Class Trace

    • Constructor Detail

      • Trace

        public Trace()
    • Method Detail

      • 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
      • computeSpecialProperties

        public int computeSpecialProperties()
        Get the static properties of this expression (other than its type). The result is bit-significant. These properties are used for optimizations. In general, if property bit is set, it is true, but if it is unset, the value is unknown.
        Overrides:
        computeSpecialProperties in class SystemFunction
        Returns:
        the special properties, as a bit-significant integer
      • evaluateItem

        public Item evaluateItem​(XPathContext context)
                          throws XPathException
        Evaluate the function
        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
      • traceItem

        public static void traceItem​(Item val,
                                     java.lang.String label,
                                     java.io.PrintStream out)
      • iterate

        public SequenceIterator iterate​(XPathContext context)
                                 throws XPathException
        Iterate over the results of the function
        Overrides:
        iterate in class Expression
        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
      • call

        public SequenceIterator call​(SequenceIterator[] arguments,
                                     XPathContext context)
                              throws XPathException
        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