Compositional Patterns of Non-Functional Properties for Contract Negotiation

Providing powerful and fine-grained capabilities for the analysis and management of non-functional properties is a major challenge for component-based software systems. This article presents an approach that relies on some integration patterns of non-functional properties in hierarchical software components. These patterns are based on a classification of low-level non-functional properties, which takes into account their nature and lifecycle. They make explicit the implementation of these properties in relation with components. The proposed model also provides appropriate support for some forms of compositional reasoning on theses properties. The compositional patterns have been implemented on a hierarchical component platform and directly exploited in non-functional contract negotiation on a validating application. The proposed patterns enable negotiation processes to be precisely propagated down the component hierarchy, so that better runtime adaptations can be conducted on reaction to non-functional degradations.