All Packages  Class Hierarchy  This Package  Previous  Next  Index

Class java.util.GregorianCalendar 

java.lang.Object
   |
   +----java.util.Calendar
           |
           +----java.util.GregorianCalendar
public class GregorianCalendar
extends Calendar
GregorianCalendar is a concrete subclass of Calendar and provides the standard calendar used by most of the world.

The standard (Gregorian) calendar has 2 eras, AD and BC.

This implementation handles a single discontinuity, which corresponds by default to the date the Gregorian calendar was instituted (October 15, 1582 in some countries, later in others). This cutover date may be changed by the caller.

Prior to the institution of the Gregorian calendar, New Year's Day was March 25. To avoid confusion, this calendar always uses January 1. A manual adjustment may be made if desired for dates that are prior to the Gregorian changeover and which fall between January 1 and March 24.

Example: 

 	// get the supported ids for GMT-08:00 (Pacific Standard Time)
 String[] ids = TimeZone.getAvailableIDs(-8 * 60 * 60 * 1000);
 	// if no ids were returned, something is wrong. get out.
 if (ids.length == 0)
     System.exit(0);
 	// begin output
 System.out.println("Current Time");
 	// create a Pacific Standard Time time zone
 SimpleTimeZone pdt = new SimpleTimeZone(-8 * 60 * 60 * 1000, ids[0]);
 	// set up rules for daylight savings time
 pdt.setStartRule(Calendar.APRIL, 1, Calendar.SUNDAY, 2 * 60 * 60 * 1000);
 pdt.setEndRule(Calendar.OCTOBER, -1, Calendar.SUNDAY, 2 * 60 * 60 * 1000);
 	// create a GregorianCalendar with the Pacific Daylight time zone
	// and the current date and time
 Calendar calendar = new GregorianCalendar(pdt);
 Date trialTime = new Date();
 calendar.setTime(trialTime);
	// print out a bunch of interesting things
 System.out.println("ERA: " + calendar.get(Calendar.ERA));
 System.out.println("YEAR: " + calendar.get(Calendar.YEAR));
 System.out.println("MONTH: " + calendar.get(Calendar.MONTH));
 System.out.println("WEEK_OF_YEAR: " + calendar.get(Calendar.WEEK_OF_YEAR));
 System.out.println("WEEK_OF_MONTH: " + calendar.get(Calendar.WEEK_OF_MONTH));
 System.out.println("DATE: " + calendar.get(Calendar.DATE));
 System.out.println("DAY_OF_MONTH: " + calendar.get(Calendar.DAY_OF_MONTH));
 System.out.println("DAY_OF_YEAR: " + calendar.get(Calendar.DAY_OF_YEAR));
 System.out.println("DAY_OF_WEEK: " + calendar.get(Calendar.DAY_OF_WEEK));
 System.out.println("DAY_OF_WEEK_IN_MONTH: "
                    + calendar.get(Calendar.DAY_OF_WEEK_IN_MONTH));
 System.out.println("AM_PM: " + calendar.get(Calendar.AM_PM));
 System.out.println("HOUR: " + calendar.get(Calendar.HOUR));
 System.out.println("HOUR_OF_DAY: " + calendar.get(Calendar.HOUR_OF_DAY));
 System.out.println("MINUTE: " + calendar.get(Calendar.MINUTE));
 System.out.println("SECOND: " + calendar.get(Calendar.SECOND));
 System.out.println("MILLISECOND: " + calendar.get(Calendar.MILLISECOND));
 System.out.println("ZONE_OFFSET: "
                    + (calendar.get(Calendar.ZONE_OFFSET)/(60*60*1000)));
 System.out.println("DST_OFFSET: "
                    + (calendar.get(Calendar.DST_OFFSET)/(60*60*1000)));
 System.out.println("Current Time, with hour reset to 3");
 calendar.clear(Calendar.HOUR_OF_DAY); // so doesn't override
 calendar.set(Calendar.HOUR, 3);
 System.out.println("ERA: " + calendar.get(Calendar.ERA));
 System.out.println("YEAR: " + calendar.get(Calendar.YEAR));
 System.out.println("MONTH: " + calendar.get(Calendar.MONTH));
 System.out.println("WEEK_OF_YEAR: " + calendar.get(Calendar.WEEK_OF_YEAR));
 System.out.println("WEEK_OF_MONTH: " + calendar.get(Calendar.WEEK_OF_MONTH));
 System.out.println("DATE: " + calendar.get(Calendar.DATE));
 System.out.println("DAY_OF_MONTH: " + calendar.get(Calendar.DAY_OF_MONTH));
 System.out.println("DAY_OF_YEAR: " + calendar.get(Calendar.DAY_OF_YEAR));
 System.out.println("DAY_OF_WEEK: " + calendar.get(Calendar.DAY_OF_WEEK));
 System.out.println("DAY_OF_WEEK_IN_MONTH: "
                    + calendar.get(Calendar.DAY_OF_WEEK_IN_MONTH));
 System.out.println("AM_PM: " + calendar.get(Calendar.AM_PM));
 System.out.println("HOUR: " + calendar.get(Calendar.HOUR));
 System.out.println("HOUR_OF_DAY: " + calendar.get(Calendar.HOUR_OF_DAY));
 System.out.println("MINUTE: " + calendar.get(Calendar.MINUTE));
 System.out.println("SECOND: " + calendar.get(Calendar.SECOND));
 System.out.println("MILLISECOND: " + calendar.get(Calendar.MILLISECOND));
 System.out.println("ZONE_OFFSET: "
        + (calendar.get(Calendar.ZONE_OFFSET)/(60*60*1000))); // in hours
 System.out.println("DST_OFFSET: "
        + (calendar.get(Calendar.DST_OFFSET)/(60*60*1000))); // in hours

See Also:
Calendar, TimeZone

Variable Index

o AD
Useful constant for GregorianCalendar.
o BC
Useful constant for GregorianCalendar.

Constructor Index

o GregorianCalendar()
Constructs a default GregorianCalendar using the current time in the default time zone with the default locale.
o GregorianCalendar(int, int, int)
Constructs a GregorianCalendar with the given date set in the default time zone with the default locale.
o GregorianCalendar(int, int, int, int, int)
Constructs a GregorianCalendar with the given date and time set for the default time zone with the default locale.
o GregorianCalendar(int, int, int, int, int, int)
Constructs a GregorianCalendar with the given date and time set for the default time zone with the default locale.
o GregorianCalendar(Locale)
Constructs a GregorianCalendar based on the current time in the default time zone with the given locale.
o GregorianCalendar(TimeZone)
Constructs a GregorianCalendar based on the current time in the given time zone with the default locale.
o GregorianCalendar(TimeZone, Locale)
Constructs a GregorianCalendar based on the current time in the given time zone with the given locale.

Method Index

o add(int, int)
Overrides Calendar Date Arithmetic function.
o after(Object)
Overrides Calendar Compares the time field records.
o before(Object)
Overrides Calendar Compares the time field records.
o clone()
Overrides Cloneable
o computeFields()
Overrides Calendar Converts UTC as milliseconds to time field values.
o computeTime()
Overrides Calendar Converts time field values to UTC as milliseconds.
o equals(Object)
Overrides Calendar Compares the time field records.
o getGreatestMinimum(int)
Returns highest minimum value for the given field if varies.
o getGregorianChange()
Gets the Gregorian Calendar change date.
o getLeastMaximum(int)
Returns lowest maximum value for the given field if varies.
o getMaximum(int)
Returns maximum value for the given field.
o getMinimum(int)
Returns minimum value for the given field.
o hashCode()
Override hashCode.
o isLeapYear(int)
Determines if the given year is a leap year.
o roll(int, boolean)
Overrides Calendar Time Field Rolling function.
o setGregorianChange(Date)
Sets the GregorianCalendar change date.

Variables

o AD 
Properties Public Constant 
   AD=int
Useful constant for GregorianCalendar.

o BC 
Properties Public Constant 
   BC=int
Useful constant for GregorianCalendar.

Constructors

o GregorianCalendar 
    method GregorianCalendar() public
Constructs a default GregorianCalendar using the current time in the default time zone with the default locale.

o GregorianCalendar 
    method GregorianCalendar(zone=TimeZone) public
Constructs a GregorianCalendar based on the current time in the given time zone with the default locale.

Parameters:
zone - the given time zone.
o GregorianCalendar 
    method GregorianCalendar(aLocale=Locale) public
Constructs a GregorianCalendar based on the current time in the default time zone with the given locale.

Parameters:
aLocale - the given locale.
o GregorianCalendar 
    method GregorianCalendar(zone=TimeZone, -
                             aLocale=Locale) public
Constructs a GregorianCalendar based on the current time in the given time zone with the given locale.

Parameters:
zone - the given time zone.
aLocale - the given locale.
o GregorianCalendar 
    method GregorianCalendar(year=int, -
                             month=int, -
                             date=int) public
Constructs a GregorianCalendar with the given date set in the default time zone with the default locale.

Parameters:
year - the value used to set the YEAR time field in the calendar.
month - the value used to set the MONTH time field in the calendar. Month value is 0-based. e.g., 0 for January.
date - the value used to set the DATE time field in the calendar.
o GregorianCalendar 
    method GregorianCalendar(year=int, -
                             month=int, -
                             date=int, -
                             hour=int, -
                             minute=int) public
Constructs a GregorianCalendar with the given date and time set for the default time zone with the default locale.

Parameters:
year - the value used to set the YEAR time field in the calendar.
month - the value used to set the MONTH time field in the calendar. Month value is 0-based. e.g., 0 for January.
date - the value used to set the DATE time field in the calendar.
hour - the value used to set the HOUR_OF_DAY time field in the calendar.
minute - the value used to set the MINUTE time field in the calendar.
o GregorianCalendar 
    method GregorianCalendar(year=int, -
                             month=int, -
                             date=int, -
                             hour=int, -
                             minute=int, -
                             second=int) public
Constructs a GregorianCalendar with the given date and time set for the default time zone with the default locale.

Parameters:
year - the value used to set the YEAR time field in the calendar.
month - the value used to set the MONTH time field in the calendar. Month value is 0-based. e.g., 0 for January.
date - the value used to set the DATE time field in the calendar.
hour - the value used to set the HOUR_OF_DAY time field in the calendar.
minute - the value used to set the MINUTE time field in the calendar.
second - the value used to set the SECOND time field in the calendar.

Methods

o setGregorianChange 
    method setGregorianChange(date=Date)  public
Sets the GregorianCalendar change date. This is the point when the switch from Julian dates to Gregorian dates occurred. Default is 00:00:00 local time, October 15, 1582. Previous to this time and date will be Julian dates.

Parameters:
date - the given Gregorian cutover date.
o getGregorianChange 
    method getGregorianChange() returns Date public   final
Gets the Gregorian Calendar change date. This is the point when the switch from Julian dates to Gregorian dates occurred. Default is 00:00:00 local time, October 15, 1582. Previous to this time and date will be Julian dates.

Returns:
the Gregorian cutover time for this calendar.
o isLeapYear 
    method isLeapYear(year=int) returns boolean public
Determines if the given year is a leap year. Returns true if the given year is a leap year.

Parameters:
year - the given year.
Returns:
true if the given year is a leap year; false otherwise.
o computeFields 
    method computeFields()  Inheritable
Overrides Calendar Converts UTC as milliseconds to time field values.

Overrides:
computeFields in class Calendar
o computeTime 
    method computeTime()  Inheritable
Overrides Calendar Converts time field values to UTC as milliseconds.

Throws: IllegalArgumentException
if an unknown field is given.
Overrides:
computeTime in class Calendar
o clone 
    method clone() returns Object public
Overrides Cloneable

Overrides:
clone in class Calendar
o hashCode 
    method hashCode() returns int public    protect
Override hashCode. Generates the hash code for the GregorianCalendar object

Overrides:
hashCode in class Object
o equals 
    method equals(obj=Object) returns boolean public
Overrides Calendar Compares the time field records. Equivalent to comparing result of conversion to UTC. Please see Calendar.equals for descriptions on parameters and the return value.

Overrides:
equals in class Calendar
o before 
    method before(when=Object) returns boolean public
Overrides Calendar Compares the time field records. Equivalent to comparing result of conversion to UTC. Please see Calendar.before for descriptions on parameters and the return value.

Overrides:
before in class Calendar
o after 
    method after(when=Object) returns boolean public
Overrides Calendar Compares the time field records. Equivalent to comparing result of conversion to UTC. Please see Calendar.after for descriptions on parameters and the return value.

Overrides:
after in class Calendar
o add 
    method add(field=int, -
               amount=int)  public
Overrides Calendar Date Arithmetic function. Adds the specified (signed) amount of time to the given time field, based on the calendar's rules.

Parameters:
field - the time field.
amount - the amount of date or time to be added to the field.
Throws: IllegalArgumentException
if an unknown field is given.
Overrides:
add in class Calendar
o roll 
    method roll(field=int, -
                up=boolean)  public
Overrides Calendar Time Field Rolling function. Rolls (up/down) a single unit of time on the given time field.

Parameters:
field - the time field.
up - Indicates if rolling up or rolling down the field value.
Throws: IllegalArgumentException
if an unknown field value is given.
Overrides:
roll in class Calendar
o getMinimum 
    method getMinimum(field=int) returns int public
Returns minimum value for the given field. e.g. for Gregorian DAY_OF_MONTH, 1 Please see Calendar.getMinimum for descriptions on parameters and the return value.

Overrides:
getMinimum in class Calendar
o getMaximum 
    method getMaximum(field=int) returns int public
Returns maximum value for the given field. e.g. for Gregorian DAY_OF_MONTH, 31 Please see Calendar.getMaximum for descriptions on parameters and the return value.

Overrides:
getMaximum in class Calendar
o getGreatestMinimum 
    method getGreatestMinimum(field=int) returns int public
Returns highest minimum value for the given field if varies. Otherwise same as getMinimum(). For Gregorian, no difference. Please see Calendar.getGreatestMinimum for descriptions on parameters and the return value.

Overrides:
getGreatestMinimum in class Calendar
o getLeastMaximum 
    method getLeastMaximum(field=int) returns int public
Returns lowest maximum value for the given field if varies. Otherwise same as getMaximum(). For Gregorian DAY_OF_MONTH, 28 Please see Calendar.getLeastMaximum for descriptions on parameters and the return value.

Overrides:
getLeastMaximum in class Calendar 
All Packages  Class Hierarchy  This Package  Previous  Next  Index