Class Copy

    • Constructor Detail

      • Copy

        public Copy​(Expression select,
                    boolean selectSpecified,
                    boolean copyNamespaces,
                    boolean inheritNamespaces,
                    SchemaType schemaType,
                    int validation)
        Create a shallow copy instruction
        Parameters:
        select - selects the node (or other item) to be copied. Never null.
        selectSpecified - true if the select attribute of xsl:copy was specified explicitly (in which case the context for evaluating the body will change)
        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

      • getSelectExpression

        public Expression getSelectExpression()
        Get the expression that selects the node or other item to be copied
        Returns:
        the select expression. This will be a context item expression if no select attribute was supplied.
      • isSelectSpecified

        public boolean isSelectSpecified()
        Ask whether the select attribute was explicitly specified
        Returns:
        true if it was
      • isCopyNamespaces

        public boolean isCopyNamespaces()
        Ask whether namespace nodes are to be copied (in the case of an element)
        Returns:
        true if all in-scope namespaces are to be copied
      • 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,
                                    ExpressionVisitor.ContextItemType 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 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
      • replaceSubExpression

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

        public int getIntrinsicDependencies()
        Determine which aspects of the context the expression depends on. The result is a bitwise-or'ed value composed from constants such as XPathContext.VARIABLES and XPathContext.CURRENT_NODE. The default implementation combines the intrinsic dependencies of this expression with the dependencies of the subexpressions, computed recursively. This is overridden for expressions such as FilterExpression where a subexpression's dependencies are not necessarily inherited by the parent expression.
        Overrides:
        getIntrinsicDependencies in class Expression
        Returns:
        a set of bit-significant flags identifying the dependencies of the 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
      • iterateSubExpressions

        public java.util.Iterator<Expression> iterateSubExpressions()
        Get the immediate sub-expressions of this expression.
        Overrides:
        iterateSubExpressions in class ParentNodeConstructor
        Returns:
        an iterator containing the sub-expressions of this expression
      • 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,
                                   ExpressionVisitor.ContextItemType 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)
      • getNewBaseURI

        public java.lang.String getNewBaseURI​(XPathContext context,
                                              NodeInfo copiedNode)
        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
        copiedNode -
        Returns:
        the base URI
      • getActiveNamespaces

        public NamespaceBinding[] 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:
        the set of namespace bindings.
        Throws:
        XPathException - if an error occurs
      • processLeavingTail

        public TailCall processLeavingTail​(XPathContext context)
                                    throws XPathException
        Description copied from class: ElementCreator
        Evaluate the instruction to produce a new element node. This method is typically used when there is a parent element or document in a result tree, to which the new element is added.
        Specified by:
        processLeavingTail in interface TailCallReturner
        Overrides:
        processLeavingTail in class ElementCreator
        Parameters:
        context - XPath dynamic evaluation context
        Returns:
        null (this instruction never returns a tail call)
        Throws:
        XPathException - if a dynamic error occurs during the evaluation of the instruction
      • 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
        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
      • processLeft

        public void processLeft​(java.util.Stack<XPathContext> contextStack,
                                java.util.Stack<java.lang.Object> state)
                         throws XPathException
        Process the first half of the instruction in streaming mode
        Specified by:
        processLeft in interface DivisibleInstruction
        Overrides:
        processLeft in class ElementCreator
        Parameters:
        contextStack - the dynamic evaluation context
        state - a stack on which the instruction can save state information for use during the corresponding
        Throws:
        XPathException - if a dynamic error occurs
      • processRight

        public void processRight​(java.util.Stack<XPathContext> contextStack,
                                 java.util.Stack<java.lang.Object> state)
                          throws XPathException
        Process the second half of the instruction in streaming mode
        Specified by:
        processRight in interface DivisibleInstruction
        Overrides:
        processRight in class ElementCreator
        Parameters:
        contextStack - the stack of XPath context objects for the current execution state
        state - a stack on which the instruction can save state information for use during the corresponding
        Throws:
        XPathException - if a dynamic error occurs
      • 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