Object-oriented Quality Research Articles

Visualization of object-oriented software in a city metaphor: Comprehending the implemented variability and its technical debt

While many large-scale software systems intensively implement variability to reuse software and speed up development, they often do not document it, hampering its comprehension. This is especially the case for variability-rich object-oriented (OO) systems that heavily rely on existing OO mechanisms (i.e., inheritance, overloading and some patterns) to implement it in a single codebase. With no traceability information, the variability is buried in the codebase, hampering its identification, analysis, and understanding. While variability management becomes increasingly difficult over the system evolution, the implementation mechanisms also bring additional complexity to the codebase, which eventually leads to technical debt, threatening even more the software quality.In this article, we report on the design and evaluation of an extensible visualization, VariCity, that exhibits zones of high density of OO variability implementations. It relies on the city metaphor to represent the classes of the system as buildings whose dimensions are used to show variability metrics inherent to the implementation classes. They are linked together through streets depicting usage relationships and grouping in neighborhoods classes using each other. The extensibility of VariCity is demonstrated with VariMetrics, which highlights OO quality metrics on the buildings, revealing quality-critical classes concentrating variability implementations. We evaluate the visualization capacity to reveal zones concentrating variability implementations and being quality-critical by applying it to multiple variability-intensive open source software systems. We also report on a controlled experiment comparing the gain brought by the visualization to the use of an IDE.

SQMetrics: An Educational Software Quality Assessment Tool for Java

Over the years, various software quality measurement models have been proposed and used in academia and the software industry to assess the quality of produced code and to obtain guidelines for its improvement. In this article, we describe the design and functionality of SQMetrics, a tool for calculating object-oriented quality metrics for projects written in Java. SQMetrics provides the convenience of measuring small code, mainly covering academic or research needs. In this context, the application can be used by students of software engineering courses to make measurements and comparisons in their projects and gradually increase their quality by improving the calculated metrics. Teachers, on the other hand, can use SQMetrics to evaluate students’ Java projects and grade them in proportion to their quality. The contribution of the proposed tool is three-fold, as it has been: (a) tested for its completeness and functionality by comparing it with widely known similar tools, (b) evaluated for its usability and value as a learning aid by students, and (c) statistically tested for its value as a teachers’ aid assisting in the evaluation of student projects. Our findings verify SQMetrics’ effectiveness in helping software engineering students learn critical concepts and improve the quality of their code, as well as in helping teachers assess the quality of students’ Java projects and make more informed grading decisions.

An efficient logistic regression and ant colony optimization-based object-oriented quality prediction

In this paper an efficient logistic regression and ant colony optimization-based object-oriented quality prediction has been presented. The dataset has been considered based on the object-oriented codes. The code considered here are completely equipped with object-oriented features for the complete analysis. The major parameters considered for the experimentation are class, object, inheritance and dynamic behavior. Class and objects have been considered for the class labels and memory requirements checking with the proper stack call and constructor invocation. Inheritance has been considered for the code reusability testing. Dynamic behavior has been tested for the runtime allocation. Then clustering algorithm is used for the parameter preprocessing and grouping based on the parameters. For data filtration chi-square testing has been applied. Then logistic regression and ant colony optimization (LR-ACO) have been considered for the final classification. Then F-Measure, Odd Ratio and Power have been considered for the analysis of the classification based on LR-ACO. The result after LR-ACO shows better accuracy as comparison to the previous methods.

Object oriented quality prediction through artificial intelligence and machine learning: a survey

Software quality estimation is an important aspect as it eliminates design and code defects. Object- oriented quality metrics prediction can help in the estimation of software quality of any defects and the chances of errors. In this paper a survey and the case analytics have been presented for the object-oriented quality prediction. It shows the analytical and experimental aspects of previous methodologies. This survey also elaborates different object-oriented parameters which is useful for the same problem. It also elaborates the problem aspects as well the limitations for the future directions. Machine learning and artificial intelligence methods have been considered mostly for this survey. The parameters considered are inheritance, dynamic behavior, encapsulation, objects etc.

Quality-centric security pattern mutations

Security patterns are a means to encapsulate and communicate proven security solutions. They are well-established approaches for integrating security into the software development process. The literature includes a large array of security patterns categorized into various catalogs, from which the designers can choose a pattern suitable to the problem at hand. Previous efforts to choose appropriate security patterns have only considered the different functionality of the patterns. However, the solution structure of the chosen pattern will integrate with the overall software design and therefore affect many quality attributes such as flexibility and security. Thus, non-functional requirements should also be considered when opting to add a pattern to an existing software design. This will allow the designers to choose between alternative solutions based not only on functionality but also on the quality requirements put forth by different stakeholders. We propose the concept of quality-centric security pattern mutations which are created by mutating current patterns using design refactoring rules. These mutations offer the same behavior as the initial pattern but with varying effects on quality attributes such as flexibility, reusability, extendibility, and security. We have selected two well-established access control patterns as our case studies. We have used both object-oriented quality metrics and design security assessment metrics for quality evaluation and utilized petri nets to analyze behavior preservation. Our assessments demonstrate that the newly created mutations offer varying levels of quality while preserving the original pattern functionality.

“The Queer Feeling We All Know”: Queer Objects and Orientations in Edith Wharton's (Haunted) Houses

"The Queer Feeling We All Know":Queer Objects and Orientations in Edith Wharton's (Haunted) Houses Shannon Brennan In the night that follows his impetuous stab at heteronormativity, Edith Wharton's queerest character is startled to consciousness by his sense of an intruding, untoward object. "I was waked by the queer feeling we all know," Andrew Culwin reflects, "—the feeling that there was something in the room that hadn't been there when I fell asleep" (43). Culwin, the interpellated narrator of "The Eyes," has just surprised himself by proposing marriage to a young cousin—a proposal that he sees as his "suddenly undertak[ing] to promote the moral order of the world" (42). That night, he experiences his "queer feeling," waking to the sense—and then the sight—of a pair of ghostly eyes. Culwin flees their presence, and flees his fiancée, too, embarking on a trajectory that will lead him to Europe, to Hong Kong, and, eventually, to the intimate library where he narrates his story to a few male friends whom he is lustily said to "lik[e] … juicy" (38). We might thus say that his "queer feeling" leads to Culwin's queer orientation. Then again, since this feeling was aroused by the suspicion that the room Culwin occupies has been mysteriously reconfigured, it might be more accurate to recognize that his "queer feeling" was always a matter of his position in space—that is, it has always been a matter of orientation. I am interested in the emphatically spatial, haptic, and object-oriented quality of this scene of queer reorientation. Equally intriguing is its asserted universality: the proposal that "queer feeling" is a thing that "we all know."1 Taking my cue from Culwin's suggestive phrase, I would like to make a few proposals regarding the construction of queer space in what Annette Benert has referred to as Wharton's "architectural imagination." Wharton, I suggest, renders queerness an always-available mode of experience during a period that was increasingly invested in understanding sexual orientation to be a matter of identity. [End Page 82] While Maria Farland and Richard Kaye have shown how Wharton's theories of sexuality were tied to the medical and juridical discourses of her time, I argue that Wharton's writing stages the queering potential of the nonhuman environment.2 Hers is a theory of the queer feelings and alignments produced by the spaces we inhabit. Beyond positing a "theor[y] of space," Wharton offers a preliminary account of queer subjectivity as the uncanny experience of one's position within a choreography of people, furniture, and objects (Somers 41).3 It is just this spatial aspect of sexual orientation that renders queerness a consistent potential available to the characters and interpellated readers of Wharton's oeuvre. What might be queer about our relation to the environment? The New Materialist theories of Sara Ahmed and Mel Chen offer two potential strategies for addressing this question. "Bodies are gendered, sexualized, and raced," Ahmed notes, "by how they extend into space" (5). The structure of a room and the objects in it can naturalize particular lifelines and exclude others; they can make certain subjects feel at home while putting others in their place. In this account, queerness is a phenomenological experience, the sense of disorientation that comes of recognizing oneself and one's desires to be out of place—a precarity that also generates possibilities. Like Ahmed, Chen frames queerness in terms of an affective relation to the environment; however, her work is less focused on the experience of alignment than on humans' reciprocal interaction with the material world. Chen locates queerness in the moments when we violate the "proper intimacies" dictated by our ontological scale (11). Language and custom distinguish subjects and objects, animals and matter, and racialized, sexualized, and gendered persons according to hierarchies of "animacy." To cross these boundaries, recognizing our affective and biological relationship with the presumably inanimate environment—to love the couch that enfolds me in its cushions, for instance—is to queer a commonsense ideological scheme. The discussions of "queer orientation" and "queer feeling" that follow are based in these two concepts. Queer orientation involves the social/sexual...

Constructing models for predicting extract subclass refactoring opportunities using object-oriented quality metrics

ContextRefactoring is a maintenance task that refers to the process of restructuring software source code to enhance its quality without affecting its external behavior. Inspecting and analyzing the source code of the system under consideration to identify the classes in need of extract subclass refactoring (ESR) is a time consuming and costly process. ObjectiveThis paper explores the abilities of several quality metrics considered individually and in combination to predict the classes in need of ESR. MethodFor a given a class, this paper empirically investigates, using univariate logistic regression analysis, the abilities of 25 existing size, cohesion, and coupling metrics to predict whether the class is in need of restructuring by extracting a subclass from it. In addition, models of combined metrics based on multivariate logistic regression analysis were constructed and validated to predict the classes in need of ESR, and the best model is justifiably recommended. We explored the statistical relations between the values of the selected metrics and the decisions of the developers of six open source Java systems with respect to whether the classes require ESR. ResultsThe results indicate that there was a strong statistical relation between some of the quality metrics and the decision of whether ESR activity was required. From a statistical point of view, the recommended model of metrics has practical thresholds that lead to an outstanding classification of the classes into those that require ESR and those that do not. ConclusionThe proposed model can be applied to automatically predict the classes in need of ESR and present them as suggestions to developers working to enhance the system during the maintenance phase. In addition, the model is capable of ranking the classes of the system under consideration according to their degree of need of ESR.

Improving the applicability of object-oriented class cohesion metrics

Context Class cohesion is an important object-oriented quality attribute. It refers to the degree of relatedness between the methods and attributes of a class. Several metrics have been proposed to measure the extent to which the class members are related. Most of these metrics have undefined values for a relatively high percentage of classes, which limits their applicability. The classes that have undefined values lack methods, attributes, or parameter types, or they include only a single method. Objective We improve the applicability of the class cohesion metrics by defining their values for such special classes. In addition, we theoretically and empirically validate the improved metrics. Method We theoretically examine whether the defined values satisfy the key cohesion properties. In addition, we empirically validate the metrics before and after the improvements to test whether the defined values improve the ability of the metrics to evaluate class cohesion. We also explore the correlation between the metrics and the presence of faulty classes to indirectly determine the strength or weakness of the metrics in indicating class quality. Results The results show that our assigned values for the undefined cases do not violate the key cohesion properties and considerably improve the ability of the metrics to explain the presence of faulty classes and may therefore improve their ability to indicate the quality of the class design. Conclusions Having the class cohesion metrics defined for all possible cases improves the applicability of the metrics and potentially increases their precision in indicating class quality.

An empirical validation of object‐oriented class complexity metrics and their ability to predict error‐prone classes in highly iterative, or agile, software: a case study

AbstractEmpirical studies have shown complexity metrics to be good predictors of testing effort and maintainability in traditional, imperative programming languages. Empirical validation studies have also shown that complexity is a good predictor of initial quality and reliability in object‐oriented (OO) software. To date, one of the most empirically validated OO complexity metrics is the Chidamber and Kemerer Weighted Methods in a Class (WMC). However, there are many more OO complexity metrics whose predictive power has not been as extensively explored. In this study, we explore the predictive ability of several complexity‐related metrics for OO software that have not been heavily validated. We do this by exploring their ability to measure quality in an evolutionary software process, by correlating these metrics to defect data for six versions of Rhino, an open‐source implementation of JavaScript written in Java. Using statistical techniques such as Spearman's correlation, principal component analysis, binary logistic regression models and their respective validations, we show that some lesser known complexity metrics including Michura et al.'s standard deviation method complexity and Etzkorn et al.'s average method complexity are more consistent predictors of OO quality than any variant of the Chidamber and Kemerer WMC metric. We also show that these metrics are useful in identifying fault‐prone classes in software developed using highly iterative or agile software development processes. Copyright © 2008 John Wiley & Sons, Ltd.

A quantitative approach for evaluating the quality of design patterns

In recent years, the influence of design patterns on software quality has attracted an increasing attention in the area of software engineering, as design patterns encapsulate valuable knowledge to resolve design problems, and more importantly to improve design quality. As the paradigm continues to increase in popularity, a systematic and objective approach to verify the design of a pattern is increasingly important. The intent session in a design pattern indicates the problem the design pattern wants to resolve, and the solution session describes the structural model for the problem. When the problem in the intent is a quality problem, the structure model should provide a solution to improve the relevant quality. In this work we provide an approach, based on object-oriented quality model, to validate if a design pattern is well-designed, i.e., it answers the question of the proposed structural model really resolves the quality problems described in the intent. We propose a validation approach to help pattern developers check if a design pattern is well-designed. In addition, a quantitative method is proposed to measure the effectiveness of the quality improvement of a design pattern that pattern users can determine which design patterns are applicable to meet their functional and quality requirements.

Towards a suite of quality metrics for KADS-domain knowledge

In this paper, the quality metrics suite for object oriented (OO) design is partially used as an initial concept to develop metrics for statically measuring quality of KADS-domain knowledge bases. KADS-domain knowledge bases have common characteristics with OO, and other distinct features that limit the usage of some OO quality metrics. Therefore, new sets of domain knowledge quality metrics are proposed. The proposed matrices are enriched with an automatic tool used to measure quality of real world expert systems. In order to assess the effectiveness of these proposed quality metrics, these metrics were applied on a sample of real world agriculture application domains developed by CLAES (The Central Laboratory of Agriculture Expert System). Finally, complete analysis of the results obtained due to applying these metrics is presented.

Object-oriented H.263 compatible video coding platform for conferencing applications

This paper describes a prototype video coding platform meant for the conception and testing of multimedia products such as next-generation videophones. The platform is largely based on ITU-T Recommendation H.263, with a number of additional object-oriented quality enhancement features which make it especially well suited for very low bit-rate coding of "head-and-shoulders" video material typical of real-time multimedia applications, video teleconferencing, and video telephony. These features consist of: (1) segmentation into objects of interest, (2) segmentation-based prefiltering, (3) model-assisted rate control, (4) adaptive vector quantization, and finally (5) segmentation-based postfiltering. In the spirit of Recommendation H.263, these enhancements are modular and can be selectively turned on or off, thereby enabling a wide variety of coding modes.

Empirical research in object-oriented quality

Empirical research in object-oriented quality

Empirical research in object-oriented quality

Empirical research in object-oriented quality