Abstract
In a product line model, the product line developer often specifies not only high-level domain features but also their low-level realization steps. We see two challenges against deriving and intended products w.r.t. the specification of feature realizations: (1) The developer is not provided with immediate feedback on the realization steps at design time. (2) How to ensure that the realization steps are consistent with high-level features. The Common Variability Language (CVL) is a generic language for modeling variability and the CVL tool can be used for product line development. We propose two extensions to the CVL tool to address the aforementioned challenges: (1) A simulator that simulates the feature realizations and visualizes the resulting product model at design time. (2) A consistency checker that checks if the realizations are consistent with high-level features. We illustrate these two added procedures by applying them to the development of a train control product line. A tool prototype is implemented and used for evaluation