Class CopyOf

All Implemented Interfaces:
Serializable, SourceLocator, Container, Expression, TailCallReturner, InstructionInfoProvider

public class CopyOf extends Instruction
An xsl:copy-of element in the stylesheet.
See Also:
  • Constructor Details

    • CopyOf

      public CopyOf(Expression select, boolean copyNamespaces, int validation, SchemaType schemaType, boolean rejectDuplicatAttributes)
  • Method Details

    • setReadOnce

      public void setReadOnce(boolean b)
    • createsNewNodes

      public final boolean createsNewNodes()
      Determine whether this instruction creates new nodes. The result depends on the type of the select expression.
      Overrides:
      createsNewNodes in class Instruction
    • getInstructionNameCode

      public int getInstructionNameCode()
      Get the name of this instruction, for diagnostics and tracing
      Overrides:
      getInstructionNameCode in class Instruction
    • setRequireDocumentOrElement

      public void setRequireDocumentOrElement(boolean requireDocumentOrElement)
      For XQuery, the operand (select) must be a single element or document node.
      Parameters:
      requireDocumentOrElement -
    • getImplementationMethod

      public int getImplementationMethod()
      An implementation of Expression must provide at least one of the methods evaluateItem(), iterate(), or process(). This method indicates which of these methods is provided. This implementation provides both iterate() and process() methods natively.
      Specified by:
      getImplementationMethod in interface Expression
      Overrides:
      getImplementationMethod in class Instruction
    • processLeavingTail

      public TailCall processLeavingTail(XPathContext context) throws XPathException
      Process this xsl:copy-of instruction
      Specified by:
      processLeavingTail in interface TailCallReturner
      Specified by:
      processLeavingTail in class Instruction
      Parameters:
      context - the dynamic context for the transformation
      Returns:
      null - this implementation of the method never returns a TailCall
      Throws:
      XPathException
    • copyAttribute

      static void copyAttribute(NodeInfo source, SchemaType schemaType, int validation, Instruction instruction, XPathContext context, boolean rejectDuplicates) throws XPathException
      Method shared by xsl:copy and xsl:copy-of to copy an attribute node
      Parameters:
      source - the node to be copied
      schemaType - the simple type against which the value is to be validated, if any
      validation - one of preserve, strip, strict, lax
      instruction - the calling instruction, used for diagnostics
      context - the dynamic context
      rejectDuplicates - true if duplicate attributes with the same name are disallowed (XQuery)
      Throws:
      XPathException
    • simplify

      public Expression simplify(StaticContext env) throws XPathException
      Description copied from class: Instruction
      Simplify an expression. This performs any static optimization (by rewriting the expression as a different expression). The default implementation does nothing.
      Specified by:
      simplify in interface Expression
      Specified by:
      simplify in class Instruction
      Parameters:
      env - the static context
      Returns:
      the simplified expression
      Throws:
      XPathException - if an error is discovered during expression rewriting
    • getItemType

      public ItemType getItemType(TypeHierarchy th)
      Description copied from class: Instruction
      Get the item type of the items returned by evaluating this instruction
      Specified by:
      getItemType in interface Expression
      Overrides:
      getItemType in class Instruction
      Parameters:
      th -
      Returns:
      the static item type of the instruction
    • getCardinality

      public int getCardinality()
      Description copied from class: ComputedExpression
      Determine the static cardinality of the expression. This establishes how many items there will be in the result of the expression, at compile time (i.e., without actually evaluating the result.
      Specified by:
      getCardinality in interface Expression
      Overrides:
      getCardinality in class ComputedExpression
      Returns:
      one of the values Cardinality.ONE_OR_MORE, Cardinality.ZERO_OR_MORE, Cardinality.EXACTLY_ONE, Cardinality.ZERO_OR_ONE, Cardinality.EMPTY. This default implementation returns ZERO_OR_MORE (which effectively gives no information).
    • getDependencies

      public int getDependencies()
      Description copied from class: ComputedExpression
      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.
      Specified by:
      getDependencies in interface Expression
      Overrides:
      getDependencies in class ComputedExpression
      Returns:
      a set of bit-significant flags identifying the dependencies of the expression
    • promoteInst

      protected void promoteInst(PromotionOffer offer) throws XPathException
      Description copied from class: Instruction
      Handle promotion offers, that is, non-local tree rewrites.
      Overrides:
      promoteInst in class Instruction
      Parameters:
      offer - The type of rewrite being offered
      Throws:
      XPathException
    • typeCheck

      public Expression typeCheck(StaticContext env, ItemType contextItemType) throws XPathException
      Description copied from interface: 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.

      Parameters:
      env - the static context of the expression
      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
    • optimize

      public Expression optimize(Optimizer opt, StaticContext env, ItemType contextItemType) throws XPathException
      Description copied from interface: 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.

      Parameters:
      opt - the optimizer in use. This provides access to supporting functions; it also allows different optimization strategies to be used in different circumstances.
      env - the static context of the expression
      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
    • display

      public void display(int level, PrintStream out, Configuration config)
      Diagnostic print of expression structure. The expression is written to the System.err output stream
      Parameters:
      level - indentation level for this expression
      out -
      config -
    • iterateSubExpressions

      public Iterator iterateSubExpressions()
      Description copied from class: ComputedExpression
      Get the immediate sub-expressions of this expression. Default implementation returns a zero-length array, appropriate for an expression that has no sub-expressions.
      Specified by:
      iterateSubExpressions in interface Expression
      Overrides:
      iterateSubExpressions in class ComputedExpression
      Returns:
      an iterator containing the sub-expressions of this expression
    • replaceSubExpression

      public boolean replaceSubExpression(Expression original, Expression replacement)
      Replace one subexpression by a replacement subexpression
      Specified by:
      replaceSubExpression in interface Container
      Overrides:
      replaceSubExpression in class ComputedExpression
      Parameters:
      original - the original subexpression
      replacement - the replacement subexpression
      Returns:
      true if the original subexpression is found
    • evaluateItem

      public Item evaluateItem(XPathContext context) throws XPathException
      Return the first item if there is one, or null if not
      Specified by:
      evaluateItem in interface Expression
      Overrides:
      evaluateItem in class Instruction
      Parameters:
      context -
      Returns:
      the result of evaluating the instruction
      Throws:
      XPathException
    • iterate

      public SequenceIterator iterate(XPathContext context) throws XPathException
      Description copied from class: Instruction
      Return an Iterator to iterate over the values of a sequence. The value of every expression can be regarded as a sequence, so this method is supported for all expressions. This default implementation handles iteration for expressions that return singleton values: for non-singleton expressions, the subclass must provide its own implementation.
      Specified by:
      iterate in interface Expression
      Overrides:
      iterate in class Instruction
      Parameters:
      context - supplies the context for evaluation
      Returns:
      a SequenceIterator that can be used to iterate over the result of the expression
      Throws:
      XPathException - if any dynamic error occurs evaluating the expression