net.sf.saxon.value
Class DateValue

java.lang.Object
  net.sf.saxon.value.Value
      net.sf.saxon.value.AtomicValue
          net.sf.saxon.value.CalendarValue
              net.sf.saxon.value.GDateValue
                  net.sf.saxon.value.DateValue

All Implemented Interfaces:

Serializable, Comparable, PullEvent, SequenceIterable, GroundedValue, Item, ValueRepresentation, ConversionResult

public class DateValue
extends GDateValue
implements Comparable

A value of type Date. Note that a Date may include a TimeZone.

See Also:

Serialized Form

Field Summary

Fields inherited from class net.sf.saxon.value.CalendarValue

NO_TIMEZONE

Fields inherited from class net.sf.saxon.value.Value

EMPTY_CLASS_ARRAY, INDETERMINATE_ORDERING

Fields inherited from interface net.sf.saxon.om.ValueRepresentation

EMPTY_VALUE_ARRAY

Fields inherited from interface net.sf.saxon.om.ValueRepresentation

EMPTY_VALUE_ARRAY

Constructor Summary

DateValue(CharSequence s)
Constructor: create a date value from a supplied string, in ISO 8601 format

DateValue(GregorianCalendar calendar, int tz)
Create a DateValue

DateValue(int year, byte month, byte day)
Constructor given a year, month, and day.

DateValue(int year, byte month, byte day, int tz)
Constructor given a year, month, and day, and timezone.

DateValue(int year, byte month, byte day, int tz, AtomicType type)
Constructor given a year, month, and day, and timezone, and an AtomicType representing a subtype of xs:date.

Method Summary

CalendarValue	add(DurationValue duration) Add a duration to a date
CalendarValue	adjustTimezone(int timezone) Return a new date with the same normalized value, but in a different timezone.
int	compareTo(Object v2) Context-free comparison of two DateValue values.
ConversionResult	convertPrimitive(BuiltInAtomicType requiredType, boolean validate, XPathContext context) Convert to target data type
AtomicValue	copyAsSubType(AtomicType typeLabel) Make a copy of this date value, but with a new type label
static DateValue	dateFromJulianDayNumber(int julianDayNumber) Get the Gregorian date corresponding to a particular Julian day number.
CharSequence	getCanonicalLexicalRepresentation() Get the canonical lexical representation as defined in XML Schema.
AtomicValue	getComponent(int component) Get a component of the value.
static int	getDayOfWeek(int year, int month, int day) Get the day of the week.
static int	getDayWithinYear(int year, int month, int day) Get the ordinal day number within the year (1 Jan = 1, 1 Feb = 32, etc)
static int	getJulianDayNumber(int year, int month, int day) Calculate the Julian day number at 00:00 on a given date.
BuiltInAtomicType	getPrimitiveType() Determine the primitive type of the value.
CharSequence	getStringValueCS() Convert to string
static int	getWeekNumber(int year, int month, int day) Get the ISO week number for a given date.
static int	getWeekNumberWithinMonth(int year, int month, int day) Get the week number within a month.
static ConversionResult	makeDateValue(CharSequence in) Static factory method: construct a DateValue from a string in the lexical form of a date, returning a ValidationFailure if the supplied string is invalid
DayTimeDurationValue	subtract(CalendarValue other, XPathContext context) Determine the difference between two points in time, as a duration
static DateValue	tomorrow(int year, byte month, byte day) Get the date that immediately follows a given date
static DateValue	yesterday(int year, byte month, byte day) Get the date that immediately precedes a given date

Methods inherited from class net.sf.saxon.value.GDateValue

compareTo, convertToJava, equals, getCalendar, getComparisonKey, getDay, getMonth, getSchemaComparable, getYear, hashCode, isLeapYear, isValidDate, toDateTime

Methods inherited from class net.sf.saxon.value.CalendarValue

adjustTimezone, appendTimezone, appendTimezone, getStringValue, getTimezoneInMinutes, getXPathComparable, hasTimezone, removeTimezone, setTimezoneInMinutes

Methods inherited from class net.sf.saxon.value.AtomicValue

asAtomic, checkPermittedContents, convert, convert, effectiveBooleanValue, getCardinality, getItemType, getLength, getTypedValue, getTypeLabel, isNaN, itemAt, iterate, process, setTypeLabel, subsequence, toString

Methods inherited from class net.sf.saxon.value.Value

asItem, asItem, asIterator, asValue, convertJavaObjectToXPath, convertToJava, fromItem, getIterator, iterate, makeQNameValue, reduce, stringToNumber

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

DateValue

public DateValue(int year,
                 byte month,
                 byte day)

Constructor given a year, month, and day. Performs no validation.

Parameters:

year - The year as held internally (note that the year before 1AD is 0)

month - The month, 1-12

day - The day 1-31

DateValue

public DateValue(int year,
                 byte month,
                 byte day,
                 int tz)

Constructor given a year, month, and day, and timezone. Performs no validation.

Parameters:

year - The year as held internally (note that the year before 1AD is 0)

month - The month, 1-12

day - The day 1-31

tz - the timezone displacement in minutes from UTC. Supply the value CalendarValue.NO_TIMEZONE if there is no timezone component.

DateValue

public DateValue(int year,
                 byte month,
                 byte day,
                 int tz,
                 AtomicType type)

Constructor given a year, month, and day, and timezone, and an AtomicType representing a subtype of xs:date. Performs no validation.

Parameters:

year - The year as held internally (note that the year before 1AD is 0)

month - The month, 1-12

day - The day 1-31

tz - the timezone displacement in minutes from UTC. Supply the value CalendarValue.NO_TIMEZONE if there is no timezone component.

type - the type. This must be a type derived from xs:date, and the value must conform to this type. The method does not check these conditions.

DateValue

public DateValue(CharSequence s)
          throws ValidationException

Constructor: create a date value from a supplied string, in ISO 8601 format

Parameters:

s - the lexical form of the date value

Throws:

ValidationException - if the supplied string is not a valid date

DateValue

public DateValue(GregorianCalendar calendar,
                 int tz)

Create a DateValue

Parameters:

calendar - the absolute date/time value

tz - The timezone offset from GMT in minutes, positive or negative; or the special value NO_TIMEZONE indicating that the value is not in a timezone

Method Detail

makeDateValue

public static ConversionResult makeDateValue(CharSequence in)

Static factory method: construct a DateValue from a string in the lexical form of a date, returning a ValidationFailure if the supplied string is invalid

Parameters:

in - the lexical form of the date

Returns:

either a DateValue or a ValidationFailure

getPrimitiveType

public BuiltInAtomicType getPrimitiveType()

Determine the primitive type of the value. This delivers the same answer as getItemType().getPrimitiveItemType(). The primitive types are the 19 primitive types of XML Schema, plus xs:integer, xs:dayTimeDuration and xs:yearMonthDuration, and xs:untypedAtomic. For external objects, the result is AnyAtomicType.

Specified by:

getPrimitiveType in class AtomicValue

Returns:

the primitive type

tomorrow

public static DateValue tomorrow(int year,
                                 byte month,
                                 byte day)

Get the date that immediately follows a given date

Parameters:

year - the year

month - the month (1-12)

day - the day (1-31)

Returns:

a new DateValue with no timezone information

yesterday

public static DateValue yesterday(int year,
                                  byte month,
                                  byte day)

Get the date that immediately precedes a given date

Parameters:

year - the year

month - the month (1-12)

day - the day (1-31)

Returns:

a new DateValue with no timezone information

convertPrimitive

public ConversionResult convertPrimitive(BuiltInAtomicType requiredType,
                                         boolean validate,
                                         XPathContext context)

Convert to target data type

Parameters:

requiredType - an integer identifying the required atomic type

context - the XPath dynamic context

validate - true if validation is required. If set to false, the caller guarantees that the value is valid for the target data type, and that further validation is therefore not required. Note that a validation failure may be reported even if validation was not requested.

Returns:

an AtomicValue, a value of the required type; or an ErrorValue

getStringValueCS

public CharSequence getStringValueCS()

Convert to string

Specified by:

getStringValueCS in interface Item

Specified by:

getStringValueCS in interface ValueRepresentation

Overrides:

getStringValueCS in class AtomicValue

Returns:

ISO 8601 representation.

See Also:

Item.getStringValue()

getCanonicalLexicalRepresentation

public CharSequence getCanonicalLexicalRepresentation()

Get the canonical lexical representation as defined in XML Schema. This is not always the same as the result of casting to a string according to the XPath rules. For xs:date, the timezone is adjusted to be in the range +12:00 to -11:59

Overrides:

getCanonicalLexicalRepresentation in class Value

Returns:

the canonical lexical representation if defined in XML Schema; otherwise, the result of casting to string according to the XPath 2.0 rules

copyAsSubType

public AtomicValue copyAsSubType(AtomicType typeLabel)

Make a copy of this date value, but with a new type label

Specified by:

copyAsSubType in class AtomicValue

Parameters:

typeLabel - the new type label: must be a subtype of xs:date

Returns:

the new xs:date value

adjustTimezone

public CalendarValue adjustTimezone(int timezone)

Return a new date with the same normalized value, but in a different timezone. This is called only for a DateValue that has an explicit timezone

Specified by:

adjustTimezone in class CalendarValue

Parameters:

timezone - the new timezone offset, in minutes

Returns:

the time in the new timezone. This will be a new TimeValue unless no change was required to the original value

getComponent

public AtomicValue getComponent(int component)
                         throws XPathException

Get a component of the value. Returns null if the timezone component is requested and is not present.

Overrides:

getComponent in class AtomicValue

Parameters:

component - identifies the required component, as a constant defined in class Component, for example Component.HOURS

Returns:

the value of the requested component of this value

Throws:

XPathException

add

public CalendarValue add(DurationValue duration)
                  throws XPathException

Add a duration to a date

Specified by:

add in class CalendarValue

Parameters:

duration - the duration to be added (may be negative)

Returns:

the new date

Throws:

XPathException - if the duration is an xs:duration, as distinct from a subclass thereof

subtract

public DayTimeDurationValue subtract(CalendarValue other,
                                     XPathContext context)
                              throws XPathException

Determine the difference between two points in time, as a duration

Overrides:

subtract in class CalendarValue

Parameters:

other - the other point in time

context - the XPath dynamic context

Returns:

the duration as an xs:dayTimeDuration

Throws:

XPathException - for example if one value is a date and the other is a time

compareTo

public int compareTo(Object v2)

Context-free comparison of two DateValue values. For this to work, the two values must either both have a timezone or both have none.

Specified by:

compareTo in interface Comparable

Parameters:

v2 - the other value

Returns:

the result of the comparison: -1 if the first is earlier, 0 if they are equal, +1 if the first is later

Throws:

ClassCastException - if the values are not comparable (which might be because no timezone is available)

getJulianDayNumber

public static int getJulianDayNumber(int year,
                                     int month,
                                     int day)

Calculate the Julian day number at 00:00 on a given date. This algorithm is taken from http://vsg.cape.com/~pbaum/date/jdalg.htm and http://vsg.cape.com/~pbaum/date/jdalg2.htm (adjusted to handle BC dates correctly)

Note that this assumes dates in the proleptic Gregorian calendar

Parameters:

year - the year

month - the month (1-12)

day - the day (1-31)

Returns:

the Julian day number

dateFromJulianDayNumber

public static DateValue dateFromJulianDayNumber(int julianDayNumber)

Get the Gregorian date corresponding to a particular Julian day number. The algorithm is taken from http://www.hermetic.ch/cal_stud/jdn.htm#comp

Parameters:

julianDayNumber - the Julian day number

Returns:

a DateValue with no timezone information set

getDayWithinYear

public static int getDayWithinYear(int year,
                                   int month,
                                   int day)

Get the ordinal day number within the year (1 Jan = 1, 1 Feb = 32, etc)

Parameters:

year - the year

month - the month (1-12)

day - the day (1-31)

Returns:

the ordinal day number within the year

getDayOfWeek

public static int getDayOfWeek(int year,
                               int month,
                               int day)

Get the day of the week. The days of the week are numbered from 1 (Monday) to 7 (Sunday)

Parameters:

year - the year

month - the month (1-12)

day - the day (1-31)

Returns:

the day of the week, 1=Monday .... 7=Sunday

getWeekNumber

public static int getWeekNumber(int year,
                                int month,
                                int day)

Get the ISO week number for a given date. The days of the week are numbered from 1 (Monday) to 7 (Sunday), and week 1 in any calendar year is the week (from Monday to Sunday) that includes the first Thursday of that year

Parameters:

year - the year

month - the month (1-12)

day - the day (1-31)

Returns:

the ISO week number

getWeekNumberWithinMonth

public static int getWeekNumberWithinMonth(int year,
                                           int month,
                                           int day)

Get the week number within a month. This is required for the XSLT format-date() function, and the rules are not entirely clear. The days of the week are numbered from 1 (Monday) to 7 (Sunday), and by analogy with the ISO week number, we consider that week 1 in any calendar month is the week (from Monday to Sunday) that includes the first Thursday of that month. Unlike the ISO week number, we put the previous days in week zero.

Parameters:

year - the year

month - the month (1-12)

day - the day (1-31)

Returns:

the week number within a month