Maleku: an evolutionary visual software analytics tool for providing insights into software evolution

Software maintenance is a complex process that requires the understanding and comprehension of software project details. It involves the understanding of the evolution of the software project, hundreds of software components and the relationships among software items in the form of inheritance, interface implementation, coupling and cohesion. Consequently, the aim of evolutionary visual software analytics is to support software project managers and developers during software maintenance. It takes into account the mining of evolutionary data, the subsequent analysis of the results produced by the mining process for producing evolution facts, the use of visualizations supported by interaction techniques and the active participation of users. Hence, this paper proposes an evolutionary visual software analytics tool for the exploration and comparison of project structural, interface implementation and class hierarchy data, and the correlation of structural data with metrics, as well as socio-technical relationships. Its main contribution is a tool that automatically retrieves evolutionary software facts and represent them using a scalable visualization design

Code smells detection and visualization: A systematic literature review

Context: Code smells (CS) tend to compromise software quality and also demand more effort by developers to maintain and evolve the application throughout its life-cycle. They have long been catalogued with corresponding mitigating solutions called refactoring operations. Objective: This SLR has a twofold goal: the first is to identify the main code smells detection techniques and tools discussed in the literature, and the second is to analyze to which extent visual techniques have been applied to support the former. Method: Over 83 primary studies indexed in major scientific repositories were identified by our search string in this SLR. Then, following existing best practices for secondary studies, we applied inclusion/exclusion criteria to select the most relevant works, extract their features and classify them. Results: We found that the most commonly used approaches to code smells detection are search-based (30.1%), and metric-based (24.1%). Most of the studies (83.1%) use open-source software, with the Java language occupying the first position (77.1%). In terms of code smells, God Class (51.8%), Feature Envy (33.7%), and Long Method (26.5%) are the most covered ones. Machine learning techniques are used in 35% of the studies. Around 80% of the studies only detect code smells, without providing visualization techniques. In visualization-based approaches several methods are used, such as: city metaphors, 3D visualization techniques. Conclusions: We confirm that the detection of CS is a non trivial task, and there is still a lot of work to be done in terms of: reducing the subjectivity associated with the definition and detection of CS; increasing the diversity of detected CS and of supported programming languages; constructing and sharing oracles and datasets to facilitate the replication of CS detection and visualization techniques validation experiments.Comment: submitted to ARC

Code smells detection and visualization: A systematic literature review

Context: Code smells (CS) tend to compromise software quality and also demand more effort by developers to maintain and evolve the application throughout its life-cycle. They have long been cataloged with corresponding mitigating solutions called refactoring operations. Objective: This SLR has a twofold goal: the first is to identify the main code smells detection techniques and tools discussed in the literature, and the second is to analyze to which extent visual techniques have been applied to support the former. Method: Over 83 primary studies indexed in major scientific repositories were identified by our search string in this SLR. Then, following existing best practices for secondary studies, we applied inclusion/exclusion criteria to select the most relevant works, extract their features and classify them. Results: We found that the most commonly used approaches to code smells detection are search-based (30.1%), and metric-based (24.1%). Most of the studies (83.1%) use open-source software, with the Java language occupying the first position (77.1%). In terms of code smells, God Class (51.8%), Feature Envy (33.7%), and Long Method (26.5%) are the most covered ones. Machine learning techniques are used in 35% of the studies. Around 80% of the studies only detect code smells, without providing visualization techniques. In visualization-based approaches, several methods are used, such as city metaphors, 3D visualization techniques. Conclusions: We confirm that the detection of CS is a non-trivial task, and there is still a lot of work to be done in terms of: reducing the subjectivity associated with the definition and detection of CS; increasing the diversity of detected CS and of supported programming languages; constructing and sharing oracles and datasets to facilitate the replication of CS detection and visualization techniques validation experiments.info:eu-repo/semantics/acceptedVersio

On porting software visualization tools to the web

Software systems are hard to understand due to the complexity and the sheer size of the data to be analyzed. Software visualization tools are a great help as they can sum up large quantities of data in dense, meaningful pictures. Traditionally, such tools come in the form of desktop applications. Modern web frameworks are about to change this status quo, as building software visualization tools as web applications can help in making them available to a larger audience in a collaborative setting. Such a migration comes with a number of promises, perils, and technical implications that must be considered before starting any migration process. In this paper, we share our experiences in porting two such tools to the web and provide guidelines about the porting. In particular, we discuss promises and perils that go hand in hand with such an endeavor and present a number of technological alternatives that are available to implement web-based visualization

Streamlining code smells: Using collective intelligence and visualization

Context. Code smells are seen as major source of technical debt and, as such, should be detected and removed. Code smells have long been catalogued with corresponding mitigating solutions called refactoring operations. However, while the latter are supported in current IDEs (e.g., Eclipse), code smells detection scaffolding has still many limitations. Researchers argue that the subjectiveness of the code smells detection process is a major hindrance to mitigate the problem of smells-infected code. Objective. This thesis presents a new approach to code smells detection that we have called CrowdSmelling and the results of a validation experiment for this approach. The latter is based on supervised machine learning techniques, where the wisdom of the crowd (of software developers) is used to collectively calibrate code smells detection algorithms, thereby lessening the subjectivity issue. Method. In the context of three consecutive years of a Software Engineering course, a total “crowd” of around a hundred teams, with an average of three members each, classified the presence of 3 code smells (Long Method, God Class, and Feature Envy) in Java source code. These classifications were the basis of the oracles used for training six machine learning algorithms. Over one hundred models were generated and evaluated to determine which machine learning algorithms had the best performance in detecting each of the aforementioned code smells. Results. Good performances were obtained for God Class detection (ROC=0.896 for Naive Bayes) and Long Method detection (ROC=0.870 for AdaBoostM1), but much lower for Feature Envy (ROC=0.570 for Random Forrest). Conclusions. Obtained results suggest that Crowdsmelling is a feasible approach for the detection of code smells, but further validation experiments are required to cover more code smells and to increase external validityContexto. Os cheiros de código são a principal causa de dívida técnica (technical debt), como tal, devem ser detectados e removidos. Os cheiros de código já foram há muito tempo catalogados juntamente com as correspondentes soluções mitigadoras chamadas operações de refabricação (refactoring). No entanto, embora estas últimas sejam suportadas nas IDEs actuais (por exemplo, Eclipse), a deteção de cheiros de código têm ainda muitas limitações. Os investigadores argumentam que a subjectividade do processo de deteção de cheiros de código é um dos principais obstáculo à mitigação do problema da qualidade do código. Objectivo. Esta tese apresenta uma nova abordagem à detecção de cheiros de código, a que chamámos CrowdSmelling, e os resultados de uma experiência de validação para esta abordagem. A nossa abordagem de CrowdSmelling baseia-se em técnicas de aprendizagem automática supervisionada, onde a sabedoria da multidão (dos programadores de software) é utilizada para calibrar colectivamente algoritmos de detecção de cheiros de código, diminuindo assim a questão da subjectividade. Método. Em três anos consecutivos, no âmbito da Unidade Curricular de Engenharia de Software, uma "multidão", num total de cerca de uma centena de equipas, com uma média de três membros cada, classificou a presença de 3 cheiros de código (Long Method, God Class, and Feature Envy) em código fonte Java. Estas classificações foram a base dos oráculos utilizados para o treino de seis algoritmos de aprendizagem automática. Mais de cem modelos foram gerados e avaliados para determinar quais os algoritmos de aprendizagem de máquinas com melhor desempenho na detecção de cada um dos cheiros de código acima mencionados. Resultados. Foram obtidos bons desempenhos na detecção do God Class (ROC=0,896 para Naive Bayes) e na detecção do Long Method (ROC=0,870 para AdaBoostM1), mas muito mais baixos para Feature Envy (ROC=0,570 para Random Forrest). Conclusões. Os resultados obtidos sugerem que o Crowdsmelling é uma abordagem viável para a detecção de cheiros de código, mas são necessárias mais experiências de validação para cobrir mais cheiros de código e para aumentar a validade externa

Software Visualization in 3D: Implementation, Evaluation, and Applicability

The focus of this thesis is on the implementation, the evaluation and the useful application of the third dimension in software visualization. Software engineering is characterized by a complex interplay of different stakeholders that produce and use several artifacts. Software visualization is used as one mean to address this increasing complexity. It provides role- and task-specific views of artifacts that contain information about structure, behavior, and evolution of a software system in its entirety. The main potential of the third dimension is the possibility to provide multiple views in one software visualization for all three aspects. However, empirical findings concerning the role of the third dimension in software visualization are rare. Furthermore, there are only few 3D software visualizations that provide multiple views of a software system including all three aspects. Finally, the current tool support lacks of generating easy integrateable, scalable, and platform independent 2D, 2.5D, and 3D software visualizations automatically. Hence, the objective is to develop a software visualization that represents all important structural entities and relations of a software system, that can display behavioral and evolutionary aspects of a software system as well, and that can be generated automatically. In order to achieve this objective the following research methods are applied. A literature study is conducted, a software visualization generator is conceptualized and prototypically implemented, a structured approach to plan and design controlled experiments in software visualization is developed, and a controlled experiment is designed and performed to investigate the role of the third dimension in software visualization. The main contributions are an overview of the state-of-the-art in 3D software visualization, a structured approach including a theoretical model to control influence factors during controlled experiments in software visualization, an Eclipse-based generator for producing automatically role- and task-specific 2D, 2.5D, and 3D software visualizations, the controlled experiment investigating the role of the third dimension in software visualization, and the recursive disk metaphor combining the findings with focus on the structure of software including useful applications of the third dimension regarding behavior and evolution

Visualisation of Linked Data – Reprise

Linked Data promises to serve as a disruptor of traditional approaches to data management and use, promoting the push from the traditional Web of documents to a Web of data. The ability for data consumers to adopt a follow your nose approach, traversing links defined within a dataset or across independently-curated datasets, is an essential feature of this new Web of Data, enabling richer knowledge retrieval thanks to synthesis across multiple sources of, and views on, inter-related datasets. But for the Web of Data to be successful, we must design novel ways of interacting with the corresponding very large amounts of complex, interlinked, multi-dimensional data throughout its management cycle. The design of user interfaces for Linked Data, and more specifically interfaces that represent the data visually, play a central role in this respect. Contributions to this special issue on Linked Data visualisation investigate different approaches to harnessing visualisation as a tool for exploratory discovery and basic-to-advanced analysis. The papers in this volume illustrate the design and construction of intuitive means for end-users to obtain new insight and gather more knowledge, as they follow links defined across datasets over the Web of Data