A design model for object-oriented systems with explicit architecture

Developing software systems from components involves defining the overall architecture where such components will cooperate. We argue that major problems with current approaches to component based software development stem from the fact that architecture is implicit in the components' code. The paper presents a design model for object oriented systems which makes architecture explicit by letting architecture-transparent components be instantiated and coordinated by separate entities implementing architectural concepts. A brief discussion of the application of the model to the design of a concrete system demonstrates how explicit architecture can enhance the reusability of both components and design elements, and ease the implementation of user-directed dynamic reconfiguration.