Package net.sf.saxon.expr

Class CompareToIntegerConstant

    • Constructor Detail

      • CompareToIntegerConstant

        public CompareToIntegerConstant​(Expression operand,
                                int operator,
                                long comparand)
        Create the expression
        Parameters:
        operand - the operand to be compared with an integer constant. This must have a static type of NUMERIC, and a cardinality of EXACTLY ONE
        operator - the comparison operator, one of Token.FEQ, Token.FNE, Token.FGE, Token.FGT, Token.FLE, Token.FLT
        comparand - the integer constant

    • Method Detail

      • getComparand

        public long getComparand()
        Get the integer value on the rhs of the expression
        Returns:
        the integer constant

      • getImplementationMethod

        public int getImplementationMethod()
        An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process(). This method indicates which of these methods is provided directly. The other methods will always be available indirectly, using an implementation that relies on one of the other methods.
        Specified by:
        getImplementationMethod in class Expression
        Returns:
        the value Expression.EVALUATE_METHOD

      • computeSpecialProperties

        public int computeSpecialProperties()
        Description copied from class: UnaryExpression
        Get the static properties of this expression (other than its type). The result is bit-signficant. These properties are used for optimizations. In general, if property bit is set, it is true, but if it is unset, the value is unknown.
        Overrides:
        computeSpecialProperties in class UnaryExpression
        Returns:
        the special properties, as a bit-significant integer

      • copy

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

      • equals

        public boolean equals​(Object other)
        Is this expression the same as another expression?
        Overrides:
        equals in class UnaryExpression
        Parameters:
        other - the expression to be compared with this one
        Returns:
        true if the two expressions are statically equivalent

      • computeHashCode

        public int computeHashCode()
        Hashcode supporting equals()
        Overrides:
        computeHashCode in class UnaryExpression
        Returns:
        a computed hash code

      • evaluateItem

        public BooleanValue evaluateItem​(XPathContext context)
                          throws XPathException
        Evaluate an expression as a single item. This always returns either a single Item or null (denoting the empty sequence). No conversion is done. This method should not be used unless the static type of the expression is a subtype of "item" or "item?": that is, it should not be called if the expression may return a sequence. There is no guarantee that this condition will be detected.
        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 context)
                              throws XPathException
        Get the effective boolean value of the expression. This returns false if the value is the empty sequence, a zero-length string, a number equal to zero, or the boolean false. Otherwise it returns true.
        Overrides:
        effectiveBooleanValue in class Expression
        Parameters:
        context - 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

      • optimize

        public Expression optimize​(ExpressionVisitor visitor,
                           ContextItemStaticInfo contextInfo)
                    throws XPathException
        Perform optimisation of an expression and its subexpressions. This is the third and final phase of static optimization.

        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 UnaryExpression
        Parameters:
        visitor - the expression visitor
        contextInfo - 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)

      • getExpressionName

        public 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 export() output displaying the expression.

      • getItemType

        public ItemType getItemType()
        Determine the data type of the expression, if possible. All expression return sequences, in general; this method determines the type of the items within the sequence, assuming that (a) this is known in advance, and (b) it is the same for all items in the sequence.

        This method should always return a result, though it may be the best approximation that is available at the time.

        Overrides:
        getItemType in class UnaryExpression
        Returns:
        a value such as Type.STRING, Type.BOOLEAN, Type.NUMBER, Type.NODE, or Type.ITEM (meaning not known at compile time)

      • export

        public void export​(ExpressionPresenter destination)
            throws XPathException
        Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.
        Specified by:
        export in interface ExportAgent
        Overrides:
        export in class UnaryExpression
        Parameters:
        destination - the expression presenter used to display the structure
        Throws:
        XPathException - if the export fails, for example if an expression is found that won't work in the target environment.

      • toString

        public String toString()

        The toString() method for an expression attempts to give a representation of the expression in an XPath-like form.

        For subclasses of Expression that represent XPath expressions, the result should always be a string that parses as an XPath 3.0 expression

        Overrides:
        toString in class UnaryExpression
        Returns:
        a representation of the expression as a string

      • toShortString

        public String toShortString()
        Produce a short string identifying the expression for use in error messages
        Overrides:
        toShortString in class UnaryExpression
        Returns:
        a short string, sufficient to identify the expression

      • getSingletonOperator

        public int getSingletonOperator()
        Get the primitive (singleton) operator used: one of Token.FEQ, Token.FNE, Token.FLT, Token.FGT, Token.FLE, Token.FGE
        Specified by:
        getSingletonOperator in interface ComparisonExpression

      • convertsUntypedToOther

        public boolean convertsUntypedToOther()
        Determine whether untyped atomic values should be converted to the type of the other operand
        Specified by:
        convertsUntypedToOther in interface ComparisonExpression
        Returns:
        true if untyped values should be converted to the type of the other operand, false if they should be converted to strings.