Specify Use cases with Aspects and Variability

The use case specification has three main goals: (i) further detail the requirements based on legacy documentation (ii) specify use case variability (iii) identify crosscutting and non-crosscutting use cases. In order to achieve the first goal, we elicited the use cases based on existing documents of legacy applications. Fantechi et al. proposed an approach to use legacy requirements document to specify SPL variability [31]. Even the use of legacy applications can be useful to understand them. Use case variability is determined based on features variability, which has already been specified in the feature model. PLUS method [19] represents the use case variability with stereotypes (kernel, alternative, and optional). Use cases can also represent crosscutting concerns as proposed Jacobson and Ng [32, Chapter 6.2]. Crosscutting concerns are represented by use case extensions, which add new behavior to the existing use cases. In this way, both variability and crosscutting concerns are represented.