Class Minimax

    • Constructor Detail

      • Minimax

        public Minimax()
    • Method Detail

      • setIgnoreNaN

        public void setIgnoreNaN​(boolean ignore)
        Indicate whether NaN values should be ignored. For the external min() and max() function, a NaN value in the input causes the result to be NaN. Internally, however, min() and max() are also used in such a way that NaN values should be ignored.
        Parameters:
        ignore - true if NaN values are to be ignored when computing the min or max.
      • isIgnoreNaN

        public boolean isIgnoreNaN()
        Test whether NaN values are to be ignored
        Returns:
        true if NaN values are to be ignored. This is the case for internally-generated min() and max() functions used to support general comparisons
      • getImplementationMethod

        public int getImplementationMethod()
        Get implementation method
        Overrides:
        getImplementationMethod in class SystemFunction
        Returns:
        a value that indicates this function is capable of being streamed
      • typeCheck

        public Expression typeCheck​(ExpressionVisitor visitor,
                                    ExpressionVisitor.ContextItemType contextItemType)
                             throws XPathException
        Type-check the expression
        Overrides:
        typeCheck in class FunctionCall
        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,
                                   ExpressionVisitor.ContextItemType 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 SystemFunction
        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)
      • getItemType

        public ItemType getItemType​(TypeHierarchy th)
        Determine the item type of the value returned by the function
        Overrides:
        getItemType in class SystemFunction
        Parameters:
        th - the type hierarchy cache
        Returns:
        the statically inferred type of the expression
      • copy

        public Expression copy()
        Copy an expression. This makes a deep copy.
        Overrides:
        copy in class CollatingFunction
        Returns:
        the copy of the original expression
      • equals

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

        public Item evaluateItem​(XPathContext context)
                          throws XPathException
        Evaluate the function
        Overrides:
        evaluateItem in class Expression
        Parameters:
        context - 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
      • minimax

        public static AtomicValue minimax​(SequenceIterator iter,
                                          int operation,
                                          AtomicComparer atomicComparer,
                                          boolean ignoreNaN,
                                          XPathContext context)
                                   throws XPathException
        Static method to evaluate the minimum or maximum of a sequence
        Parameters:
        iter - Iterator over the input sequence
        operation - either MIN or MAX
        atomicComparer - an AtomicComparer used to compare values
        ignoreNaN - true if NaN values are to be ignored
        context - dynamic evaluation context
        Returns:
        the min or max value in the sequence, according to the rules of the fn:min() or fn:max() functions
        Throws:
        XPathException - typically if non-comparable values are found in the sequence