Towards Adaptive Systems through Requirements@Runtime

Software systems must adapt their behavior in response to changes in the environment or in the requirements they are supposed to meet. Despite adaptation capabilities could be modeled with great detail at design time, anticipating all possible adaptations is not always feasible. To address this problem the requirements model of the system, which also includes the adaptation capabilities, is conceived as a runtime entity. This way, it is possible to trace requirements/adaptation changes and propagate them onto the application instances. This paper leverages the FLAGS [1] methodology, which provides a goal model to represent adaptations and a runtime infrastructure to manage requirements@runtime. First, this paper explains how the FLAGS infrastructure can support requirements@runtime, by managing the interplay between the requirements and the executing applications. Finally, it describes how this infrastructure can be used to adapt the system, and, consequently, support the evolution of requirements.