Class Copy

All Implemented Interfaces:
Serializable, SourceLocator, LocationProvider, SaxonLocator, EvaluableItem, SequenceIterable, TailCallReturner, InstructionInfo, Locator

public class Copy extends ElementCreator
Handler for xsl:copy elements in stylesheet.
See Also:
  • Constructor Details

    • 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 Details

    • 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 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
    • outputNamespaceNodes

      protected void outputNamespaceNodes(XPathContext context, Receiver receiver) throws XPathException
      Callback to output namespace nodes for the new element.
      Specified by:
      outputNamespaceNodes in class ElementCreator
      Parameters:
      context - The execution context
      receiver - the Receiver where the namespace nodes are to be written
      Throws:
      XPathException
    • 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
    • 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
    • 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