Class TransmissionAdjunct

java.lang.Object
com.saxonica.ee.stream.adjunct.StreamingAdjunct
com.saxonica.ee.stream.adjunct.TransmissionAdjunct
All Implemented Interfaces:
FeedMaker
Direct Known Subclasses:
AbsorbingFunctionCallAdjunct, AdjacentTextNodeMergerAdjunct, ArrayBlockAdjunct, BlockAdjunct, CardinalityCheckerAdjunct, ChooseAdjunct, ConditionalBlockAdjunct, CurrentMergeGroupStreamer, DeepDescentFunctionCallAdjunct, DocumentSorterAdjunct, FilterFunctionCallAdjunct, FilteringAdjunct, ForEachAdjunct, InsertBeforeStreamer, ItemCheckerAdjunct, IterateAdjunct, LetExpressionAdjunctB, OnEmptyAdjunct, OnNonEmptyAdjunct, ShallowDescentFunctionCallAdjunct, SwitchAdjunct, TraceExprAdjunct, TraceStreamer, TreatFnStreamer, TryCatchAdjunct, VennExpressionAdjunct, WherePopulatedAdjunct

public abstract class TransmissionAdjunct extends StreamingAdjunct implements FeedMaker
A subclass of StreamingAdjunct used for expressions that have a sequence-valued operand with usage transmission. Such expressions may appear as a filter for striding or crawling nodes, in which case they need to filter (or in some cases augment) the event stream rather than operating at the level of composed items.
  • Constructor Details

    • TransmissionAdjunct

      public TransmissionAdjunct()
  • Method Details

    • getWatchMaker

      public WatchMaker getWatchMaker(boolean forGrouping) throws XPathException
      Description copied from class: StreamingAdjunct
      Get a WatchMaker, a factory class that creates a Watch to evaluate this expression in streaming mode. This method will only be called if the getImplementationMethod() method of the expression includes the value Expression.WATCH_METHOD
      Overrides:
      getWatchMaker in class StreamingAdjunct
      Parameters:
      forGrouping - true if the selected items are being grouped
      Returns:
      a Watchmaker to evaluate the expression, or null if it is not streamable with respect to the specificed argument.
      Throws:
      XPathException - in the event of a failure
    • makeTransmissionFlow

      public Trigger makeTransmissionFlow(WatchManager watchManager, Expression exp, ItemFeed out, XPathContext context) throws XPathException
      Make a Trigger that implements this expression in streaming mode. This method is used for an expression that is striding or crawling, and it delivers a Trigger connected to a sequence of Feeds which together have the effect of delivering a sequence of events and/or items that together represent the results of this instruction. This method MUST be implemented for every expression that has an operand whose usage is transmission (and for every such operand).
      Parameters:
      watchManager - the WatchManager that fires this trigger
      exp - the expression
      out - the next action in the push pipeline for evaluation
      context - the XPath dynamic context
      Returns:
      the Trigger (a Watch with a pattern)
      Throws:
      XPathException - if a dynamic evaluation error occurs.