net.sf.saxon.functions
Class TreatFn

java.lang.Object
  net.sf.saxon.expr.ComputedExpression
      net.sf.saxon.expr.FunctionCall
          net.sf.saxon.functions.SystemFunction
              net.sf.saxon.functions.TreatFn

All Implemented Interfaces:

Serializable, Expression

public class TreatFn
extends SystemFunction

This class supports the XPath 2.0 functions exactly-one(), one-or-more(), zero-or-one(). Because Saxon doesn't do strict static type checking, these are essentially identity functions; the run-time type checking is done as part of the function call mechanism

See Also:

Serialized Form

Field Summary

Fields inherited from class net.sf.saxon.functions.SystemFunction

operation

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

argument

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

lineNumber, NO_ARGUMENTS, staticProperties

Constructor Summary

TreatFn()

Method Summary

Item	evaluateItem(XPathContext context) Evaluate the function
SequenceIterator	iterate(XPathContext context) Iterate over the results of the function

Methods inherited from class net.sf.saxon.functions.SystemFunction

addContextDocumentArgument, checkArguments, computeCardinality, display, getDetails, getItemType, getName, getRequiredType, main, makeSystemFunction, useContextItemAsDefault

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

analyze, checkArgumentCount, getNumberOfArguments, getSubExpressions, preEvaluate, promote, setArguments, simplify, simplifyArguments

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

computeDependencies, computeSpecialProperties, computeStaticProperties, dynamicError, effectiveBooleanValue, evaluateAsString, getCardinality, getDependencies, getIntrinsicDependencies, getLineNumber, getSpecialProperties, markTailFunctionCalls, setLineNumber, typeError

Methods inherited from class java.lang.Object

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

Constructor Detail

TreatFn

public TreatFn()

Method Detail

evaluateItem

public Item evaluateItem(XPathContext context)
                  throws XPathException

Evaluate the function

Specified by:

evaluateItem in interface Expression

Overrides:

evaluateItem in class ComputedExpression

Parameters:

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

Returns:

the node or atomic value that results from evaluating the expression; or null to indicate that the result is an empty sequence

Throws:

XPathException - if any dynamic error occurs evaluating the expression

iterate

public SequenceIterator iterate(XPathContext context)
                         throws XPathException

Iterate over the results of the function

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