ModelVars2SPL : an automated approach to reengineer model variants into software product lines

Orientadora : Profª. Drª. Silvia R. VergilioCoorientador : Prof Dr. Roberto E. Lopez-HerrejonTese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Exatas, Programa de Pós-Graduação em Informática. Defesa: Curitiba, 11/04/2017Inclui referências : f. 74-82Área de concentração : Ciência da computaçãoResumo: Linhas de Produto de Software (LPSs) são famílias de sistemas de software relacionados que são desenvolvidos para um segmento de mercado ou domínio. Comumente, LPSs surgem de um conjunto de variantes existentes, quando a manutenção e/ou evolução individuais tornam-se complexas. Contudo, as abordagens encontradas na literatura para extração de LPS a partir de variantes existentes não dão suporte a modelos de projeto, são parcialmente automatizadas, ou não refletem restrições de domínio em termos de combinação de características. Para lidar com estas limitações, o objetivo deste trabalho é apresentar uma abordagem automatizada para fazer a reengenharia de variantes de modelos em uma LPS, chamada ModelVars2SPL (Variantes de Modelos para Linha de Produto de Software, do Inglês Model Variants to Software Product Line). A entrada para a abordagem é um conjunto de diagramas de classe Linguagem de Modelagem Unificada (UML) e uma lista de características que estes implementam. Todo o processo de reengenharia é coberto, e a saída inclui (i) um Modelo de Características, que representa a combinação de características das variantes de entrada, e (ii) uma Arquitetura de Linha de Produto, que representa uma arquitetura global com características anotadas. O processo de reengenharia da ModelVars2SPL é composto por quatro passos, sendo dois deles apoiados em técnicas baseadas em busca, e os dois outros baseados em algoritmos determinísticos. Não existe a necessidade de especialistas humanos para obter soluções. Para avaliar a abordagem proposta, foi conduzido um experimento para aferir a qualidade das soluções obtidas. A qualidade dos Modelos de Características e das Arquiteturas de Linha de Produto foi medida considerando-se o quão bem as variantes de entrada foram representadas. Além disso, a qualidade das saídas em cada passo da abordagem foi avaliada levando-se em consideração os objetivos do processo de reengenharia. Para a experimentação utilizaram-se dez estudos de caso representando dois cenários diferentes. Os resultados da avaliação mostram que a abordagem consegue obter soluções com alto grau de corretude em termos de representação das variantes de entrada, e que as saídas dos passos estão de acordo com as fases do processo de reengenharia. Com base em um exemplo de uso de uma solução mostra-se como os artefatos de LPS obtidos facilitam a atividade de manutenção. Palavras-chave: Reúso, Reengenharia, Linha de Produto de Software, Extração de LPS, Engenharia de Software Baseada em Busca.Abstract: Software Product Lines (SPLs) are families of related software systems developed for specific market segments or domains. SPLs commonly emerge from sets of existing variants when their individual maintenance and/or evolution become complex. However, current approaches for SPL extraction from existing variants do not support design models, are partially automated, or do not reflect domain constraints in terms of feature combinations. To tackle these limitations, the goal of this work is to present an automated approach to reengineer model variants into an SPL, called ModelVars2SPL (Model Variants to Software Product Line). The input of the approach is a set of Unified Modeling Language (UML) class diagrams and the list of features they implement. All the reengineering process is covered, and the output includes (i) a Feature Model, which represents the combinations of features of the input variants, and (ii) a Product Line Architecture, which represents a global architecture with feature-related annotations. The reengineering process of ModelVars2SPL is composed of four steps, two of them rely on searchbased techniques and the others are based on deterministic algorithms. There is no need for human experts for obtaining solutions. We conducted an experiment to evaluate the quality of the solutions obtained with the proposed approach. The quality of the FMs and PLAs was measured by considering how well these artifacts represent the input variants. Furthermore, we evaluate the quality of the outputs in each step of the approach taking into account the goals of the reengineering process. For the experimentation we used ten case studies representing two di_erent scenarios. The results of the evaluation show that the approach can obtain solutions with high degree of correctness in terms of representing the input variants, and that the outputs of the steps are in accordance to the phases of the reengineering process. Based on an example of use we show how the obtained FM and PLA make easier the maintenance activity. Keywords: Reuse, Reengineering, Software Product Line, SPL extraction, Search-Based Software Engineering

Maßgeschneiderte Produktlinienextraktion

Industry faces an increasing number of challenges regarding the functionality, efficiency and reliability of software. A common approach to reduce the linked development effort and respective costs are model-based languages, such as Matlab/Simulink and statecharts. While these languages help companies during development of single systems, the high demand for customized software is an increasing challenge. As a result, variants with high similarity and only slight differences have to be developed in an efficient way. As reimplementation of complex functionality for each variant is no option, copies of existing solutions are often modified for new customers. In the short-run, this so-called clone-and-own approach allows to save costs as existing solutions can easily be reused. However, this approach also involves risks as the relations between the copied systems are rarely documented and errors have to be fixed for each variant in isolation. Thus, with a growing number of potentially large system copies, the resulting maintenance effort can become a problem. To overcome these problems, this thesis contributes an approach to semi-automatically migrate existing model variants to software product lines. These product lines allow to generate all variants from the identified reusable artifacts. As industry uses a variety of different modeling languages, the focus of the approach lies on an easy adaptation for different languages. Furthermore, the approach can be custom-tailored to include domain knowledge or language-specific details in the variability identification. The first step of the approach performs a high-level analysis of variants to identify outliers (e.g., variants that diverged too much from the rest) and clusters of strongly related variants. The second step executes variability mining to identify corresponding low-level variability relations (i.e. the common and varying parts) for these clusters. The third step uses these detailed variability relations for an automatic migration of the compared variants to a delta-oriented software product line. The approach is evaluated using publicly available case studies with industrial background as well as model variants provided by an industry partner.Die Industrie steht einer steigenden Anzahl an Herausforderungen bezüglich der Funktionalität, Effizienz und Zuverlässigkeit von Software gegenüber. Um den damit verbundenen Entwicklungsaufwand und entsprechende Kosten zu reduzieren, werden häufig modellbasierte Sprachen wie Matlab/Simulink oder Zustandsautomaten eingesetzt. Obwohl diese Sprachen die Unternehmen während der Entwicklung von Einzelsystemen unterstützen, führt die große Nachfrage nach maßgeschneiderter Software zu neuen Herausforderungen. Entsprechend müssen Varianten mit hoher Ähnlichkeit und nur geringfügigen Unterschieden effizient entwickelt werden. Da eine Neuimplementierung komplexer Funktionalität für jede Variante keine Option darstellt, werden häufig Kopien existierender Lösungen für Kunden angepasst. Auf kurze Sicht ermöglicht dieser sogenannte clone-and-own-Ansatz Kosten zu sparen, da existierende Lösungen leicht wiederverwendet werden können. Jedoch birgt der Ansatz auch Risiken, da Beziehungen zwischen den Systemkopien selten dokumentiert werden und Fehler für jede der Variante einzeln behoben werden müssen. Somit kann mit einer wachsenden Anzahl an möglicherweise umfangreichen Systemkopien der Wartungsaufwand zu einem Problem werden. Um diese Probleme zu lösen, bietet diese Arbeit einen Ansatz zur semi-automatischen Überführung existierender Modellvarianten in Softwareproduktlinien. Diese ermöglichen eine anschließende Generierung der Varianten aus den identifizierten wiederverwendbaren Artefakten. Da in der Industrie eine große Menge von Modellierungssprachen eingesetzt wird, liegt der Fokus auf der einfachen Adaption für unterschiedliche Sprachen. Zusätzlich kann durch Einbeziehung von Expertenwissen oder sprachspezifische Details die Variabilitätsidentifikation beeinflusst werden. Der erste Schritt des Ansatzes analysiert die Varianten auf hohem Abstraktionslevel, um Außenseiter (z.B. Varianten die stark von den restlichen Variaten abweichen) und Cluster von stark verwandten Varianten zu identifizieren. Der zweite Schritt analysiert diese Cluster auf niedrigem Abstraktionslevel, um entsprechende Variabilitätsrelationen (d.h. gemeinsame und unterschiedliche Teile) zu identifizieren. Der dritte Schritt nutzt diese detaillierten Variabilitätsrelationen für eine automatische Migration der verglichenen Varianten in eine delta-orientierte Softwareproduktlinie. Der Ansatz ist an Fallstudien mit industriellem Kontext sowie Modellvarianten eines Industriepartners evaluiert worden