Vander Alves

Refactoring product lines

Adoption strategies for Software Product Lines (SPL) frequently involve bootstrapping existing products into a SPL and extending an existing SPL to encompass another product. One way to do that is to use program refactorings. However, the traditional notion of refactoring does not handle appropriately feature models (FM), nor transformations involving multiple instances of the same SPL. For instance, it is not desirable to apply a refactoring into a SPL and reduce its configurability. In this paper, we extend the traditional notion of refactoring to an SPL context. Besides refactoring programs, FMs must also be refactored. We present a set of sound refactorings for FMs. We evaluate this extended refactoring definition for SPL in a real case study in the mobile games domain.

Requirements engineering for software product lines: A systematic literature review

Context: Software product line engineering (SPLE) is a growing area showing promising results in research and practice. In order to foster its further development and acceptance in industry, it is necessary to assess the quality of the research so that proper evidence for adoption and validity are ensured. This holds in particular for requirements engineering (RE) within SPLE, where a growing number of approaches have been proposed. Objective: This paper focuses on RE within SPLE and has the following goals: assess research quality, synthesize evidence to suggest important implications for practice, and identify research trends, open problems, and areas for improvement. Method: A systematic literature review was conducted with three research questions and assessed 49 studies, dated from 1990 to 2009. Results: The evidence for adoption of the methods is not mature, given the primary focus on toy examples. The proposed approaches still have serious limitations in terms of rigor, credibility, and validity of their findings. Additionally, most approaches still lack tool support addressing the heterogeneity and mostly textual nature of requirements formats as well as address only the proactive SPLE adoption strategy. Conclusions: Further empirical studies should be performed with sufficient rigor to enhance the body of evidence in RE within SPLE. In this context, there is a clear need for conducting studies comparing alternative methods. In order to address scalability and popularization of the approaches, future research should be invested in tool support and in addressing combined SPLE adoption strategies.

Extracting and evolving mobile games product lines

For some organizations, the proactive approach to product lines may be inadequate due to prohibitively high investment and risks. As an alternative, the extractive and the reactive approaches are incremental, offering moderate costs and risks, and therefore sometimes may be more appropriate. However, combining these two approaches demands a more detailed process at the implementation level. This paper presents a method for extracting a product line and evolving it, relying on a strategy that uses refactorings expressed in terms of simpler programming laws. The approach is evaluated with a case study in the domain of games for mobile devices, where variations are handled with aspect-oriented constructs.

Improving extensibility of object-oriented frameworks with aspect-oriented programming

Object-oriented frameworks are nowadays a common and useful technology used in the implementation of software system families. Despite their benefits, over the last years many researchers have described the inadequacy of object-oriented mechanisms to address the modularization and composition of many framework features, thus reducing the extent to which a framework can be extended. The crosscutting nature of many framework features is identified as one of the main causes of these problems. In this paper, we analyze how aspect-oriented programming can help to improve the design, implementation, and extension of object-oriented frameworks. We propose the concept of Extension Join Points (EJPs) as a way of designing and documenting existing crosscutting extension points. EJPs improve framework extensibility, including superior composability of the framework core functionality with other modules or frameworks. Four case studies of frameworks from diverse domains are presented to illustrate our proposal. This paper also discusses lessons learned on the application of our approach to the development and extension of these frameworks.

Investigating the safe evolution of software product lines

The adoption of a product line strategy can bring significant productivity and time to market improvements. However, evolving a product line is risky because it might impact many products and their users. So when evolving a product line to introduce new features or to improve its design, it is important to make sure that the behavior of existing products is not affected. In fact, to preserve the behavior of existing products one usually has to analyze different artifacts, like feature models, configuration knowledge and the product line core assets. To better understand this process, in this paper we discover and analyze concrete product line evolution scenarios and, based on the results of this study, we describe a number of safe evolution templates that developers can use when working with product lines. For each template, we show examples of their use in existing product lines. We evaluate the templates by also analyzing the evolution history of two different product lines and demonstrating that they can express the corresponding modifications and then help to avoid the mistakes that we identified during our analysis.

Extracting and evolving code in product lines with aspect-oriented programming

For some organizations, the proactive approach to product lines may be inadequate due to prohibitively high investment and risks. As an alternative, the extractive and the reactive approaches are incremental, offering moderate costs and risks, and therefore sometimes may be more appropriate. However, combining these two approaches demands a more detailed process at the implementation level. This paper presents a method and a tool for extracting a product line and evolving it, relying on a strategy that uses refactorings expressed in terms of simpler programming laws. The approach is evaluated with a case study in the domain of games for mobile devices, where variations are handled with aspect-oriented constructs.

Comparative analysis of porting strategies in J2ME games

Porting is a critical task in mobile device game development. The high diversity of devices requires correspondingly customized versions of a single game. Managing the variabilities among these customized versions while exploring the latent game commonality cannot be solely addressed with a single technique. This paper contributes to this task by identifying and analyzing porting challenges, and by evaluating and contrasting existing approaches within industrial-strength case studies of J2ME games. Further, we present lessons learned, proposing more effective guidelines for this process, aiming at improving the quality of the resulting applications and porting process productivity.

Managing variability in business processes: an aspect-oriented approach

Business processes specify key activities in an organization, some of which can be automated. It is often the case that replication of activities across such processes occur and failure in identifying such replication results in organizational costs. To minimize this risk and optimize organizational resources, in this paper we characterize variability in business process and propose an approach to manage such a variability. The characterization of variability relies on the study of industrial-strength applications in the Human Resources domain. The management of variability is based on a compositional and parametric approach with Aspect-Orientation. It leverages and extends an existing tool to address variability in such domain

Mapping features to aspects: a model-based generative approach

Handling the various derivations of an aspect-oriented software family architecture can be a daunting and costly task if explicit support is not systematically provided throughout early and late development stages. Aspect-oriented software development (AOSD) has been recently explored as a technique that enables software product line customization. However, the application of AOSD has been limited to modularize specific crosscutting features encountered in the implementation of software product-line architectures or frameworks. Only a few works have investigated the development of product derivation approaches for AOSD. This paper presents a model-based generative approach to mapping features to aspects across different artifacts of a product line. Our main aim is to enable the smooth and systematic derivation of aspect-oriented software family architecture. Our approach is complementary to a set of previously-proposed modularization guidelines to implement aspect-oriented frameworks. We present details about the suite of mappings supported by our generative model, illustrate them in heterogeneous case studies, and discuss several implementation issues for its accomplishment.

Modeling and Verification for Probabilistic Properties in Software Product Lines

We propose a model for feature-aware discrete-time Markov chains, called FDTMC, as a basis for verifying probabilistic properties, e.g., Reliability and availability, of product lines. To verify such properties on FDTMC, we compare three techniques. First, we experiment with two different parametric techniques to obtain this formula: the classical one builds it from the model as whole, and a new one that builds it compositionally from a sequence of modules. Finally, we propose a new technique that performs a bounded verification for the whole product line, and thus takes advantage of the high probability of common behaviors of the product line. It computes an approximate formula, represented as an arithmetic decision diagram. Experimental results on a vital signal monitoring system prototype are provided and compared for these techniques aiming at analysing them for scalability issues of size and computational time. They show complementary advantages, and we provide criteria to choose a technique depending on the characteristics of the model.