A language for high-level description of adaptive web systems
Adaptive Web systems (AWS) are Web-based systems that can adapt their features such as, presentation, content, and structure, based on users' behaviour and preferences, device capabilities, and environment attributes. A framework was developed in our research group to provide the necessary components and protocols for the development of adaptive Web systems; however, there were several issues and shortcomings (e.g. low productivity, lack of verification mechanisms, etc.) in using the framework that inspired the development of a domain-specific language for the framework. This paper focuses on the proposal, design, and implementation of AWL, the Adaptive Web Language, which is used to develop adaptive Web systems within our framework. Not only does AWL address the existing issues in the framework, but it also offers mechanisms to increase software quality attributes, especially, reusability. An example application named PENS (a personalized e-News system) is explained and implemented in AWL. AWL has been designed based on the analysis of the adaptive Web domain, having taken into account the principles of reuse-based software engineering (product-lines), domain-specific languages, and aspect-oriented programming. Specially, a novel design decision, inspired by aspect-oriented programming paradigm, allows separate specification of presentation features in an application from its adaptation features. The AWL's design decisions and their benefits are explained.