Class BooleanExpression

    • Constructor Detail

      • BooleanExpression

        public BooleanExpression​(Expression p1,
                                 int operator,
                                 Expression p2)
        Construct a boolean expression
        Parameters:
        p1 - the first operand
        operator - one of Token.AND or Token.OR
        p2 - the second operand
    • Method Detail

      • typeCheck

        public Expression typeCheck​(ExpressionVisitor visitor,
                                    ItemType contextItemType)
                             throws XPathException
        Description copied from class: BinaryExpression
        Type-check the expression. Default implementation for binary operators that accept any kind of operand
        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)
      • 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 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 if appropriate to optimize execution
        Throws:
        XPathException - if an error is discovered during this phase (typically a type error)
      • 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
      • isNegatable

        public boolean isNegatable​(ExpressionVisitor visitor)
        Check whether this specific instance of the expression is negatable
        Specified by:
        isNegatable in interface Negatable
        Returns:
        true if it is
      • negate

        public Expression negate()
        Return the negation of this boolean expression, that is, an expression that returns true when this expression returns false, and vice versa
        Specified by:
        negate in interface Negatable
        Returns:
        the negation of this expression
      • evaluateItem

        public Item evaluateItem​(XPathContext context)
                          throws XPathException
        Evaluate the expression
        Specified by:
        evaluateItem in interface EvaluableItem
        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
      • effectiveBooleanValue

        public boolean effectiveBooleanValue​(XPathContext c)
                                      throws XPathException
        Evaluate as a boolean.
        Overrides:
        effectiveBooleanValue in class Expression
        Parameters:
        c - The context in which the expression is to be evaluated
        Returns:
        the effective boolean value
        Throws:
        XPathException - if any dynamic error occurs evaluating the expression
      • getItemType

        public ItemType getItemType​(TypeHierarchy th)
        Determine the data type of the expression
        Specified by:
        getItemType in class Expression
        Parameters:
        th - the type hierarchy cache
        Returns:
        BuiltInAtomicType.BOOLEAN
      • listAndComponents

        public static void listAndComponents​(Expression exp,
                                             java.util.List list)
        Construct a list containing the "anded" subexpressions of an expression: if the expression is (A and B and C), this returns (A, B, C).
        Parameters:
        exp - the expression to be decomposed
        list - the list to which the subexpressions are to be added.