Package net.sf.saxon.xpath

Class XPathFunctionCall

    • Constructor Detail

      • XPathFunctionCall

        public XPathFunctionCall​(StructuredQName name,
                         javax.xml.xpath.XPathFunction function)
        Default constructor
        Parameters:
        name - the qualified name of the function
        function - the target function

    • Method Detail

      • preEvaluate

        public Expression preEvaluate​(ExpressionVisitor visitor)
        preEvaluate: this method suppresses compile-time evaluation by doing nothing (because the external function might have side-effects and might use the context)
        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

      • getIntrinsicDependencies

        public int getIntrinsicDependencies()
        Determine which aspects of the context the expression depends on. XPath external functions are given no access to context information so they cannot have any dependencies on it.
        Overrides:
        getIntrinsicDependencies in class Expression
        Returns:
        an integer containing bit-significant flags identifying the "intrinsic" dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty

      • copy

        public Expression copy​(RebindingMap rebindings)
        Copy an expression. This makes a deep copy.
        Specified by:
        copy in class Expression
        Parameters:
        rebindings - variables that need to be re-bound
        Returns:
        the copy of the original expression

      • addToPathMap

        public PathMap.PathMapNodeSet addToPathMap​(PathMap pathMap,
                                           PathMap.PathMapNodeSet pathMapNodeSet)
        Add a representation of this expression to a PathMap. The PathMap captures a map of the nodes visited by an expression in a source tree.

        The default implementation of this method assumes that an expression does no navigation other than the navigation done by evaluating its subexpressions, and that the subexpressions are evaluated in the same context as the containing expression. The method must be overridden for any expression where these assumptions do not hold. For example, implementations exist for AxisExpression, ParentExpression, and RootExpression (because they perform navigation), and for the doc(), document(), and collection() functions because they create a new navigation root. Implementations also exist for PathExpression and FilterExpression because they have subexpressions that are evaluated in a different context from the calling expression.

        Overrides:
        addToPathMap in class Expression
        Parameters:
        pathMap - the PathMap to which the expression should be added
        pathMapNodeSet - the PathMapNodeSet to which the paths embodied in this expression should be added
        Returns:
        the pathMapNode representing the focus established by this expression, in the case where this expression is the first operand of a path expression or filter expression. For an expression that does navigation, it represents the end of the arc in the path map that describes the navigation route. For other expressions, it is the same as the input pathMapNode.

      • call

        public Sequence call​(XPathContext context,
                     Sequence[] argValues)
              throws XPathException
        Call an extension function previously identified using the bind() method. A subclass can override this method.
        Specified by:
        call in interface Callable
        Parameters:
        context - The XPath dynamic context
        argValues - The values of the arguments
        Returns:
        The value returned by the extension function
        Throws:
        XPathException - if a dynamic error occurs during the evaluation of the expression

      • getItemType

        public ItemType getItemType()
        Determine the data type of the expression, if possible. All expressions return sequences, in general; this method determines the type of the items within the sequence, assuming that (a) this is known in advance, and (b) it is the same for all items in the sequence.

        This method will always return a result, though it may be the best approximation that is available at the time.

        Specified by:
        getItemType in class Expression
        Returns:
        the item type

      • computeCardinality

        protected int computeCardinality()
        Determine the cardinality of the result
        Specified by:
        computeCardinality in class Expression
        Returns:
        ZERO_OR_MORE (we don't know)