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

Class BoundedWorkQueue

java.lang.Object

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

Direct Known Subclasses:

SequencedQueue

public class BoundedWorkQueue
extends Object

Implementation of a Bounded Queue, a queue with a fixed number of slots. Used primarily to feed data to Processing Units, it is filled by a producer like ArtifactProducer and consumed by ProcessingUnit(s). When the queue is full it will block a request for enqueue until a slot frees up.

There are 2 dequeue calls. One returns null if the queue is empty, the other can be given a timeout - and it will wait up to that time waiting for something to get enqueued.

Field Summary

Fields

Modifier and Type	Field and Description
protected CPMEngine	cpm The cpm.
protected int	numberElementsInQueue The number elements in queue.
protected LinkedList	queue The queue.
protected int	queueMaxSize The queue max size.
protected String	queueName The queue name.
protected static int	WAIT_TIMEOUT The Constant WAIT_TIMEOUT.

Constructor Summary

Constructors

Constructor and Description
BoundedWorkQueue(int aQueueSize, String aQueueName, CPMEngine aCpmEngine) Initialize the instance.

Method Summary

Modifier and Type	Method and Description
Object	dequeue() Removes an object from the front of the queue according to FIFO.
Object	dequeue(long aTimeout) Returns an object from the queue.
void	enqueue(Object anObject) Enqueues a given object onto the queue.
int	getCapacity() Returns the queue capacity.
int	getCurrentSize() Returns number of elements in the queue.
String	getName() Returns Queue name.
void	invalidate(org.apache.uima.cas.CAS[] aCasObjectList) Invalidate.

Methods inherited from class java.lang.Object

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

Field Detail

queueMaxSize

protected final int queueMaxSize

The queue max size.

queue

protected LinkedList queue

The queue.

numberElementsInQueue

protected int numberElementsInQueue

The number elements in queue.

queueName

protected String queueName

The queue name.

cpm

protected CPMEngine cpm

The cpm.

WAIT_TIMEOUT

protected static final int WAIT_TIMEOUT

The Constant WAIT_TIMEOUT.

See Also:

Constant Field Values

Constructor Detail

BoundedWorkQueue

public BoundedWorkQueue(int aQueueSize,
                        String aQueueName,
                        CPMEngine aCpmEngine)

Initialize the instance.

Parameters:

aQueueSize - - fixed size for this queue (capacity)

aQueueName - - name for this queue

aCpmEngine - - CPE Engine reference

Method Detail

getName

public String getName()

Returns Queue name.

Returns:

- name of the queue

getCurrentSize

public int getCurrentSize()

Returns number of elements in the queue. Special case handles EOFToken.

Returns:

- number of elements in the queue

getCapacity

public int getCapacity()

Returns the queue capacity.

Returns:

- queue max size

enqueue

public void enqueue(Object anObject)

Enqueues a given object onto the queue. It blocks if the queue is full.

Parameters:

anObject - - an object to enqueue

dequeue

public Object dequeue()

Removes an object from the front of the queue according to FIFO.

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.

Parameters:

aTimeout - - max millis to wait for an object

Returns:

- Object from the queue, or null if time out

invalidate

public void invalidate(org.apache.uima.cas.CAS[] aCasObjectList)

Invalidate.

Parameters:

aCasObjectList - the a cas object list