com.ibm.icu.util
public abstract class Calendar extends Object implements Serializable, Cloneable, Comparable
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
{@link Date}
for information about the Date
class.)
Note: This class is similar, but not identical, to the class
java.util.Calendar
. Changes are detailed below.
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", and "japanese". For
example:
will return an instance of JapaneseCalendar (using en_US conventions for minimum days in first week, start day of week, et cetera).Calendar cal = Calendar.getInstance(new ULocale("en_US@calendar=japanese"));
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, two 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), or
there may be inconsistent information (such as "Tuesday, July 15, 1996" --
July 15, 1996 is actually a Monday).
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
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 {@link 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
f
after the call minus the value of fieldf
before 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
f
is changed, then its value is adjusted to be as close as possible to its expected value. A smaller field represents a smaller unit of time.HOUR
is a smaller field 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_MONTH
is 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 {@link #roll roll} and {@link #add 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 com.ibm.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 {@link #internalSet} and
{@link #internalGet}. Motivation: Subclasses should
not directly access data members.time
long word is private
now
instead of protected
. Subclasses may access it using
the method {@link #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
({@link #add(int, int) add} and {@link #roll(int, int) 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 {@link #handleComputeFields}). 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
{@link #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
constants {@link #MIN_DATE},
{@link #MAX_DATE}, {@link #MIN_MILLIS},
{@link #MAX_MILLIS}, {@link #MIN_JULIAN}, and
{@link #MAX_JULIAN} should be used. Motivation: With
the addition of the {@link #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
.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 {@link #ERA}, {@link #YEAR},
{@link #EXTENDED_YEAR}, {@link #MONTH},
{@link #DAY_OF_MONTH}, and {@link #DAY_OF_YEAR} fields are
computed by the subclass, based on the Julian day. All other fields
are computed by Calendar
.
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.
Other methods
limitType
. This method only needs to handle the
fields {@link #ERA}, {@link #YEAR}, {@link #MONTH},
{@link #WEEK_OF_YEAR}, {@link #WEEK_OF_MONTH},
{@link #DAY_OF_MONTH}, {@link #DAY_OF_YEAR},
{@link #DAY_OF_WEEK_IN_MONTH}, {@link #YEAR_WOY}, and
{@link #EXTENDED_YEAR}. Other fields are invariant (with
respect to calendar system) and are handled by the base
class.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)
.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
at least {@link #BASE_FIELD_COUNT} and no more than
{@link #MAX_FIELD_COUNT}.DateFormat
appropriate to this calendar. This is only
required if a calendar subclass redefines the use of a field (for
example, changes the {@link #ERA} field from a symbolic field
to a numeric one) or defines an additional field.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: {@link #AM_PM},
{@link #HOUR}, {@link #HOUR_OF_DAY}, {@link #MINUTE},
{@link #SECOND}, {@link #MILLISECOND},
{@link #ZONE_OFFSET}, and {@link #DST_OFFSET}.GregorianCalendar
fields: the
{@link #YEAR}, {@link #MONTH}, and
{@link #DAY_OF_MONTH}. As a result, Calendar
always computes these fields, even for non-Gregorian calendar
systems. These fields are available to subclasses.WEEK_OF_YEAR,
WEEK_OF_MONTH
, {@link #DAY_OF_WEEK_IN_MONTH},
{@link #DOW_LOCAL}, {@link #YEAR_WOY} are all computed in
a consistent way in the base class, based on the
{@link #EXTENDED_YEAR}, {@link #DAY_OF_YEAR},
{@link #MONTH}, and {@link #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 ~5,000,000 BCE to ~5,000,000 CE. Programmers
should use the constants {@link #MIN_DATE} (or
{@link #MIN_MILLIS} or {@link #MIN_JULIAN}) and
{@link #MAX_DATE} (or {@link #MAX_MILLIS} or
{@link #MAX_JULIAN}) 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
{@link #handleGetLimit} to return appropriate limits on
{@link #YEAR}, {@link #ERA}, etc. fields. Then, if the
calendar is set to not be lenient, out-of-range field values will
trigger an exception.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
{@link #EXTENDED_YEAR} is computed as TUN + 20 * (KATUN
+ 20 * BAKTUN)
. The Calendar
base class uses
the {@link #EXTENDED_YEAR} field to compute the week-related
fields.See Also: Date GregorianCalendar TimeZone DateFormat
UNKNOWN: ICU 2.0
Field Summary | |
---|---|
static int | AM
Value of the AM_PM field indicating the
period of the day from midnight to just before noon. |
static int | AM_PM
Field number for get and set indicating
whether the HOUR is before or after noon.
|
static int | APRIL
Value of the MONTH field indicating the
fourth month of the year. |
static int | AUGUST
Value of the MONTH field indicating the
eighth month of the year. |
protected static int | BASE_FIELD_COUNT
The number of fields defined by this class. |
static int | DATE
Field number for get and set indicating the
day of the month. |
static int | DAY_OF_MONTH
Field number for get and set indicating the
day of the month. |
static int | DAY_OF_WEEK
Field number for get and set indicating the day
of the week. |
static 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. |
static int | DAY_OF_YEAR
Field number for get and set indicating the day
number within the current year. |
static int | DECEMBER
Value of the MONTH field indicating the
twelfth month of the year. |
static int | DOW_LOCAL
Field number for get() and set()
indicating the localized day of week. |
static int | DST_OFFSET
Field number for get and set indicating the
daylight savings offset in milliseconds. |
protected static int | EPOCH_JULIAN_DAY
The Julian day of the epoch, that is, January 1, 1970 on the
Gregorian calendar. |
static int | ERA
Field number for get and set indicating the
era, e.g., AD or BC in the Julian calendar. |
static int | EXTENDED_YEAR
Field number for get() and set()
indicating the extended year. |
static int | FEBRUARY
Value of the MONTH field indicating the
second month of the year. |
static int | FRIDAY
Value of the DAY_OF_WEEK field indicating
Friday. |
protected static int | GREATEST_MINIMUM
Limit type for getLimit() and handleGetLimit()
indicating the greatest minimum value that a field can take. |
static int | HOUR
Field number for get and set indicating the
hour of the morning or afternoon. |
static int | HOUR_OF_DAY
Field number for get and set indicating the
hour of the day. |
protected static 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. |
static int | JANUARY
Value of the MONTH field indicating the
first month of the year. |
protected static int | JAN_1_1_JULIAN_DAY
The Julian day of the Gregorian epoch, that is, January 1, 1 on the
Gregorian calendar. |
static int | JULIAN_DAY
Field number for get() and set()
indicating the modified Julian day number. |
static int | JULY
Value of the MONTH field indicating the
seventh month of the year. |
static int | JUNE
Value of the MONTH field indicating the
sixth month of the year. |
protected static int | LEAST_MAXIMUM
Limit type for getLimit() and handleGetLimit()
indicating the least maximum value that a field can take. |
static int | MARCH
Value of the MONTH field indicating the
third month of the year. |
protected static int | MAXIMUM
Limit type for getLimit() and handleGetLimit()
indicating the maximum value that a field can take (greatest maximum). |
protected static Date | MAX_DATE
The maximum supported Date . |
protected static int | MAX_FIELD_COUNT
The maximum number of fields possible. |
protected static int | MAX_JULIAN
The maximum supported Julian day. |
protected static long | MAX_MILLIS
The maximum supported epoch milliseconds. |
static int | MAY
Value of the MONTH field indicating the
fifth month of the year. |
static int | MILLISECOND
Field number for get and set indicating the
millisecond within the second.
|
static int | MILLISECONDS_IN_DAY
Field number for get() and set()
indicating the milliseconds in the day. |
protected static int | MINIMUM
Limit type for getLimit() and handleGetLimit()
indicating the minimum value that a field can take (least minimum). |
protected static 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() . |
static int | MINUTE
Field number for get and set indicating the
minute within the hour.
|
protected static Date | MIN_DATE
The minimum supported Date . |
protected static int | MIN_JULIAN
The minimum supported Julian day. |
protected static long | MIN_MILLIS
The minimum supported epoch milliseconds. |
static int | MONDAY
Value of the DAY_OF_WEEK field indicating
Monday. |
static int | MONTH
Field number for get and set indicating the
month. |
static int | NOVEMBER
Value of the MONTH field indicating the
eleventh month of the year. |
static int | OCTOBER
Value of the MONTH field indicating the
tenth month of the year. |
protected static long | ONE_DAY
The number of milliseconds in one day. |
protected static int | ONE_HOUR
The number of milliseconds in one hour. |
protected static int | ONE_MINUTE
The number of milliseconds in one minute. |
protected static int | ONE_SECOND
The number of milliseconds in one second. |
protected static long | ONE_WEEK
The number of milliseconds in one week. |
static int | PM
Value of the AM_PM field indicating the
period of the day from noon to just before midnight. |
protected static int | RESOLVE_REMAP
Value to OR against resolve table field values for remapping. |
static int | SATURDAY
Value of the DAY_OF_WEEK field indicating
Saturday. |
static int | SECOND
Field number for get and set indicating the
second within the minute.
|
static int | SEPTEMBER
Value of the MONTH field indicating the
ninth month of the year. |
static int | SUNDAY
Value of the DAY_OF_WEEK field indicating
Sunday. |
static int | THURSDAY
Value of the DAY_OF_WEEK field indicating
Thursday. |
static int | TUESDAY
Value of the DAY_OF_WEEK field indicating
Tuesday. |
static int | UNDECIMBER
Value of the MONTH field indicating the
thirteenth month of the year. |
protected static int | UNSET
Value of the time stamp stamp[] indicating that
a field has not been set since the last call to clear() . |
static int | WEDNESDAY
Value of the DAY_OF_WEEK field indicating
Wednesday. |
static int | WEEKDAY
Value returned by getDayOfWeekType(int dayOfWeek) to indicate a
weekday. |
static int | WEEKEND
Value returned by getDayOfWeekType(int dayOfWeek) to indicate a
weekend day. |
static int | WEEKEND_CEASE
Value returned by getDayOfWeekType(int dayOfWeek) to indicate a
day that starts as the weekend and transitions to a weekday.
|
static int | WEEKEND_ONSET
Value returned by getDayOfWeekType(int dayOfWeek) to indicate a
day that starts as a weekday and transitions to the weekend.
|
static int | WEEK_OF_MONTH
Field number for get and set indicating the
week number within the current month. |
static int | WEEK_OF_YEAR
Field number for get and set indicating the
week number within the current year. |
static int | YEAR
Field number for get and set indicating the
year. |
static int | YEAR_WOY
Field number for get() and set()
indicating the extended year corresponding to the
WEEK_OF_YEAR field. |
static int | ZONE_OFFSET
Field number for get and set indicating the
raw offset from GMT in milliseconds. |
Constructor Summary | |
---|---|
protected | Calendar()
Constructs a Calendar with the default time zone
and locale. |
protected | Calendar(TimeZone zone, Locale aLocale)
Constructs a calendar with the specified time zone and locale. |
protected | Calendar(TimeZone zone, ULocale locale)
Constructs a calendar with the specified time zone and locale. |
Method Summary | |
---|---|
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.
|
void | clear()
Clears the values of all the time fields. |
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
Calendar objects.
|
int | compareTo(Object that)
Implement comparable API as a convenience override of
{@link #compareTo(Calendar)}. |
protected void | complete()
Fills in any unset fields in the time field list. |
protected void | computeFields()
Converts the current millisecond time value time to
field values in fields[] . |
protected void | computeGregorianFields(int julianDay)
Compute the Gregorian calendar year, month, and day of month from the
Julian day. |
protected int | computeGregorianMonthStart(int year, int month)
Compute the Julian day of a month of the Gregorian calendar.
|
protected int | computeJulianDay()
Compute the Julian day number as specified by this calendar's fields. |
protected int | computeMillisInDay()
Compute the milliseconds in the day from the fields. |
protected void | computeTime()
Converts the current field values in fields[] to the
millisecond time value time . |
protected int | computeZoneOffset(long millis, int millisInDay)
This method can assume EXTENDED_YEAR has been set. |
boolean | equals(Object obj)
Compares this calendar to the specified object.
|
int | fieldDifference(Date when, int field)
[NEW]
Return the difference between the given time and the time this
calendar object is set to. |
protected String | fieldName(int field)
Return a string name for a field, for debugging and exceptions. |
protected static long | floorDivide(long numerator, long denominator)
Divide two long integers, returning the floor of the quotient.
|
protected static int | floorDivide(int numerator, int denominator)
Divide two integers, returning the floor of the quotient.
|
protected static int | floorDivide(int numerator, int denominator, int[] remainder)
Divide two integers, returning the floor of the quotient, and
the modulus remainder.
|
protected static int | floorDivide(long numerator, int denominator, int[] remainder)
Divide two integers, returning the floor of the quotient, and
the modulus remainder.
|
int | get(int field)
Gets the value for a given time field. |
int | getActualMaximum(int field)
Return the maximum value that this field could have, given the
current date. |
int | getActualMinimum(int field)
Return the minimum value that this field could have, given the current date.
|
static Locale[] | getAvailableLocales()
Gets the list of locales for which Calendars are installed. |
static ULocale[] | getAvailableULocales()
Gets the list of locales for which Calendars are installed. |
DateFormat | getDateTimeFormat(int dateStyle, int timeStyle, Locale loc)
Return a DateFormat appropriate to this calendar.
|
DateFormat | getDateTimeFormat(int dateStyle, int timeStyle, ULocale loc)
Return a DateFormat appropriate to this calendar.
|
int | getDayOfWeekType(int dayOfWeek)
Return whether the given day of the week is a weekday, a
weekend day, or a day that transitions from one to the other,
in this calendar system. |
String | getDisplayName(Locale loc)
Return the name of this calendar in the language of the given locale. |
String | getDisplayName(ULocale loc)
Return the name of this calendar in the language of the given locale. |
int | getFieldCount()
Return the number of fields defined by this calendar. |
protected int[][][] | getFieldResolutionTable()
Return the field resolution array for this calendar. |
int | getFirstDayOfWeek()
Gets what the first day of the week is; e.g., Sunday in US,
Monday in France. |
int | getGreatestMinimum(int field)
Gets the highest minimum value for the given field if varies.
|
protected int | getGregorianDayOfMonth()
Return the day of month (1-based) on the Gregorian calendar as
computed by computeGregorianFields() . |
protected int | getGregorianDayOfYear()
Return the day of year (1-based) on the Gregorian calendar as
computed by computeGregorianFields() . |
protected int | getGregorianMonth()
Return the month (0-based) on the Gregorian calendar as computed by
computeGregorianFields() . |
protected int | getGregorianYear()
Return the extended year on the Gregorian calendar as computed by
computeGregorianFields() . |
static Calendar | getInstance()
Gets a calendar using the default time zone and locale. |
static Calendar | getInstance(TimeZone zone)
Gets a calendar using the specified time zone and default locale. |
static Calendar | getInstance(Locale aLocale)
Gets a calendar using the default time zone and specified locale. |
static Calendar | getInstance(ULocale locale)
Gets a calendar using the default time zone and specified locale. |
static Calendar | getInstance(TimeZone zone, Locale aLocale)
Gets a calendar with the specified time zone and locale. |
static Calendar | getInstance(TimeZone zone, ULocale locale)
Gets a calendar with the specified time zone and locale. |
int | getLeastMaximum(int field)
Gets the lowest maximum value for the given field if varies.
|
protected int | getLimit(int field, int limitType)
Return a limit for a field. |
ULocale | getLocale(ULocale.Type type)
Return the locale that was used to create this object, or null.
|
int | getMaximum(int field)
Gets the maximum value for the given time field.
e.g. for Gregorian DAY_OF_MONTH, 31. |
int | getMinimalDaysInFirstWeek()
Gets what the minimal days required in the first week of the year are;
e.g., if the first week is defined as one that contains the first day
of the first month of a year, getMinimalDaysInFirstWeek returns 1. |
int | getMinimum(int field)
Gets the minimum value for the given time field.
e.g., for Gregorian DAY_OF_MONTH, 1. |
protected int | getStamp(int field)
Return the timestamp of a field. |
Date | getTime()
Gets this Calendar's current time. |
long | getTimeInMillis()
Gets this Calendar's current time as a long. |
TimeZone | getTimeZone()
Gets the time zone. |
String | getType()
Return the current Calendar type.
|
int | getWeekendTransition(int dayOfWeek)
Return the time during the day at which the weekend begins or end in
this calendar system. |
protected static int | gregorianMonthLength(int y, int m)
Return the length of a month of the Gregorian calendar. |
protected static int | gregorianPreviousMonthLength(int y, int m)
Return the length of a previous month of the Gregorian calendar. |
protected void | handleComputeFields(int julianDay)
Subclasses may override this method to compute several fields
specific to each calendar system. |
protected int | handleComputeJulianDay(int bestField)
Subclasses may override this. |
protected abstract int | handleComputeMonthStart(int eyear, int month, boolean useMonth)
Return the Julian day number of day before the first day of the
given month in the given extended year. |
protected 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. |
protected DateFormat | handleGetDateFormat(String pattern, Locale locale)
Create a DateFormat appropriate to this calendar.
|
protected DateFormat | handleGetDateFormat(String pattern, ULocale locale)
Create a DateFormat appropriate to this calendar.
|
protected abstract int | handleGetExtendedYear()
Return the extended year defined by the current fields. |
protected abstract int | handleGetLimit(int field, int limitType)
Subclass API for defining limits of different types.
|
protected int | handleGetMonthLength(int extendedYear, int month)
Return the number of days in the given month of the given extended
year of this calendar system. |
protected int | handleGetYearLength(int eyear)
Return the number of days in the given extended year of this
calendar system. |
int | hashCode()
Returns a hash code for this calendar. |
protected int | internalGet(int field)
Gets the value for a given time field. |
protected int | internalGet(int field, int defaultValue)
Get the value for a given time field, or return the given default
value if the field is not set. |
protected long | internalGetTimeInMillis()
Return the current milliseconds without recomputing. |
protected void | internalSet(int field, int value)
Set a field to a value. |
boolean | isEquivalentTo(Calendar other)
Returns true if the given Calendar object is equivalent to this
one. |
protected static boolean | isGregorianLeapYear(int year)
Determines if the given year is a leap year. |
boolean | isLenient()
Tell whether date/time interpretation is to be lenient. |
boolean | isSet(int field)
Determines if the given time field has a value set. |
boolean | isWeekend(Date date)
Return true if the given date and time is in the weekend in
this calendar system. |
boolean | isWeekend()
Return true if this Calendar's current date and time is in the
weekend in this calendar system. |
protected static int | julianDayToDayOfWeek(int julian)
Return the day of week, from SUNDAY to SATURDAY, given a Julian day. |
protected static long | julianDayToMillis(int julian)
Converts Julian day to time as milliseconds. |
protected static int | millisToJulianDay(long millis)
Converts time as milliseconds to Julian day. |
protected int | newerField(int defaultField, int alternateField)
Return the field that is newer, either defaultField, or
alternateField. |
protected int | newestStamp(int first, int last, int bestStampSoFar)
Return the newest stamp of a given range of fields. |
protected 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.
|
protected void | prepareGetActual(int field, boolean isMinimum)
Prepare this calendar for computing the actual minimum or maximum.
|
protected int | resolveFields(int[][][] precedenceTable)
Given a precedence table, return the newest field combination in
the table, or -1 if none is found.
|
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. |
void | set(int field, int value)
Sets the time field with the given value. |
void | set(int year, int month, int date)
Sets the values for the fields year, month, and date.
|
void | set(int year, int month, int date, int hour, int minute)
Sets the values for the fields year, month, date, hour, and minute.
|
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.
|
void | setFirstDayOfWeek(int value)
Sets what the first day of the week is; e.g., Sunday in US,
Monday in France. |
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 | 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. |
String | toString()
Return a string representation of this calendar. |
protected void | validateField(int field)
Validate a single field of this calendar. |
protected void | validateField(int field, int min, int max)
Validate a single field of this calendar given its minimum and
maximum allowed value. |
protected void | validateFields()
Ensure that each field is within its valid range by calling {@link
#validateField(int)} on each field that has been set. |
protected int | weekNumber(int desiredDay, int dayOfPeriod, int dayOfWeek)
Return the week number of a day, within a period. |
protected int | weekNumber(int dayOfPeriod, int dayOfWeek)
Return the week number of a day, within a period. |
AM_PM
field indicating the
period of the day from midnight to just before noon.UNKNOWN: ICU 2.0
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
.
UNKNOWN: ICU 2.0
MONTH
field indicating the
fourth month of the year.UNKNOWN: ICU 2.0
MONTH
field indicating the
eighth month of the year.UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
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: DAY_OF_MONTH
UNKNOWN: ICU 2.0
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: DATE
UNKNOWN: ICU 2.0
get
and set
indicating the day
of the week. This field takes values SUNDAY
,
MONDAY
, TUESDAY
, WEDNESDAY
,
THURSDAY
, FRIDAY
, and SATURDAY
.See Also: SUNDAY MONDAY TUESDAY WEDNESDAY THURSDAY FRIDAY SATURDAY
UNKNOWN: ICU 2.0
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: DAY_OF_WEEK WEEK_OF_MONTH
UNKNOWN: ICU 2.0
get
and set
indicating the day
number within the current year. The first day of the year has value 1.UNKNOWN: ICU 2.0
MONTH
field indicating the
twelfth month of the year.UNKNOWN: ICU 2.0
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.UNKNOWN: ICU 2.0
get
and set
indicating the
daylight savings offset in milliseconds.UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
get
and set
indicating the
era, e.g., AD or BC in the Julian calendar. This is a calendar-specific
value; see subclass documentation.
UNKNOWN: ICU 2.0
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.UNKNOWN: ICU 2.0
MONTH
field indicating the
second month of the year.UNKNOWN: ICU 2.0
DAY_OF_WEEK
field indicating
Friday.UNKNOWN: ICU 2.0
getLimit()
and handleGetLimit()
indicating the greatest minimum value that a field can take.
UNKNOWN: ICU 2.0
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: AM_PM HOUR_OF_DAY
UNKNOWN: ICU 2.0
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: HOUR
UNKNOWN: ICU 2.0
stamp[]
indicating that a field
has been set via computations from the time or from other fields.See Also: UNSET MINIMUM_USER_STAMP
UNKNOWN: ICU 2.0
MONTH
field indicating the
first month of the year.UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
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.UNKNOWN: ICU 2.0
MONTH
field indicating the
seventh month of the year.UNKNOWN: ICU 2.0
MONTH
field indicating the
sixth month of the year.UNKNOWN: ICU 2.0
getLimit()
and handleGetLimit()
indicating the least maximum value that a field can take.
UNKNOWN: ICU 2.0
MONTH
field indicating the
third month of the year.UNKNOWN: ICU 2.0
getLimit()
and handleGetLimit()
indicating the maximum value that a field can take (greatest maximum).
UNKNOWN: ICU 2.0
Date
. This value is equivalent
to MAX_JULIAN
and MAX_MILLIS
.UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
MAX_MILLIS
and MAX_DATE
.See Also: JULIAN_DAY
UNKNOWN: ICU 2.0
MAX_JULIAN
and MAX_DATE
.UNKNOWN: ICU 2.0
MONTH
field indicating the
fifth month of the year.UNKNOWN: ICU 2.0
get
and set
indicating the
millisecond within the second.
E.g., at 10:04:15.250 PM the MILLISECOND
is 250.UNKNOWN: ICU 2.0
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.UNKNOWN: ICU 2.0
getLimit()
and handleGetLimit()
indicating the minimum value that a field can take (least minimum).
UNKNOWN: ICU 2.0
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: UNSET INTERNALLY_SET
UNKNOWN: ICU 2.0
get
and set
indicating the
minute within the hour.
E.g., at 10:04:15.250 PM the MINUTE
is 4.UNKNOWN: ICU 2.0
Date
. This value is equivalent
to MIN_JULIAN
and MIN_MILLIS
.UNKNOWN: ICU 2.0
MIN_MILLIS
and MIN_DATE
.See Also: JULIAN_DAY
UNKNOWN: ICU 2.0
MIN_JULIAN
and MIN_DATE
.UNKNOWN: ICU 2.0
DAY_OF_WEEK
field indicating
Monday.UNKNOWN: ICU 2.0
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.See Also: JANUARY FEBRUARY MARCH APRIL MAY JUNE JULY AUGUST SEPTEMBER OCTOBER NOVEMBER DECEMBER UNDECIMBER
UNKNOWN: ICU 2.0
MONTH
field indicating the
eleventh month of the year.UNKNOWN: ICU 2.0
MONTH
field indicating the
tenth month of the year.UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
AM_PM
field indicating the
period of the day from noon to just before midnight.UNKNOWN: ICU 2.0
See Also: Calendar
UNKNOWN: ICU 2.0
DAY_OF_WEEK
field indicating
Saturday.UNKNOWN: ICU 2.0
get
and set
indicating the
second within the minute.
E.g., at 10:04:15.250 PM the SECOND
is 15.UNKNOWN: ICU 2.0
MONTH
field indicating the
ninth month of the year.UNKNOWN: ICU 2.0
DAY_OF_WEEK
field indicating
Sunday.UNKNOWN: ICU 2.0
DAY_OF_WEEK
field indicating
Thursday.UNKNOWN: ICU 2.0
DAY_OF_WEEK
field indicating
Tuesday.UNKNOWN: ICU 2.0
MONTH
field indicating the
thirteenth month of the year. Although GregorianCalendar
does not use this value, lunar calendars do.UNKNOWN: ICU 2.0
stamp[]
indicating that
a field has not been set since the last call to clear()
.See Also: INTERNALLY_SET MINIMUM_USER_STAMP
UNKNOWN: ICU 2.0
DAY_OF_WEEK
field indicating
Wednesday.UNKNOWN: ICU 2.0
See Also: WEEKEND WEEKEND_ONSET WEEKEND_CEASE Calendar
UNKNOWN: ICU 2.0
See Also: WEEKDAY WEEKEND_ONSET WEEKEND_CEASE Calendar
UNKNOWN: ICU 2.0
See Also: WEEKDAY WEEKEND WEEKEND_ONSET Calendar
UNKNOWN: ICU 2.0
See Also: WEEKDAY WEEKEND WEEKEND_CEASE Calendar
UNKNOWN: ICU 2.0
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.
UNKNOWN: ICU 2.0
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.
UNKNOWN: ICU 2.0
get
and set
indicating the
year. This is a calendar-specific value; see subclass documentation.UNKNOWN: ICU 2.0
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
.UNKNOWN: ICU 2.0
get
and set
indicating the
raw offset from GMT in milliseconds.UNKNOWN: ICU 2.0
See Also: TimeZone
UNKNOWN: ICU 2.0
Parameters: zone the time zone to use aLocale the locale for the week data
UNKNOWN: ICU 2.0
Parameters: zone the time zone to use locale the ulocale for the week data
UNKNOWN: ICU 3.2 This API might change or be removed in a future release.
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 {@link #MONTH MONTH} field for the Gregorian date 1/31/96, the {@link #DAY_OF_MONTH DAY_OF_MONTH} field must be adjusted so that the result is 2/29/96 rather than the invalid 2/31/96.
The com.ibm.icu.util.Calendar
implementation of this method is able to add to
all fields except for {@link #ERA ERA}, {@link #DST_OFFSET DST_OFFSET},
and {@link #ZONE_OFFSET 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 {@link #getActualMinimum getActualMinimum} and
{@link #getActualMaximum 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
{@link HebrewCalendar#add 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 the time field. amount 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: Calendar
UNKNOWN: ICU 2.0
Parameters: when the Calendar to be compared with this Calendar.
Returns: true if the current time of this Calendar is after the time of Calendar when; false otherwise.
UNKNOWN: ICU 2.0
Parameters: when the Calendar to be compared with this Calendar.
Returns: true if the current time of this Calendar is before the time of Calendar when; false otherwise.
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
Parameters: field the time field to be cleared.
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
Calendar
objects.
Parameters: that the Calendar
to compare to this.
Returns: 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.
UNKNOWN: ICU 3.4 This API might change or be removed in a future release.
UNKNOWN: ICU 3.4 This API might change or be removed in a future release.
UNKNOWN: ICU 2.0
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: Calendar
UNKNOWN: ICU 2.0
See Also: Calendar
UNKNOWN: ICU 2.0
Parameters: year extended Gregorian year month zero-based Gregorian month
Returns: the Julian day number of the day before the first day of the given month in the given extended year
See Also: Calendar
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
fields[]
to the
millisecond time value time
.UNKNOWN: ICU 2.0
Parameters: millis milliseconds of the date fields (local midnight millis) millisInDay milliseconds of the time fields; may be out or range.
Returns: total zone offset (raw + DST) for the given moment
UNKNOWN: ICU 2.0
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 the object to compare with.
Returns: true
if the objects are the same;
false
otherwise.
UNKNOWN: ICU 2.0
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 the date to compare this calendar's time to field the field in which to compute the result
Returns: the difference, either positive or negative, between
this calendar's time and when
, in terms of
field
.
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
Unlike the built-in division, this is mathematically well-behaved.
E.g., -1/4
=> 0
but floorDivide(-1,4)
=> -1.
Parameters: numerator the numerator denominator a divisor which must be > 0
Returns: the floor of the quotient.
UNKNOWN: ICU 2.0
Unlike the built-in division, this is mathematically well-behaved.
E.g., -1/4
=> 0
but floorDivide(-1,4)
=> -1.
Parameters: numerator the numerator denominator a divisor which must be > 0
Returns: the floor of the quotient.
UNKNOWN: ICU 2.0
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 the numerator denominator a divisor which must be > 0 remainder 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: the floor of the quotient.
UNKNOWN: ICU 2.0
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 the numerator denominator a divisor which must be > 0 remainder 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: the floor of the quotient.
UNKNOWN: ICU 2.0
Parameters: field the given time field.
Returns: the value for the given time field.
UNKNOWN: ICU 2.0
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 ChineseCalendar.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 the field whose maximum is desired
Returns: the maximum of the given field for the current date of this calendar
UNKNOWN: ICU 2.0
For example, assume {@link #getMinimalDaysInFirstWeek getMinimalDaysInFirstWeek}
returns 4 and {@link #getFirstDayOfWeek 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 the field whose actual minimum value is desired.
Returns: the minimum of the given field for the current date of this calendar
UNKNOWN: ICU 2.0
Returns: the list of locales for which Calendars are installed.
UNKNOWN: ICU 2.0
Returns: the list of locales for which Calendars are installed.
UNKNOWN: ICU 3.2 This API might change or be removed in a future release.
DateFormat
appropriate to this calendar.
Subclasses wishing to specialize this behavior should override
handleGetDateFormat()
See Also: Calendar
UNKNOWN: ICU 2.0
DateFormat
appropriate to this calendar.
Subclasses wishing to specialize this behavior should override
handleGetDateFormat()
See Also: Calendar
UNKNOWN: ICU 3.2 This API might change or be removed in a future release.
Parameters: dayOfWeek either SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, or SATURDAY
Returns: either WEEKDAY, WEEKEND, WEEKEND_ONSET, or WEEKEND_CEASE
Throws: IllegalArgumentException if dayOfWeek is not between SUNDAY and SATURDAY, inclusive
See Also: WEEKDAY WEEKEND WEEKEND_ONSET WEEKEND_CEASE Calendar isWeekend isWeekend
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
UNKNOWN: ICU 3.2 This API might change or be removed in a future release.
set()
and get()
are
0..getFieldCount()-1
.UNKNOWN: ICU 2.0
See Also: Calendar
UNKNOWN: ICU 2.0
Returns: the first day of the week.
UNKNOWN: ICU 2.0
Parameters: field the given time field.
Returns: the highest minimum value for the given time field.
UNKNOWN: ICU 2.0
computeGregorianFields()
.See Also: Calendar
UNKNOWN: ICU 2.0
computeGregorianFields()
.See Also: Calendar
UNKNOWN: ICU 2.0
computeGregorianFields()
.See Also: Calendar
UNKNOWN: ICU 2.0
computeGregorianFields()
.See Also: Calendar
UNKNOWN: ICU 2.0
Returns: a Calendar.
UNKNOWN: ICU 2.0
Parameters: zone the time zone to use
Returns: a Calendar.
UNKNOWN: ICU 2.0
Parameters: aLocale the locale for the week data
Returns: a Calendar.
UNKNOWN: ICU 2.0
Parameters: locale the ulocale for the week data
Returns: a Calendar.
UNKNOWN: ICU 3.2 This API might change or be removed in a future release.
Parameters: zone the time zone to use aLocale the locale for the week data
Returns: a Calendar.
UNKNOWN: ICU 2.0
Parameters: zone the time zone to use locale the ulocale for the week data
Returns: a Calendar.
UNKNOWN: ICU 3.2 This API might change or be removed in a future release.
Parameters: field the given time field.
Returns: the lowest maximum value for the given time field.
UNKNOWN: ICU 2.0
Parameters: field the field, from 0..getFieldCount()-1 limitType the type specifier for the limit
See Also: MINIMUM GREATEST_MINIMUM LEAST_MAXIMUM MAXIMUM
UNKNOWN: ICU 2.0
Note: This method will be implemented in ICU 3.0; ICU 2.8 contains a partial preview implementation. The * actual locale is returned correctly, but the valid locale is not, in most cases.
Parameters: type type of information requested, either {@link com.ibm.icu.util.ULocale#VALID_LOCALE} or {@link com.ibm.icu.util.ULocale#ACTUAL_LOCALE}.
Returns: the information specified by type, or null if this object was not constructed from locale data.
See Also: ULocale VALID_LOCALE ACTUAL_LOCALE
UNKNOWN: ICU 2.8 (retain) This API might change or be removed in a future release.
Parameters: field the given time field.
Returns: the maximum value for the given time field.
UNKNOWN: ICU 2.0
Returns: the minimal days required in the first week of the year.
UNKNOWN: ICU 2.0
Parameters: field the given time field.
Returns: the minimum value for the given time field.
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
Returns: the current time.
UNKNOWN: ICU 2.0
Returns: the current time as UTC milliseconds from the epoch.
UNKNOWN: ICU 2.0
Returns: the time zone object associated with this calendar.
UNKNOWN: ICU 2.0
Returns: type of calendar (gregorian, etc)
UNKNOWN: ICU 3.0
Parameters: dayOfWeek either SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, or SATURDAY
Returns: the milliseconds after midnight at which the weekend begins or ends
Throws: IllegalArgumentException if dayOfWeek is not WEEKEND_ONSET or WEEKEND_CEASE
See Also: Calendar isWeekend isWeekend
UNKNOWN: ICU 2.0
Parameters: y the extended year m the 0-based month number
Returns: the number of days in the given month
UNKNOWN: ICU 2.0
Parameters: y the extended year m the 0-based month number
Returns: the number of days in the month previous to the given month
UNKNOWN: ICU 2.0
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.
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
Parameters: eyear the extended year month the zero-based month, or 0 if useMonth is false useMonth 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: the Julian day number of the day before the first day of the given month and year
UNKNOWN: ICU 2.0
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
.UNKNOWN: ICU 2.0
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 the pattern, specific to the DateFormat
subclass locale the locale for which the symbols should be drawn
Returns: a DateFormat
appropriate to this calendar
UNKNOWN: ICU 2.0
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 the pattern, specific to the DateFormat
subclass locale the locale for which the symbols should be drawn
Returns: a DateFormat
appropriate to this calendar
UNKNOWN: ICU 3.2 This API might change or be removed in a future release.
Returns: the extended year
UNKNOWN: ICU 2.0
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 one of the above field numbers limitType one of MINIMUM
, GREATEST_MINIMUM
,
LEAST_MAXIMUM
, or MAXIMUM
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
Returns: a hash code value for this object.
UNKNOWN: ICU 2.0
Parameters: field the given time field.
Returns: the value for the given time field.
UNKNOWN: ICU 2.0
Parameters: field the given time field. defaultValue value to return if field is not set
Returns: the value for the given time field of defaultValue if the field is unset
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
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.UNKNOWN: ICU 2.0
Parameters: other the Calendar to be compared with this Calendar
UNKNOWN: ICU 2.4
Parameters: year the given year.
Returns: true if the given year is a leap year; false otherwise.
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
Returns: true if the given time field has a value set; false otherwise.
UNKNOWN: ICU 2.0
Parameters: date the date and time
Returns: true if the given date and time is part of the weekend
See Also: Calendar Calendar isWeekend
UNKNOWN: ICU 2.0
Returns: true if the given date and time is part of the weekend
See Also: Calendar Calendar isWeekend
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
Parameters: julian the given Julian day number.
Returns: time as milliseconds.
UNKNOWN: ICU 2.0
Parameters: millis the given milliseconds.
Returns: the Julian day number.
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
Subclassing:
This utility method is intended for use by subclasses that need to implement
their own overrides of {@link #roll roll} and {@link #add add}.
Note:
pinField
is implemented in terms of
{@link #getActualMinimum getActualMinimum}
and {@link #getActualMaximum 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 The calendar field whose value should be pinned.
UNKNOWN: ICU 2.0
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.
UNKNOWN: ICU 2.0
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.
UNKNOWN: ICU 2.0
roll({@link #DATE}, true)
When rolling on the {@link #YEAR} field, it will roll the year value in the range between 1 and the value returned by calling {@link #getMaximum getMaximum}({@link #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.
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 the calendar field to roll.
up 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.
UNKNOWN: ICU 2.0
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 {@link #MONTH MONTH} field for the Gregorian date 1/31/96 by +1, the {@link #DAY_OF_MONTH DAY_OF_MONTH} field must be adjusted so that the result is 2/29/96 rather than the invalid 2/31/96.
The com.ibm.icu.util.Calendar
implementation of this method is able to roll
all fields except for {@link #ERA ERA}, {@link #DST_OFFSET DST_OFFSET},
and {@link #ZONE_OFFSET 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 {@link #getActualMinimum getActualMinimum} and {@link #getActualMaximum getActualMaximum}.
For most such fields, simple addition, subtraction, and modulus operations
are sufficient to perform the roll. For week-related fields,
the results of {@link #getFirstDayOfWeek getFirstDayOfWeek} and
{@link #getMinimalDaysInFirstWeek 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
{@link HebrewCalendar#roll 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 the calendar field to roll. amount 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.
UNKNOWN: ICU 2.0
Parameters: field the given time field. value the value to be set for the given time field.
UNKNOWN: ICU 2.0
clear
first.Parameters: year the value used to set the YEAR time field. month the value used to set the MONTH time field. Month value is 0-based. e.g., 0 for January. date the value used to set the DATE time field.
UNKNOWN: ICU 2.0
clear
first.Parameters: year the value used to set the YEAR time field. month the value used to set the MONTH time field. Month value is 0-based. e.g., 0 for January. date the value used to set the DATE time field. hour the value used to set the HOUR_OF_DAY time field. minute the value used to set the MINUTE time field.
UNKNOWN: ICU 2.0
clear
first.Parameters: year the value used to set the YEAR time field. month the value used to set the MONTH time field. Month value is 0-based. e.g., 0 for January. date the value used to set the DATE time field. hour the value used to set the HOUR_OF_DAY time field. minute the value used to set the MINUTE time field. second the value used to set the SECOND time field.
UNKNOWN: ICU 2.0
Parameters: value the given first day of the week.
UNKNOWN: ICU 2.0
See Also: DateFormat
UNKNOWN: ICU 2.0
Parameters: value the given minimal days required in the first week of the year.
UNKNOWN: ICU 2.0
Note: Calling setTime()
with
Date(Long.MAX_VALUE)
or Date(Long.MIN_VALUE)
may yield incorrect field values from get()
.
Parameters: date the given Date.
UNKNOWN: ICU 2.0
Parameters: millis the new time in UTC milliseconds from the epoch.
UNKNOWN: ICU 2.0
Parameters: value the given time zone.
UNKNOWN: ICU 2.0
null
.
Returns: a string representation of this calendar.
UNKNOWN: ICU 2.0
Calendar.validateField()
.See Also: Calendar
UNKNOWN: ICU 2.0
IllegalArgumentException
. Subclasses may
use this method in their implementation of {@link
#validateField(int)}.UNKNOWN: ICU 2.0
UNKNOWN: ICU 2.0
Subclassing:
This method is intended for use by subclasses in implementing their
{@link #computeTime computeTime} and/or {@link #computeFields computeFields} methods.
It is often useful in {@link #getActualMinimum getActualMinimum} and
{@link #getActualMaximum 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 The {@link #DAY_OF_YEAR DAY_OF_YEAR} or
{@link #DAY_OF_MONTH DAY_OF_MONTH} whose week number is desired.
Should be 1 for the first day of the period.
dayOfPeriod The {@link #DAY_OF_YEAR DAY_OF_YEAR}
or {@link #DAY_OF_MONTH DAY_OF_MONTH} for a day in the period whose
{@link #DAY_OF_WEEK DAY_OF_WEEK} is specified by the
dayOfWeek
parameter.
Should be 1 for first day of period.
dayOfWeek The {@link #DAY_OF_WEEK DAY_OF_WEEK} for the day
corresponding to the dayOfPeriod
parameter.
1-based with 1=Sunday.
Returns: The week number (one-based), or zero if the day falls before the first week because {@link #getMinimalDaysInFirstWeek getMinimalDaysInFirstWeek} is more than one.
UNKNOWN: ICU 2.0
Subclassing:
This method is intended for use by subclasses in implementing their
{@link #computeTime computeTime} and/or {@link #computeFields computeFields} methods.
It is often useful in {@link #getActualMinimum getActualMinimum} and
{@link #getActualMaximum getActualMaximum} as well.
Parameters: dayOfPeriod The {@link #DAY_OF_YEAR DAY_OF_YEAR} or
{@link #DAY_OF_MONTH DAY_OF_MONTH} whose week number is desired.
Should be 1 for the first day of the period.
dayOfWeek The {@link #DAY_OF_WEEK DAY_OF_WEEK} for the day
corresponding to the dayOfPeriod
parameter.
1-based with 1=Sunday.
Returns: The week number (one-based), or zero if the day falls before the first week because {@link #getMinimalDaysInFirstWeek getMinimalDaysInFirstWeek} is more than one.
UNKNOWN: ICU 2.0