With the popularity of ubiquitous computing, contextaware applications become clearly necessary. This kind of applications allows mobile users to universally access services in respect to any user context including his computing environment. Challenges for these applications are to easily manipulate both context collection and analysis and to react dynamically to every relevant evolution in the execution context state. To face these issues, we propose in this article, a generic and extensible way to model context-awareness of any application using model-driven engineering (MDE) approach. We illustrate our solution by modeling a contextaware e-commerce application