Supporting the grow-and-prune model for evolving software product lines

207 p.Software Product Lines (SPLs) aim at supporting the development of a whole family of software products through a systematic reuse of shared assets. To this end, SPL development is separated into two interrelated processes: (1) domain engineering (DE), where the scope and variability of the system is defined and reusable core-assets are developed; and (2) application engineering (AE), where products are derived by selecting core assets and resolving variability. Evolution in SPLs is considered to be more challenging than in traditional systems, as both core-assets and products need to co-evolve. The so-called grow-and-prune model has proven great flexibility to incrementally evolve an SPL by letting the products grow, and later prune the product functionalities deemed useful by refactoring and merging them back to the reusable SPL core-asset base. This Thesis aims at supporting the grow-and-prune model as for initiating and enacting the pruning. Initiating the pruning requires SPL engineers to conduct customization analysis, i.e. analyzing how products have changed the core-assets. Customization analysis aims at identifying interesting product customizations to be ported to the core-asset base. However, existing tools do not fulfill engineers needs to conduct this practice. To address this issue, this Thesis elaborates on the SPL engineers' needs when conducting customization analysis, and proposes a data-warehouse approach to help SPL engineers on the analysis. Once the interesting customizations have been identified, the pruning needs to be enacted. This means that product code needs to be ported to the core-asset realm, while products are upgraded with newer functionalities and bug-fixes available in newer core-asset releases. Herein, synchronizing both parties through sync paths is required. However, the state of-the-art tools are not tailored to SPL sync paths, and this hinders synchronizing core-assets and products. To address this issue, this Thesis proposes to leverage existing Version Control Systems (i.e. git/Github) to provide sync operations as first-class construct

Combining Multiple Granularity Variability in a Software Product Line Approach for Web Engineering

[Abstract] Context: Web engineering involves managing a high diversity of artifacts implemented in different languages and with different levels of granularity. Technological companies usually implement variable artifacts of Software Product Lines (SPLs) using annotations, being reluctant to adopt hybrid, often complex, approaches combining composition and annotations despite their benefits. Objective: This paper proposes a combined approach to support fine and coarse-grained variability for web artifacts. The proposal allows web developers to continue using annotations to handle fine-grained variability for those artifacts whose variability is very difficult to implement with a composition-based approach, but obtaining the advantages of the composition-based approach for the coarse-grained variable artifacts. Methods: A combined approach based on feature modeling that integrates annotations into a generic composition-based approach. We propose the definition of compositional and annotative variation points with custom-defined semantics, which is resolved by a scaffolding-based derivation engine. The approach is evaluated on a real-world web-based SPL by applying a set of variability metrics, as well as discussing its quality criteria in comparison with annotations, compositional, and combined existing approaches. Results: Our approach effectively handles both fine and coarse-grained variability. The mapping between the feature model and the web artifacts promotes the traceability of the features and the uniformity of the variation points regardless of the granularity of the web artifacts. Conclusions: Using well-known techniques of SPLs from an architectural point of view, such as feature modeling, can improve the design and maintenance of variable web artifacts without the need of introducing complex approaches for implementing the underlying variability.The work of the authors from the Universidad de Málaga is supported by the projects Magic P12-TIC1814 (post-doctoral research grant), MEDEA RTI2018-099213-B-I00 (co-financed by FEDER funds), Rhea P18-FR-1081 (MCI/AEI/FEDER, UE), LEIA UMA18-FEDERIA-157, TASOVA MCIU-AEI TIN2017-90644-REDT and, European Union’s H2020 research and innovation program under grant agreement DAEMON 101017109. The work of the authors from the Universidade da Coruña has been funded by MCIN/AEI/10.13039/501100011033, NextGenerationEU/PRTR, FLATCITY-POC: PDC2021-121239-C31 ; MCIN/AEI/10.13039/501100011033 EXTRACompact: PID2020-114635RB-I00 ; GAIN/Xunta de Galicia/ERDF CEDCOVID: COV20/00604 ; Xunta de Galicia/FEDER-UE GRC: ED431C 2021/53 ; MICIU/FEDER-UE BIZDEVOPSGLOBAL: RTI-2018-098309-B-C32 ; MCIN/AEI/10.13039/501100011033 MAGIST: PID2019-105221RB-C41Junta de Andalucía; P12-TIC-1814Universidad de Málaga; UMA18-FEDERIA-157Xunta de Galicia; COV20/00604Xunta de Galicia; ED431C 2021/53Junta de Andalucía; P18-FR-108

Supporting the grow-and-prune model for evolving software product lines

207 p.Software Product Lines (SPLs) aim at supporting the development of a whole family of software products through a systematic reuse of shared assets. To this end, SPL development is separated into two interrelated processes: (1) domain engineering (DE), where the scope and variability of the system is defined and reusable core-assets are developed; and (2) application engineering (AE), where products are derived by selecting core assets and resolving variability. Evolution in SPLs is considered to be more challenging than in traditional systems, as both core-assets and products need to co-evolve. The so-called grow-and-prune model has proven great flexibility to incrementally evolve an SPL by letting the products grow, and later prune the product functionalities deemed useful by refactoring and merging them back to the reusable SPL core-asset base. This Thesis aims at supporting the grow-and-prune model as for initiating and enacting the pruning. Initiating the pruning requires SPL engineers to conduct customization analysis, i.e. analyzing how products have changed the core-assets. Customization analysis aims at identifying interesting product customizations to be ported to the core-asset base. However, existing tools do not fulfill engineers needs to conduct this practice. To address this issue, this Thesis elaborates on the SPL engineers' needs when conducting customization analysis, and proposes a data-warehouse approach to help SPL engineers on the analysis. Once the interesting customizations have been identified, the pruning needs to be enacted. This means that product code needs to be ported to the core-asset realm, while products are upgraded with newer functionalities and bug-fixes available in newer core-asset releases. Herein, synchronizing both parties through sync paths is required. However, the state of-the-art tools are not tailored to SPL sync paths, and this hinders synchronizing core-assets and products. To address this issue, this Thesis proposes to leverage existing Version Control Systems (i.e. git/Github) to provide sync operations as first-class construct

Automated analysis of feature models: Quo vadis?

Feature models have been used since the 90's to describe software product lines as a way of reusing common parts in a family of software systems. In 2010, a systematic literature review was published summarizing the advances and settling the basis of the area of Automated Analysis of Feature Models (AAFM). From then on, different studies have applied the AAFM in different domains. In this paper, we provide an overview of the evolution of this field since 2010 by performing a systematic mapping study considering 423 primary sources. We found six different variability facets where the AAFM is being applied that define the tendencies: product configuration and derivation; testing and evolution; reverse engineering; multi-model variability-analysis; variability modelling and variability-intensive systems. We also confirmed that there is a lack of industrial evidence in most of the cases. Finally, we present where and when the papers have been published and who are the authors and institutions that are contributing to the field. We observed that the maturity is proven by the increment in the number of journals published along the years as well as the diversity of conferences and workshops where papers are published. We also suggest some synergies with other areas such as cloud or mobile computing among others that can motivate further research in the future.Ministerio de Economía y Competitividad TIN2015-70560-RJunta de Andalucía TIC-186

Open-source software product line extraction processes: the ArgoUML-SPL and Phaser cases

Software Product Lines (SPLs) are rarely developed from scratch. Commonly, they emerge from one product when there is a need to create tailored variants, or from existing variants created in an ad-hoc way once their separated maintenance and evolution become challenging. Despite the vast literature about re-engineering systems into SPLs and related technical approaches, there is a lack of detailed analysis of the process itself and the effort involved. In this paper, we provide and analyze empirical data of the extraction processes of two open source case studies, namely ArgoUML and Phaser. Both cases emerged from the transition of a monolithic system into an SPL. The analysis relies on information mined from the version control history of their respective source-code repositories and the discussion with developers that took part in the process. Unlike previous works that focused mostly on the structural results of the final SPL, the contribution of this study is an in-depth characterization of the processes. With this work, we aimed at providing a deeper understanding of the strategies for SPL extraction and their implications. Our results indicate that the source code changes can range from almost a fourth to over half of the total lines of code. Developers may or may not use branching strategies for feature extraction. Additionally, the problems faced during the extraction process may be due to lack of tool support, complexity on managing feature dependencies and issues with feature constraints. We made publicly available the datasets and the analysis scripts of both case studies to be used as a baseline for extractive SPL adoption research and practice.This research was partially funded by CNPq, grant no. 408356/2018-9; FAPPR, grant no. 51435; and FAPERJ PDR-10 Fellowship 202073/2020. Open access funding provided by Johannes Kepler University Lin

Fundamental Approaches to Software Engineering

This open access book constitutes the proceedings of the 23rd International Conference on Fundamental Approaches to Software Engineering, FASE 2020, which took place in Dublin, Ireland, in April 2020, and was held as Part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2020. The 23 full papers, 1 tool paper and 6 testing competition papers presented in this volume were carefully reviewed and selected from 81 submissions. The papers cover topics such as requirements engineering, software architectures, specification, software quality, validation, verification of functional and non-functional properties, model-driven development and model transformation, software processes, security and software evolution

Integration of Quality Attributes in Software Product Line Development

Different approaches for building modern software systems in complex and open environments have been proposed in the last few years. Some efforts try to apply Software Product Line (SPL) approach to take advantage of the massive reuse for producing software systems that share a common set of features. In general quality assurance is a crucial activity for success in software industry, but it is even more important when talking about Software Product Lines since the intensive reuse of assets makes the quality attributes (a measurable physical or abstract property of an entity) of the assets to be transmitted to the whole SPL scope. However, despite the importance that quality has in software product line development, most of the methodologies being applied in Software Product Line Development focus only on managing the commonalities and variability within the product line and not giving support to the non--¿ functional requirements that the products must fit. The main goal of this master final work is to introduce quality attributes in early stages of software product line development processes by means of the definition of a production plan that, on one hand, integrates quality as an additional view for describing the extension of the software product line and, on the other hand introduces the quality attributes as a decision factor during product configuration and when selecting among design alternatives. Our approach has been defined following the Model--¿ Driven Software Development paradigm. Therefore all the software artifacts defined had its correspondent metamodels and the processes defined rely on automated model transformations. Finally in order to illustrate the feasibility of the approach we have integrated the quality view in an SPL example in the context of safety critical embedded systems on the automotive domain.González Huerta, J. (2011). Integration of Quality Attributes in Software Product Line Development. http://hdl.handle.net/10251/15835Archivo delegad

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

Reengineering legacy software products into software product line

Ph.DDOCTOR OF PHILOSOPH