java.util
Class Calendar

java.lang.Object
  |
  +--java.util.Calendar

Direct Known Subclasses:

SimpleCalendar

public abstract class Calendar

extends Object

This is a utility class for storing time in a useful format
(Currently only supports Gregorian time)

Field Summary

static int	AM AM ranges from 00:00 on a 24 hour clock
static int	AM_PM
static int	APRIL
static int	AUGUST
static int	DATE
static int	DAY_OF_MONTH
static int	DAY_OF_WEEK
static int	DECEMBER
static int	FEBRUARY
protected int[]	fields The array that holds the field data
static int	FRIDAY
static int	HOUR
static int	HOUR_OF_DAY
static int	JANUARY
static int	JULY
static int	JUNE
static int	MARCH
static int	MAY
static int	MILLISECOND
static int	MINUTE
static int	MONDAY
static int	MONTH
static int	NOVEMBER
static int	OCTOBER
static int	PM PM ranges from 12:00 on a 24 hour clock
static int	SATURDAY
static int	SECOND
static int	SEPTEMBER
static int	SUNDAY
static int	THURSDAY
protected long	time The time value, which is the number of milliseconds since Jan 1, 1970 This is always kept up to date
static int	TUESDAY
static int	WEDNESDAY
static int	YEAR

Constructor Summary

protected

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

Method Summary

boolean	after(Object cal2) Compares the 'raw' UTC time in this Calendar with the UTC time of the given Calendar (non-Calendar objects return false) and return true if this Calendar is 'later' than the given Calendar.
boolean	before(Object cal2) Compares the 'raw' UTC time in this Calendar with the UTC time of the given Calendar (non-Calendar objects return false) and return true if this Calendar is 'earlier' than the given Calendar
protected abstract void	computeFields() Set the field values from the current time
protected abstract void	computeTime() Set the time from the current field values
boolean	equals(Object obj) Returns true if the given object represents a Calendar with the same time value as this one.
int	get(int field) Gets the value of the given field.
static Calendar	getInstance() Gets a calendar using the default time zone and default locale. (com.dctl.j2me.date.GMTCalendar and com.dctl.j2me.date.GMTTimeZone
static Calendar	getInstance(TimeZone zone) Gets a calendar using the specified time zone and default locale.
Date	getTime() Get the current time of this Calendar.
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 object
void	set(int field, int value) Sets the time field (except DAY_OF_WEEK) with the given value.
void	setTime(Date date) Sets the current time using the given Date
protected void	setTimeInMillis(long millis) Sets the current time from the given value
void	setTimeZone(TimeZone value) Sets the time zone to the given zone

Methods inherited from class java.lang.Object

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

Field Detail

YEAR

public static final int YEAR

See Also:

Constant Field Values

MONTH

public static final int MONTH

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DATE

public static final int DATE

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DAY_OF_MONTH

public static final int DAY_OF_MONTH

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DAY_OF_WEEK

public static final int DAY_OF_WEEK

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AM_PM

public static final int AM_PM

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HOUR

public static final int HOUR

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HOUR_OF_DAY

public static final int HOUR_OF_DAY

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MINUTE

public static final int MINUTE

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SECOND

public static final int SECOND

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MILLISECOND

public static final int MILLISECOND

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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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Constant Field Values

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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AM

public static final int AM

AM ranges from 00:00 on a 24 hour clock

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Constant Field Values

PM

public static final int PM

PM ranges from 12:00 on a 24 hour clock

See Also:

Constant Field Values

time

protected long time

The time value, which is the number of milliseconds since Jan 1, 1970 This is always kept up to date

fields

protected int[] fields

The array that holds the field data

Constructor Detail

Calendar

protected Calendar()

Constructs a Calendar with the default time zone and default locale.

Method Detail

after

public boolean after(Object cal2)

Compares the 'raw' UTC time in this Calendar with the UTC time of the given Calendar (non-Calendar objects return false) and return true if this Calendar is 'later' than the given Calendar.

Parameters:

cal2 - another Calendar

Returns:

true if the current time of this Calendar is before the time of the given Calendar, false otherwise.

before

public boolean before(Object cal2)

Compares the 'raw' UTC time in this Calendar with the UTC time of the given Calendar (non-Calendar objects return false) and return true if this Calendar is 'earlier' than the given Calendar

Parameters:

cal2 - another Calendar

Returns:

true if the current time of this Calendar is before the time of the given Calendar, false otherwise.

equals

public boolean equals(Object obj)

Returns true if the given object represents a Calendar with the same time value as this one.

Overrides:

equals in class Object

Parameters:

obj - the object for comparison

Returns:

true if the objects have the same value, false otherwise

get

public final int get(int field)

Gets the value of the given field. The side effect of this is that the fields are brought up to date prior to the value being returned, so if the date was set to 29th Feb 1973 (not a leap year) then a get of the DATE field would return 1, as the date would have been rationalised to the 1st March 1973. This is an expensive call the first time it is made after the calendar has been created or modified as the fields must be calculated. Subsequent calls simply return values and are therefore very quick.

Returns:

the field value.

Throws:

ArrayIndexOutOfBoundsException - an invalid parameter is given

getInstance

public static Calendar getInstance()

Gets a calendar using the default time zone and default locale.
(com.dctl.j2me.date.GMTCalendar and
com.dctl.j2me.date.GMTTimeZone

Returns:

the default GMT Calendar.

getInstance

public static Calendar getInstance(TimeZone zone)

Gets a calendar using the specified time zone and default locale.

Parameters:

zone - the time zone to use

Returns:

a Calendar.

getTime

public final Date getTime()

Get the current time of this Calendar.

Returns:

the 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).

Returns:

the current time as UTC milliseconds from the epoch.

getTimeZone

public TimeZone getTimeZone()

Gets the time zone object

Returns:

the time zone

set

public final void set(int field,
                      int value)

Sets the time field (except DAY_OF_WEEK) with the given value.

Permissible Values

The only fields that allow negative values are :

1. DATE
2. DAY_OF_MONTH
3. MONTH

This method will ignore any negative values for other fields. The fields mentioned above are also the only fields that allow out-of-range values. So setting the DATE to 40 in January will result in the date becoming the 9th Feb: likewise setting the DATE to -1 in February will give a date of 31st Jan. Setting the month to -1 will give a date of December in the previous year. The Calendar ignores requests to set out of range values for any of the other fields (e.g setting the minute to 70 is ignored rather than giving a time of 10 minutes into the next hour).

Time and Date

Setting the time will never alter the date.

Automatic Changing Of Fields

When the set method is called, the field values remain at their given values until the get method is called, or one of the other set methods is called to set the absolute time, in which case the field data is invalidated.

Parameters:

field - the given time field.
The largest supported year is 268435455.

value - the value to be set for the given time field.

Throws:

ArrayIndexOutOfBoundsException - if an illegal field parameter is received.

setTime

public final void setTime(Date date)

Sets the current time using the given Date

setTimeInMillis

protected void setTimeInMillis(long millis)

Sets the current time from the given value

setTimeZone

public void setTimeZone(TimeZone value)

Sets the time zone to the given zone

Parameters:

value - the given time zone.

computeFields

protected abstract void computeFields()

Set the field values from the current time

computeTime

protected abstract void computeTime()

Set the time from the current field values