net.sf.saxon.expr
Class ErrorExpression

java.lang.Object
  |
  +--net.sf.saxon.expr.ComputedExpression
        |
        +--net.sf.saxon.expr.ErrorExpression

All Implemented Interfaces:

Expression, java.io.Serializable

public class ErrorExpression

extends ComputedExpression

Error expression: this expression is generated when the supplied expression cannot be parsed, and the containing element enables forwards-compatible processing. It defers the generation of an error message until an attempt is made to evaluate the expression

See Also:

Serialized Form

Field Summary

 

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

lineNumber, NO_ARGUMENTS, staticProperties

 

Constructor Summary

ErrorExpression(XPathException exception)           Constructor

 

Method Summary
Expression	analyze(StaticContext env)           Type-check the expression.
int	computeCardinality()           Determine the static cardinality
void	display(int level, NamePool pool)           Diagnostic print of expression structure
Item	evaluateItem(XPathContext context)           Evaluate the expression.
ItemType	getItemType()           Determine the data type of the expression, if possible
SequenceIterator	iterate(XPathContext context)           Iterate over the expression.

 

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

computeDependencies, computeSpecialProperties, computeStaticProperties, dynamicError, effectiveBooleanValue, evaluateAsString, getCardinality, getDependencies, getIntrinsicDependencies, getLineNumber, getSourceLocator, getSpecialProperties, getSubExpressions, markTailFunctionCalls, promote, setLineNumber, simplify, typeError

 

Methods inherited from class java.lang.Object

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

 

Constructor Detail

ErrorExpression

public ErrorExpression(XPathException exception)

Constructor

Parameters:

exception - the error found when parsing this expression

analyze

public Expression analyze(StaticContext env)
                   throws XPathException

Type-check the expression.

Parameters:

env - the static context of the expression

Returns:

the original expression, rewritten to perform necessary run-time type checks, and to perform other type-related optimizations

XPathException

evaluateItem

public Item evaluateItem(XPathContext context)
                  throws XPathException

Evaluate the expression. This always throws the exception registered when the expression was first parsed.

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 expression. This always throws the exception registered when the expression was first parsed.

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

getItemType

public ItemType getItemType()

Determine the data type of the expression, if possible

Returns:

Type.ITEM (meaning not known in advance)

computeCardinality

public int computeCardinality()

Determine the static cardinality

Specified by:

computeCardinality in class ComputedExpression

display

public void display(int level,
                    NamePool pool)

Diagnostic print of expression structure

Parameters:

level - indentation level for this expression