Class Error

All Implemented Interfaces:
Serializable, SourceLocator, LocationProvider, SaxonLocator, CallableExpression, InstructionInfo, Locator

public class Error extends SystemFunction implements CallableExpression
Implement XPath function fn:error()
See Also:
  • Constructor Details

    • Error

      public Error()
  • Method Details

    • computeSpecialProperties

      public int computeSpecialProperties()
      Description copied from class: SystemFunction
      Determine the special properties of this expression. The general rule is that a system function call is non-creative if its return type is atomic, or if all its arguments are non-creative. This is overridden for the generate-id() function, which is considered creative if its operand is creative (because the result depends on the identity of the operand)
      Overrides:
      computeSpecialProperties in class SystemFunction
      Returns:
      the special properties, as a bit-significant integer
    • preEvaluate

      public Expression preEvaluate(ExpressionVisitor visitor)
      preEvaluate: this method suppresses compile-time evaluation by doing nothing
      Overrides:
      preEvaluate in class FunctionCall
      Parameters:
      visitor - an expression visitor
      Returns:
      the result of the early evaluation, or the original expression, or potentially a simplified expression
    • isVacuousExpression

      public boolean isVacuousExpression()
      Determine whether this is a vacuous expression as defined in the XQuery update specification
      Overrides:
      isVacuousExpression in class Expression
      Returns:
      true if this expression is vacuous
    • evaluateItem

      public Item evaluateItem(XPathContext context) throws XPathException
      Evaluation of the expression always throws an error
      Overrides:
      evaluateItem in class Expression
      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
    • evaluatePendingUpdates

      public void evaluatePendingUpdates(XPathContext context, PendingUpdateList pul) throws XPathException
      Evaluate an updating expression, adding the results to a Pending Update List. The default implementation of this method, which is used for non-updating expressions, throws an UnsupportedOperationException
      Overrides:
      evaluatePendingUpdates in class Expression
      Parameters:
      context - the XPath dynamic evaluation context
      pul - the pending update list to which the results should be written
      Throws:
      XPathException - if evaluation fails
    • error

      public <EO extends Item> Item error(XPathContext context, QNameValue errorCode, StringValue desc, SequenceIterator<EO> errObject) throws XPathException
      Throws:
      XPathException
    • call

      public SequenceIterator<? extends Item> call(SequenceIterator<? extends Item>[] arguments, XPathContext context) throws XPathException
      Description copied from interface: CallableExpression
      Evaluate the expression
      Specified by:
      call in interface CallableExpression
      Parameters:
      arguments - the values of the arguments, supplied as SequenceIterators
      context - the dynamic evaluation context
      Returns:
      the result of the evaluation, in the form of a SequenceIterator
      Throws:
      XPathException - if a dynamic error occurs during the evaluation of the expression