Impact Analysis and Change Management of UML Models

The use of Unified Model Language (UML) analysis/design models on large projectsleads to a large number of interdependent UML diagrams. As software systems evolve,those diagrams undergo changes to, for instance, correct errors or address changes in therequirements. Those changes can in turn lead to subsequent changes to other elements inthe UML diagrams. Impact analysis is then defined as the process of identifying thepotential consequences (side-effects) of a change, and estimating what needs to bemodified to accomplish a change. In this article, we propose a UML model-basedapproach to impact analysis that can be applied before any implementation of thechanges, thus allowing an early decision-making and change planning process. We firstverify that the UML diagrams are consistent (consistency check). Then changes betweentwo different versions of a UML model are identified according to a change taxonomy,and model elements that are directly or indirectly impacted by those changes (i.e., mayundergo changes) are determined using formally defined impact analysis rules (writtenwith Object Constraint Language). A measure of distance between a changed elementand potentially impacted elements is also proposed to prioritize the results of impactanalysis according to their likelihood of occurrence. We also present a prototype tool thatprovides automated support for our impact analysis strategy, that we then apply on a casestudy to validate both the implementation and methodology.