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 java.lang.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
protected int	numberElementsInQueue
protected java.util.LinkedList	queue
protected int	queueMaxSize
protected java.lang.String	queueName
protected static int	WAIT_TIMEOUT

Constructor Summary

Constructors

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

Method Summary

Methods

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

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

queue

protected java.util.LinkedList queue

numberElementsInQueue

protected int numberElementsInQueue

queueName

protected java.lang.String queueName

cpm

protected CPMEngine cpm

WAIT_TIMEOUT

protected static final int WAIT_TIMEOUT

See Also:

Constant Field Values

Constructor Detail

BoundedWorkQueue

public BoundedWorkQueue(int aQueueSize,
                java.lang.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 java.lang.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(java.lang.Object anObject)

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

Parameters:

anObject - - an object to enqueue

dequeue

public java.lang.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 java.lang.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(CAS[] aCasObjectList)