Miguel A. Laguna

A systematic mapping study on software product line evolution: From legacy system reengineering to product line refactoring

Software product lines (SPLs) are used in industry to develop families of similar software systems. Legacy systems, either highly configurable or with a story of versions and local variations, are potential candidates for reconfiguration as SPLs using reengineering techniques. Existing SPLs can also be restructured using specific refactorings to improve their internal quality. Although many contributions (including industrial experiences) can be found in the literature, we lack a global vision covering the whole life cycle of an evolving product line. This study aims to survey existing research on the reengineering of legacy systems into SPLs and the refactoring of existing SPLs in order to identify proven approaches and pending challenges for future research in both subfields. We launched a systematic mapping study to find as much literature as possible, covering the diverse terms involved in the search string (restructuring, refactoring, reengineering, etc. always connected with SPLs) and filtering the papers using relevance criteria. The 74 papers selected were classified with respect to several dimensions: main focus, research and contribution type, academic or industrial validation if included, etc. We classified the research approaches and analyzed their feasibility for use in industry. The results of the study indicate that the initial works focused on the adaptation of generic reengineering processes to SPL extraction. Starting from that foundation, several trends have been detected in recent research: the integrated or guided reengineering of (typically object-oriented) legacy code and requirements; specific aspect-oriented or feature-oriented refactoring into SPLs, and more recently, refactoring for the evolution of existing product lines. A majority of papers include academic or industrial case studies, though only a few are based on quantitative data. The degree of maturity of both subfields is different: Industry examples for the reengineering of the legacy system subfield are abundant, although more evaluation research is needed to provide better evidence for adoption in industry. Product line evolution through refactoring is an emerging topic with some pending challenges. Although it has recently received some attention, the theoretical foundation is rather limited in this subfield and should be addressed in the near future. To sum up, the main contributions of this work are the classification of research approaches as well as the analysis of remaining challenges, open issues, and research opportunities.

Requirements Variability Support Through MDA™ and Graph Transformation

One of the most important factors of success in the development of a software product line is the elicitation, management, and representation of variability. Feature models, are used as a key artifact to express requirements variability and are the basis for the domain architecture design. In this context, this article explores the possible advantages of Model Driven Engineering (MDE) and shows an automated transformation from the feature model to the architecture model. This transformation is understood as a graph transformation process because it offers a natural way to represent model transformations. The transformation is applied by the definition of a simple context-sensitive graph grammar where production rules are obtained from metamodels of both feature and architecture models.

Eliciting Non-Functional Requirements Interactions Using the Personal Construct Theory

Complex goal oriented information models such as i* and the non functional requirements framework bring up the need to model relationships between goals. In particular when dealing with non-functional goals, also known as softgoals, the modeler faces the problem of how to elicit the complex web of intertwined relationships that exist between them. We tackle this problem by using the personal construct theory (PCT), a well known work in cognitive science. We describe the results of applying PCT to the problem of finding relationships between nonfunctional goals. The process is a heuristic one, and our results, so far, are positive

Product line variability support by FORM and Mecano model integration

A product line definition must cover several systems, for this reason additional requirements are included as product line assets during domain engineering. Generic assets are presented to cover all components the product line instances are built from, and their corresponding composition rules. These generic assets embrace common and variable product aspects supporting the variability in product line definition and instantiation.This paper is devoted to present the problem of handling product line variability in every life-cycle stage by the integration of the ideas of the domain engineering method FORM (Feature-Oriented Reuse Method) and the Mecano Model, which defines a coarse-grained reusable element structure.

Reuse, Standardization, and Transformation of Requirements

Correct requirements determination is a critical factor in software development. Having stored reusable requirements elements, both qualified and classified, in a repository might contribute to reducing the error probability in requirements specifications but the diversity of requirements formats is a constraint for their reuse. To solve this problem, a common requirements model allowing the standardization and transformation of some types of requirements in others is presented. The transformations use an intermediate representation based on Petri nets, which provides rigor to the models and allows its consistency to be checked. Transformation algorithms are defined and implemented as part of a requirements management and reuse tool.

Mobile health monitoring and smart sensors: a product line approach

The evolution of the population pyramid in developed countries, with an increasing proportion of aged people introduces new challenges to the public and private assistance services. A form of improving these services while keeping controlled the associated costs is to use remote continuous assistance. Wireless sensors allow obtaining real-time information of health parameters in a non-intrusive way. The determination of alert values for these parameters and the computing possibilities of the current mobile devices can facilitate a faster intervention which will minimize risks linked to delays in medical assistance. However, the diversity of risk situations is a factor that increases costs as many similar but not exactly identical products will be necessary now and in the future. We aim to solve this problem using an approach of software product lines, as multiple options can be easily incorporated to each final product implementation. This article presents the product line generic architecture and some examples of application, using wireless sensors connected to a central station by means of a smart phone, which is able to detect alarm situations.

Applying Personal Construct Theory to Requirements Elicitation

One of the main approaches to Requirements Engineering is Goal-Oriented Requirement Engineering. This approach, based in Artificial Intelligence models, argues that goals are a natural and high level abstraction concept to elicit and represent requirements. Another advantage of goals is that they help non-functional requirements representation and reasoning. Although the goal oriented approach helps in representation and analysis, the problem of eliciting goals and their refinement is not trivial. In this article, we explore several applications to goal elicitation using a psychological theory: the Personal Construct Theory (PCT). This theory, stated by Kelly in 1955, can be used to elicit goals and their relationships. The choice of this theory is based in that it has a statistical base, therefore it is more precise and user independent than others. Finally, PCT can be amenable to automation by means of the Repertory Grid technique, widely studied in the Knowledge eliciting field.

A user requirements elicitation tool

Use cases are nowadays the favoured technique for defining the functional requirements of a software system. Their use implies that most of the desired functionality of the new system is well known. The aim of this work is a methodological proposal (and a tool to support it) to accurately define this functionality, starting from the way the end users currently do their work. This method and tool are independent of the development paradigm and could generate useful results for the most frequently used CASE tools with the addition of the appropriate translators.

Remote Monitoring and Fall Detection: Multiplatform Java Based Mobile Applications

Life quality of dependent persons is associated with personal autonomy and mobility, between others parameters. But the development of mobile applications for autonomy support is a challenging activity. Some of the challenges are the diversity of target platforms (including display sizes, keypads or tactile screens variations in each platform), and the limits in memory size, processing resources, battery duration, etc. For these reasons, a software product line (SPL) approach can provide a considerable advantage in mobile application development. This article presents a SPL that makes possible the remote monitoring of dependent people to facilitate their autonomy. Wireless sensors allow real-time information such as heart rate or oxygen saturation level to be controlled. Risk situations, including fall detection, critical in elderly persons who live alone, can also be detected. In the SPL approach, only the required features are incorporated in each concrete product (avoiding the device overload with a resource-costly extensive solution). The article presents an Android/Symbian based SPL architecture, using Bluetooth wireless sensors connected to a Smartphone. The mobile system is able to detect alarm situations and is remotely connected to a central system, aimed for its use in elderly residences.

A Software Product Line Approach for E-Commerce Systems

This article reports a successful experience of software product line development in the domain of e-commerce applications. Product lines are challenging for small organizations, so we propose to use conventional tools for most of development activities. Trace ability between the features and the UML architectural models is achieved by means of the package merge mechanism of the UML 2, as representation of the variability at design level. The management of feature models is integrated within a conventional IDE tool, using a plug-in developed by our research group. The combination of basic variability management techniques and conventional tools make the developments of e-commerce applications easier as it removes the need for specialized tools and personnel.