net.sf.saxon.value
Class AtomicValue

java.lang.Object
  net.sf.saxon.value.Value
      net.sf.saxon.value.AtomicValue

All Implemented Interfaces:

Serializable, Expression, Item

Direct Known Subclasses:

AnyURIValue, AtomicUserDefinedValue, Base64BinaryValue, BooleanValue, CalendarValue, DurationValue, HexBinaryValue, NumericValue, ObjectValue, QNameValue, StringValue

public abstract class AtomicValue
extends Value
implements Item

A AtomicValue is a value that isn't a sequence and isn't a node. More strictly, it is any sequence of length one whose content is not a node.

See Also:

Serialized Form

Constructor Summary

AtomicValue()

Method Summary

int	conversionPreference(Class required) Get conversion preference for this value to a Java class.
AtomicValue	convert(AtomicType targetType) Convert the value to a given type.
AtomicValue	convert(AtomicType targetType, NamespaceResolver resolver) Convert the value to a namespace-sensitive type, that is, a QName or NOTATION.
abstract AtomicValue	convert(int requiredType) Convert the value to a given type.
Object	convertToJava(Class target) Convert to Java object (for passing to external functions)
boolean	effectiveBooleanValue(XPathContext context) Get the effective boolean value of the value
String	evaluateAsString(XPathContext context) Evaluate as a string
Item	evaluateItem(XPathContext context) Evaluate the value (this simply returns the value unchanged)
int	getCardinality() Determine the static cardinality
AtomicValue	getComponent(int component) Method to extract components of a value.
AtomicValue	getPrimitiveValue() Get the primitive value (the value in the value space).
SequenceIterator	getTypedValue() Get the typed value of this item
SequenceIterator	iterate(XPathContext context) Iterate over the (single) item in the sequence

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

analyze, asItem, asValue, collapseWhitespace, getDependencies, getSpecialProperties, getSubExpressions, inverse, normalizeWhitespace, promote, simplify, stringToInteger, stringToNumber, trimWhitespace

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface net.sf.saxon.om.Item

getStringValue

Methods inherited from interface net.sf.saxon.expr.Expression

display, getItemType

Constructor Detail

AtomicValue

public AtomicValue()

Method Detail

getCardinality

public final int getCardinality()

Determine the static cardinality

Specified by:

getCardinality in interface Expression

Returns:

code identifying the cardinality

See Also:

Cardinality

convert

public abstract AtomicValue convert(int requiredType)
                             throws XPathException

Convert the value to a given type. The result of the conversion will be an atomic value of the required type. This method works only where the target type is a built-in type.

Parameters:

requiredType - type code of the required atomic type

Returns:

the result of the conversion, if conversion was possible. This will always be an instance of the class corresponding to the type of value requested

Throws:

XPathException - if conversion is not allowed for this required type, or if the particular value cannot be converted

convert

public final AtomicValue convert(AtomicType targetType)
                          throws XPathException

Convert the value to a given type. The result of the conversion will be an atomic value of the required type. This method works where the target type is a built-in atomic type and also where it is a user-defined atomic type.

Throws:

XPathException

convert

public final AtomicValue convert(AtomicType targetType,
                                 NamespaceResolver resolver)
                          throws XPathException

Convert the value to a namespace-sensitive type, that is, a QName or NOTATION. The result of the conversion will be an atomic value of the required type. This method works where the target type is a built-in atomic type and also where it is a user-defined atomic type.

Throws:

XPathException

evaluateItem

public Item evaluateItem(XPathContext context)
                  throws XPathException

Evaluate the value (this simply returns the value unchanged)

Specified by:

evaluateItem in interface Expression

Parameters:

context - the evaluation context (not used in this implementation)

Returns:

the value, unchanged

Throws:

XPathException

iterate

public final SequenceIterator iterate(XPathContext context)

Iterate over the (single) item in the sequence

Specified by:

iterate in interface Expression

Parameters:

context - the evaluation context (not used in this implementation)

Returns:

a SequenceIterator that iterates over the single item in this value

evaluateAsString

public final String evaluateAsString(XPathContext context)
                              throws XPathException

Evaluate as a string

Specified by:

evaluateAsString in interface Expression

Parameters:

context - The context in which the expression is to be evaluated

Returns:

the value of the expression, evaluated in the current context. The expression must return a string or (); if the value of the expression is (), this method returns "".

Throws:

XPathException - if any dynamic error occurs evaluating the expression

getTypedValue

public final SequenceIterator getTypedValue()

Get the typed value of this item

Specified by:

getTypedValue in interface Item

Returns:

the typed value of the expression (which is this value)

getPrimitiveValue

public AtomicValue getPrimitiveValue()

Get the primitive value (the value in the value space). This returns an AtomicValue of a class that would be used to represent the primitive value. In effect this means that for built-in types, it returns the value itself, but for user-defined type, it returns the primitive value minus the type annotation

effectiveBooleanValue

public boolean effectiveBooleanValue(XPathContext context)

Get the effective boolean value of the value

Specified by:

effectiveBooleanValue in interface Expression

Parameters:

context - the evaluation context (not used in this implementation)

Returns:

true, unless the value is boolean false, numeric zero, or zero-length string

getComponent

public AtomicValue getComponent(int component)
                         throws XPathException

Method to extract components of a value. Implemented by some subclasses, but defined at this level for convenience

Throws:

XPathException

conversionPreference

public int conversionPreference(Class required)

Get conversion preference for this value to a Java class. A low result indicates higher preference. This method is overridden in subclasses, but it contains common functionality to supply a scalar value to a method expecting a list or iterator.

Specified by:

conversionPreference in class Value

convertToJava

public Object convertToJava(Class target)
                     throws XPathException

Convert to Java object (for passing to external functions)

Specified by:

convertToJava in class Value

Parameters:

target - The class required by the external function

Returns:

an object of the target class

Throws:

XPathException