Goals and Business Rules as the Central Design Mechanism

Current UML based behavioral requirements focus on the specification of use cases. Business rules are seen as a very important part of the requirements but are either considered as a separate entity or, at best, attached to use cases. Some authors have recognized the need to include business rules within use cases but there are no concrete guidelines on how to do it. In this paper we propose a technique that uses business rules as the driving mechanism behind the design process. By explicitly defining business rules in collaborations of a group of actors, we are able to find the policies governing the behavior of the different actors involved. When we decide to consider one of these actors as the system to be designed, these policies enable us to define the goals of this system. These goals are implemented as use cases which themselves are governed by business rules for the system. When considering this system as a set of parts we loop back to the beginning of our process but at a different organizational level.