Package com.saxonica.ee.stream.adjunct

Class CurrentMergeGroupStreamer

java.lang.Object
com.saxonica.ee.stream.adjunct.StreamingAdjunct
com.saxonica.ee.stream.adjunct.TransmissionAdjunct
com.saxonica.ee.stream.adjunct.CurrentMergeGroupStreamer
All Implemented Interfaces:
FeedMaker
public class CurrentMergeGroupStreamer extends TransmissionAdjunct
Generate streaming code for a call on current-merge-group().

  • Constructor Details

    • CurrentMergeGroupStreamer

      public CurrentMergeGroupStreamer()

  • Method Details

    • computeStreamability

      public PostureAndSweep computeStreamability(ContextItemStaticInfoEE contextInfo, List<String> reasons)
      Description copied from class: StreamingAdjunct
      Compute the posture and sweep of this expression as defined in the W3C streamability specifications. This must be implemented in all subclasses that don't use the general streamability rules. The implementation should have the side-effect of computing the streamability of all subexpressions, recursively.
      Overrides:
      computeStreamability in class StreamingAdjunct
      Parameters:
      contextInfo - Information about the context item type and posture
      reasons - the caller may supply a list, in which case the implementation may add to this; the contents are human-readable messages explaining why the expression is not streamable.
      Returns:
      the posture and sweep of the expression

    • toStreamingPattern

      public Pattern toStreamingPattern(Configuration config)
      Convert this expression to a streaming pattern (a pattern used internally to match nodes during push processing of an event stream)
      Overrides:
      toStreamingPattern in class StreamingAdjunct
      Parameters:
      config - the Saxon configuration
      Returns:
      the equivalent pattern if conversion succeeds; otherwise null

    • makeTransmissionFlow

      public Trigger makeTransmissionFlow(WatchManager watchManager, Expression exp, ItemFeed out, XPathContext context) throws XPathException
      Description copied from class: TransmissionAdjunct
      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).
      Overrides:
      makeTransmissionFlow in class TransmissionAdjunct
      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.

    • makeItemFeed

      public ItemFeed makeItemFeed(WatchManager watchManager, ItemFeed out, XPathContext context) throws XPathException
      Throws:
      XPathException