Class Copy

    • Constructor Detail

      • Copy

        public Copy​(boolean copyNamespaces,
                    boolean inheritNamespaces,
                    SchemaType schemaType,
                    int validation)
        Create a shallow copy instruction
        Parameters:
        copyNamespaces - true if namespace nodes are to be copied when copying an element
        inheritNamespaces - true if child elements are to inherit the namespace nodes of their parent
        schemaType - the Schema type against which the content is to be validated
        validation - the schema validation mode
    • Method Detail

      • simplify

        public Expression simplify​(ExpressionVisitor visitor)
                            throws XPathException
        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 ParentNodeConstructor
        Parameters:
        visitor - an expression visitor
        Returns:
        the simplified expression
        Throws:
        XPathException - if an error is discovered during expression rewriting
      • typeCheck

        public Expression typeCheck​(ExpressionVisitor visitor,
                                    ItemType contextItemType)
                             throws XPathException
        Description copied from class: Expression
        Perform type checking of an expression and its subexpressions. This is the second phase of static optimization.

        This checks statically that the operands of the expression have the correct type; if necessary it generates code to do run-time type checking or type conversion. A static type error is reported only if execution cannot possibly succeed, that is, if a run-time type error is inevitable. The call may return a modified form of the expression.

        This method is called after all references to functions and variables have been resolved to the declaration of the function or variable. However, the types of such functions and variables may not be accurately known if they have not been explicitly declared.

        If the implementation returns a value other than "this", then it is required to ensure that the parent pointer and location information in the returned expression have been set up correctly. It should not rely on the caller to do this, although for historical reasons many callers do so.

        Overrides:
        typeCheck in class ParentNodeConstructor
        Parameters:
        visitor - an expression visitor
        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 to perform necessary run-time type checks, and to perform other type-related optimizations
        Throws:
        XPathException - if an error is discovered during this phase (typically a type error)
      • 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
      • getInstructionNameCode

        public int getInstructionNameCode()
        Get 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
      • getItemType

        public ItemType getItemType​(TypeHierarchy th)
        Get the item type of the result of this instruction.
        Overrides:
        getItemType in class ElementCreator
        Parameters:
        th - the type hierarchy cache
        Returns:
        The context item type.
      • optimize

        public Expression optimize​(ExpressionVisitor visitor,
                                   ItemType contextItemType)
                            throws XPathException
        Description copied from class: Expression
        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 ParentNodeConstructor
        Parameters:
        visitor - an expression visitor
        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:
        XPathException - if an error is discovered during this phase (typically a type error)
      • getNameCode

        public int getNameCode​(XPathContext context)
                        throws XPathException
        Callback from ElementCreator when constructing an element
        Specified by:
        getNameCode in class ElementCreator
        Parameters:
        context - XPath dynamic evaluation context
        Returns:
        the namecode of the element to be constructed
        Throws:
        XPathException
      • getNewBaseURI

        public java.lang.String getNewBaseURI​(XPathContext context)
        Get the base URI of a copied element node (the base URI is retained in the new copy)
        Specified by:
        getNewBaseURI in class ElementCreator
        Parameters:
        context - XPath dynamic evaluation context
        Returns:
        the base URI
      • getActiveNamespaces

        public int[] getActiveNamespaces()
                                  throws XPathException
        Callback to get a list of the intrinsic namespaces that need to be generated for the element. The result is an array of namespace codes, the codes either occupy the whole array or are terminated by a -1 entry. A result of null is equivalent to a zero-length array.
        Overrides:
        getActiveNamespaces in class ElementCreator
        Returns:
        an array of namespace codes, the codes either occupy the whole array or are terminated by a -1 entry. A result of null is equivalent to a zero-length array.
        Throws:
        XPathException
      • evaluateItem

        public Item 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
        Specified by:
        evaluateItem in interface EvaluableItem
        Overrides:
        evaluateItem in class ElementCreator
        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