Composition of Qualitative Adaptation Policies

In a highly dynamic environment, software systems requires a capacity of self-adaptation to fit the environment and the user needs evolution, which increases the software architecture complexity. Despite most current execution platforms include some facilities for handling dynamic adaptation, current design methodologies do not address this issue. One of the requirement for such a design process is to describe adaptation policies in a composable and qualitative fashion in order to cope with complexity. This paper introduces an approach for describing adaptation policies in a qualitative way while keeping the compositionality of adaptation policies. The basic example of a Web server is used to illustrate how to specify and to compose two adaptations policies which handle respectively the use of a cache and the deployment of new data sources.