Class StreamInstr

All Implemented Interfaces:
Pusher, ExportAgent, Locatable, IdentityComparable, Traceable

public class StreamInstr extends SourceDocument implements Pusher
Implementation of the xsl:source-document (streamable="yes") instruction
  • Constructor Details

  • Method Details

    • setSpaceStrippingRule

      public void setSpaceStrippingRule(SpaceStrippingRule rule)
      Description copied from class: SourceDocument
      Set the whitespace stripping rule to be used. (This method is used when reloading the instruction from a SEF file)
      Overrides:
      setSpaceStrippingRule in class SourceDocument
      Parameters:
      rule - the whitespace stripping rule
    • optimize

      public Expression optimize(ExpressionVisitor visitor, ContextItemStaticInfo contextItemType) throws XPathException
      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 SourceDocument
      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)
    • prepareForStreaming

      public Expression prepareForStreaming(PackageData pack) throws XPathException
      Throws:
      XPathException
    • prepareForStreaming

      public void prepareForStreaming() throws XPathException
      Overrides:
      prepareForStreaming in class Expression
      Throws:
      XPathException
    • checkStreamability

      public Expression checkStreamability(List<String> reasons, boolean enabled, boolean strict) throws XPathException
      Throws:
      XPathException
    • mayCreateNewNodes

      public boolean mayCreateNewNodes()
      Determine whether this instruction creates new nodes. This implementation returns a default value of false
      Overrides:
      mayCreateNewNodes in class SourceDocument
      Returns:
      true if the instruction creates new nodes (or if it can't be proved that it doesn't)
    • computeDependencies

      public int computeDependencies()
      Compute the dependencies of an expression, as the union of the dependencies of its subexpressions. (This is overridden for path expressions and filter expressions, where the dependencies of a subexpression are not all propogated). This method should be called only once, to compute the dependencies; after that, getDependencies should be used.
      Overrides:
      computeDependencies in class SourceDocument
      Returns:
      the depencies, as a bit-mask
    • computeSpecialProperties

      protected int computeSpecialProperties()
      Get the static properties of this expression (other than its type). The result is bit-signficant. These properties are used for optimizations. In general, if property bit is set, it is true, but if it is unset, the value is unknown.
      Overrides:
      computeSpecialProperties in class SourceDocument
      Returns:
      a set of flags indicating static properties of this expression
    • getAction

      public Inversion getAction()
    • copy

      public Expression copy(RebindingMap rebindings)
      Copy an expression. This makes a deep copy.
      Overrides:
      copy in class SourceDocument
      Parameters:
      rebindings - variables that need to be re-bound
      Returns:
      the copy of the original expression
    • push

      public void push(Outputter output, XPathContext context) throws XPathException
      Evaluate the instruction in push mode
      Specified by:
      push in interface Pusher
      Overrides:
      push in class SourceDocument
      Parameters:
      output - the final destination for the output of the instruction
      context - the evaluation context
      Throws:
      XPathException - in the event of a failure
      QuitParsingException - if there was an early exit, that is, if the instruction was evaluated without reading the input to completion
    • iterate

      public SequenceIterator iterate(XPathContext context) throws XPathException
      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 implementation uses two threads: the instruction is evaluated in push mode in a child thread (using the process() method), putting its results on a queue, from which this method reads them.
      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
    • process

      public void process(Outputter output, XPathContext context) throws XPathException
      Process the instruction, without returning any tail calls
      Overrides:
      process in class Instruction
      Parameters:
      output - the destination for the result
      context - The dynamic context, giving access to the current node
      Throws:
      XPathException - if a dynamic error occurs
    • getExportTag

      public String getExportTag()
      Overrides:
      getExportTag in class SourceDocument
    • getElaborator

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