3,285 research outputs found
RePOR: Mimicking humans on refactoring tasks. Are we there yet?
Refactoring is a maintenance activity that aims to improve design quality
while preserving the behavior of a system. Several (semi)automated approaches
have been proposed to support developers in this maintenance activity, based on
the correction of anti-patterns, which are `poor' solutions to recurring design
problems. However, little quantitative evidence exists about the impact of
automatically refactored code on program comprehension, and in which context
automated refactoring can be as effective as manual refactoring. Leveraging
RePOR, an automated refactoring approach based on partial order reduction
techniques, we performed an empirical study to investigate whether automated
refactoring code structure affects the understandability of systems during
comprehension tasks. (1) We surveyed 80 developers, asking them to identify
from a set of 20 refactoring changes if they were generated by developers or by
a tool, and to rate the refactoring changes according to their design quality;
(2) we asked 30 developers to complete code comprehension tasks on 10 systems
that were refactored by either a freelancer or an automated refactoring tool.
To make comparison fair, for a subset of refactoring actions that introduce new
code entities, only synthetic identifiers were presented to practitioners. We
measured developers' performance using the NASA task load index for their
effort, the time that they spent performing the tasks, and their percentages of
correct answers. Our findings, despite current technology limitations, show
that it is reasonable to expect a refactoring tools to match developer code
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
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
Mutation Testing as a Safety Net for Test Code Refactoring
Refactoring is an activity that improves the internal structure of the code
without altering its external behavior. When performed on the production code,
the tests can be used to verify that the external behavior of the production
code is preserved. However, when the refactoring is performed on test code,
there is no safety net that assures that the external behavior of the test code
is preserved. In this paper, we propose to adopt mutation testing as a means to
verify if the behavior of the test code is preserved after refactoring.
Moreover, we also show how this approach can be used to identify the part of
the test code which is improperly refactored
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
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