Class FunctionCall

    • Field Detail

      • argument

        protected Expression[] argument
        The array of expressions representing the actual parameters to the function call
    • Constructor Detail

      • FunctionCall

        public FunctionCall()
    • Method Detail

      • setFunctionName

        public final void setFunctionName​(StructuredQName name)
        Set the name of the function being called
        Parameters:
        name - the name of the function
      • getFunctionName

        public StructuredQName getFunctionName()
        Get the qualified of the function being called
        Returns:
        the qualified name
      • getNumberOfArguments

        public final int getNumberOfArguments()
        Determine the number of actual arguments supplied in the function call
        Returns:
        the arity (the number of arguments)
      • setArguments

        public void setArguments​(Expression[] args)
        Method called by the expression parser when all arguments have been supplied
        Parameters:
        args - the expressions contained in the argument list of the function call
      • getArguments

        public Expression[] getArguments()
        Get the expressions supplied as actual arguments to the function
        Returns:
        the array of expressions supplied in the argument list of the function call
      • simplify

        public Expression simplify​(ExpressionVisitor visitor)
                            throws XPathException
        Simplify the function call. Default method is to simplify each of the supplied arguments and evaluate the function if all are now known.
        Overrides:
        simplify in class Expression
        Parameters:
        visitor - an expression visitor
        Returns:
        the simplified expression
        Throws:
        XPathException - if an error is discovered during expression rewriting
      • simplifyArguments

        protected final Expression simplifyArguments​(ExpressionVisitor visitor)
                                              throws XPathException
        Simplify the arguments of the function. Called from the simplify() method of each function.
        Parameters:
        visitor - an expression visitor
        Returns:
        the result of simplifying the arguments of the expression
        Throws:
        XPathException
      • typeCheck

        public Expression typeCheck​(ExpressionVisitor visitor,
                                    ItemType contextItemType)
                             throws XPathException
        Type-check the expression. This also calls preEvaluate() to evaluate the function if all the arguments are constant; functions that do not require this behavior can override the preEvaluate method.
        Overrides:
        typeCheck in class Expression
        Parameters:
        visitor - an expression visitor
        contextItemType - the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set to Type.ITEM_TYPE
        Returns:
        the original expression, rewritten to perform necessary run-time type checks, and to perform other type-related optimizations
        Throws:
        XPathException - if an error is discovered during this phase (typically a type error)
      • optimize

        public Expression optimize​(ExpressionVisitor visitor,
                                   ItemType contextItemType)
                            throws XPathException
        Perform optimisation of an expression and its subexpressions.

        This method is called after all references to functions and variables have been resolved to the declaration of the function or variable, and after all type checking has been done.

        Overrides:
        optimize in class Expression
        Parameters:
        visitor - an expression visitor
        contextItemType - the static type of "." at the point where this expression is invoked. The parameter is set to null if it is known statically that the context item will be undefined. If the type of the context item is not known statically, the argument is set to Type.ITEM_TYPE
        Returns:
        the original expression, rewritten if appropriate to optimize execution
        Throws:
        XPathException - if an error is discovered during this phase (typically a type error)
      • preEvaluate

        public Expression preEvaluate​(ExpressionVisitor visitor)
                               throws XPathException
        Pre-evaluate a function at compile time. Functions that do not allow pre-evaluation, or that need access to context information, can override this method.
        Parameters:
        visitor - an expression visitor
        Returns:
        the result of the early evaluation, or the original expression, or potentially a simplified expression
        Throws:
        XPathException
      • promote

        public Expression promote​(PromotionOffer offer)
                           throws XPathException
        Promote this expression if possible
        Overrides:
        promote in class Expression
        Parameters:
        offer - details of the offer, for example the offer to move expressions that don't depend on the context to an outer level in the containing expression
        Returns:
        if the offer is not accepted, return this expression unchanged. Otherwise return the result of rewriting the expression to promote this subexpression
        Throws:
        XPathException - if any error is detected
      • checkArguments

        protected abstract void checkArguments​(ExpressionVisitor visitor)
                                        throws XPathException
        Method supplied by each class of function to check arguments during parsing, when all the argument expressions have been read
        Parameters:
        visitor - the expression visitor
        Throws:
        XPathException
      • checkArgumentCount

        protected int checkArgumentCount​(int min,
                                         int max,
                                         ExpressionVisitor visitor)
                                  throws XPathException
        Check number of arguments.
        A convenience routine for use in subclasses.
        Parameters:
        min - the minimum number of arguments allowed
        max - the maximum number of arguments allowed
        visitor - an expression visitor
        Returns:
        the actual number of arguments
        Throws:
        XPathException - if the number of arguments is out of range
      • iterateSubExpressions

        public java.util.Iterator iterateSubExpressions()
        Get the immediate subexpressions of this expression
        Overrides:
        iterateSubExpressions in class Expression
        Returns:
        an iterator containing the sub-expressions of this expression
      • replaceSubExpression

        public boolean replaceSubExpression​(Expression original,
                                            Expression replacement)
        Replace one subexpression by a replacement subexpression
        Overrides:
        replaceSubExpression in class Expression
        Parameters:
        original - the original subexpression
        replacement - the replacement subexpression
        Returns:
        true if the original subexpression is found
      • addExternalFunctionCallToPathMap

        public PathMap.PathMapNodeSet addExternalFunctionCallToPathMap​(PathMap pathMap,
                                                                       PathMap.PathMapNodeSet pathMapNodes)
        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.

        Parameters:
        pathMap - the PathMap to which the expression should be added
        pathMapNodes - the node in the PathMap representing the focus at the point where this expression is called. Set to null if this expression appears at the top level, in which case the expression, if it is registered in the path map at all, must create a new path map root.
        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.
      • getDisplayName

        public final java.lang.String getDisplayName()
        Get the name of the function for display in messages
        Returns:
        the name of the function as a lexical QName
      • toString

        public java.lang.String toString()
        The toString() method for an expression attempts to give a representation of the expression in an XPath-like form, but there is no guarantee that the syntax will actually be true XPath. In the case of XSLT instructions, the toString() method gives an abstracted view of the syntax
        Overrides:
        toString in class Expression
      • explain

        public void explain​(ExpressionPresenter out)
        Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.
        Specified by:
        explain in class Expression
        Parameters:
        out - the expression presenter used to display the structure
      • equals

        public boolean equals​(java.lang.Object o)
        Determine whether two expressions are equivalent
        Overrides:
        equals in class java.lang.Object
      • hashCode

        public int hashCode()
        Get hashCode in support of equals() method
        Overrides:
        hashCode in class java.lang.Object