Extending UML 2.0 metamodel for complementary usages of the /spl Lt/extend/spl Gt/ relationship within use case variability specification

Software product lines and related approaches, like software factories, are starting to capture the attention of the industry practitioners. Nevertheless, their adoption outside the research community and big companies is still very restricted. We believe that model-driven approaches, like OMG's MDA, with proper tool support, can bring the advantages of product lines to a broader audience. For this to become a reality, model-driven methods should integrate requirements models into the software development process. In this paper, we discuss the semantics of use case relationships and their formalization using activity diagrams to support variability specification. Particularly, we propose an extension to the LtextendGt relationship that supports the adoption of UML 2.0 use case diagrams into model-driven methods. Our proposal results from our work with 4SRS (4 step rule set), a model-driven method in which use cases are the central model for requirements specification and model transformation