Package net.sf.saxon.expr.instruct

Class Copy

java.lang.Object
net.sf.saxon.expr.Expression
net.sf.saxon.expr.instruct.Instruction
net.sf.saxon.expr.instruct.ParentNodeConstructor
net.sf.saxon.expr.instruct.ElementCreator
net.sf.saxon.expr.instruct.Copy
All Implemented Interfaces:
ExportAgent, InstructionWithComplexContent, ValidatingInstruction, Locatable, IdentityComparable, Traceable
public class Copy extends ElementCreator
Handler for xsl:copy elements in stylesheet. This only handles copying of the context item. An xsl:copy with a select attribute is handled by wrapping the instruction in an xsl:for-each.

  • Constructor Details

    • Copy

      public Copy(boolean copyNamespaces, boolean inheritNamespaces, SchemaType schemaType, int validation)
      Create a shallow copy instruction

      param select selects the node (or other item) to be copied. Never null. param selectSpecified true if the select attribute of xsl:copy was specified explicitly (in which case the context for evaluating the body will change)

      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

    • setCopyNamespaces

      public void setCopyNamespaces(boolean copy)
      Say whether namespace nodes are to be copied (in the case of an element)
      Parameters:
      copy - set to true if namespace nodes are to be copied

    • 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() 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 Expression
      Returns:
      the simplified expression (or the original if unchanged, or if modified in-situ)
      Throws:
      XPathException - if an error is discovered during expression rewriting

    • typeCheck

      public Expression typeCheck(ExpressionVisitor visitor, ContextItemStaticInfo contextInfo) 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.

      Overrides:
      typeCheck in class ParentNodeConstructor
      Parameters:
      visitor - an expression visitor
      contextInfo - Information available statically about the context item: whether it is (possibly) absent; its static type; its streaming posture.
      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(RebindingMap rebindings)
      Copy this expression (don't be confused by the method name). This makes a deep copy.
      Specified by:
      copy in class Expression
      Parameters:
      rebindings - variables that need to be re-bound
      Returns:
      the copy of the original expression

    • setSelectItemType

      public void setSelectItemType(ItemType type)
      Set the item type of the input
      Parameters:
      type - the item type

    • 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

    • operands

      public Iterable<Operand> operands()
      Get the immediate sub-expressions of this expression, with information about the relationship of each expression to its parent expression. Default implementation returns a zero-length array, appropriate for an expression that has no sub-expressions.
      Specified by:
      operands in class Instruction
      Returns:
      an iterator containing the sub-expressions of this expression

    • getItemType

      public ItemType getItemType()
      Get the item type of the result of this instruction.
      Overrides:
      getItemType in class ElementCreator
      Returns:
      The context item type.

    • optimize

      public Expression optimize(ExpressionVisitor visitor, ContextItemStaticInfo 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)

    • outputNamespaceNodes

      public void outputNamespaceNodes(Outputter receiver, NodeName nodeName, ElementCreator.ElementCreationDetails details) throws XPathException
      Callback to output namespace nodes for the new element.
      Specified by:
      outputNamespaceNodes in class ElementCreator
      Parameters:
      receiver - the Receiver where the namespace nodes are to be written
      nodeName - the element name
      details - the node being copied (for xsl:copy), otherwise null
      Throws:
      XPathException - if any error occurs

    • copyUnparsedEntities

      public static void copyUnparsedEntities(NodeInfo source, Outputter out) throws XPathException
      Throws:
      XPathException

    • evaluateItem

      public Item 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

    • getStreamerName

      public String getStreamerName()
      Get the (partial) name of a class that supports streaming of this kind of expression
      Overrides:
      getStreamerName in class ElementCreator
      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

    • 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.

    • getElaborator

      public Elaborator getElaborator()
      Description copied from class: Expression
      Make an elaborator for this expression
      Overrides:
      getElaborator in class Expression
      Returns:
      an appropriate Elaborator