edu.uci.isr.yancees.dispatcher
Interface EventDispatcherAdapterInterface


public interface EventDispatcherAdapterInterface

Title: Yancees Notification Server

Description: Yet ANother Configurable Extensible Event Service

Copyright: Copyright (c) 2003

Company: School of Information and Computer Science - University of California, Irvine

Version:
1.0
Author:
Roberto Silveira Silva Filho

Method Summary
 void connect(java.lang.String address)
          Connects and initializes the registered dispatchers This method is used by the server-specific adapters
 java.lang.String getAdapterName()
           
 void publish(EventInterface evnt)
           
 void resumeDispatcher(EventDispatcherListenerInterface li)
          resumes the delivery of notifications to the given subscriber n.
 void shutdownDispatcher()
          closes this Dispatcher service access point.
 void subscribe(SubscriptionInterface sub, EventDispatcherListenerInterface li)
          subscribes for sequences of events matching pattern p.
 void suspendDispatcher(EventDispatcherListenerInterface li)
          suspends the delivery of notifications to the given subscriber li.
 void unsubscribe(EventDispatcherListenerInterface li)
          cancels all the subscriptions posted by n.
 void unsubscribe(SubscriptionInterface sub, EventDispatcherListenerInterface li)
          cancels the subscriptions, posted by li, whose subscripton sub' is covered by subscripiton p.
 

Method Detail

publish

void publish(EventInterface evnt)
             throws DispatcherException
Parameters:
evt - The event to publish.
Throws:
DispatcherException
See Also:
Event

subscribe

void subscribe(SubscriptionInterface sub,
               EventDispatcherListenerInterface li)
               throws DispatcherException
subscribes for sequences of events matching pattern p.

Notice that given the distributed nature of some implementations of Dispatcher interface, there exist race conditions that might affect the semantics of subscriptions. A subscriber might miss some notifications published before or while the subscription is processed by Dispatcher.

Also, keep in mind that the current implementation of Dispatcher does not enforce any temporal order for the delivery of notifications. This limitation might affect the recognition of patterns. For example, two notifications x and y, generated at time tx and ty respectively, with tx < ty, in that order matching a pattern P=(fx fy), might in fact reach the subscriber at times Tx and Ty, with Tx > Ty, in which case pattern P would not be matched.

Parameters:
li - is the subscriber
sub - is the subscription pattern
Throws:
DispatcherException
See Also:
unsubscribe(edu.uci.isr.yancees.SubscriptionInterface, edu.uci.isr.yancees.dispatcher.EventDispatcherListenerInterface)

unsubscribe

void unsubscribe(SubscriptionInterface sub,
                 EventDispatcherListenerInterface li)
                 throws DispatcherException
cancels the subscriptions, posted by li, whose subscripton sub' is covered by subscripiton p.

Unsubscriptions might incurr in the same kind of race conditions as subscriptions. Dispatcher will stop sending notifications to the subscriber only after it has completed the processing of the unsubscription. Due to the distributed nature of some implementations of Dispatcher, this might result in some additional ``unsolicited'' notifications.

Parameters:
li - is the subscriber interface
Throws:
DispatcherException
See Also:
subscribe(edu.uci.isr.yancees.SubscriptionInterface, edu.uci.isr.yancees.dispatcher.EventDispatcherListenerInterface)

unsubscribe

void unsubscribe(EventDispatcherListenerInterface li)
                 throws DispatcherException
cancels all the subscriptions posted by n.

Parameters:
li - is the subscriber
Throws:
DispatcherException
See Also:
subscribe(edu.uci.isr.yancees.SubscriptionInterface, edu.uci.isr.yancees.dispatcher.EventDispatcherListenerInterface)

suspendDispatcher

void suspendDispatcher(EventDispatcherListenerInterface li)
                       throws DispatcherException
suspends the delivery of notifications to the given subscriber li.

Parameters:
li - subscriber to be suspended
Throws:
DispatcherException

resumeDispatcher

void resumeDispatcher(EventDispatcherListenerInterface li)
                      throws DispatcherException
resumes the delivery of notifications to the given subscriber n.

Parameters:
n - subscriber to be resumed
Throws:
DispatcherException

shutdownDispatcher

void shutdownDispatcher()
                        throws DispatcherException
closes this Dispatcher service access point. This method releases any system resources associated with the access point. In case this access point is connected to other Dispatcher servers, this method will properly disconnect it.

Throws:
DispatcherException

connect

void connect(java.lang.String address)
             throws DispatcherException
Connects and initializes the registered dispatchers This method is used by the server-specific adapters

Parameters:
address - is the address of the server.
Throws:
DispatcherException

getAdapterName

java.lang.String getAdapterName()
Returns:
a name that identifies this adapter.