Package net.sf.saxon.expr.instruct

Class DocumentInstr

    • Constructor Detail

      • DocumentInstr

        public DocumentInstr​(boolean textOnly,
                     UnicodeString constantText)
        Create a document constructor instruction
        Parameters:
        textOnly - true if the content contains text nodes only
        constantText - if the content contains text nodes only and the text is known at compile time, supplies the textual content

    • Method Detail

      • operands

        public java.lang.Iterable<Operand> operands()
        Description copied from class: Expression
        Get the immediate sub-expressions of this expression, with information about the relationship of each expression to its parent expression. Default implementation works off the results of iterateSubExpressions()

        If the expression is a Callable, then it is required that the order of the operands returned by this function is the same as the order of arguments supplied to the corresponding call() method.

        Specified by:
        operands in class Instruction
        Returns:
        an iterator containing the sub-expressions of this expression

      • isTextOnly

        public boolean isTextOnly()
        Determine whether this is a "text only" document: essentially, an XSLT xsl:variable that contains a single text node or xsl:value-of instruction.
        Returns:
        true if this is a text-only document

      • getConstantText

        public UnicodeString getConstantText()
        For a text-only instruction, determine if the text value is fixed and if so return it; otherwise return null
        Returns:
        the fixed text value if appropriate; otherwise null

      • computeSpecialProperties

        protected int computeSpecialProperties()
        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 Instruction
        Returns:
        a set of flags indicating static properties of this expression

      • getStringValueExpression

        public Expression getStringValueExpression()
        In the case of a text-only instruction (xsl:variable containing a text node or one or more xsl:value-of instructions), return an expression that evaluates to the textual content as an instance of xs:untypedAtomic
        Returns:
        an expression that evaluates to the textual content

      • copy

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

      • processLeavingTail

        public TailCall processLeavingTail​(Outputter output,
                                   XPathContext context)
                            throws XPathException
        Description copied from class: Instruction
        ProcessLeavingTail: called to do the real work of this instruction. This method must be implemented in each subclass. The results of the instruction are written to the current Receiver, which can be obtained via the Controller.
        Specified by:
        processLeavingTail in interface TailCallReturner
        Specified by:
        processLeavingTail in class Instruction
        Parameters:
        output - the destination for the result
        context - The dynamic context of the transformation, giving access to the current node, the current variables, etc.
        Returns:
        null if the instruction has completed execution; or a TailCall indicating a function call or template call that is delegated to the caller, to be made after the stack has been unwound so as to save stack space.
        Throws:
        XPathException - if a dynamic error occurs during the evaluation of the instruction

      • evaluateItem

        public NodeInfo evaluateItem​(XPathContext context)
                      throws XPathException
        Evaluate as an item.
        Overrides:
        evaluateItem in class Instruction
        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

      • getInstructionNameCode

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

      • export

        public void export​(ExpressionPresenter out)
            throws XPathException
        Diagnostic print of expression structure. The abstract expression tree is written to the supplied output destination.
        Specified by:
        export in interface ExportAgent
        Specified by:
        export in class Expression
        Parameters:
        out - 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.

      • getStreamerName

        public java.lang.String getStreamerName()
        Get the (partial) name of a class that supports streaming of this kind of expression
        Overrides:
        getStreamerName in class Expression
        Returns:
        the partial name of a class that can be instantiated to provide streaming support in Saxon-EE, or null if there is no such class