Package org.apache.uima.collection.impl.cpm.engine

Class SequencedQueue

java.lang.Object
org.apache.uima.collection.impl.cpm.engine.BoundedWorkQueue
org.apache.uima.collection.impl.cpm.engine.SequencedQueue
public class SequencedQueue extends BoundedWorkQueue
This component extends the Bound Queue by guaranteeing delivery of CASes in sequential order. Large documents may be split into smaller chunks and and each is processed asynchronously. Since these chunks are processed at different speeds (in multi-pipeline CPE configurations), they may arrive at the queue out of order. The Cas Consumer may need those chunks in the correct order. This component checks each CAS metadata for a clue to see if the CAS is part of a larger sequence. If so, it sets its internal state so that it can expect the proper chunk to come in. A timer thread is used to make sure that this component does not wait indefinitely for expected chunk. If the timer goes off, the entire document ( and all its CASes) are invalidated.

  • Field Details

    • statusCbL

      protected ArrayList statusCbL
      The status cb L.

  • Constructor Details

    • SequencedQueue

      public SequencedQueue(int aQueueSize, String aQueueName, CPMEngine aCpmEngine)
      Initialize this queue.
      Parameters:
      aQueueSize - - the size of the queue
      aQueueName - - the name of the queue
      aCpmEngine - - reference to the CPE

  • Method Details

    • dequeue

      public Object dequeue()
      Removes an object from the front of the queue according to FIFO model. It sequences chunks so that they are returned in the right sequential order. It handles out of sequence CAS arrivals and returns it in a wraper.
      Overrides:
      dequeue in class BoundedWorkQueue
      Returns:
      object dequeued from the head of the queue

    • dequeue

      public Object dequeue(long aTimeout)
      Returns an object from the queue. It will wait for the object to show up in the queue until a given timer expires.
      Overrides:
      dequeue in class BoundedWorkQueue
      Parameters:
      aTimeout - - max millis to wait for an object
      Returns:
      - Object from the queue, or null if time out

    • invalidate

      public void invalidate(CAS[] aCasObjectList)
      Description copied from class: BoundedWorkQueue
      Invalidate.
      Overrides:
      invalidate in class BoundedWorkQueue
      Parameters:
      aCasObjectList - the a cas object list

    • doNotifyListeners

      protected void doNotifyListeners(Object aCas, EntityProcessStatus aEntityProcStatus)
      Notifies all configured listeners. Makes sure that appropriate type of Cas is sent to the listener. Conversions take place to ensure compatibility.
      Parameters:
      aCas - - Cas to pass to listener
      aEntityProcStatus - - status object containing exceptions and trace info