Package net.sf.saxon.expr

Class ArithmeticExpression

    • Field Detail

      • simplified

        protected boolean simplified

    • Constructor Detail

      • ArithmeticExpression

        public ArithmeticExpression​(Expression p0,
                            int operator,
                            Expression p1)
        Create an arithmetic expression
        Parameters:
        p0 - the first operand
        operator - the operator, for example Token.PLUS
        p1 - the second operand

    • Method Detail

      • getExpressionName

        public java.lang.String getExpressionName()
        Get a name identifying the kind of expression, in terms meaningful to a user.
        Overrides:
        getExpressionName in class Expression
        Returns:
        a name identifying the kind of expression, in terms meaningful to a user. The name will always be in the form of a lexical XML QName, and should match the name used in explain() output displaying the expression.

      • getCalculator

        public Calculator getCalculator()
        Get the calculator allocated to evaluate this expression
        Returns:
        the calculator, a helper object that does the actual calculation

      • typeCheck

        public Expression typeCheck​(ExpressionVisitor visitor,
                            ExpressionVisitor.ContextItemType contextItemType)
                     throws XPathException
        Type-check the expression statically. We try to work out which particular arithmetic function to use if the types of operands are known an compile time.
        Overrides:
        typeCheck in class BinaryExpression
        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)

      • getIntegerBounds

        public IntegerValue[] getIntegerBounds()
        For an expression that returns an integer or a sequence of integers, get a lower and upper bound on the values of the integers that may be returned, from static analysis. The default implementation returns null, meaning "unknown" or "not applicable". Other implementations return an array of two IntegerValue objects, representing the lower and upper bounds respectively. The values UNBOUNDED_LOWER and UNBOUNDED_UPPER are used by convention to indicate that the value may be arbitrarily large. The values MAX_STRING_LENGTH and MAX_SEQUENCE_LENGTH are used to indicate values limited by the size of a string or the size of a sequence.
        Overrides:
        getIntegerBounds in class Expression
        Returns:
        the lower and upper bounds of integer values in the result, or null to indicate unknown or not applicable.

      • copy

        public Expression copy()
        Copy an expression. This makes a deep copy.
        Specified by:
        copy in class Expression
        Returns:
        the copy of the original expression

      • compute

        public static AtomicValue compute​(AtomicValue value0,
                                  int operator,
                                  AtomicValue value1,
                                  XPathContext context)
                           throws XPathException
        Static method to apply arithmetic to two values
        Parameters:
        value0 - the first value
        operator - the operator as denoted in the Calculator class, for example Calculator.PLUS
        value1 - the second value
        context - the XPath dynamic evaluation context
        Returns:
        the result of the arithmetic operation
        Throws:
        XPathException

      • mapOpCode

        public static int mapOpCode​(int op)
        Map operator codes from those in the Token class to those in the Calculator class
        Parameters:
        op - an operator denoted by a constant in the Token class, for example Token.PLUS
        Returns:
        an operator denoted by a constant defined in the Calculator class, for example Calculator.PLUS

      • getItemType

        public ItemType getItemType​(TypeHierarchy th)
        Determine the data type of the expression, insofar as this is known statically
        Specified by:
        getItemType in class Expression
        Parameters:
        th - the type hierarchy cache
        Returns:
        the atomic type of the result of this arithmetic expression

      • evaluateItem

        public Item evaluateItem​(XPathContext context)
                  throws XPathException
        Evaluate the expression.
        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