Composite Contract Enforcement in Hierarchical Component Systems

Abstract

International audienceAbadi and Lamport established a general theorem for composing specifications [1] . Based on an assume-guarantee principle, it enables one to prove the specification of a composite system from the ones of its components. But the general application of this theorem to software composition is not that straightforward because the resulting abstract specification of the composite depends upon the hidden guarantees of its subcomponents. In this paper, we investigate how this result can be exploited without blurring responsibilities between the different participants. Our contributions leverage an existing contracting framework for hierarchical software components [7] , in which contracts are first-class objects during configuration and run times. This framework already associates specifications and responsibilities to software components, within the traditional horizontal form of composition. We show here how the vertical one can be made operational using the theorem as a sound formal basis. The resulting composite contracts make possible not only to detect violations, but also to determine and exploit precisely responsibilities upon them, related to both forms of composition

Contracts-Based Control Integration into Software Systems

“…The combination of several kinds of contracts have also been proposed for hierarchical components, with the coupling of executable assertions and temporal logic [13] and with some composition properties enabling the creation of a composite contract [14]. Contrary to these approaches, our work is tailored to the feedback loop architecture, ensuring more properties on the data flow synchronization, framing the implementation while being more technology agnostic.…”

Contract Aware Components, 10 years after

“…In this section we use the Confract approach [11] as an example architecture to illustrate elaborate means of contract management (especially negotiation and monitoring). Confract is a contract management framework for the Fractal [8] component model.…”

“…Synchronization (or coordination) and quality of service contracts describe more global features and are easily attached to the component itself. In his thesis, G. Waignier [30] proposes a systematic approach using contracts at many structural levels: operation, port, whole component, assembly of components (this is made possible by the Confract component model [11])…”