Class ScalarSystemFunction

    • Field Detail

      • ZERO_LENGTH_STRING

        public static final One ZERO_LENGTH_STRING
        Static constant representing a zero-length string
    • Constructor Detail

      • ScalarSystemFunction

        public ScalarSystemFunction()
    • Method Detail

      • evaluate

        public abstract AtomicValue evaluate​(Item arg,
                                             XPathContext context)
                                      throws XPathException
        Abstract method that must be supplied in subclasses to perform the evaluation
        Parameters:
        arg - the supplied argument
        context - the dynamic context
        Returns:
        the result of the evaluation
        Throws:
        XPathException - if a dynamic error occurs
      • resultWhenEmpty

        public ZeroOrOne resultWhenEmpty()
        Method that may be supplied in subclasses, to indicate the result that is returned when an empty sequence is supplied as the argument value. The default is to return the empty sequence
        Returns:
        the result of evaluation when the supplied argument is an empty sequence
      • call

        public final ZeroOrOne call​(XPathContext context,
                                    Sequence[] arguments)
                             throws XPathException
        Evaluate the expression
        Parameters:
        context - the dynamic evaluation context
        arguments - the values of the arguments, supplied as Sequences
        Returns:
        the result of the evaluation, in the form of a Sequence
        Throws:
        XPathException - if a dynamic error occurs during the evaluation of the expression
      • makeFunctionCall

        public Expression makeFunctionCall​(Expression[] arguments)
        Description copied from class: SystemFunction
        Make an expression that either calls this function, or that is equivalent to a call on this function
        Overrides:
        makeFunctionCall in class SystemFunction
        Parameters:
        arguments - the supplied arguments to the function call
        Returns:
        either a function call on this function, or an expression that delivers the same result