2,362 research outputs found
A heuristic-based approach to code-smell detection
Encapsulation and data hiding are central tenets of the object oriented paradigm. Deciding what data and behaviour to form into a class and where to draw the line between its public and private details can make the difference between a class that is an understandable, flexible and reusable abstraction and one which is not. This decision is a difficult one and may easily result in poor encapsulation which can then have serious implications for a number of system qualities. It is often hard to identify such encapsulation problems within large software systems until they cause a maintenance problem (which is usually too late) and attempting to perform such analysis manually can also be tedious and error prone. Two of the common encapsulation problems that can arise as a consequence of this decomposition process are data classes and god classes. Typically, these two problems occur together – data classes are lacking in functionality that has typically been sucked into an over-complicated and domineering god class. This paper describes the architecture of a tool which automatically detects data and god classes that has been developed as a plug-in for the Eclipse IDE. The technique has been evaluated in a controlled study on two large open source systems which compare the tool results to similar work by Marinescu, who employs a metrics-based approach to detecting such features. The study provides some valuable insights into the strengths and weaknesses of the two approache
Refactoring Legacy JavaScript Code to Use Classes: The Good, The Bad and The Ugly
JavaScript systems are becoming increasingly complex and large. To tackle the
challenges involved in implementing these systems, the language is evolving to
include several constructions for programming- in-the-large. For example,
although the language is prototype-based, the latest JavaScript standard, named
ECMAScript 6 (ES6), provides native support for implementing classes. Even
though most modern web browsers support ES6, only a very few applications use
the class syntax. In this paper, we analyze the process of migrating structures
that emulate classes in legacy JavaScript code to adopt the new syntax for
classes introduced by ES6. We apply a set of migration rules on eight legacy
JavaScript systems. In our study, we document: (a) cases that are
straightforward to migrate (the good parts); (b) cases that require manual and
ad-hoc migration (the bad parts); and (c) cases that cannot be migrated due to
limitations and restrictions of ES6 (the ugly parts). Six out of eight systems
(75%) contain instances of bad and/or ugly cases. We also collect the
perceptions of JavaScript developers about migrating their code to use the new
syntax for classes.Comment: Paper accepted at 16th International Conference on Software Reuse
(ICSR), 2017; 16 page
A Systematic Aspect-Oriented Refactoring and Testing Strategy, and its Application to JHotDraw
Aspect oriented programming aims at achieving better modularization for a
system's crosscutting concerns in order to improve its key quality attributes,
such as evolvability and reusability. Consequently, the adoption of
aspect-oriented techniques in existing (legacy) software systems is of interest
to remediate software aging. The refactoring of existing systems to employ
aspect-orientation will be considerably eased by a systematic approach that
will ensure a safe and consistent migration.
In this paper, we propose a refactoring and testing strategy that supports
such an approach and consider issues of behavior conservation and (incremental)
integration of the aspect-oriented solution with the original system. The
strategy is applied to the JHotDraw open source project and illustrated on a
group of selected concerns. Finally, we abstract from the case study and
present a number of generic refactorings which contribute to an incremental
aspect-oriented refactoring process and associate particular types of
crosscutting concerns to the model and features of the employed aspect
language. The contributions of this paper are both in the area of supporting
migration towards aspect-oriented solutions and supporting the development of
aspect languages that are better suited for such migrations.Comment: 25 page
Proactive Empirical Assessment of New Language Feature Adoption via Automated Refactoring: The Case of Java 8 Default Methods
Programming languages and platforms improve over time, sometimes resulting in
new language features that offer many benefits. However, despite these
benefits, developers may not always be willing to adopt them in their projects
for various reasons. In this paper, we describe an empirical study where we
assess the adoption of a particular new language feature. Studying how
developers use (or do not use) new language features is important in
programming language research and engineering because it gives designers
insight into the usability of the language to create meaning programs in that
language. This knowledge, in turn, can drive future innovations in the area.
Here, we explore Java 8 default methods, which allow interfaces to contain
(instance) method implementations.
Default methods can ease interface evolution, make certain ubiquitous design
patterns redundant, and improve both modularity and maintainability. A focus of
this work is to discover, through a scientific approach and a novel technique,
situations where developers found these constructs useful and where they did
not, and the reasons for each. Although several studies center around assessing
new language features, to the best of our knowledge, this kind of construct has
not been previously considered.
Despite their benefits, we found that developers did not adopt default
methods in all situations. Our study consisted of submitting pull requests
introducing the language feature to 19 real-world, open source Java projects
without altering original program semantics. This novel assessment technique is
proactive in that the adoption was driven by an automatic refactoring approach
rather than waiting for developers to discover and integrate the feature
themselves. In this way, we set forth best practices and patterns of using the
language feature effectively earlier rather than later and are able to possibly
guide (near) future language evolution. We foresee this technique to be useful
in assessing other new language features, design patterns, and other
programming idioms
Refactoring, reengineering and evolution: paths to Geant4 uncertainty quantification and performance improvement
Ongoing investigations for the improvement of Geant4 accuracy and
computational performance resulting by refactoring and reengineering parts of
the code are discussed. Issues in refactoring that are specific to the domain
of physics simulation are identified and their impact is elucidated.
Preliminary quantitative results are reported.Comment: To be published in the Proc. CHEP (Computing in High Energy Physics)
201
Structured Review of Code Clone Literature
This report presents the results of a structured review of code clone literature. The aim of the review is to assemble a conceptual model of clone-related concepts which helps us to reason about clones. This conceptual model unifies clone concepts from a wide range of literature, so that findings about clones can be compared with each other
Search based software engineering: Trends, techniques and applications
© ACM, 2012. This is the author's version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. The definitive version is available from the link below.In the past five years there has been a dramatic increase in work on Search-Based Software Engineering (SBSE), an approach to Software Engineering (SE) in which Search-Based Optimization (SBO) algorithms are used to address problems in SE. SBSE has been applied to problems throughout the SE lifecycle, from requirements and project planning to maintenance and reengineering. The approach is attractive because it offers a suite of adaptive automated and semiautomated solutions in situations typified by large complex problem spaces with multiple competing and conflicting objectives.
This article provides a review and classification of literature on SBSE. The work identifies research trends and relationships between the techniques applied and the applications to which they have been applied and highlights gaps in the literature and avenues for further research.EPSRC and E
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