Package net.sf.saxon.expr.instruct

Class NamespaceConstructor

    • Constructor Detail

      • NamespaceConstructor

        public NamespaceConstructor​(Expression name)
        Create an xsl:namespace instruction for dynamic construction of namespace nodes
        Parameters:
        name - the expression to evaluate the name of the node (that is, the prefix)

    • Method Detail

      • getNameExpression

        public Expression getNameExpression()
        Get the expression that defines the namespace node's name
        Returns:
        the expression that defines the namespace node's name (that is, the namespace prefix)

      • getInstructionNameCode

        public int getInstructionNameCode()
        Set the name of this instruction for diagnostic and tracing purposes
        Overrides:
        getInstructionNameCode in class Instruction
        Returns:
        a code identifying the instruction: typically but not always the fingerprint of a name in the XSLT namespace

      • simplify

        public Expression simplify​(ExpressionVisitor visitor)
                    throws XPathException
        Description copied from class: Instruction
        Simplify an expression. This performs any static optimization (by rewriting the expression as a different expression). The default implementation does nothing.
        Overrides:
        simplify in class SimpleNodeConstructor
        Parameters:
        visitor - an expression visitor
        Returns:
        the simplified expression
        Throws:
        XPathException - if an error is discovered during expression rewriting

      • getItemType

        public ItemType getItemType​(TypeHierarchy th)
        Description copied from class: Instruction
        Get the item type of the items returned by evaluating this instruction
        Overrides:
        getItemType in class Instruction
        Parameters:
        th - the type hierarchy cache
        Returns:
        the static item type of the instruction

      • getCardinality

        public int getCardinality()
        Description copied from class: Expression
        Determine the static cardinality of the expression. This establishes how many items there will be in the result of the expression, at compile time (i.e., without actually evaluating the result.
        Overrides:
        getCardinality in class Expression
        Returns:
        one of the values Cardinality.ONE_OR_MORE, Cardinality.ZERO_OR_MORE, Cardinality.EXACTLY_ONE, Cardinality.ZERO_OR_ONE, Cardinality.EMPTY. This default implementation returns ZERO_OR_MORE (which effectively gives no information).

      • promoteInst

        protected void promoteInst​(PromotionOffer offer)
                    throws XPathException
        Description copied from class: SimpleNodeConstructor
        Offer promotion for subexpressions. The offer will be accepted if the subexpression is not dependent on the factors (e.g. the context item) identified in the PromotionOffer. By default the offer is not accepted - this is appropriate in the case of simple expressions such as constant values and variable references where promotion would give no performance advantage. This method is always called at compile time.
        Overrides:
        promoteInst in class SimpleNodeConstructor
        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
        Throws:
        XPathException - if any error is detected

      • iterateSubExpressions

        public java.util.Iterator<Expression> iterateSubExpressions()
        Description copied from class: Expression
        Get the immediate sub-expressions of this expression. Default implementation returns a zero-length array, appropriate for an expression that has no sub-expressions.
        Overrides:
        iterateSubExpressions in class SimpleNodeConstructor
        Returns:
        an iterator containing the sub-expressions of this expression

      • 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

      • replaceSubExpression

        public boolean replaceSubExpression​(Expression original,
                                    Expression replacement)
        Replace one subexpression by a replacement subexpression
        Overrides:
        replaceSubExpression in class SimpleNodeConstructor
        Parameters:
        original - the original subexpression
        replacement - the replacement subexpression
        Returns:
        true if the original subexpression is found

      • evaluateNodeName

        public NodeName evaluateNodeName​(XPathContext context)
                          throws XPathException
        Description copied from class: SimpleNodeConstructor
        Run-time method to compute the name of the node being constructed. This is overridden for nodes that have a name. The default implementation returns -1, which is suitable for unnamed nodes such as comments
        Overrides:
        evaluateNodeName in class SimpleNodeConstructor
        Parameters:
        context - the XPath dynamic evaluation context
        Returns:
        the name pool nameCode identifying the name of the constructed node
        Throws:
        XPathException - if any failure occurs

      • evaluateItem

        public NodeInfo evaluateItem​(XPathContext context)
                      throws XPathException
        Evaluate as an expression. We rely on the fact that when these instructions are generated by XQuery, there will always be a valueExpression to evaluate the content
        Overrides:
        evaluateItem in class SimpleNodeConstructor
        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

      • explain

        public void explain​(ExpressionPresenter out)
        Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.
        Specified by:
        explain in class Expression
        Parameters:
        out - the expression presenter used to display the structure