Package net.sf.saxon.ma.map

Class MapFunctionSet.MapGet

    • Constructor Detail

      • MapGet

        public MapGet()

    • Method Detail

      • supplyTypeInformation

        public void supplyTypeInformation​(ExpressionVisitor visitor,
                                  ContextItemStaticInfo contextItemType,
                                  Expression[] arguments)
                           throws XPathException
        Method called during static type checking. This method may be implemented in subclasses so that functions can take advantage of knowledge of the types of the arguments that will be supplied.
        Overrides:
        supplyTypeInformation in class SystemFunction
        Parameters:
        visitor - an expression visitor, providing access to the static context and configuration
        contextItemType - information about whether the context item is set, and what its type is
        arguments - the expressions appearing as arguments in the function call
        Throws:
        XPathException - if an error is detected

      • getResultItemType

        public ItemType getResultItemType​(Expression[] args)
        Get the return type, given knowledge of the actual arguments
        Overrides:
        getResultItemType in class SystemFunction
        Parameters:
        args - the actual arguments supplied
        Returns:
        the best available item type that the function will return

      • getCardinality

        public int getCardinality​(Expression[] args)
        Get the cardinality, given knowledge of the actual arguments
        Overrides:
        getCardinality in class SystemFunction
        Parameters:
        args - the actual arguments supplied
        Returns:
        the most precise available cardinality that the function will return

      • makeOptimizedFunctionCall

        public Expression makeOptimizedFunctionCall​(ExpressionVisitor visitor,
                                            ContextItemStaticInfo contextInfo,
                                            Expression... arguments)
                                     throws XPathException
        Allow the function to create an optimized call based on the values of the actual arguments
        Overrides:
        makeOptimizedFunctionCall in class SystemFunction
        Parameters:
        visitor - the expression visitor
        contextInfo - information about the context item
        arguments - the supplied arguments to the function call. Note: modifying the contents of this array should not be attempted, it is likely to have no effect.
        Returns:
        either a function call on this function, or an expression that delivers the same result, or null indicating that no optimization has taken place
        Throws:
        XPathException - if an error is detected

      • call

        public Sequence call​(XPathContext context,
                     Sequence[] arguments)
              throws XPathException
        Description copied from interface: Callable
        Call the Callable.
        Parameters:
        context - the dynamic evaluation context
        arguments - the values of the arguments, supplied as Sequences.

        Generally it is advisable, if calling iterate() to process a supplied sequence, to call it only once; if the value is required more than once, it should first be converted to a GroundedValue by calling the utility method SequenceTool.toGroundedValue().

        If the expected value is a single item, the item should be obtained by calling Sequence.head(): it cannot be assumed that the item will be passed as an instance of Item or AtomicValue.

        It is the caller's responsibility to perform any type conversions required to convert arguments to the type expected by the callee. An exception is where this Callable is explicitly an argument-converting wrapper around the original Callable.

        Returns:
        the result of the evaluation, in the form of a Sequence. It is the responsibility of the callee to ensure that the type of result conforms to the expected result type.
        Throws:
        XPathException - if a dynamic error occurs during the evaluation of the expression