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org.apache.excalibur.event.impl
Class AbstractQueue

java.lang.Object
  org.apache.excalibur.event.impl.AbstractQueue

All Implemented Interfaces:

Queue, Sink, Source

Direct Known Subclasses:

DefaultQueue, FixedSizeQueue

public abstract class AbstractQueue

extends java.lang.Object

implements Queue

Provides the base functionality for the other Queue types.

Author:

Avalon Development Team

Field Summary

protected static java.lang.Object[]	EMPTY_ARRAY An empty array used as a return value when the Queue is empty
protected DequeueInterceptor	m_interceptor
protected EnqueuePredicate	m_predicate
protected long	m_timeout The number of milliseconds to wait

Fields inherited from interface org.apache.excalibur.event.Queue

ROLE

Constructor Summary

AbstractQueue()

Method Summary

protected void	block(java.lang.Object lock) Encapsulates the logic to block the Queue for the amount of time specified by the timeout.
int	canAccept() Default for canAccept()
DequeueInterceptor	getDequeueInterceptor() Return the dequeue executable for this sink.
EnqueuePredicate	getEnqueuePredicate() Return the EnqueuePredicate that is already set for this Queue.
boolean	isFull() Check to see if the Queue is full.
int	maxSize() Default maxSize to -1 which is unbounded
void	setDequeueInterceptor(DequeueInterceptor executable) Set the dequeue executable for this sink.
void	setEnqueuePredicate(EnqueuePredicate predicate) Set the EnqueuePredicate to limit entries into this Queue.
void	setTimeout(long millis) Set the timeout for the Queue in milliseconds.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.excalibur.event.Source

dequeue, dequeue, dequeueAll, size

Methods inherited from interface org.apache.excalibur.event.Sink

enqueue, enqueue, prepareEnqueue, size, tryEnqueue

Field Detail

EMPTY_ARRAY

protected static final java.lang.Object[] EMPTY_ARRAY

An empty array used as a return value when the Queue is empty

m_timeout

protected long m_timeout

The number of milliseconds to wait

m_predicate

protected EnqueuePredicate m_predicate

m_interceptor

protected DequeueInterceptor m_interceptor

Constructor Detail

AbstractQueue

public AbstractQueue()

Method Detail

canAccept

public int canAccept()

Default for canAccept()

Specified by:

canAccept in interface Sink

Returns:

how many elements we can enqueue

maxSize

public int maxSize()

Default maxSize to -1 which is unbounded

Specified by:

maxSize in interface Sink

Returns:

the maximum number of elements

isFull

public boolean isFull()

Check to see if the Queue is full. The method uses the maxSize and size methods to determine whether the queue is full.

Specified by:

isFull in interface Sink

Returns:

true if there is no room in the Queue

setTimeout

public void setTimeout(long millis)

Set the timeout for the Queue in milliseconds. The default timeout is 0, which means that we don't wait at all.

Specified by:

setTimeout in interface Source

Parameters:

millis - The number of milliseconds to block waiting for events to be enqueued

block

protected void block(java.lang.Object lock)

Encapsulates the logic to block the Queue for the amount of time specified by the timeout.

Parameters:

lock - The object used as the mutex.

setEnqueuePredicate

public void setEnqueuePredicate(EnqueuePredicate predicate)

Set the EnqueuePredicate to limit entries into this Queue.

Specified by:

setEnqueuePredicate in interface Queue

Parameters:

predicate - the enqueue predicate for this sink

getEnqueuePredicate

public EnqueuePredicate getEnqueuePredicate()

Return the EnqueuePredicate that is already set for this Queue.

Specified by:

getEnqueuePredicate in interface Queue

Returns:

EnqueuePredicate the enqueue predicate for this sink.

setDequeueInterceptor

public void setDequeueInterceptor(DequeueInterceptor executable)

Set the dequeue executable for this sink. This mechanism allows users to define a methods that will be executed before or after dequeuing elements from a source

Specified by:

setDequeueInterceptor in interface Queue

Parameters:

executable - The dequeue executable for this sink.

Since:

Sep 23, 2002

getDequeueInterceptor

public DequeueInterceptor getDequeueInterceptor()

Return the dequeue executable for this sink.

Specified by:

getDequeueInterceptor in interface Queue

Returns:

DequeueInterceptor The dequeue executable for this sink.

Since:

Sep 23, 2002