Modelling Architectural Decisions under Changing Requirements

One of the approaches for documenting software architecture is to treat it as a set of architectural design decisions. Such decisions are always made in the context of requirements that must be fulfilled and in the context of decisions that were made before. Currently, models for representing architectural decisions are mainly concentrated on showing the decision making process of the initial architectural design. However, decisions that have been made in such a process may need to be changed during further evolution and maintenance of the software architecture, typically in response to the new or changed requirements. A graphical modelling notation for documenting architectural decisions (Maps of Architectural Decisions) has been developed by our team. In this paper, it is presented how this notation could be used to model architectural decisions under changing requirements. It is proposed how one decision change could be effectively propagated through the rest of the architectural decision model and how a rigorous and tool-supported process of updating such models could be organized.