---|---|
String |
|
String getDisplayName (Locale loc)
Returns the name of this calendar in the language of the given locale.
| Parameters | |
|---|---|
loc |
Locale
|
| Returns | |
|---|---|
String |
|
int getFieldCount ()
[icu] Returns the number of fields defined by this calendar. Valid field
arguments to set() and get() are
0..getFieldCount()-1.
| Returns | |
|---|---|
int |
|
int getFirstDayOfWeek ()
Returns what the first day of the week is,
where 1 = SUNDAY and 7 = SATURDAY.
e.g., Sunday in US, Monday in France
| Returns | |
|---|---|
int |
the first day of the week, where 1 = SUNDAY and 7 = SATURDAY.
|
int getGreatestMinimum (int field)
Returns the highest minimum value for the given field if varies. Otherwise same as getMinimum(). For Gregorian, no difference.
| Parameters | |
|---|---|
field |
int:
the given time field. |
| Returns | |
|---|---|
int |
the highest minimum value for the given time field. |
Calendar getInstance ()
Returns a calendar using the default time zone and locale.
| Returns | |
|---|---|
Calendar |
a Calendar. |
Calendar getInstance (Locale aLocale)
Returns a calendar using the default time zone and specified locale.
| Parameters | |
|---|---|
aLocale |
Locale:
the locale for the week data |
| Returns | |
|---|---|
Calendar |
a Calendar. |
Calendar getInstance (TimeZone zone, Locale aLocale)
Returns a calendar with the specified time zone and locale.
| Parameters | |
|---|---|
zone |
TimeZone:
the time zone to use |
aLocale |
Locale:
the locale for the week data |
| Returns | |
|---|---|
Calendar |
a Calendar. |
Calendar getInstance (TimeZone zone, ULocale locale)
Returns a calendar with the specified time zone and locale.
| Parameters | |
|---|---|
zone |
TimeZone:
the time zone to use |
locale |
ULocale:
the ulocale for the week data |
| Returns | |
|---|---|
Calendar |
a Calendar. |
Calendar getInstance (TimeZone zone)
Returns a calendar using the specified time zone and default locale.
| Parameters | |
|---|---|
zone |
TimeZone:
the time zone to use |
| Returns | |
|---|---|
Calendar |
a Calendar. |
Calendar getInstance (ULocale locale)
Returns a calendar using the default time zone and specified locale.
| Parameters | |
|---|---|
locale |
ULocale:
the ulocale for the week data |
| Returns | |
|---|---|
Calendar |
a Calendar. |
String[] getKeywordValuesForLocale (String key, ULocale locale, boolean commonlyUsed)
[icu] Given a key and a locale, returns an array of string values in a preferred order that would make a difference. These are all and only those values where the open (creation) of the service with the locale formed from the input locale plus input keyword and that value has different behavior than creation with the input locale alone.
| Parameters | |
|---|---|
key |
String:
one of the keys supported by this service. For now, only
"calendar" is supported. |
locale |
ULocale:
the locale |
commonlyUsed |
boolean:
if set to true it will return only commonly used values
with the given locale in preferred order. Otherwise,
it will return all the available values for the locale. |
| Returns | |
|---|---|
String[] |
an array of string values for the given key and the locale. |
int getLeastMaximum (int field)
Returns the lowest maximum value for the given field if varies. Otherwise same as getMaximum(). e.g., for Gregorian DAY_OF_MONTH, 28.
| Parameters | |
|---|---|
field |
int:
the given time field. |
| Returns | |
|---|---|
int |
the lowest maximum value for the given time field. |
int getMaximum (int field)
Returns the maximum value for the given time field. e.g. for Gregorian DAY_OF_MONTH, 31.
| Parameters | |
|---|---|
field |
int:
the given time field. |
| Returns | |
|---|---|
int |
the maximum value for the given time field. |
int getMinimalDaysInFirstWeek ()
Returns what the minimal days required in the first week of the year are. That is, if the first week is defined as one that contains the first day of the first month of a year, getMinimalDaysInFirstWeek returns 1. If the minimal days required must be a full week, getMinimalDaysInFirstWeek returns 7.
| Returns | |
|---|---|
int |
the minimal days required in the first week of the year. |
int getMinimum (int field)
Returns the minimum value for the given time field. e.g., for Gregorian DAY_OF_MONTH, 1.
| Parameters | |
|---|---|
field |
int:
the given time field. |
| Returns | |
|---|---|
int |
the minimum value for the given time field. |
int getRepeatedWallTimeOption ()
[icu]Gets the behavior for handling wall time repeating multiple times at negative time zone offset transitions.
| Returns | |
|---|---|
int |
the behavior for handling repeating wall time, either
WALLTIME_FIRST or WALLTIME_LAST. |
int getSkippedWallTimeOption ()
[icu]Gets the behavior for handling skipped wall time at positive time zone offset transitions.
| Returns | |
|---|---|
int |
the behavior for handling skipped wall time, one of
WALLTIME_FIRST, WALLTIME_LAST and WALLTIME_NEXT_VALID. |
Date getTime ()
Returns this Calendar's current time.
| Returns | |
|---|---|
Date |
the current time. |
long getTimeInMillis ()
Returns this Calendar's current time as a long.
| Returns | |
|---|---|
long |
the current time as UTC milliseconds from the epoch. |
TimeZone getTimeZone ()
Returns the time zone.
| Returns | |
|---|---|
TimeZone |
the time zone object associated with this calendar. |
String getType ()
[icu] Returns the calendar type name string for this Calendar object. The returned string is the legacy ICU calendar attribute value, for example, "gregorian" or "japanese".
See type="old type name" for the calendar attribute of locale IDs at http://www.unicode.org/reports/tr35/#Key_Type_Definitions
| Returns | |
|---|---|
String |
legacy calendar type name string |
Calendar.WeekData getWeekData ()
[icu] Return simple, immutable struct-like class for access to the weekend data in this calendar.
| Returns | |
|---|---|
Calendar.WeekData |
the WeekData for this calendar. |
Calendar.WeekData getWeekDataForRegion (String region)
[icu] Return simple, immutable struct-like class for access to the CLDR weekend data.
| Parameters | |
|---|---|
region |
String:
The input region. The results are undefined if the region code is not valid. |
| Returns | |
|---|---|
Calendar.WeekData |
the WeekData for the input region. It is never null. |
int hashCode ()
Returns a hash code for this calendar.
| Returns | |
|---|---|
int |
a hash code value for this object. |
boolean isEquivalentTo (Calendar other)
[icu] Returns true if the given Calendar object is equivalent to this one. An equivalent Calendar will behave exactly as this one does, but it may be set to a different time. By contrast, for the equals() method to return true, the other Calendar must be set to the same time.
| Parameters | |
|---|---|
other |
Calendar:
the Calendar to be compared with this Calendar
|
| Returns | |
|---|---|
boolean |
|
boolean isLenient ()
Tell whether date/time interpretation is to be lenient.
| Returns | |
|---|---|
boolean |
|
boolean isSet (int field)
Determines if the given time field has a value set.
| Parameters | |
|---|---|
field |
int
|
| Returns | |
|---|---|
boolean |
true if the given time field has a value set; false otherwise. |
boolean isWeekend (Date date)
[icu] Returns true if the given date and time is in the weekend in this calendar system. Equivalent to calling setTime() followed by isWeekend(). Note: This method changes the time this calendar is set to.
| Parameters | |
|---|---|
date |
Date:
the date and time |
| Returns | |
|---|---|
boolean |
true if the given date and time is part of the weekend |
boolean isWeekend ()
[icu] Returns true if this Calendar's current date and time is in the weekend in this calendar system.
| Returns | |
|---|---|
boolean |
true if the given date and time is part of the weekend |
void roll (int field,
boolean up)
Rolls (up/down) a single unit of time on the given field. If the field is rolled past its maximum allowable value, it will "wrap" back to its minimum and continue rolling. For example, to roll the current date up by one day, you can call:
roll(
DATE, true)
When rolling on the YEAR field, it will roll the year
value in the range between 1 and the value returned by calling
getMaximum(YEAR).
When rolling on certain fields, the values of other fields may conflict and
need to be changed. For example, when rolling the MONTH field
for the Gregorian date 1/31/96 upward, the DAY_OF_MONTH field
must be adjusted so that the result is 2/29/96 rather than the invalid
2/31/96.
Rolling up always means rolling forward in time (unless the limit of the field is reached, in which case it may pin or wrap), so for the Gregorian calendar, starting with 100 BC and rolling the year up results in 99 BC. When eras have a definite beginning and end (as in the Chinese calendar, or as in most eras in the Japanese calendar) then rolling the year past either limit of the era will cause the year to wrap around. When eras only have a limit at one end, then attempting to roll the year past that limit will result in pinning the year at that limit. Note that for most calendars in which era 0 years move forward in time (such as Buddhist, Hebrew, or Islamic), it is possible for add or roll to result in negative years for era 0 (that is the only way to represent years before the calendar epoch in such calendars).
Note: Calling roll(field, true) N times is not necessarily equivalent to calling roll(field, N). For example, imagine that you start with the date Gregorian date January 31, 1995. If you call roll(Calendar.MONTH, 2), the result will be March 31, 1995. But if you call roll(Calendar.MONTH, true), the result will be February 28, 1995. Calling it one more time will give March 28, 1995, which is usually not the desired result.
Note: You should always use roll and add rather than attempting to perform arithmetic operations directly on the fields of a Calendar. It is quite possible for Calendar subclasses to have fields with non-linear behavior, for example missing months or days during non-leap years. The subclasses' add and roll methods will take this into account, while simple arithmetic manipulations may give invalid results.
| Parameters | |
|---|---|
field |
int:
the calendar field to roll. |
up |
boolean:
indicates if the value of the specified time field is to be
rolled up or rolled down. Use true if rolling up,
false otherwise. |
| Throws | |
|---|---|
IllegalArgumentException |
if the field is invalid or refers to a field that cannot be handled by this method. |
See also:
void roll (int field,
int amount)
Rolls (up/down) a specified amount time on the given field. For
example, to roll the current date up by three days, you can call
roll(Calendar.DATE, 3). If the
field is rolled past its maximum allowable value, it will "wrap" back
to its minimum and continue rolling.
For example, calling roll(Calendar.DATE, 10)
on a Gregorian calendar set to 4/25/96 will result in the date 4/5/96.
When rolling on certain fields, the values of other fields may conflict and
need to be changed. For example, when rolling the MONTH field
for the Gregorian date 1/31/96 by +1, the DAY_OF_MONTH field
must be adjusted so that the result is 2/29/96 rather than the invalid
2/31/96.
Rolling by a positive value always means rolling forward in time (unless the limit of the field is reached, in which case it may pin or wrap), so for the Gregorian calendar, starting with 100 BC and rolling the year by + 1 results in 99 BC. When eras have a definite beginning and end (as in the Chinese calendar, or as in most eras in the Japanese calendar) then rolling the year past either limit of the era will cause the year to wrap around. When eras only have a limit at one end, then attempting to roll the year past that limit will result in pinning the year at that limit. Note that for most calendars in which era 0 years move forward in time (such as Buddhist, Hebrew, or Islamic), it is possible for add or roll to result in negative years for era 0 (that is the only way to represent years before the calendar epoch in such calendars).
[icu] Note: the ICU implementation of this method is able to roll
all fields except for ERA, DST_OFFSET,
and ZONE_OFFSET. Subclasses may, of course, add support for
additional fields in their overrides of roll.
Note: You should always use roll and add rather than attempting to perform arithmetic operations directly on the fields of a Calendar. It is quite possible for Calendar subclasses to have fields with non-linear behavior, for example missing months or days during non-leap years. The subclasses' add and roll methods will take this into account, while simple arithmetic manipulations may give invalid results.
Subclassing:
This implementation of roll assumes that the behavior of the
field is continuous between its minimum and maximum, which are found by
calling getActualMinimum and getActualMaximum.
For most such fields, simple addition, subtraction, and modulus operations
are sufficient to perform the roll. For week-related fields,
the results of getFirstDayOfWeek and
getMinimalDaysInFirstWeek are also necessary.
Subclasses can override these two methods if their values differ from the defaults.
Subclasses that have fields for which the assumption of continuity breaks
down must overide roll to handle those fields specially.
For example, in the Hebrew calendar the month "Adar I"
only occurs in leap years; in other years the calendar jumps from
Shevat (month #4) to Adar (month #6). The
HebrewCalendar.roll method takes this into account,
so that rolling the month of Shevat by one gives the proper result (Adar) in a
non-leap year.
| Parameters | |
|---|---|
field |
int:
the calendar field to roll. |
amount |
int:
the amount by which the field should be rolled. |
| Throws | |
|---|---|
IllegalArgumentException |
if the field is invalid or refers to a field that cannot be handled by this method. |
See also:
void set (int year,
int month,
int date,
int hour,
int minute,
int second)
Sets the values for the fields year, month, date, hour, minute, and second.
Previous values of other fields are retained. If this is not desired,
call clear() first.
| Parameters | |
|---|---|
year |
int:
the value used to set the YEAR time field. |
month |
int:
the value used to set the MONTH time field.
Month value is 0-based. e.g., 0 for January. |
date |
int:
the value used to set the DATE time field. |
hour |
int:
the value used to set the HOUR_OF_DAY time field. |
minute |
int:
the value used to set the MINUTE time field. |
second |
int:
the value used to set the SECOND time field.
|
void set (int year,
int month,
int date,
int hour,
int minute)
Sets the values for the fields year, month, date, hour, and minute.
Previous values of other fields are retained. If this is not desired,
call clear() first.
| Parameters | |
|---|---|
year |
int:
the value used to set the YEAR time field. |
month |
int:
the value used to set the MONTH time field.
Month value is 0-based. e.g., 0 for January. |
date |
int:
the value used to set the DATE time field. |
hour |
int:
the value used to set the HOUR_OF_DAY time field. |
minute |
int:
the value used to set the MINUTE time field.
|
void set (int field,
int value)
Sets the time field with the given value.
| Parameters | |
|---|---|
field |
int:
the given time field. |
value |
int:
the value to be set for the given time field.
|
void set (int year,
int month,
int date)
Sets the values for the fields year, month, and date.
Previous values of other fields are retained. If this is not desired,
call clear() first.
| Parameters | |
|---|---|
year |
int:
the value used to set the YEAR time field. |
month |
int:
the value used to set the MONTH time field.
Month value is 0-based. e.g., 0 for January. |
date |
int:
the value used to set the DATE time field.
|
void setFirstDayOfWeek (int value)
Sets what the first day of the week is,
where 1 = SUNDAY and 7 = SATURDAY.
| Parameters | |
|---|---|
value |
int:
the given first day of the week, where 1 = SUNDAY and 7 = SATURDAY.
|
void setLenient (boolean lenient)
Specify whether or not date/time interpretation is to be lenient. With lenient interpretation, a date such as "February 942, 1996" will be treated as being equivalent to the 941st day after February 1, 1996. With strict interpretation, such dates will cause an exception to be thrown.
| Parameters | |
|---|---|
lenient |
boolean
|
See also:
void setMinimalDaysInFirstWeek (int value)
Sets what the minimal days required in the first week of the year are. For example, if the first week is defined as one that contains the first day of the first month of a year, call the method with value 1. If it must be a full week, use value 7.
| Parameters | |
|---|---|
value |
int:
the given minimal days required in the first week
of the year.
|
void setRepeatedWallTimeOption (int option)
[icu]Sets the behavior for handling wall time repeating multiple times
at negative time zone offset transitions. For example, 1:30 AM on
November 6, 2011 in US Eastern time (Ameirca/New_York) occurs twice;
1:30 AM EDT, then 1:30 AM EST one hour later. When WALLTIME_FIRST
is used, the wall time 1:30AM in this example will be interpreted as 1:30 AM EDT
(first occurrence). When WALLTIME_LAST is used, it will be
interpreted as 1:30 AM EST (last occurrence). The default value is
WALLTIME_LAST.
| Parameters | |
|---|---|
option |
int:
the behavior for handling repeating wall time, either
WALLTIME_FIRST or WALLTIME_LAST. |
| Throws | |
|---|---|
IllegalArgumentException |
when option is neither
WALLTIME_FIRST nor WALLTIME_LAST. |
void setSkippedWallTimeOption (int option)
[icu]Sets the behavior for handling skipped wall time at positive time zone offset
transitions. For example, 2:30 AM on March 13, 2011 in US Eastern time (America/New_York)
does not exist because the wall time jump from 1:59 AM EST to 3:00 AM EDT. When
WALLTIME_FIRST is used, 2:30 AM is interpreted as 30 minutes before 3:00 AM
EDT, therefore, it will be resolved as 1:30 AM EST. When WALLTIME_LAST
is used, 2:30 AM is interpreted as 31 minutes after 1:59 AM EST, therefore, it will be
resolved as 3:30 AM EDT. When WALLTIME_NEXT_VALID is used, 2:30 AM will
be resolved as next valid wall time, that is 3:00 AM EDT. The default value is
WALLTIME_LAST.
Note:This option is effective only when this calendar is lenient.
When the calendar is strict, such non-existing wall time will cause an exception.
| Parameters | |
|---|---|
option |
int:
the behavior for handling skipped wall time at positive time zone
offset transitions, one of WALLTIME_FIRST, WALLTIME_LAST and
WALLTIME_NEXT_VALID. |
| Throws | |
|---|---|
IllegalArgumentException |
when option is not any of
WALLTIME_FIRST, WALLTIME_LAST and WALLTIME_NEXT_VALID. |
void setTime (Date date)
Sets this Calendar's current time with the given Date.
Note: Calling setTime with
Date(Long.MAX_VALUE) or Date(Long.MIN_VALUE)
may yield incorrect field values from get(int).
| Parameters | |
|---|---|
date |
Date:
the given Date.
|
void setTimeInMillis (long millis)
Sets this Calendar's current time from the given long value. An IllegalIcuArgumentException is thrown when millis is outside the range permitted by a Calendar object when in strict mode. When in lenient mode the out of range values are pinned to their respective min/max.
| Parameters | |
|---|---|
millis |
long:
the new time in UTC milliseconds from the epoch.
|
void setTimeZone (TimeZone value)
Sets the time zone with the given time zone value.
| Parameters | |
|---|---|
value |
TimeZone:
the given time zone.
|
Calendar setWeekData (Calendar.WeekData wdata)
[icu] Set data in this calendar based on the WeekData input.
| Parameters | |
|---|---|
wdata |
Calendar.WeekData:
The week data to use |
| Returns | |
|---|---|
Calendar |
this, for chaining |
String toString ()
Returns a string representation of this calendar. This method
is intended to be used only for debugging purposes, and the
format of the returned string may vary between implementations.
The returned string may be empty but may not be null.
| Returns | |
|---|---|
String |
a string representation of this calendar. |
void computeFields ()
Converts the current millisecond time value time to
field values in fields[]. This synchronizes the time
field values with a new time that is set for the calendar. The time
is not recomputed first; to recompute the time, then the
fields, call the complete method.
See also:
void computeGregorianFields (int julianDay)
Compute the Gregorian calendar year, month, and day of month from the Julian day. These values are not stored in fields, but in member variables gregorianXxx. They are used for time zone computations and by subclasses that are Gregorian derivatives. Subclasses may call this method to perform a Gregorian calendar millis->fields computation. To perform a Gregorian calendar fields->millis computation, call computeGregorianMonthStart().
| Parameters | |
|---|---|
julianDay |
int
|
See also:
int computeGregorianMonthStart (int year,
int month)
Compute the Julian day of a month of the Gregorian calendar. Subclasses may call this method to perform a Gregorian calendar fields->millis computation. To perform a Gregorian calendar millis->fields computation, call computeGregorianFields().
| Parameters | |
|---|---|
year |
int:
extended Gregorian year |
month |
int:
zero-based Gregorian month |
| Returns | |
|---|---|
int |
the Julian day number of the day before the first day of the given month in the given extended year |
See also:
int computeJulianDay ()
Compute the Julian day number as specified by this calendar's fields.
| Returns | |
|---|---|
int |
|
int computeMillisInDay ()
Compute the milliseconds in the day from the fields. This is a value from 0 to 23:59:59.999 inclusive, unless fields are out of range, in which case it can be an arbitrary value. This value reflects local zone wall time.
| Returns | |
|---|---|
int |
|
void computeTime ()
Converts the current field values in fields[] to the
millisecond time value time.
int computeZoneOffset (long millis,
int millisInDay)
This method can assume EXTENDED_YEAR has been set.
| Parameters | |
|---|---|
millis |
long:
milliseconds of the date fields (local midnight millis) |
millisInDay |
int:
milliseconds of the time fields; may be out
or range. |
| Returns | |
|---|---|
int |
total zone offset (raw + DST) for the given moment |
String fieldName (int field)
Returns a string name for a field, for debugging and exceptions.
| Parameters | |
|---|---|
field |
int
|
| Returns | |
|---|---|
String |
|
int floorDivide (int numerator,
int denominator,
int[] remainder)
Divide two integers, returning the floor of the quotient, and the modulus remainder.
Unlike the built-in division, this is mathematically well-behaved.
E.g., -1/4 => 0 and -1%4 => -1,
but floorDivide(-1,4) => -1 with remainder[0] => 3.
| Parameters | |
|---|---|
numerator |
int:
the numerator |
denominator |
int:
a divisor which must be > 0 |
remainder |
int:
an array of at least one element in which the value
numerator mod denominator is returned. Unlike numerator
% denominator, this will always be non-negative. |
| Returns | |
|---|---|
int |
the floor of the quotient. |
int floorDivide (int numerator,
int denominator)
Divide two integers, returning the floor of the quotient.
Unlike the built-in division, this is mathematically well-behaved.
E.g., -1/4 => 0
but floorDivide(-1,4) => -1.
| Parameters | |
|---|---|
numerator |
int:
the numerator |
denominator |
int:
a divisor which must be > 0 |
| Returns | |
|---|---|
int |
the floor of the quotient. |
long floorDivide (long numerator,
long denominator)
Divide two long integers, returning the floor of the quotient.
Unlike the built-in division, this is mathematically well-behaved.
E.g., -1/4 => 0
but floorDivide(-1,4) => -1.
| Parameters | |
|---|---|
numerator |
long:
the numerator |
denominator |
long:
a divisor which must be > 0 |
| Returns | |
|---|---|
long |
the floor of the quotient. |
int floorDivide (long numerator,
int denominator,
int[] remainder)
Divide two integers, returning the floor of the quotient, and the modulus remainder.
Unlike the built-in division, this is mathematically well-behaved.
E.g., -1/4 => 0 and -1%4 => -1,
but floorDivide(-1,4) => -1 with remainder[0] => 3.
| Parameters | |
|---|---|
numerator |
long:
the numerator |
denominator |
int:
a divisor which must be > 0 |
remainder |
int:
an array of at least one element in which the value
numerator mod denominator is returned. Unlike numerator
% denominator, this will always be non-negative. |
| Returns | |
|---|---|
int |
the floor of the quotient. |
int[][][] getFieldResolutionTable ()
Returns the field resolution array for this calendar. Calendars that define additional fields or change the semantics of existing fields should override this method to adjust the field resolution semantics accordingly. Other subclasses should not override this method.
| Returns | |
|---|---|
int[][][] |
|
See also:
int getGregorianDayOfMonth ()
Returns the day of month (1-based) on the Gregorian calendar as
computed by computeGregorianFields().
| Returns | |
|---|---|
int |
|
See also:
int getGregorianDayOfYear ()
Returns the day of year (1-based) on the Gregorian calendar as
computed by computeGregorianFields().
| Returns | |
|---|---|
int |
|
See also:
int getGregorianMonth ()
Returns the month (0-based) on the Gregorian calendar as computed by
computeGregorianFields().
| Returns | |
|---|---|
int |
|
See also:
int getGregorianYear ()
Returns the extended year on the Gregorian calendar as computed by
computeGregorianFields().
| Returns | |
|---|---|
int |
|
See also:
int getLimit (int field,
int limitType)
Returns a limit for a field.
| Parameters | |
|---|---|
field |
int:
the field, from 0..getFieldCount()-1 |
limitType |
int:
the type specifier for the limit |
| Returns | |
|---|---|
int |
|
int getStamp (int field)
Returns the timestamp of a field.
| Parameters | |
|---|---|
field |
int
|
| Returns | |
|---|---|
int |
|
int gregorianMonthLength (int y,
int m)
Returns the length of a month of the Gregorian calendar.
| Parameters | |
|---|---|
y |
int:
the extended year |
m |
int:
the 0-based month number |
| Returns | |
|---|---|
int |
the number of days in the given month |
int gregorianPreviousMonthLength (int y,
int m)
Returns the length of a previous month of the Gregorian calendar.
| Parameters | |
|---|---|
y |
int:
the extended year |
m |
int:
the 0-based month number |
| Returns | |
|---|---|
int |
the number of days in the month previous to the given month |
void handleComputeFields (int julianDay)
Subclasses may override this method to compute several fields specific to each calendar system. These are:
In addition, subclasses should compute any subclass-specific fields, that is, fields from BASE_FIELD_COUNT to getFieldCount() - 1.
The default implementation in Calendar implements
a pure proleptic Gregorian calendar.
| Parameters | |
|---|---|
julianDay |
int
|
int handleComputeJulianDay (int bestField)
Subclasses may override this. This method calls handleGetMonthLength() to obtain the calendar-specific month length.
| Parameters | |
|---|---|
bestField |
int
|
| Returns | |
|---|---|
int |
|
int handleComputeMonthStart (int eyear,
int month,
boolean useMonth)
Returns the Julian day number of day before the first day of the given month in the given extended year. Subclasses should override this method to implement their calendar system.
| Parameters | |
|---|---|
eyear |
int:
the extended year |
month |
int:
the zero-based month, or 0 if useMonth is false |
useMonth |
boolean:
if false, compute the day before the first day of
the given year, otherwise, compute the day before the first day of
the given month |
| Returns | |
|---|---|
int |
the Julian day number of the day before the first day of the given month and year |
int[] handleCreateFields ()
Subclasses that use additional fields beyond those defined in
Calendar should override this method to return an
int[] array of the appropriate length. The length
must be at least BASE_FIELD_COUNT and no more than
MAX_FIELD_COUNT.
| Returns | |
|---|---|
int[] |
|
DateFormat handleGetDateFormat (String pattern, String override, Locale locale)
Creates a DateFormat appropriate to this calendar.
This is a framework method for subclasses to override. This method
is responsible for creating the calendar-specific DateFormat and
DateFormatSymbols objects as needed.
| Parameters | |
|---|---|
pattern |
String:
the pattern, specific to the DateFormat
subclass |
override |
String:
The override string. A numbering system override string can take one of the following forms:
1). If just a numbering system name is specified, it applies to all numeric fields in the date format pattern.
2). To specify an alternate numbering system on a field by field basis, use the field letters from the pattern
followed by an = sign, followed by the numbering system name. For example, to specify that just the year
be formatted using Hebrew digits, use the override "y=hebr". Multiple overrides can be specified in a single
string by separating them with a semi-colon. For example, the override string "m=thai;y=deva" would format using
Thai digits for the month and Devanagari digits for the year. |
locale |
Locale:
the locale for which the symbols should be drawn |
| Returns | |
|---|---|
DateFormat |
a DateFormat appropriate to this calendar
|
DateFormat handleGetDateFormat (String pattern, ULocale locale)
Creates a DateFormat appropriate to this calendar.
This is a framework method for subclasses to override. This method
is responsible for creating the calendar-specific DateFormat and
DateFormatSymbols objects as needed.
| Parameters | |
|---|---|
pattern |
String:
the pattern, specific to the DateFormat
subclass |
locale |
ULocale:
the locale for which the symbols should be drawn |
| Returns | |
|---|---|
DateFormat |
a DateFormat appropriate to this calendar
|
DateFormat handleGetDateFormat (String pattern, Locale locale)
Creates a DateFormat appropriate to this calendar.
This is a framework method for subclasses to override. This method
is responsible for creating the calendar-specific DateFormat and
DateFormatSymbols objects as needed.
| Parameters | |
|---|---|
pattern |
String:
the pattern, specific to the DateFormat
subclass |
locale |
Locale:
the locale for which the symbols should be drawn |
| Returns | |
|---|---|
DateFormat |
a DateFormat appropriate to this calendar
|
int handleGetExtendedYear ()
Returns the extended year defined by the current fields. This will use the EXTENDED_YEAR field or the YEAR and supra-year fields (such as ERA) specific to the calendar system, depending on which set of fields is newer.
| Returns | |
|---|---|
int |
the extended year |
int handleGetLimit (int field,
int limitType)
Subclass API for defining limits of different types. Subclasses must implement this method to return limits for the following fields:
ERA YEAR MONTH WEEK_OF_YEAR WEEK_OF_MONTH DAY_OF_MONTH DAY_OF_YEAR DAY_OF_WEEK_IN_MONTH YEAR_WOY EXTENDED_YEAR
| Parameters | |
|---|---|
field |
int:
one of the above field numbers |
limitType |
int:
one of MINIMUM, GREATEST_MINIMUM,
LEAST_MAXIMUM, or MAXIMUM
|
| Returns | |
|---|---|
int |
|
int handleGetMonthLength (int extendedYear,
int month)
Returns the number of days in the given month of the given extended year of this calendar system. Subclasses should override this method if they can provide a more correct or more efficient implementation than the default implementation in Calendar.
| Parameters | |
|---|---|
extendedYear |
int
|
month |
int
|
| Returns | |
|---|---|
int |
|
int handleGetYearLength (int eyear)
Returns the number of days in the given extended year of this calendar system. Subclasses should override this method if they can provide a more correct or more efficient implementation than the default implementation in Calendar.
| Parameters | |
|---|---|
eyear |
int
|
| Returns | |
|---|---|
int |
|
int internalGet (int field)
Returns the value for a given time field. This is an internal method for subclasses that does not trigger any calculations.
| Parameters | |
|---|---|
field |
int:
the given time field. |
| Returns | |
|---|---|
int |
the value for the given time field. |
int internalGet (int field,
int defaultValue)
Returns the value for a given time field, or return the given default value if the field is not set. This is an internal method for subclasses that does not trigger any calculations.
| Parameters | |
|---|---|
field |
int:
the given time field. |
defaultValue |
int:
value to return if field is not set |
| Returns | |
|---|---|
int |
the value for the given time field of defaultValue if the field is unset |
long internalGetTimeInMillis ()
Returns the current milliseconds without recomputing.
| Returns | |
|---|---|
long |
|
void internalSet (int field,
int value)
Set a field to a value. Subclasses should use this method when
computing fields. It sets the time stamp in the
stamp[] array to INTERNALLY_SET. If a
field that may not be set by subclasses is passed in, an
IllegalArgumentException is thrown. This prevents
subclasses from modifying fields that are intended to be
calendar-system invariant.
| Parameters | |
|---|---|
field |
int
|
value |
int
|
boolean isGregorianLeapYear (int year)
Determines if the given year is a leap year. Returns true if the given year is a leap year.
| Parameters | |
|---|---|
year |
int:
the given year. |
| Returns | |
|---|---|
boolean |
true if the given year is a leap year; false otherwise. |
int julianDayToDayOfWeek (int julian)
Returns the day of week, from SUNDAY to SATURDAY, given a Julian day.
| Parameters | |
|---|---|
julian |
int
|
| Returns | |
|---|---|
int |
|
long julianDayToMillis (int julian)
Converts Julian day to time as milliseconds.
| Parameters | |
|---|---|
julian |
int:
the given Julian day number. |
| Returns | |
|---|---|
long |
time as milliseconds. |
int millisToJulianDay (long millis)
Converts time as milliseconds to Julian day.
| Parameters | |
|---|---|
millis |
long:
the given milliseconds. |
| Returns | |
|---|---|
int |
the Julian day number. |
int newerField (int defaultField,
int alternateField)
Returns the field that is newer, either defaultField, or alternateField. If neither is newer or neither is set, return defaultField.
| Parameters | |
|---|---|
defaultField |
int
|
alternateField |
int
|
| Returns | |
|---|---|
int |
|
int newestStamp (int first,
int last,
int bestStampSoFar)
Returns the newest stamp of a given range of fields.
| Parameters | |
|---|---|
first |
int
|
last |
int
|
bestStampSoFar |
int
|
| Returns | |
|---|---|
int |
|
void pinField (int field)
Adjust the specified field so that it is within
the allowable range for the date to which this calendar is set.
For example, in a Gregorian calendar pinning the DAY_OF_MONTH
field for a calendar set to April 31 would cause it to be set
to April 30.
Subclassing:
This utility method is intended for use by subclasses that need to implement
their own overrides of roll and add.
Note:
pinField is implemented in terms of
getActualMinimum
and getActualMaximum. If either of those methods uses
a slow, iterative algorithm for a particular field, it would be
unwise to attempt to call pinField for that field. If you
really do need to do so, you should override this method to do
something more efficient for that field.
| Parameters | |
|---|---|
field |
int:
The calendar field whose value should be pinned. |
void prepareGetActual (int field,
boolean isMinimum)
Prepare this calendar for computing the actual minimum or maximum. This method modifies this calendar's fields; it is called on a temporary calendar.
Rationale: The semantics of getActualXxx() is to return the maximum or minimum value that the given field can take, taking into account other relevant fields. In general these other fields are larger fields. For example, when computing the actual maximum DAY_OF_MONTH, the current value of DAY_OF_MONTH itself is ignored, as is the value of any field smaller.
The time fields all have fixed minima and maxima, so we don't need to worry about them. This also lets us set the MILLISECONDS_IN_DAY to zero to erase any effects the time fields might have when computing date fields.
DAY_OF_WEEK is adjusted specially for the WEEK_OF_MONTH and WEEK_OF_YEAR fields to ensure that they are computed correctly.
| Parameters | |
|---|---|
field |
int
|
isMinimum |
boolean
|
int resolveFields (int[][][] precedenceTable)
Given a precedence table, return the newest field combination in the table, or -1 if none is found.
The precedence table is a 3-dimensional array of integers. It may be thought of as an array of groups. Each group is an array of lines. Each line is an array of field numbers. Within a line, if all fields are set, then the time stamp of the line is taken to be the stamp of the most recently set field. If any field of a line is unset, then the line fails to match. Within a group, the line with the newest time stamp is selected. The first field of the line is returned to indicate which line matched.
In some cases, it may be desirable to map a line to field that
whose stamp is NOT examined. For example, if the best field is
DAY_OF_WEEK then the DAY_OF_WEEK_IN_MONTH algorithm may be used. In
order to do this, insert the value REMAP_RESOLVE | F at
the start of the line, where F is the desired return
field value. This field will NOT be examined; it only determines
the return value if the other fields in the line are the newest.
If all lines of a group contain at least one unset field, then no line will match, and the group as a whole will fail to match. In that case, the next group will be processed. If all groups fail to match, then -1 is returned.
| Parameters | |
|---|---|
precedenceTable |
int
|
| Returns | |
|---|---|
int |
|
void validateField (int field)
Validate a single field of this calendar. Subclasses should
override this method to validate any calendar-specific fields.
Generic fields can be handled by
Calendar.validateField().
| Parameters | |
|---|---|
field |
int
|
See also:
void validateField (int field,
int min,
int max)
Validate a single field of this calendar given its minimum and
maximum allowed value. If the field is out of range, throw a
descriptive IllegalArgumentException. Subclasses may
use this method in their implementation of validateField(int).
| Parameters | |
|---|---|
field |
int
|
min |
int
|
max |
int
|
void validateFields ()
Ensure that each field is within its valid range by calling validateField(int) on each field that has been set. This method
should only be called if this calendar is not lenient.
See also:
int weekNumber (int desiredDay,
int dayOfPeriod,
int dayOfWeek)
Returns the week number of a day, within a period. This may be the week number in
a year or the week number in a month. Usually this will be a value >= 1, but if
some initial days of the period are excluded from week 1, because
getMinimalDaysInFirstWeek is > 1, then
the week number will be zero for those
initial days. This method requires the day number and day of week for some
known date in the period in order to determine the day of week
on the desired day.
Subclassing:
This method is intended for use by subclasses in implementing their
computeTime and/or computeFields methods.
It is often useful in getActualMinimum and
getActualMaximum as well.
This variant is handy for computing the week number of some other day of a period (often the first or last day of the period) when its day of the week is not known but the day number and day of week for some other day in the period (e.g. the current date) is known.
| Parameters | |
|---|---|
desiredDay |
int:
The DAY_OF_YEAR or
DAY_OF_MONTH whose week number is desired.
Should be 1 for the first day of the period. |
dayOfPeriod |
int:
The DAY_OF_YEAR
or DAY_OF_MONTH for a day in the period whose
DAY_OF_WEEK is specified by the
dayOfWeek parameter.
Should be 1 for first day of period. |
dayOfWeek |
int:
The DAY_OF_WEEK for the day
corresponding to the dayOfPeriod parameter.
1-based with 1=Sunday. |
| Returns | |
|---|---|
int |
The week number (one-based), or zero if the day falls before
the first week because
getMinimalDaysInFirstWeek
is more than one.
|
int weekNumber (int dayOfPeriod,
int dayOfWeek)
Returns the week number of a day, within a period. This may be the week number in
a year, or the week number in a month. Usually this will be a value >= 1, but if
some initial days of the period are excluded from week 1, because
getMinimalDaysInFirstWeek is > 1,
then the week number will be zero for those
initial days. This method requires the day of week for the given date in order to
determine the result.
Subclassing:
This method is intended for use by subclasses in implementing their
computeTime and/or computeFields methods.
It is often useful in getActualMinimum and
getActualMaximum as well.
| Parameters | |
|---|---|
dayOfPeriod |
int:
The DAY_OF_YEAR or
DAY_OF_MONTH whose week number is desired.
Should be 1 for the first day of the period. |
dayOfWeek |
int:
The DAY_OF_WEEK for the day
corresponding to the dayOfPeriod parameter.
1-based with 1=Sunday. |
| Returns | |
|---|---|
int |
The week number (one-based), or zero if the day falls before
the first week because
getMinimalDaysInFirstWeek
is more than one.
|