org.apache.excalibur.event
Interface Queue

All Superinterfaces:

Sink, Source

All Known Implementing Classes:

AbstractQueue

public interface Queue

extends Source, Sink

A Source implements the side of an event queue where QueueElements are dequeued operations only.

The interface design is heavily influenced by Matt Welsh's SandStorm server, his demonstration of the SEDA architecture. We have deviated where we felt the design differences where better.

Author:

Avalon Development Team

Field Summary

static java.lang.String

ROLE

Method Summary

DequeueInterceptor	getDequeueInterceptor() Return the dequeue executable for this sink.
EnqueuePredicate	getEnqueuePredicate() Return the enqueue predicate for this sink.
void	setDequeueInterceptor(DequeueInterceptor executable) Set the dequeue executable for this sink.
void	setEnqueuePredicate(EnqueuePredicate enqueuePredicate) Set the enqueue predicate for this sink.

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

dequeue, dequeue, dequeueAll, setTimeout, size

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

canAccept, enqueue, enqueue, isFull, maxSize, prepareEnqueue, size, tryEnqueue

Field Detail

ROLE

public static final java.lang.String ROLE

Method Detail

setEnqueuePredicate

public void setEnqueuePredicate(EnqueuePredicate enqueuePredicate)

Set the enqueue predicate for this sink. This mechanism allows user to define a method that will 'screen' QueueElementIF's during the enqueue procedure to either accept or reject them. The enqueue predicate runs in the context of the caller of Sink.enqueue(Object), which means it must be simple and fast. This can be used to implement many interesting m_sink-thresholding policies, such as simple count threshold, credit-based mechanisms, and more.

Parameters:

enqueuePredicate - the enqueue predicate for this sink

Since:

Feb 10, 2003

getEnqueuePredicate

public EnqueuePredicate getEnqueuePredicate()

Return the enqueue predicate for this sink.

Returns:

EnqueuePredicate the enqueue predicate for this sink.

Since:

Feb 10, 2003

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

Parameters:

executable - The dequeue executable for this sink.

Since:

Feb 10, 2003

getDequeueInterceptor

public DequeueInterceptor getDequeueInterceptor()

Return the dequeue executable for this sink.

Returns:

DequeueInterceptor The dequeue executable for this sink.

Since:

Feb 10, 2003