The development of a Software Product Line (SPL) is a demanding task for all stages of the software development process, especially for requirements engineering. The identification and modelling of common and variable characteristics are an essential task during the requirements engineering process. Communicating variability to stakeholders affects the success of projects significantly.
Modelling variability can be done from different views and on different levels of abstraction. Whereas the level of abstraction determines the granularity of descriptions of characteristics, different views reveal information about perspectives on a system. Therefore the domain can be modelled from a static point of view to reveal information about structural hierarchies. Feature modelling is one methodology to express these hierarchies through compositional-relationships combined with variability information.
Modelling variability from a behavioral point of view has been neglected so far. To overcome this deficiency one aim of this project is to analyze methods and notations to express functional variability in variant operation sequences. Use Cases and Use Case diagrams have been chosen to be an adequate notation to express functional behavior, but have to be extended by concepts and modelling elements to express variability.
Our research group has developed a prototype of a requirements engineering tool, named RequiLine that supports the management of requirements and feature models, equally. The development of RequiLine has been mainly driven by the identified requirements for an adequate tool support for product lines and therefore to overcome the deficiencies existing requirements engineering tools have in managing variability and dependencies. Our experience shows, that requirements engineering tools are used together with graphical editors to draw feature models. Unfortunately the created drawings do lack of any semantic and could not be used for queries or consistency checks. RequiLine is a first study to close this gap.
Update: Unfortunately, the RequiLine website is not available anymore.