Package net.sf.saxon.expr

Class UserFunctionCall

  • All Implemented Interfaces:
    java.io.Serializable, javax.xml.transform.SourceLocator, Container, Expression, InstructionInfoProvider
    public class UserFunctionCall
extends FunctionCall
implements InstructionInfoProvider
    This class represents a call to a function defined in the stylesheet or query. It is used for all user-defined functions in XQuery, and for a limited class of user-defined functions in XSLT: those that can be reduced to the evaluation of a single expression.
    See Also:
    Serialized Form

    • Constructor Detail

      • UserFunctionCall

        public UserFunctionCall()

    • Method Detail

      • setStaticType

        public void setStaticType​(SequenceType type)
        Set the static type

      • getFunction

        public UserFunction getFunction()
        Get the function that is being called by this function call

      • setConfirmed

        public void setConfirmed​(boolean conf)
        Set this function as confirmed (the function being called is known to exist) or not

      • isConfirmed

        public boolean isConfirmed()
        Determine whether this function call is confirmed

      • getItemType

        public ItemType getItemType​(TypeHierarchy th)
        Determine the data type of the expression, if possible
        Specified by:
        getItemType in interface Expression
        Parameters:
        th -
        Returns:
        Type.ITEM (meaning not known in advance)

      • getIntrinsicDependencies

        public int getIntrinsicDependencies()
        Description copied from class: ComputedExpression
        Determine the intrinsic dependencies of an expression, that is, those which are not derived from the dependencies of its subexpressions. For example, position() has an intrinsic dependency on the context position, while (position()+1) does not. The default implementation of the method returns 0, indicating "no dependencies".
        Overrides:
        getIntrinsicDependencies in class ComputedExpression
        Returns:
        a set of bit-significant flags identifying the "intrinsic" dependencies. The flags are documented in class net.sf.saxon.value.StaticProperty

      • typeCheck

        public Expression typeCheck​(StaticContext env,
                            ItemType contextItemType)
                     throws XPathException
        Description copied from class: FunctionCall
        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.
        Specified by:
        typeCheck in interface Expression
        Overrides:
        typeCheck in class FunctionCall
        Parameters:
        env - the static context of the expression
        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:
        StaticError - if an error is discovered during this phase (typically a type error)
        XPathException

      • optimize

        public Expression optimize​(Optimizer opt,
                           StaticContext env,
                           ItemType contextItemType)
                    throws XPathException
        Description copied from class: FunctionCall
        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.

        Specified by:
        optimize in interface Expression
        Overrides:
        optimize in class FunctionCall
        Parameters:
        opt - the optimizer in use. This provides access to supporting functions; it also allows different optimization strategies to be used in different circumstances.
        env - the static context of the expression
        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:
        net.sf.saxon.trans.StaticError - if an error is discovered during this phase (typically a type error)
        XPathException

      • computeArgumentEvaluationModes

        public void computeArgumentEvaluationModes()

      • markTailFunctionCalls

        public boolean markTailFunctionCalls​(int nameCode,
                                     int arity)
        Mark tail-recursive calls on stylesheet functions. This marks the function call as tailRecursive if if is a call to the containing function, and in this case it also returns "true" to the caller to indicate that a tail call was found.
        Overrides:
        markTailFunctionCalls in class ComputedExpression
        Returns:
        true if a tail recursive call was found and if this call accounts for the whole of the value.

      • getImplementationMethod

        public int getImplementationMethod()
        Description copied from class: ComputedExpression
        An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process(). This method indicates which of these methods is provided directly. The other methods will always be available indirectly, using an implementation that relies on one of the other methods.
        Specified by:
        getImplementationMethod in interface Expression
        Overrides:
        getImplementationMethod in class ComputedExpression

      • evaluateItem

        public Item evaluateItem​(XPathContext c)
                  throws XPathException
        Call the function, returning the value as an item. This method will be used only when the cardinality is zero or one. If the function is tail recursive, it returns an Object representing the arguments to the next (recursive) call
        Specified by:
        evaluateItem in interface Expression
        Overrides:
        evaluateItem in class ComputedExpression
        Parameters:
        c - 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

      • iterate

        public SequenceIterator iterate​(XPathContext c)
                         throws XPathException
        Call the function, returning an iterator over the results. (But if the function is tail recursive, it returns an iterator over the arguments of the recursive call)
        Specified by:
        iterate in interface Expression
        Overrides:
        iterate in class ComputedExpression
        Parameters:
        c - 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

      • dynamicCall

        public ValueRepresentation dynamicCall​(ValueRepresentation[] suppliedArguments,
                                       XPathContext context)
                                throws XPathException
        Call the function dynamically. For this to be possible, the static arguments of the function call must have been set up as SuppliedParameterReference objects. The actual arguments are placed on the callee's stack, and the type conversion takes place "in situ".
        Throws:
        XPathException

      • display

        public void display​(int level,
                    java.io.PrintStream out,
                    Configuration config)
        Description copied from interface: Expression
        Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.
        Specified by:
        display in interface Expression
        Overrides:
        display in class FunctionCall
        Parameters:
        level - indentation level for this expression
        out - Output destination