UML Aspect Specification Using Role Models

We demonstrate a flexible technique for aspect specification using the UML. The technique uses Role Models to specify design aspects. Roles allow greater flexibility in an aspect over other template-based techniques (e.g. profile extensions). While Role Models do allow us to create templates, they also allow us to create flexible specifications that can be applied by identifying existing model elements that can play aspect roles either as is, or with augmentation based on the aspect specification. This additional capability means that our aspect designs can be applied to specific system designs with fewer constraints on the designer and the initial system models. We demonstrate this flexibility by applying a design aspect developed for one problem domain to a problem in a different domain. No changes are needed in the aspect models, although not all portions of the aspect specification are used in the second problem. In addition, there is no need to constrain the problem in the new application of the aspect; the specification technique is flexible enough that we can apply the aspect without change. We are also able to use the same set of weaving rules to compose the aspect with models of the new problem.