Politecnico di Bari
Service compositions need to continuously self-adapt to cope with unexpected failures. In this paper, adaptation becomes a fundamental requirement that must be elicited along with the other functional and non functional requirements. Besides modeling, effective adaptation also demands means to trigger it at runtime as soon as the actual behavior of the composition deviates from stated requirements. This paper extends traditional goal models with adaptive goals to support continuous adaptation. Goals become live, runtime entities whose satisfaction level is dynamically updated. Furthermore, boundary infringement triggers adaptation capabilities. The paper also provides a methodology to trace goals onto the underlying composition, assess goals satisfaction at runtime, and activate adaptation consequently.