net.sf.saxon.value

Class DateValue

public class DateValue extends GDateValue implements Comparable

A value of type Date. Note that a Date may include a TimeZone.
Constructor Summary
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.
DateValue(CharSequence s)
Constructor: create a date value from a supplied string, in ISO 8601 format
DateValue(GregorianCalendar calendar, int tz)
Create a DateValue
Method Summary
CalendarValueadd(DurationValue duration)
Add a duration to a date
CalendarValueadjustTimezone(int timezone)
Return a new date with the same normalized value, but in a different timezone.
intcompareTo(Object v2)
Context-free comparison of two DateValue values.
ConversionResultconvertPrimitive(BuiltInAtomicType requiredType, boolean validate, XPathContext context)
Convert to target data type
AtomicValuecopyAsSubType(AtomicType typeLabel)
Make a copy of this date value, but with a new type label
static DateValuedateFromJulianDayNumber(int julianDayNumber)
Get the Gregorian date corresponding to a particular Julian day number.
CharSequencegetCanonicalLexicalRepresentation()
Get the canonical lexical representation as defined in XML Schema.
static intgetDayOfWeek(int year, int month, int day)
Get the day of the week.
static intgetDayWithinYear(int year, int month, int day)
Get the ordinal day number within the year (1 Jan = 1, 1 Feb = 32, etc)
static intgetJulianDayNumber(int year, int month, int day)
Calculate the Julian day number at 00:00 on a given date.
CharSequencegetPrimitiveStringValue()
Convert to string
BuiltInAtomicTypegetPrimitiveType()
Determine the primitive type of the value.
static intgetWeekNumber(int year, int month, int day)
Get the ISO week number for a given date.
static intgetWeekNumberWithinMonth(int year, int month, int day)
Get the week number within a month.
static ConversionResultmakeDateValue(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
DayTimeDurationValuesubtract(CalendarValue other, XPathContext context)
Determine the difference between two points in time, as a duration
static DateValuetomorrow(int year, byte month, byte day)
Get the date that immediately follows a given date
static DateValueyesterday(int year, byte month, byte day)
Get the date that immediately precedes a given date

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 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 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)
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

add

public CalendarValue add(DurationValue duration)
Add a duration to a date

Parameters: duration the duration to be added (may be negative)

Returns: the new date

Throws: net.sf.saxon.trans.XPathException if the duration is an xs:duration, as distinct from a subclass thereof

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

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

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.

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)

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

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

copyAsSubType

public AtomicValue copyAsSubType(AtomicType typeLabel)
Make a copy of this date value, but with a new type label

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

Returns: the new xs:date value

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

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

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

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

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

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

getPrimitiveStringValue

public CharSequence getPrimitiveStringValue()
Convert to string

Returns: ISO 8601 representation.

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.

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

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

subtract

public DayTimeDurationValue subtract(CalendarValue other, XPathContext context)
Determine the difference between two points in time, as a duration

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

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