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 Summary

Fields

Modifier and Type	Field and Description
protected ArrayList	statusCbL

Fields inherited from class org.apache.uima.collection.impl.cpm.engine.BoundedWorkQueue

cpm, numberElementsInQueue, queue, queueMaxSize, queueName, WAIT_TIMEOUT

Constructor Summary

Constructors

Constructor and Description
SequencedQueue(int aQueueSize, String aQueueName, CPMEngine aCpmEngine) Initialize this queue

Method Summary

Modifier and Type	Method and Description
Object	dequeue() Removes an object from the front of the queue according to FIFO model.
Object	dequeue(long aTimeout) Returns an object from the queue.
protected void	doNotifyListeners(Object aCas, EntityProcessStatus aEntityProcStatus) Notifies all configured listeners.
void	invalidate(CAS[] aCasObjectList)

Methods inherited from class org.apache.uima.collection.impl.cpm.engine.BoundedWorkQueue

enqueue, getCapacity, getCurrentSize, getName

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

statusCbL

protected ArrayList statusCbL

Constructor Detail

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 Detail

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)

Overrides:

invalidate in class BoundedWorkQueue

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