The design of a configurable, extensible and dynamic notification service

Abstract

Publish/subscribe infrastructures, specifically notification servers, are used in a large spectrum of distributed applications as their basic communication and integration infrastructure. With their recent popularization, notification servers are being developed to support specific application domains. At the same time, generalpurpose notification servers provide a large set of functionality for a broad set of applications. With so many options, developers face the dilemma of choosing between application-specific or generalpurpose notification servers. In both cases, however, the set of features provided by the servers are usually neither extensible nor configurable, making their customization to specific application domains a difficult task. In this work, a more flexible approach is proposed -a customizable, extensible and dynamic architecture for notification services -which allows the customization of the notification service to different application domains. The extensibility model is presented according to the design framework proposed by Rosemblum and Wolf. A preliminary implementation of the prototype is also discussed, as well as configuration examples.

Extending WS-Notification with an Expressive Event Notification Broker

“…The WS-Notification specifications can be compared to publish/subscribe mechanisms such as the CORBA Event Service [26] and the CORBA Notification Service [7,15]. But the WSN specification is arguably more expressive when it comes to event filtering, since both the notification message and the producer can be the subject of a filter expression, whereas CORBA derivatives can only constrain the message itself, based on filterable body elements [7,15].…”

“…But the WSN specification is arguably more expressive when it comes to event filtering, since both the notification message and the producer can be the subject of a filter expression, whereas CORBA derivatives can only constrain the message itself, based on filterable body elements [7,15]. Nonetheless, WSN still lacks support for advanced features concerning implicit service interactions [35,34] that are currently available in CORBA-based systems such as the READY Notification Service [14,13].…”

“…This specification standardizes the way in which notification topics are constructed. A topic compares to a CORBA event channel on which related events are published [7]. The specification allows topics to be structured hierarchically into topic trees that can be grown dynamically, as such supporting the runtime extension of notification channels.…”

“…This is due to the lack of support for centralized filtering of events based on functional or QoS properties [31]. The problem is solved by the CORBA Notification Service [7], which introduces structured events that contain filterable body elements modelled as key-value pairs. Such filters cut down traffic, and hence increase the scalabability of the notification system.…”

Towards an architectural treatment of software security

“…The secure WebDAV connector and the YANCEES [13] event notification connector connect these components together. The architecture is depicted in Figure 2 …”