Class DocumentSorter

    • Constructor Detail

      • DocumentSorter

        public DocumentSorter​(Expression base)
    • Method Detail

      • optimize

        public Expression optimize​(Optimizer opt,
                                   StaticContext env,
                                   ItemType contextItemType)
                            throws XPathException
        Description copied from class: UnaryExpression
        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.

        Specified by:
        optimize in interface Expression
        Overrides:
        optimize in class UnaryExpression
        Parameters:
        opt - the optimizer in use. This provides access to supporting functions; it also allows different optimization strategies to be used in different circumstances.
        env - the static context of the expression
        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:
        net.sf.saxon.trans.StaticError - if an error is discovered during this phase (typically a type error)
        XPathException
      • 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
      • promote

        public Expression promote​(PromotionOffer offer)
                           throws XPathException
        Promote this expression if possible
        Specified by:
        promote in interface Expression
        Overrides:
        promote in class UnaryExpression
        Parameters:
        offer - details of the offer, for example the offer to move expressions that don't depend on the context to an outer level in the containing expression
        Returns:
        if the offer is not accepted, return this expression unchanged. Otherwise return the result of rewriting the expression to promote this subexpression
        Throws:
        XPathException - if any error is detected
      • iterate

        public SequenceIterator iterate​(XPathContext context)
                                 throws XPathException
        Description copied from class: ComputedExpression
        Return an Iterator to iterate over the values of a sequence. The value of every expression can be regarded as a sequence, so this method is supported for all expressions. This default implementation handles iteration for expressions that return singleton values: for non-singleton expressions, the subclass must provide its own implementation.
        Specified by:
        iterate in interface Expression
        Overrides:
        iterate in class ComputedExpression
        Parameters:
        context - supplies the context for evaluation
        Returns:
        a SequenceIterator that can be used to iterate over the result of the expression
        Throws:
        XPathException - if any dynamic error occurs evaluating the expression
      • effectiveBooleanValue

        public boolean effectiveBooleanValue​(XPathContext context)
                                      throws XPathException
        Description copied from class: ComputedExpression
        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.
        Specified by:
        effectiveBooleanValue in interface Expression
        Overrides:
        effectiveBooleanValue in class ComputedExpression
        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
      • displayOperator

        protected java.lang.String displayOperator​(Configuration config)
        Give a string representation of the operator for use in diagnostics
        Specified by:
        displayOperator in class UnaryExpression
        Parameters:
        config -
        Returns:
        the operator, as a string