com.icl.saxon.expr
Class ErrorExpression

java.lang.Object
  com.icl.saxon.expr.Expression
      com.icl.saxon.expr.ErrorExpression

public class ErrorExpression

extends Expression

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

Field Summary

Fields inherited from class com.icl.saxon.expr.Expression

staticContext

Constructor Summary

ErrorExpression(XPathException exception)
Constructor

Method Summary

void	display(int level) Diagnostic print of expression structure
Value	evaluate(Context c) Evaluate this expression.
int	getDataType() Determine the data type of the expression, if possible
int	getDependencies() Determine which aspects of the context the expression depends on.
Expression	reduce(int dependencies, Context context) Perform a partial evaluation of the expression, by eliminating specified dependencies on the context.

Methods inherited from class com.icl.saxon.expr.Expression

containsReferences, enumerate, evaluateAsBoolean, evaluateAsNodeSet, evaluateAsNumber, evaluateAsString, getStaticContext, indent, isContextDocumentNodeSet, make, outputStringValue, setStaticContext, simplify, usesCurrent

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

Method Detail

evaluate

public Value evaluate(Context c)
               throws XPathException

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

Specified by:

evaluate in class Expression

Parameters:

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

Returns:

the value of the expression, evaluated in the current context

Throws:

XPathException

getDataType

public int getDataType()

Determine the data type of the expression, if possible

Specified by:

getDataType in class Expression

Returns:

Value.ANY (meaning not known in advance)

getDependencies

public int getDependencies()

Determine which aspects of the context the expression depends on. The result is a bitwise-or'ed value composed from constants such as Context.VARIABLES and Context.CURRENT_NODE

Specified by:

getDependencies in class Expression

reduce

public Expression reduce(int dependencies,
                         Context context)
                  throws XPathException

Perform a partial evaluation of the expression, by eliminating specified dependencies on the context.

Specified by:

reduce in class Expression

Parameters:

dependencies - The dependencies to be removed

context - The context to be used for the partial evaluation

Returns:

a new expression that does not have any of the specified dependencies

Throws:

XPathException

display

public void display(int level)

Diagnostic print of expression structure

Specified by:

display in class Expression