Class RelationalExpression


  • final class RelationalExpression
    extends BinaryExpression
    Relational Expression: a boolean expression that compares two expressions for equals, not-equals, greater-than or less-than.
    • Constructor Detail

      • RelationalExpression

        public RelationalExpression()
        Default constructor
      • RelationalExpression

        public RelationalExpression​(Expression p1,
                                    int op,
                                    Expression p2)
        Create a relational expression identifying the two operands and the operator
        Parameters:
        p1 - the left-hand operand
        op - the operator, as a token returned by the Tokenizer (e.g. Tokenizer.LT)
        p2 - the right-hand operand
    • Method Detail

      • evaluate

        public Value evaluate​(Context c)
                       throws XPathException
        Evaluate the expression in a given context
        Specified by:
        evaluate in class Expression
        Parameters:
        c - the given context for evaluation
        Returns:
        a BooleanValue representing the result of the numeric comparison of the two operands
        Throws:
        XPathException
      • evaluateAsBoolean

        public boolean evaluateAsBoolean​(Context c)
                                  throws XPathException
        Evaluate the expression in a given context
        Overrides:
        evaluateAsBoolean in class Expression
        Parameters:
        c - the given context for evaluation
        Returns:
        a boolean representing the result of the numeric comparison of the two operands
        Throws:
        XPathException
      • getDataType

        public int getDataType()
        Determine the data type of the expression
        Specified by:
        getDataType in class Expression
        Returns:
        Value.BOOLEAN
      • reduce

        public Expression reduce​(int dependencies,
                                 Context context)
                          throws XPathException
        Perform a partial evaluation of the expression, by eliminating specified dependencies on the context.
        Specified by:
        reduce in class Expression
        Parameters:
        dependencies - The dependencies to be removed
        context - The context to be used for the partial evaluation
        Returns:
        a new expression that does not have any of the specified dependencies
        Throws:
        XPathException