com.saxonica.extra
Class StringMirrorExpression

java.lang.Object
  net.sf.saxon.expr.ComputedExpression
      net.sf.saxon.expr.UnaryExpression
          com.saxonica.extra.StringMirrorExpression

All Implemented Interfaces:

Container, Expression, InstructionInfoProvider, java.io.Serializable, javax.xml.transform.SourceLocator

public final class StringMirrorExpression

extends UnaryExpression

A StringMirrorExpression is used internally when indexing values that may be typed or untypedAtomic. Given a sequence of atomic values, it returns a sequence consisting of all the original atomic values, plus copies of those values that aren't strings or untyped atomic, converted to untyped atomic. For example, if the input sequence is (3,4,"+",5) then the output is (3,"3",4,"4","+",5,"5").

It is thus equivalent to:

for $in in $sequence return ($in, xdt:untypedAtomic($in)[not($in instanceof xs:string or $in instanceof xdt:untypedAtomic)])

See Also:

Serialized Form

Field Summary

Fields inherited from class net.sf.saxon.expr.UnaryExpression

operand

Fields inherited from class net.sf.saxon.expr.ComputedExpression

locationId, staticProperties

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

EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD

Constructor Summary

StringMirrorExpression(Expression base)

Method Summary

int	computeCardinality() Get the static cardinality of the expression
int	computeSpecialProperties() Determine the special properties of this expression
protected java.lang.String	displayOperator(NamePool pool) Give a string representation of the operator for use in diagnostics
ItemType	getItemType(TypeHierarchy th) Get the static type of the expression
SequenceIterator	iterate(XPathContext context) Return an Iterator to iterate over the values of a sequence.

Methods inherited from class net.sf.saxon.expr.UnaryExpression

display, equals, getBaseExpression, hashCode, iterateSubExpressions, optimize, promote, simplify, typeCheck

Methods inherited from class net.sf.saxon.expr.ComputedExpression

adoptChildExpression, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, getCardinality, getColumnNumber, getConstructType, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getInstructionInfo, getIntrinsicDependencies, getLineNumber, getLocationId, getLocationProvider, getParentExpression, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, hasBadParentPointer, markTailFunctionCalls, process, resetStaticProperties, setLocationId, setParentExpression, suppressValidation, typeError, typeError

Methods inherited from class java.lang.Object

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

Constructor Detail

StringMirrorExpression

public StringMirrorExpression(Expression base)

Method Detail

computeCardinality

public int computeCardinality()

Get the static cardinality of the expression

Overrides:

computeCardinality in class UnaryExpression

getItemType

public ItemType getItemType(TypeHierarchy th)

Get the static type of the expression

Specified by:

getItemType in interface Expression

Overrides:

getItemType in class UnaryExpression

Parameters:

th -

Returns:

the item type of the items in the result sequence, insofar as this is known statically.

computeSpecialProperties

public int computeSpecialProperties()

Determine the special properties of this expression

Overrides:

computeSpecialProperties in class UnaryExpression

Returns:

StaticProperty.NON_CREATIVE.

iterate

public SequenceIterator iterate(XPathContext context)
                         throws XPathException

Return an Iterator to iterate over the values of a sequence. The value of every expression can be regarded as a sequence, so this method is supported for all expressions. This default implementation handles iteration for expressions that return singleton values: for non-singleton expressions, the subclass must provide its own implementation.

Specified by:

iterate in interface Expression

Overrides:

iterate in class ComputedExpression

Parameters:

context - supplies the context for evaluation

Returns:

a SequenceIterator that can be used to iterate over the result of the expression

Throws:

XPathException - if any dynamic error occurs evaluating the expression

displayOperator

protected java.lang.String displayOperator(NamePool pool)

Give a string representation of the operator for use in diagnostics

Specified by:

displayOperator in class UnaryExpression

Returns:

the operator, as a string