java.util
Class Calendar

java.lang.Object
  extended by java.util.Calendar
All Implemented Interfaces:
Serializable, Cloneable, Comparable<Calendar>
Direct Known Subclasses:
GregorianCalendar

public abstract class Calendar
extends Object
implements Serializable, Cloneable, Comparable<Calendar>

This class is an abstract base class for Calendars, which can be used to convert between Date objects and a set of integer fields which represent YEAR, MONTH, DAY, etc. The Date object represents a time in milliseconds since the Epoch.
This class is locale sensitive. To get the Object matching the current locale you can use getInstance. You can even provide a locale or a timezone. getInstance returns currently a GregorianCalendar for the current date.
If you want to convert a date from the Year, Month, Day, DayOfWeek, etc. Representation to a Date-Object, you can create a new Calendar with getInstance(), clear() all fields, set(int,int) the fields you need and convert it with getTime().
If you want to convert a Date-object to the Calendar representation, create a new Calendar, assign the Date-Object with setTime(), and read the fields with get(int).
When computing the date from time fields, it may happen, that there are either two few fields set, or some fields are inconsistent. This cases will handled in a calendar specific way. Missing fields are replaced by the fields of the epoch: 1970 January 1 00:00.
To understand, how the day of year is computed out of the fields look at the following table. It is traversed from top to bottom, and for the first line all fields are set, that line is used to compute the day.

month + day_of_month
month + week_of_month + day_of_week
month + day_of_week_of_month + day_of_week
day_of_year
day_of_week + week_of_year
The hour_of_day-field takes precedence over the ampm and hour_of_ampm fields.
Note: This can differ for non-Gregorian calendar.
To convert a calendar to a human readable form and vice versa, use the java.text.DateFormat class.
Other useful things you can do with an calendar, is rolling fields (that means increase/decrease a specific field by one, propagating overflows), or adding/substracting a fixed amount to a field.

See Also:
Date, GregorianCalendar, TimeZone, DateFormat, Serialized Form

Field Summary
static int ALL_STYLES
          A style specifier for getDisplayNames(int,int,Locale) stating that names should be returned in both long and short variants.
static int AM
          Useful constant for 12-hour clock.
static int AM_PM
          Constant representing the part of the day for 12-hour clock.
static int APRIL
          Constant representing April.
protected  boolean areFieldsSet
          Tells if the fields have a valid value.
static int AUGUST
          Constant representing August.
static int DATE
          Constant representing the day time field, synonym for DAY_OF_MONTH.
static int DAY_OF_MONTH
          Constant representing the day time field.
static int DAY_OF_WEEK
          Constant representing the day of week time field.
static int DAY_OF_WEEK_IN_MONTH
          Constant representing the day-of-week-in-month field.
static int DAY_OF_YEAR
          Constant representing the day of year time field.
static int DECEMBER
          Constant representing December.
static int DST_OFFSET
          Constant representing the daylight saving time offset in milliseconds.
static int ERA
          Constant representing the era time field.
static int FEBRUARY
          Constant representing February.
static int FIELD_COUNT
          Number of time fields.
protected  int[] fields
          The time fields.
static int FRIDAY
          Constant representing Friday.
static int HOUR
          Constant representing the hour time field for 12-hour clock.
static int HOUR_OF_DAY
          Constant representing the hour of day time field for 24-hour clock.
protected  boolean[] isSet
          The flags which tell if the fields above have a value.
protected  boolean isTimeSet
          Tells if the above field has a valid value.
static int JANUARY
          Constant representing January.
static int JULY
          Constant representing July.
static int JUNE
          Constant representing June.
static int LONG
          A style specifier for getDisplayName(int,int,Locale) and getDisplayNames(int,int,Locale) stating that names should be returned in their long variant if applicable.
static int MARCH
          Constant representing March.
static int MAY
          Constant representing May.
static int MILLISECOND
          Constant representing the millisecond time field.
static int MINUTE
          Constant representing the minute of hour time field.
static int MONDAY
          Constant representing Monday.
static int MONTH
          Constant representing the month time field.
static int NOVEMBER
          Constant representing November.
static int OCTOBER
          Constant representing October.
static int PM
          Useful constant for 12-hour clock.
static int SATURDAY
          Constant representing Saturday.
static int SECOND
          Constant representing the second time field.
static int SEPTEMBER
          Constant representing September.
static int SHORT
          A style specifier for getDisplayName(int,int,Locale) and getDisplayNames(int,int,Locale) stating that names should be returned in their short variant if applicable.
static int SUNDAY
          Constant representing Sunday.
static int THURSDAY
          Constant representing Thursday.
protected  long time
          The time in milliseconds since the epoch.
static int TUESDAY
          Constant representing Tuesday.
static int UNDECIMBER
          Constant representing Undecimber.
static int WEDNESDAY
          Constant representing Wednesday.
static int WEEK_OF_MONTH
          Constant representing the week of the month time field.
static int WEEK_OF_YEAR
          Constant representing the week of the year field.
static int YEAR
          Constant representing the year time field.
static int ZONE_OFFSET
          Constant representing the time zone offset time field for the time given in the other fields.
 
Constructor Summary
protected Calendar()
          Constructs a new Calendar with the default time zone and the default locale.
protected Calendar(TimeZone zone, Locale locale)
          Constructs a new Calendar with the given time zone and the given locale.
 
Method Summary
abstract  void add(int field, int amount)
          Adds the specified amount of time to the given time field.
 boolean after(Object o)
          Compares the given calendar with this.
 boolean before(Object o)
          Compares the given calendar with this.
 void clear()
          Clears the values of all the time fields.
 void clear(int field)
          Clears the values of the specified time field.
 Object clone()
          Return a clone of this object.
 int compareTo(Calendar cal)
          Compares the time of two calendar instances.
protected  void complete()
          Fills any unset fields in the time field list
protected abstract  void computeFields()
          Converts the milliseconds since the epoch UTC (time) to time fields (fields).
protected abstract  void computeTime()
          Converts the time field values (fields) to milliseconds since the epoch UTC (time).
 boolean equals(Object o)
          Compares the given calendar with this.
 int get(int field)
          Gets the value of the specified field.
 int getActualMaximum(int field)
          Gets the actual maximum value that is allowed for the specified field.
 int getActualMinimum(int field)
          Gets the actual minimum value that is allowed for the specified field.
static Locale[] getAvailableLocales()
          Gets the set of locales for which a Calendar is available.
 String getDisplayName(int field, int style, Locale locale)
          Returns a localised textual representation of the current value of the given field using the specified style.
 Map<String,Integer> getDisplayNames(int field, int style, Locale locale)
          Returns a map linking all specified textual representations of the given field to their numerical values.
 int getFirstDayOfWeek()
          Gets what the first day of week is.
abstract  int getGreatestMinimum(int field)
          Gets the greatest minimum value that is allowed for the specified field.
static Calendar getInstance()
          Creates a calendar representing the actual time, using the default time zone and locale.
static Calendar getInstance(Locale locale)
          Creates a calendar representing the actual time, using the default time zone and the given locale.
static Calendar getInstance(TimeZone zone)
          Creates a calendar representing the actual time, using the given time zone and the default locale.
static Calendar getInstance(TimeZone zone, Locale locale)
          Creates a calendar representing the actual time, using the given time zone and locale.
abstract  int getLeastMaximum(int field)
          Gets the smallest maximum value that is allowed for the specified field.
abstract  int getMaximum(int field)
          Gets the biggest value that is allowed for the specified field.
 int getMinimalDaysInFirstWeek()
          Gets how many days are required in the first week of the year.
abstract  int getMinimum(int field)
          Gets the smallest value that is allowed for the specified field.
 Date getTime()
          Converts the time represented by this object to a Date-Object.
 long getTimeInMillis()
          Returns the time represented by this Calendar.
 TimeZone getTimeZone()
          Gets the time zone of this calendar
 int hashCode()
          Returns a hash code for this calendar.
protected  int internalGet(int field)
          Gets the value of the specified field.
 boolean isLenient()
          Tells if the date/time interpretation is lenient.
 boolean isSet(int field)
          Determines if the specified field has a valid value.
abstract  void roll(int field, boolean up)
          Rolls the specified time field up or down.
 void roll(int field, int amount)
          Rolls up or down the specified time field by the given amount.
 void set(int field, int value)
          Sets the time field with the given value.
 void set(int year, int month, int date)
          Sets the fields for year, month, and date
 void set(int year, int month, int date, int hour, int minute)
          Sets the fields for year, month, date, hour, and minute
 void set(int year, int month, int date, int hour, int minute, int second)
          Sets the fields for year, month, date, hour, and minute
 void setFirstDayOfWeek(int value)
          Sets what the first day of week is.
 void setLenient(boolean lenient)
          Specifies if the date/time interpretation should be lenient.
 void setMinimalDaysInFirstWeek(int value)
          Sets how many days are required in the first week of the year.
 void setTime(Date date)
          Sets this Calendar's time to the given Date.
 void setTimeInMillis(long time)
          Sets this Calendar's time to the given Time.
 void setTimeZone(TimeZone zone)
          Sets the time zone to the specified value.
 String toString()
          Returns a string representation of this object.
 
Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait
 

Field Detail

ERA

public static final int ERA
Constant representing the era time field.

See Also:
Constant Field Values

YEAR

public static final int YEAR
Constant representing the year time field.

See Also:
Constant Field Values

MONTH

public static final int MONTH
Constant representing the month time field. This field should contain one of the JANUARY,...,DECEMBER constants below.

See Also:
Constant Field Values

WEEK_OF_YEAR

public static final int WEEK_OF_YEAR
Constant representing the week of the year field.

See Also:
setFirstDayOfWeek(int), Constant Field Values

WEEK_OF_MONTH

public static final int WEEK_OF_MONTH
Constant representing the week of the month time field.

See Also:
setFirstDayOfWeek(int), Constant Field Values

DATE

public static final int DATE
Constant representing the day time field, synonym for DAY_OF_MONTH.

See Also:
Constant Field Values

DAY_OF_MONTH

public static final int DAY_OF_MONTH
Constant representing the day time field.

See Also:
Constant Field Values

DAY_OF_YEAR

public static final int DAY_OF_YEAR
Constant representing the day of year time field. This is 1 for the first day in month.

See Also:
Constant Field Values

DAY_OF_WEEK

public static final int DAY_OF_WEEK
Constant representing the day of week time field. This field should contain one of the SUNDAY,...,SATURDAY constants below.

See Also:
Constant Field Values

DAY_OF_WEEK_IN_MONTH

public static final int DAY_OF_WEEK_IN_MONTH
Constant representing the day-of-week-in-month field. For instance this field contains 2 for the second thursday in a month. If you give a negative number here, the day will count from the end of the month.

See Also:
Constant Field Values

AM_PM

public static final int AM_PM
Constant representing the part of the day for 12-hour clock. This should be one of AM or PM.

See Also:
Constant Field Values

HOUR

public static final int HOUR
Constant representing the hour time field for 12-hour clock.

See Also:
Constant Field Values

HOUR_OF_DAY

public static final int HOUR_OF_DAY
Constant representing the hour of day time field for 24-hour clock.

See Also:
Constant Field Values

MINUTE

public static final int MINUTE
Constant representing the minute of hour time field.

See Also:
Constant Field Values

SECOND

public static final int SECOND
Constant representing the second time field.

See Also:
Constant Field Values

MILLISECOND

public static final int MILLISECOND
Constant representing the millisecond time field.

See Also:
Constant Field Values

ZONE_OFFSET

public static final int ZONE_OFFSET
Constant representing the time zone offset time field for the time given in the other fields. It is measured in milliseconds. The default is the offset of the time zone.

See Also:
Constant Field Values

DST_OFFSET

public static final int DST_OFFSET
Constant representing the daylight saving time offset in milliseconds. The default is the value given by the time zone.

See Also:
Constant Field Values

FIELD_COUNT

public static final int FIELD_COUNT
Number of time fields.

See Also:
Constant Field Values

SUNDAY

public static final int SUNDAY
Constant representing Sunday.

See Also:
Constant Field Values

MONDAY

public static final int MONDAY
Constant representing Monday.

See Also:
Constant Field Values

TUESDAY

public static final int TUESDAY
Constant representing Tuesday.

See Also:
Constant Field Values

WEDNESDAY

public static final int WEDNESDAY
Constant representing Wednesday.

See Also:
Constant Field Values

THURSDAY

public static final int THURSDAY
Constant representing Thursday.

See Also:
Constant Field Values

FRIDAY

public static final int FRIDAY
Constant representing Friday.

See Also:
Constant Field Values

SATURDAY

public static final int SATURDAY
Constant representing Saturday.

See Also:
Constant Field Values

JANUARY

public static final int JANUARY
Constant representing January.

See Also:
Constant Field Values

FEBRUARY

public static final int FEBRUARY
Constant representing February.

See Also:
Constant Field Values

MARCH

public static final int MARCH
Constant representing March.

See Also:
Constant Field Values

APRIL

public static final int APRIL
Constant representing April.

See Also:
Constant Field Values

MAY

public static final int MAY
Constant representing May.

See Also:
Constant Field Values

JUNE

public static final int JUNE
Constant representing June.

See Also:
Constant Field Values

JULY

public static final int JULY
Constant representing July.

See Also:
Constant Field Values

AUGUST

public static final int AUGUST
Constant representing August.

See Also:
Constant Field Values

SEPTEMBER

public static final int SEPTEMBER
Constant representing September.

See Also:
Constant Field Values

OCTOBER

public static final int OCTOBER
Constant representing October.

See Also:
Constant Field Values

NOVEMBER

public static final int NOVEMBER
Constant representing November.

See Also:
Constant Field Values

DECEMBER

public static final int DECEMBER
Constant representing December.

See Also:
Constant Field Values

UNDECIMBER

public static final int UNDECIMBER
Constant representing Undecimber. This is an artificial name useful for lunar calendars.

See Also:
Constant Field Values

AM

public static final int AM
Useful constant for 12-hour clock.

See Also:
Constant Field Values

PM

public static final int PM
Useful constant for 12-hour clock.

See Also:
Constant Field Values

ALL_STYLES

public static final int ALL_STYLES
A style specifier for getDisplayNames(int,int,Locale) stating that names should be returned in both long and short variants.

Since:
1.6
See Also:
SHORT, LONG, Constant Field Values

SHORT

public static final int SHORT
A style specifier for getDisplayName(int,int,Locale) and getDisplayNames(int,int,Locale) stating that names should be returned in their short variant if applicable.

Since:
1.6
See Also:
Constant Field Values

LONG

public static final int LONG
A style specifier for getDisplayName(int,int,Locale) and getDisplayNames(int,int,Locale) stating that names should be returned in their long variant if applicable.

Since:
1.6
See Also:
Constant Field Values

fields

protected int[] fields
The time fields. The array is indexed by the constants YEAR to DST_OFFSET.


isSet

protected boolean[] isSet
The flags which tell if the fields above have a value.


time

protected long time
The time in milliseconds since the epoch.


isTimeSet

protected boolean isTimeSet
Tells if the above field has a valid value.


areFieldsSet

protected boolean areFieldsSet
Tells if the fields have a valid value. This superseeds the isSet array.

Constructor Detail

Calendar

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


Calendar

protected Calendar(TimeZone zone,
                   Locale locale)
Constructs a new Calendar with the given time zone and the given locale.

Parameters:
zone - a time zone.
locale - a locale.
Method Detail

getInstance

public static Calendar getInstance()
Creates a calendar representing the actual time, using the default time zone and locale.

Returns:
The new calendar.

getInstance

public static Calendar getInstance(TimeZone zone)
Creates a calendar representing the actual time, using the given time zone and the default locale.

Parameters:
zone - a time zone (null not permitted).
Returns:
The new calendar.
Throws:
NullPointerException - if zone is null.

getInstance

public static Calendar getInstance(Locale locale)
Creates a calendar representing the actual time, using the default time zone and the given locale.

Parameters:
locale - a locale (null not permitted).
Returns:
The new calendar.
Throws:
NullPointerException - if locale is null.

getInstance

public static Calendar getInstance(TimeZone zone,
                                   Locale locale)
Creates a calendar representing the actual time, using the given time zone and locale.

Parameters:
zone - a time zone (null not permitted).
locale - a locale (null not permitted).
Returns:
The new calendar.
Throws:
NullPointerException - if zone or locale is null.

getAvailableLocales

public static Locale[] getAvailableLocales()
Gets the set of locales for which a Calendar is available.

Returns:
the set of locales.
Throws:
MissingResourceException - if locale data couldn't be found.

computeTime

protected abstract void computeTime()
Converts the time field values (fields) to milliseconds since the epoch UTC (time). Override this method if you write your own Calendar.


computeFields

protected abstract void computeFields()
Converts the milliseconds since the epoch UTC (time) to time fields (fields). Override this method if you write your own Calendar.


getTime

public final Date getTime()
Converts the time represented by this object to a Date-Object.

Returns:
the Date.

setTime

public final void setTime(Date date)
Sets this Calendar's time to the given Date. All time fields are invalidated by this method.

Parameters:
date - the date (null not permitted).
Throws:
NullPointerException - if date is null.

getTimeInMillis

public long getTimeInMillis()
Returns the time represented by this Calendar.

Returns:
the time in milliseconds since the epoch.

setTimeInMillis

public void setTimeInMillis(long time)
Sets this Calendar's time to the given Time. All time fields are invalidated by this method.

Parameters:
time - the time in milliseconds since the epoch

get

public int get(int field)
Gets the value of the specified field. They are recomputed if they are invalid.

Parameters:
field - the time field. One of the time field constants.
Returns:
the value of the specified field
Throws:
ArrayIndexOutOfBoundsException - if the field is outside the valid range. The value of field must be >= 0 and <= FIELD_COUNT.

internalGet

protected final int internalGet(int field)
Gets the value of the specified field. This method doesn't recompute the fields, if they are invalid.

Parameters:
field - the time field. One of the time field constants.
Returns:
the value of the specified field, undefined if areFieldsSet or isSet[field] is false.
Throws:
ArrayIndexOutOfBoundsException - if the field is outside the valid range. The value of field must be >= 0 and <= FIELD_COUNT.

set

public void set(int field,
                int value)
Sets the time field with the given value. This does invalidate the time in milliseconds.

Parameters:
field - the time field. One of the time field constants
value - the value to be set.
Throws:
ArrayIndexOutOfBoundsException - if field is outside the valid range. The value of field must be >= 0 and <= FIELD_COUNT.

set

public final void set(int year,
                      int month,
                      int date)
Sets the fields for year, month, and date

Parameters:
year - the year.
month - the month, one of the constants JANUARY..UNDICEMBER.
date - the day of the month

set

public final void set(int year,
                      int month,
                      int date,
                      int hour,
                      int minute)
Sets the fields for year, month, date, hour, and minute

Parameters:
year - the year.
month - the month, one of the constants JANUARY..UNDICEMBER.
date - the day of the month
hour - the hour of day.
minute - the minute.

set

public final void set(int year,
                      int month,
                      int date,
                      int hour,
                      int minute,
                      int second)
Sets the fields for year, month, date, hour, and minute

Parameters:
year - the year.
month - the month, one of the constants JANUARY..UNDICEMBER.
date - the day of the month
hour - the hour of day.
minute - the minute.
second - the second.

clear

public final void clear()
Clears the values of all the time fields.


clear

public final void clear(int field)
Clears the values of the specified time field.

Parameters:
field - the time field. One of the time field constants.
Throws:
ArrayIndexOutOfBoundsException - if field is outside the valid range. The value of field must be >= 0 and <= FIELD_COUNT.

isSet

public final boolean isSet(int field)
Determines if the specified field has a valid value.

Returns:
true if the specified field has a value.
Throws:
ArrayIndexOutOfBoundsException - if the field is outside the valid range. The value of field must be >= 0 and <= FIELD_COUNT.

complete

protected void complete()
Fills any unset fields in the time field list


equals

public boolean equals(Object o)
Compares the given calendar with this.

Overrides:
equals in class Object
Parameters:
o - the object to that we should compare.
Returns:
true, if the given object is a calendar, that represents the same time (but doesn't necessary have the same fields).
See Also:
Object.hashCode()

hashCode

public int hashCode()
Returns a hash code for this calendar.

Overrides:
hashCode in class Object
Returns:
a hash code, which fullfits the general contract of hashCode()
See Also:
Object.equals(Object), System.identityHashCode(Object)

before

public boolean before(Object o)
Compares the given calendar with this.

Parameters:
o - the object to that we should compare.
Returns:
true, if the given object is a calendar, and this calendar represents a smaller time than the calendar o.
Throws:
ClassCastException - if o is not an calendar.
Since:
JDK1.2 you don't need to override this method

after

public boolean after(Object o)
Compares the given calendar with this.

Parameters:
o - the object to that we should compare.
Returns:
true, if the given object is a calendar, and this calendar represents a bigger time than the calendar o.
Throws:
ClassCastException - if o is not an calendar.
Since:
JDK1.2 you don't need to override this method

add

public abstract void add(int field,
                         int amount)
Adds the specified amount of time to the given time field. The amount may be negative to subtract the time. If the field overflows it does what you expect: Jan, 25 + 10 Days is Feb, 4.

Parameters:
field - the time field. One of the time field constants.
amount - the amount of time.
Throws:
ArrayIndexOutOfBoundsException - if the field is outside the valid range. The value of field must be >= 0 and <= FIELD_COUNT.

roll

public abstract void roll(int field,
                          boolean up)
Rolls the specified time field up or down. This means add one to the specified field, but don't change the other fields. If the maximum for this field is reached, start over with the minimum value.
Note: There may be situation, where the other fields must be changed, e.g rolling the month on May, 31. The date June, 31 is automatically converted to July, 1.

Parameters:
field - the time field. One of the time field constants.
up - the direction, true for up, false for down.
Throws:
ArrayIndexOutOfBoundsException - if the field is outside the valid range. The value of field must be >= 0 and <= FIELD_COUNT.

roll

public void roll(int field,
                 int amount)
Rolls up or down the specified time field by the given amount. A negative amount rolls down. The default implementation is call roll(int, boolean) for the specified amount. Subclasses should override this method to do more intuitiv things.

Parameters:
field - the time field. One of the time field constants.
amount - the amount to roll by, positive for rolling up, negative for rolling down.
Throws:
ArrayIndexOutOfBoundsException - if the field is outside the valid range. The value of field must be >= 0 and <= FIELD_COUNT.
Since:
JDK1.2

setTimeZone

public void setTimeZone(TimeZone zone)
Sets the time zone to the specified value.

Parameters:
zone - the new time zone

getTimeZone

public TimeZone getTimeZone()
Gets the time zone of this calendar

Returns:
the current time zone.

setLenient

public void setLenient(boolean lenient)
Specifies if the date/time interpretation should be lenient. If the flag is set, a date such as "February 30, 1996" will be treated as the 29th day after the February 1. If this flag is false, such dates will cause an exception.

Parameters:
lenient - true, if the date should be interpreted linient, false if it should be interpreted strict.

isLenient

public boolean isLenient()
Tells if the date/time interpretation is lenient.

Returns:
true, if the date should be interpreted linient, false if it should be interpreted strict.

setFirstDayOfWeek

public void setFirstDayOfWeek(int value)
Sets what the first day of week is. This is used for WEEK_OF_MONTH and WEEK_OF_YEAR fields.

Parameters:
value - the first day of week. One of SUNDAY to SATURDAY.

getFirstDayOfWeek

public int getFirstDayOfWeek()
Gets what the first day of week is. This is used for WEEK_OF_MONTH and WEEK_OF_YEAR fields.

Returns:
the first day of week. One of SUNDAY to SATURDAY.

setMinimalDaysInFirstWeek

public void setMinimalDaysInFirstWeek(int value)
Sets how many days are required in the first week of the year. If the first day of the year should be the first week you should set this value to 1. If the first week must be a full week, set it to 7.

Parameters:
value - the minimal days required in the first week.

getMinimalDaysInFirstWeek

public int getMinimalDaysInFirstWeek()
Gets how many days are required in the first week of the year.

Returns:
the minimal days required in the first week.
See Also:
setMinimalDaysInFirstWeek(int)

getMinimum

public abstract int getMinimum(int field)
Gets the smallest value that is allowed for the specified field.

Parameters:
field - the time field. One of the time field constants.
Returns:
the smallest value.

getMaximum

public abstract int getMaximum(int field)
Gets the biggest value that is allowed for the specified field.

Parameters:
field - the time field. One of the time field constants.
Returns:
the biggest value.

getGreatestMinimum

public abstract int getGreatestMinimum(int field)
Gets the greatest minimum value that is allowed for the specified field.

Parameters:
field - the time field. One of the time field constants.
Returns:
the greatest minimum value.

getLeastMaximum

public abstract int getLeastMaximum(int field)
Gets the smallest maximum value that is allowed for the specified field. For example this is 28 for DAY_OF_MONTH.

Parameters:
field - the time field. One of the time field constants.
Returns:
the least maximum value.

getActualMinimum

public int getActualMinimum(int field)
Gets the actual minimum value that is allowed for the specified field. This value is dependent on the values of the other fields.

Parameters:
field - the time field. One of the time field constants.
Returns:
the actual minimum value.
Throws:
ArrayIndexOutOfBoundsException - if the field is outside the valid range. The value of field must be >= 0 and <= FIELD_COUNT.
Since:
jdk1.2

getActualMaximum

public int getActualMaximum(int field)
Gets the actual maximum value that is allowed for the specified field. This value is dependent on the values of the other fields.

Parameters:
field - the time field. One of the time field constants.
Returns:
the actual maximum value.
Throws:
ArrayIndexOutOfBoundsException - if the field is outside the valid range. The value of field must be >= 0 and <= FIELD_COUNT.
Since:
jdk1.2

compareTo

public int compareTo(Calendar cal)
Compares the time of two calendar instances.

Specified by:
compareTo in interface Comparable<Calendar>
Parameters:
calendar - the calendar to which the time should be compared.
cal - the calendar to compare this instance with.
Returns:
0 if the two calendars are set to the same time, less than 0 if the time of this calendar is before that of cal, or more than 0 if the time of this calendar is after that of cal.
Throws:
NullPointerException - if cal is null.
IllegalArgumentException - if either calendar has fields set to invalid values.
Since:
1.5

clone

public Object clone()
Return a clone of this object.

Overrides:
clone in class Object
Returns:
a copy of the Object
See Also:
Cloneable

toString

public String toString()
Returns a string representation of this object. It is mainly for debugging purposes and its content is implementation specific.

Overrides:
toString in class Object
Returns:
the String representing this Object, which may be null
See Also:
Object.getClass(), Object.hashCode(), Class.getName(), Integer.toHexString(int)

getDisplayName

public String getDisplayName(int field,
                             int style,
                             Locale locale)
Returns a localised textual representation of the current value of the given field using the specified style. If there is no applicable textual representation (e.g. the field has a numeric value), then null is returned. If one does exist, then the value is obtained from get(int) and converted appropriately. For example, if the MONTH field is requested, then get(MONTH) is called. This is then converted to a textual representation based on its value and the style requested; if the LONG style is requested and the returned value is 11 from a GregorianCalendar implementation, then "December" is returned. By default, a textual representation is available for all fields which have an applicable value obtainable from DateFormatSymbols.

Parameters:
field - the calendar field whose textual representation should be obtained.
style - the style to use; either LONG or SHORT.
locale - the locale to use for translation.
Returns:
the textual representation of the given field in the specified style, or null if none is applicable.
Throws:
IllegalArgumentException - if field or style or invalid, or the calendar is non-lenient and has invalid values.
NullPointerException - if locale is null.
Since:
1.6

getDisplayNames

public Map<String,Integer> getDisplayNames(int field,
                                           int style,
                                           Locale locale)
Returns a map linking all specified textual representations of the given field to their numerical values. The textual representations included are determined by the specified style and locale. For example, if the style LONG is specified and the German locale, then the map will contain "Montag" to MONDAY, "Dienstag" to TUESDAY, "Mittwoch" to WEDNESDAY and so on. The default implementation uses the values returned by DateFormatSymbols so, for example, the style ALL_STYLES and the field MONTH will return a map filled with the values returned from DateFormatSymbols.getMonths() and DateFormatSymbols.getShortMonths(). If there are no textual representations for a given field (usually because it is purely numeric, such as the year in the GregorianCalendar), null is returned.

Parameters:
field - the calendar field whose textual representation should be obtained.
style - the style to use; either LONG, SHORT or ALL_STYLES.
locale - the locale to use for translation.
Returns:
a map of the textual representations of the given field in the specified style to their numeric values, or null if none is applicable.
Throws:
IllegalArgumentException - if field or style or invalid, or the calendar is non-lenient and has invalid values.
NullPointerException - if locale is null.
Since:
1.6