Model-driven Composition of Context-aware Web Services Using ContextUML and Aspects

Abstract

Service Oriented Architectures (SOAs) are constantly gaining ground for the provision of business to business as well as user-centric services, mainly in the form of Web Services technology. SOAs enable service providers to design and deploy new,composite service offerings out of existing component services. In order to match end-user expectations with respect to personalization and ease of use, these services should be designed in a manner that allows them to exhibit a certain level of context-awareness which is a basic element towards a richer end-user experience. However, in the majority of such services, context-handling is still tightly coupled with the core functionality of the service, resulting in a design which is difficult to implement and maintain. The paper proposes the decoupling of core service logic from context-related functionality by adopting a Model-driven approach based on a modified version of the ContextUML metamodel. Core service logic and context handling are treated as separate concerns at the modeling level as well as in the resulting source code where Aspect Oriented Programming (AOP) encapsulates contextdependent behavior in discrete code modules. The design of a restaurant finder service is used to portray the modified ContextUML metamodel and the service modeling process which is covered in full. Respective code snippets belonging to the executable version of the service (part of work in progress) are also provided, illustrating the transition from model to code and the resulting separation of concerns.

Towards Proactive Web Service Adaptation

“…In [17], an approach is proposed to address optimization and dynamic adaptation problems. In [13], a decoupling approach based upon the separation of core service logics from context related functionalities was proposed. This separation is conducted via adopting a model driven approach based upon a modified version of the context UML meta model.…”

A survey on context‐aware web service systems

“…Unlike other representations which focus on context information only and which can be used separated from the service modeling and development, ContextUML is strongly linked to service modeling that can be considered an integrated part of the service modeling. Based on an extension of ContextUML, Prezerakos and colleages have presented a model-driven approach for composing context-aware Web services (Prezerakos, et al, 2007). CoWSAMI also supports the specification of context during the service modeling phase.…”

“…We survey types of context information in terms of common types of context information and historical support. (Prezerakos, Tselikas, & Cortese, 2007) and teamwork .…”

“…Prezerakos and colleagues uses UML to model context and Web services (Prezerakos, Tselikas, & Cortese, 2007). Based on UML models, a model-driven approach for composing context-aware Web services is proposed.…”

Bringing context-aware access to the web through spoken interaction

“…For example, the Anyserver platform [16] utilizes various types of context information encoded in XML, such as device information, networks, and application type. In the Omnipresent context-aware location-based system [3], context information is modeled based on OWL, while Prezerakos et al [41] use UML to model context and web services.…”