# com.bea.xml
XmlCalendar Class

public class XmlCalendar
extends `GregorianCalendar`

An XML Schema compatible subclass of `GregorianCalendar```. XmlCalendar modifies several key details in the behavior of GregorianCalendar to make it more useful when dealing with XML dates.

It is easy to convert between XmlCalendar and `GDate```, or to parse or emit an XmlCalendar using a standard XML Schema lexical representation.

1. To match XML Schema dates, this XmlCalendar is a fully proleptic Gregorian calendar by default, which means that Gregorian calendar rules are applied backwards in time as if they had always been in effect, actual historical circumstances concerning the observance of the 1582 decree of Pope Gregory XIII notwithstanding.
2. In order to better support partially-specified dates for XML Schema, this implementation provides a stable get(field) method that does not modify the instance if you are acessing a field right after it was explicitly set: a set followed by a get will always return the same thing and will not fill in any other fields. However, if you get a field that was not explicitly set, then all the fields are still automatically filled and normalized for you, just like a regular GregorianCalendar. If you wish to force the completion and defaulting of all the fields (without hunting to get one that happens to be unset), you can always do so by calling getTime().
3. When a year is unspecified and needs to be filled in automatically (for example when using a .get or .getTime method as discussed above), the year is defaulted to year 0 (also known as 1 BC). This is different from `GregorianCalendar```, which chooses 1970. The reason 0 is preferable is that it is a leap year and so it permits the date --2-29 to be specified stably. A different default year can be chosen via the static method `XmlCalendar.setDefaultYear()```, or by setting the system property "user.defaultyear". If you do change this value, you should pick another leap year such as 2000 and avoid non-leap years such as 1900.
4. When constructing an XmlCalendar from an XML Schema formatted date or time string or GDate object, the timezone for the calendar is taken from the string if it is present, or taken to be `TimeZone.getDefault()``` if not.

   For example, the XML timezone "Z" is translated to "GMT"; the XML timezone "+05:00" is translated to "GMT+05:00".

5. Finally, this implementation provides a String constructor and a toString() method that comply with the XML Schema conventions for formatting a date. If only a subset of fields have been explicitly set, toString() produces a string with the proper subset of information.

Hierarchy
  `Object`
  `Calendar`
  `GregorianCalendar`
  `XmlCalendar`

All Implemented Interfaces
  `Cloneable`, `Serializable`

## Field Summary

Fields from java.util`.`GregorianCalendar``
`AD, BC`

Fields from java.util`.`Calendar``
`AM, AM_PM, APRIL, areFieldsSet, AUGUST, DATE, DAY_OF_MONTH, DAY_OF_WEEK, DAY_OF_WEEK_IN_MONTH, DAY_OF_YEAR, DECEMBER, DST_OFFSET, ERA, FEBRUARY, FIELD_COUNT, fields, FRIDAY, HOUR, HOUR_OF_DAY, isSet, isTimeSet, JANUARY, JULY, JUNE, MARCH, MAY, MILLISECOND, MINUTE, MONDAY, MONTH, NOVEMBER, OCTOBER, PM, SATURDAY, SECOND, SEPTEMBER, SUNDAY, THURSDAY, time, TUESDAY, UNDECIMBER, WEDNESDAY, WEEK_OF_MONTH, WEEK_OF_YEAR, YEAR, ZONE_OFFSET`

## Constructor Summary

XmlCalendar() Constructs an empty instance with no fields set.
XmlCalendar(`GDateSpecification` date) Constructs an XmlCalendar from a GDate.
XmlCalendar(int year, int month, int day, int hour, int minute, int second, `BigDecimal` fraction, int tzSign, int tzHour, int tzMinute) Constructs an XmlCalendar with the specified year, month, day, hours, minutes, seconds, and optional fractional seconds, in the specified timezone.
XmlCalendar(int year, int month, int day, int hour, int minute, int second, `BigDecimal` fraction) Constructs an XmlCalendar with the specified year, month, day, hours, minutes, seconds, and optional fractional seconds, in the default timezone.
XmlCalendar(`String` xmlSchemaDateString) Constructs an XmlCalendar for a standard XML schema formatted date string.
XmlCalendar(`Date` date) Constructs an XmlCalendar from a Date.

## Method Summary

`protected void` | `computeTime`() Overrides GregorianCalendar.computeTime to apply a different default year.
`public int` | `get`(int field) Gets the value for a given time field.
`public static int` | `getDefaultYear`() Returns the default year that is used when no year is specified.
`public static void` | `setDefaultYear`(int year) Sets the default year to be used when no year is specified.
`public `String`` | `toString`() Prints the XmlCalendar using a standard XML Schema format, as described in XmlCalendar(String s).

Methods from `java.util.`GregorianCalendar``
`add, computeFields, equals, getActualMaximum, getActualMinimum, getGreatestMinimum, getGregorianChange, getLeastMaximum, getMaximum, getMinimum, hashCode, isLeapYear, roll, roll, setGregorianChange`

Methods from `java.util.`Calendar``
`add, after, before, clear, clear, clone, complete, computeFields, computeTime, equals, getActualMaximum, getActualMinimum, getAvailableLocales, getFirstDayOfWeek, getGreatestMinimum, getInstance, getInstance, getInstance, getInstance, getLeastMaximum, getMaximum, getMinimalDaysInFirstWeek, getMinimum, getTime, getTimeInMillis, getTimeZone, hashCode, internalGet, isLenient, isSet, roll, roll, set, set, set, set, setFirstDayOfWeek, setLenient, setMinimalDaysInFirstWeek, setTime, setTimeInMillis, setTimeZone,`

Methods from class `java.lang.`Object``
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

## Constructor Detail

### XmlCalendar

    public XmlCalendar()

  Constructs an empty instance with no fields set.

### XmlCalendar

    public XmlCalendar(GDateSpecification date)

  Constructs an XmlCalendar from a GDate. If the instance is not completed, you can round-trip to an equivalent GDate by writing "new GDate(new XmlCalendar(gdate))". However, if you access any of the unset fields of the calendar, all the fields will be automatically filled in, so partial dates without timezones or other fields will not round-trip after access.

### XmlCalendar

    public XmlCalendar(int year,
                       int month,
                       int day,
                       int hour,
                       int minute,
                       int second,
                       BigDecimal fraction,
                       int tzSign,
                       int tzHour,
                       int tzMinute)

  Constructs an XmlCalendar with the specified year, month, day, hours, minutes, seconds, and optional fractional seconds, in the specified timezone.

### XmlCalendar

    public XmlCalendar(int year,
                       int month,
                       int day,
                       int hour,
                       int minute,
                       int second,
                       BigDecimal fraction)

  Constructs an XmlCalendar with the specified year, month, day, hours, minutes, seconds, and optional fractional seconds, in the default timezone.

### XmlCalendar

    public XmlCalendar(String xmlSchemaDateString)

  Constructs an XmlCalendar for a standard XML schema formatted date string. The parser accepts any of the following formats: YYYY-MM-DDThh:mm:ss - dateTime YYYY-MM-DD - date hh:mm:ss - time YYYY - gYear --MM - gMonth ---DD - gDay The parser actually accepts all 16 combinations of subsets of fields (Y, M, D, T) using the same scheme, even for combinations that are not defined as types in the schema spec, such as year, day, and time: YYYY--DDThh:mm:ss - [everything but month specified] In the string, each field must be padded to its full width, for example, January must be --01, not just --1. In particular, a year must be padded to at least four digits, so "98" is not a valid year, although "1998" and "0098" are both valid years, unambiguously 19 centuries separated from each other. A year may also be preceded by a minus symbol: 0000 is 1 BC and -0001 is 2 BC. Finally a timezone is always allowed (yet optional) at the end. Timezones must be either "Z" (UTC, which we translate to GMT), or simple offsets from UTC in the range "-14:00" to "+14:00", for example: "14:30:00-05:00" specifies 2:30 PM in the afternoon at UTC-05:00, which is the same as EST. If a timezone is not specified, the default TimeZone is used.

### XmlCalendar

    public XmlCalendar(Date date)

  Constructs an XmlCalendar from a Date. The default TimeZone is used for computing the various fields.

## Method Detail

### computeTime() Method

    protected void computeTime()

Overrides GregorianCalendar.computeTime to apply a different default year. (It must be a leap year.)

Overrides
  `GregorianCalendar.computeTime()`

### get(int) Method

    public int get(int field)

Gets the value for a given time field. Unlike the GregorianCalendar implementation, the get() does not force a complete of all fields. If you wish to force a completion of all the fields, call getTime() first.

Overrides
  `Calendar.get(int)`

### getDefaultYear() Method

    public static int getDefaultYear()

Returns the default year that is used when no year is specified.

### setDefaultYear(int) Method

    public static void setDefaultYear(int year)

Sets the default year to be used when no year is specified.

### toString() Method

    public String toString()

Prints the XmlCalendar using a standard XML Schema format, as described in XmlCalendar(String s).

Overrides
  `Calendar.toString()`