Class CopyOf

java.lang.Object
net.sf.saxon.expr.Expression
net.sf.saxon.expr.instruct.Instruction
net.sf.saxon.expr.instruct.CopyOf
All Implemented Interfaces:
Serializable, SourceLocator, LocationProvider, SaxonLocator, TailCallReturner, ValidatingInstruction, InstructionInfo, Locator
public class CopyOf extends Instruction implements ValidatingInstruction
An xsl:copy-of element in the stylesheet.
See Also:

  • Constructor Details

    • CopyOf

      public CopyOf(Expression select, boolean copyNamespaces, int validation, SchemaType schemaType, boolean rejectDuplicateAttributes)
      Create an xsl:copy-of instruction (also used in XQuery for implicit copying)
      Parameters:
      select - expression that selects the nodes to be copied
      copyNamespaces - true if namespaces are to be copied
      validation - validation mode for the result tree
      schemaType - schema type for validating the result tree
      rejectDuplicateAttributes - true if duplicate attributes are to be rejected (XQuery). False if duplicates are handled by discarding all but the first (XSLT).

  • Method Details

    • getSelectExpression

      public Expression getSelectExpression()
      Get the expression that selects the nodes to be copied
      Returns:
      the select expression

    • getValidationAction

      public int getValidationAction()
      Get the validation mode
      Specified by:
      getValidationAction in interface ValidatingInstruction
      Returns:
      the validation mode

    • isValidating

      public boolean isValidating()
      Test if the instruction is doing validation
      Returns:
      true if it is

    • getSchemaType

      public SchemaType getSchemaType()
      Get the schema type to be used for validation
      Specified by:
      getSchemaType in interface ValidatingInstruction
      Returns:
      the schema type, or null if not validating against a type

    • setStaticBaseUri

      public void setStaticBaseUri(String base)
      Set the static base URI of the xsl:copy-of instruction
      Parameters:
      base - the static base URI

    • setReadOnce

      public void setReadOnce(boolean b)
      Set the "saxon:read-once" optimization mode
      Parameters:
      b - true to enable the optimization

    • setCopyLineNumbers

      public void setCopyLineNumbers(boolean copy)
      Set whether line numbers are to be copied from the source to the result. Default is false.
      Parameters:
      copy - true if line numbers are to be copied

    • 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
      Returns:
      true if the instruction creates new nodes (or if it can't be proved that it doesn't)

    • getInstructionNameCode

      public int getInstructionNameCode()
      Get the name of this instruction, for diagnostics and tracing
      Overrides:
      getInstructionNameCode in class Instruction
      Returns:
      a code identifying the instruction: typically but not always the fingerprint of a name in the XSLT namespace

    • setRequireDocumentOrElement

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

    • isDocumentOrElementRequired

      public boolean isDocumentOrElementRequired()
      Test whether this expression requires a document or element node
      Returns:
      true if this expression requires the value of the argument to be a document or element node, false if there is no such requirement

    • setCopyForUpdate

      public void setCopyForUpdate(boolean forUpdate)
      Set whether this instruction is creating a copy for the purpose of updating (XQuery transform expression)
      Parameters:
      forUpdate - true if this copy is being created to support an update

    • isCopyForUpdate

      public boolean isCopyForUpdate()
      Ask whether this instruction is creating a copy for the purpose of updating (XQuery transform expression)
      Returns:
      true if this copy is being created to support an update

    • 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.
      Overrides:
      getImplementationMethod in class Instruction
      Returns:
      the implementation method, for example Expression.ITERATE_METHOD or Expression.EVALUATE_METHOD or Expression.PROCESS_METHOD

    • isCopyNamespaces

      public boolean isCopyNamespaces()
      Determine whether namespaces are to be copied or not
      Returns:
      true if namespaces are to be copied (the default)

    • 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

    • simplify

      public Expression simplify(ExpressionVisitor visitor) 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 class Instruction
      Parameters:
      visitor - an expression visitor
      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
      Overrides:
      getItemType in class Instruction
      Parameters:
      th - the type hierarchy cache
      Returns:
      the static item type of the instruction

    • getCardinality

      public int getCardinality()
      Description copied from class: Expression
      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.
      Overrides:
      getCardinality in class Expression
      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: Expression
      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:
      getDependencies in class Expression
      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 - if an error occurs

    • 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 Expression
      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)

    • 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 Expression
      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)

    • 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

    • iterateSubExpressions

      public Iterator<Expression> iterateSubExpressions()
      Description copied from class: Expression
      Get the immediate sub-expressions of this expression. Default implementation returns a zero-length array, appropriate for an expression that has no sub-expressions.
      Overrides:
      iterateSubExpressions in class Expression
      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
      Overrides:
      replaceSubExpression in class Expression
      Parameters:
      original - the original subexpression
      replacement - the replacement subexpression
      Returns:
      true if the original subexpression is found

    • addToPathMap

      public PathMap.PathMapNodeSet addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet)
      Add a representation of this expression to a PathMap. The PathMap captures a map of the nodes visited by an expression in a source tree.

      The default implementation of this method assumes that an expression does no navigation other than the navigation done by evaluating its subexpressions, and that the subexpressions are evaluated in the same context as the containing expression. The method must be overridden for any expression where these assumptions do not hold. For example, implementations exist for AxisExpression, ParentExpression, and RootExpression (because they perform navigation), and for the doc(), document(), and collection() functions because they create a new navigation root. Implementations also exist for PathExpression and FilterExpression because they have subexpressions that are evaluated in a different context from the calling expression.

      Overrides:
      addToPathMap in class Expression
      Parameters:
      pathMap - the PathMap to which the expression should be added
      pathMapNodeSet - the PathMapNodeSet to which the paths embodied in this expression should be added
      Returns:
      the pathMapNodeSet representing the points in the source document that are both reachable by this expression, and that represent possible results of this expression. For an expression that does navigation, it represents the end of the arc in the path map that describes the navigation route. For other expressions, it is the same as the input pathMapNode.

    • 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 - if a dynamic error occurs during the evaluation of the instruction

    • copyAttribute

      static void copyAttribute(NodeInfo source, SimpleType 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 - if a failure occurs

    • iterate

      public SequenceIterator<? extends Item> 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.
      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