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See:
Description
Class Summary | |
AnyURIValue | A string value |
AtomicValue | A AtomicValue is a value that isn't a sequence and isn't a node. |
Base64BinaryValue | A value of type xs:base64Binary |
BigIntegerValue | An integer value: note this is a subtype of decimal in XML Schema, not a primitive type. |
BooleanValue | A boolean XPath value |
CalendarValue | Abstract superclass for Date, Time, and DateTime |
Cardinality | This class contains static methods to manipulate the cardinality property of a type. |
Closure | A Closure represents a value that has not yet been evaluated: the value is represented by an expression, together with saved values of all the context variables that the expression depends on. |
DateTimeValue | A value of type DateTime |
DateValue | A value of type Date. |
DecimalValue | A decimal value |
DerivedAtomicValue | A DerivedAtomicValue is an atomic value of a user-defined type |
DoubleValue | A numeric (double precision floating point) value |
DurationValue | A value of type xs:duration |
EmptySequence | An EmptySequence object represents a sequence containing no members. |
FloatValue | A numeric (single precision floating point) value |
GDayValue | Implementation of the xs:gDay data type |
GMonthDayValue | Implementation of the xs:gYear data type |
GMonthValue | Implementation of the xs:gMonth data type |
GYearMonthValue | Implementation of the xs:gYearMonth data type |
GYearValue | Implementation of the xs:gYear data type |
HexBinaryValue | A value of type xs:hexBinary |
IntegerValue | An integer value: note this is a subtype of decimal in XML Schema, not a primitive type. |
MonthDurationValue | A value of type xsd:yearMonthDuration |
NumericValue | NumericValue is an abstract superclass for IntegerValue, DecimalValue, FloatValue, and DoubleValue |
ObjectValue | An XPath value that encapsulates a Java object. |
QNameValue | A QName value |
RestrictedStringValue | A value conforming to one of the built-in subtypes of String, specifically normalizedString, token, language, Name, NCName, ID, IDREF, ENTITY, NMTOKEN. |
SecondsDurationValue | A value of type xsd:dayTimeDuration |
SequenceExtent | A sequence value implemented extensionally. |
SequenceIntent | A SequenceIntent is sequence value that uses deferred evaluation. |
SequenceType | SequenceType: a sequence type consists of a primary type, which indicates the type of item, and a cardinality, which indicates the number of occurrences permitted. |
SequenceValue | A SequenceValue object represents a sequence whose members are all AtomicValues or Nodes. |
SingletonNode | A value that is a sequence containing zero or one nodes |
StringValue | A string value |
TextFragmentValue | This class represents a temporary tree whose root document node owns a single text node. |
TimeValue | A value of type time |
UntypedAtomicValue | An Untyped Atomic value. |
Value | A value is the result of an expression but it is also an expression in its own right. |
This package provides classes representing XPath values (that is, the results of an expression). There are different classes for different types of value.
The principal class is:
Value:
This represents the result of evaluating an expression. But a Value is also an expression in its
own right, reflecting the fact that literal values can be used syntactically wherever expressions
can be used. There are subclasses of Value for the different data types: StringValue, NumericValue,
SequenceValue, BooleanValue, and so on.
Although values are all fixed, the class SequenceIntent
deserves special mention
because it represents a value that has not yet been evaluated. It is actually a wrapper for a
SequenceIterator that can be used to obtain the values when required. This SequenceIterator will
always be context-independent, it will return the same values each time it is used. The SequenceIntent
class contains logic to ensure that if the sequence is used repeatedly, the results are saved locally
in memory: this is a trade-off to try and ensure a balance between repeated calculation of the same results,
and holding results in memory just in case they are needed again.
This package also includes the class Type
, which contains a number of methods for
handling type inferences.
Michael H. Kay
25 April 2002
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