Building Customizable Middleware using Aspect-Oriented Programming - Master\u27s Thesis, May 2002

In order to support a wide range of applications, Distributed Object Computing (DOC) middleware frameworks such as ACE and TAO have grown to include a vast number of features. For any one application, though, unused functionality either contributes to code bloat, degrades performance or both. When applied to embedded and realtime systems, these issues can preclude the use of middleware altogether. Currently, to address these concerns, middleware developers continually refactor code to relegate functionality to separate libraries. This process is tedious, time-consuming, and adds complexity for both users and developers. To address the difficulties of creating subsettable middleware, we have developed a novel method for constructing middleware using Aspect-Oriented Programming (AOP) and applied it to develop a realtime CORBA Event Channel called the Framework for Aspect Composition of an EvenT channel (FACET). FACET consists of a small, essential core that represents the basic structure and functionality of any event channel. By using aspects, additional features are woven not the core so that the resulting event channel supports all of the features needed by a given embedded application

Footprint and feature management using aspect-oriented programming techniques

Applications accrue features in response to the needs of all users, yet the associated code bloating and performance loss often render an application unsuitable for some users, particularly those interested in using the application in an embedded system. As a result, developers are often faced with either reinventing pieces of an application, custom tailored to their needs, or they are faced with the daunting task of refactoring an existing application to obtain an appropriate subset of that application’s functionality. In either case, subsequent development, maintenance and testing of the application becomes more complex, due to the effects of future revisions on all of the derived subsets. In this paper, we report on our experience in obtaining subsets of an application’s functionality, using a relatively new programming-language paradigm and tool to achieve the subsets compositionally. Instead of refactoring a large, featurerich application, a feature can be added by including that feature’s aspect in the set provided to an aspect compiler. In particular, a minimal, base implementation was developed in Java and features were added by supplying the appropriate advice to an AspectJ compiler. We describe our approach and present footprint and performance results for automatically derived subsets of an event channel.