java.util
Class Calendar

java.lang.Object
  java.util.Calendar

public abstract class Calendar
extends Object

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. Like other locale-sensitive classes, Calendar provides a class method, getInstance, for getting a generally useful object of this type. Calendar rightNow = Calendar.getInstance(); 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). When computing a Date from time fields, there may be insufficient information to compute the Date (such as only year and month but no day in the month). 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. Note: The ambiguity in interpretation of what day midnight belongs to, is resolved as so: midnight "belongs" to the following day. 23:59 on Dec 31, 1969 < 00:00 on Jan 1, 1970. 12:00 PM is midday, and 12:00 AM is midnight. 11:59 PM on Jan 1 < 12:00 AM on Jan 2 < 12:01 AM on Jan 2. 11:59 AM on Mar 10 < 12:00 PM on Mar 10 < 12:01 PM on Mar 10. 24:00 or greater are invalid. Hours greater than 12 are invalid in AM/PM mode. Setting the time will never change the date. If equivalent times are entered in AM/PM or 24 hour mode, equality will be determined by the actual time rather than the entered time. This class has been subset for J2ME based on the JDK 1.3 Calendar class. Many methods and variables have been pruned, and other methods simplified, in an effort to reduce the size of this class.

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
static int	AUGUST
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	DECEMBER
static int	FEBRUARY
static int	FRIDAY
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.
static int	JANUARY
static int	JULY
static int	JUNE
static int	MARCH
static int	MAY
static int	MILLISECOND Field number for get and set indicating the millisecond within the second.
static int	MINUTE Field number for get and set indicating the minute within the hour.
static int	MONDAY
static int	MONTH Field number for get and set indicating the month.
static int	NOVEMBER
static int	OCTOBER
static int	PM Value of the AM_PM field indicating the period of the day from noon to just before midnight.
static int	SATURDAY
static int	SECOND Field number for get and set indicating the second within the minute.
static int	SEPTEMBER
static int	SUNDAY
static int	THURSDAY
static int	TUESDAY
static int	WEDNESDAY
static int	YEAR Field number for get and set indicating the year.

Constructor Summary

protected

Calendar() Constructs a Calendar with the default time zone.

Method Summary

boolean	after(Object when) Compares the time field records.
boolean	before(Object when) Compares the time field records.
protected abstract void	computeFields() Converts the current millisecond time value time to field values in fields[].
protected abstract void	computeTime() Converts the current field values in fields[] to the millisecond time value time.
boolean	equals(Object obj) Compares this calendar to the specified object.
int	get(int field) Gets the value for a given time field.
static Calendar	getInstance() Gets a calendar using the default time zone.
static Calendar	getInstance(TimeZone zone) Gets a calendar using the specified time zone.
Date	getTime() Gets this Calendar's current time.
protected long	getTimeInMillis() Gets this Calendar's current time as a long expressed in milliseconds after January 1, 1970, 0:00:00 GMT (the epoch).
TimeZone	getTimeZone() Gets the time zone.
void	set(int field, int value) Sets the time field with the given value.
void	setTime(Date date) Sets this Calendar's current time with the given Date.
protected 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.

Methods inherited from class java.lang.Object

getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

AM_PM

public static final 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.

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PM

public static final int PM

Value of the AM_PM field indicating the period of the day from noon to just before midnight.

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AM

public static final int AM

Value of the AM_PM field indicating the period of the day from midnight to just before noon.

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YEAR

public static final int YEAR

Field number for get and set indicating the year. This is a calendar-specific value.

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MONTH

public static final int MONTH

Field number for get and set indicating the month. This is a calendar-specific value.

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DATE

public static final int DATE

Field number for get and set indicating the day of the month. This is a synonym for DAY_OF_MONTH.

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DAY_OF_MONTH

public static final int DAY_OF_MONTH

Field number for get and set indicating the day of the month. This is a synonym for DATE.

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DAY_OF_WEEK

public static final int DAY_OF_WEEK

Field number for get and set indicating the day of the week.

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HOUR

public static final 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.

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HOUR_OF_DAY

public static final 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.

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MINUTE

public static final 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.

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SECOND

public static final 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.

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MILLISECOND

public static final 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.

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SUNDAY

public static final int SUNDAY

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MONDAY

public static final int MONDAY

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TUESDAY

public static final int TUESDAY

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WEDNESDAY

public static final int WEDNESDAY

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THURSDAY

public static final int THURSDAY

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FRIDAY

public static final int FRIDAY

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SATURDAY

public static final int SATURDAY

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JANUARY

public static final int JANUARY

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FEBRUARY

public static final int FEBRUARY

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MARCH

public static final int MARCH

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APRIL

public static final int APRIL

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MAY

public static final int MAY

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JUNE

public static final int JUNE

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JULY

public static final int JULY

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AUGUST

public static final int AUGUST

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SEPTEMBER

public static final int SEPTEMBER

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OCTOBER

public static final int OCTOBER

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NOVEMBER

public static final int NOVEMBER

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DECEMBER

public static final int DECEMBER

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Constructor Detail

Calendar

protected Calendar()

Constructs a Calendar with the default time zone.

Method Detail

after

public boolean after(Object when)

Compares the time field records. Equivalent to comparing result of conversion to UTC.

before

public boolean before(Object when)

Compares the time field records. Equivalent to comparing result of conversion to UTC.

computeFields

protected abstract void computeFields()

Converts the current millisecond time value time to field values in fields[]. This allows you to sync up the time field values with a new time that is set for the calendar.

computeTime

protected abstract void computeTime()

Converts the current field values in fields[] to the millisecond time value time.

equals

public 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.

Overrides:

equals in class Object

Parameters:

obj - the reference object with which to compare.

Returns:

true if this object is the same as the obj argument; false otherwise.

get

public final int get(int field)

Gets the value for a given time field.

getInstance

public static Calendar getInstance()

Gets a calendar using the default time zone.

getInstance

public static Calendar getInstance(TimeZone zone)

Gets a calendar using the specified time zone.

getTime

public final Date getTime()

Gets this Calendar's current time.

getTimeInMillis

protected long getTimeInMillis()

Gets this Calendar's current time as a long expressed in milliseconds after January 1, 1970, 0:00:00 GMT (the epoch).

getTimeZone

public TimeZone getTimeZone()

Gets the time zone.

set

public final void set(int field,
                      int value)

Sets the time field with the given value.

setTime

public final 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().

setTimeInMillis

protected void setTimeInMillis(long millis)

Sets this Calendar's current time from the given long value.

setTimeZone

public void setTimeZone(TimeZone value)

Sets the time zone with the given time zone value.