Monitoring compliance of a software system with its high-level design models

As a complex software system evolves, its implementation tends to diverge from the intended or documented design models. Such undesirable deviation makes the system hard to understand, modify, and maintain. This paper presents a hybrid computer-assisted approach for confirming that the implementation of a system maintains its expected design models and rules. Our approach closely integrates logic-based static analysis and dynamic visualization, providing multiple code views and perspectives. We show that the hybrid technique helps determine design-implementation congruence at various levels of abstraction: concrete rules like coding guidelines, architectural models like design patterns[7] or connectors[26], and subjective design prin-ciples like low coupling and high cohesion. The utility of our approach has been demonstrated in the development of Choices, a new multimedia operating system which in-herits many design decisions and guidelines learned from experience in the construction and maintenance of its pre-decessor, Choices. 1