A contracting system for hierarchical components

This article presents the contracting system ConFract for the open and hierarchical component model Fractal. Contracts are dynamically built from specifications, currently executable assertions, at assembly times, and are updated according to dynamic reconfigurations. These contracts are not restricted to the scope of interfaces, taken separately. On the contrary, new kinds of composition contracts can be built in order to associate several external interfaces of a component, providing an “usage contract”, or several interfaces inside the component, providing an “assembly and implementation contract”. All these contracts identify fine-grained responsibilities and developers can thus easily organize the handling of contract violations and the resulting reconfigurations.