Négociation de contrats dans les systèmes à composants logiciels hiérarchiques. (Contract negotiation for hierarchical component-based software systems)

Modern software systems are characterized by their increasing complexity and the strong requirements with respect to the continuity and availability of services. To address these needs, the componentbased software engineering and the contractual approach represent two relevant approaches which aims at facilitating the construction of larger systems and increasing their reliability. In addition, non-functional properties of running systems have still to be better managed and some mechanisms that allow them to react to changes and to maintain some satisfactory quality levels are required. This thesis proposes a self-adaptation model for runtime systems that are based on both software components and contracts. Our proposal consists in defining an automated contract negotiation model which makes components negotiate themselves the contract in which their are involved. The negotiation model identifies the different basis elements required to make components operate the adaptation of the components or the contracts, and each negotiation process takes advantage of the various information contained in the contracts. Two negotiation policies are also designed to conduct the negotiation process in different ways. In particular, a compositional reasoning support is proposed to conduct the negotiation processes down into component hierarchies. The negotiation model is based on the general principles of the hierarchical software components platform, named Fractal , and on the contract model, named ConFract , and it is integrated into these two technologies. The contributions are illustrated on various examples which are extracted from a larger case study and the first experiments are described.