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java.lang.Object
|
+----java.util.Calendar
|
+----java.util.GregorianCalendar
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, BC and AD.
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.
The current implementation handles dates in a wide range, from 4716 BC up to 5000000 AD. Dates outside of that range will throw an IllegalArgumentException. This range should be broadened in the future.
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
AD
BC
GregorianCalendar()
GregorianCalendar(int, int, int)
GregorianCalendar(int, int, int, int, int)
GregorianCalendar(int, int, int, int, int, int)
GregorianCalendar(Locale)
GregorianCalendar(TimeZone)
GregorianCalendar(TimeZone, Locale)
add(int, int)
after(Object)
before(Object)
computeFields()
computeTime()
equals(Object)
getGreatestMinimum(int)
getGregorianChange()
getLeastMaximum(int)
getMaximum(int)
getMinimum(int)
hashCode()
isLeapYear(int)
roll(int, boolean)
setGregorianChange(Date)
BC
public static final int BC
AD
public static final int AD
GregorianCalendar
public GregorianCalendar()
GregorianCalendar
public GregorianCalendar(TimeZone zone)
GregorianCalendar
public GregorianCalendar(Locale aLocale)
GregorianCalendar
public GregorianCalendar(TimeZone zone,
Locale aLocale)
GregorianCalendar
public GregorianCalendar(int year,
int month,
int date)
GregorianCalendar
public GregorianCalendar(int year,
int month,
int date,
int hour,
int minute)
GregorianCalendar
public GregorianCalendar(int year,
int month,
int date,
int hour,
int minute,
int second)
setGregorianChange
public void setGregorianChange(Date date)
getGregorianChange
public final Date getGregorianChange()
isLeapYear
public boolean isLeapYear(int year)
computeFields
protected void computeFields()
complete method.
computeTime
protected void computeTime()
hashCode
public synchronized int hashCode()
equals
public boolean equals(Object obj)
before
public boolean before(Object when)
after
public boolean after(Object when)
add
public void add(int field,
int amount)
roll
public void roll(int field,
boolean up)
getMinimum
public int getMinimum(int field)
getMaximum
public int getMaximum(int field)
getGreatestMinimum
public int getGreatestMinimum(int field)
getLeastMaximum
public int getLeastMaximum(int field)
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