Formalising the Requirements of an E-Voting Software Product Line Using Event-B

A Software Product Line (SPL) is a tool/method used to generate a family of program/system variants for a specific domain, and to support a more efficient software development of future products within the same domain. A Feature Model (FM) is a popular graphical/textual representation used in SPL requirements specification; it is used to capture commonality and variability information existing in an SPL as a set of inter-related and configurable features. A concrete model of an SPL instance is obtained by binding the variation information in the FM with a configuration that meets a specific set of feature requirements. Since configuration decisions are taken prior to instantiation, invalid configurations should be detected/avoided before design begins. This paper addresses the problem of the verification of the correctness (validity) of FM instances and FM configuration during requirements modelling. It proposes a requirements model based on Event-B contexts, allowing us to check the correctness of a given configuration, before starting the correct-by-construction design and implementation process, based on refinement.