Code smell

Abstract: We provide an extensive overview of existing research in the field of software refactoring. This research is compared and discussed based on a number of different criteria: the refactoring activities that are supported, the specific techniques and formalisms that are used for supporting these activities, the types of software artifacts that are being refactored, the important issues that need to be taken into account when building refactoring tool support, and the effect of refactoring on the software process. A running example is used to explain and illustrate the main concepts.

Abstract: Code duplication or copying a code fragment and then reuse by pasting with or without any modiflcations is a well known code smell in software maintenance. Several studies show that about 5% to 20% of a software systems can contain duplicated code, which is basically the results of copying existing code fragments and using then by pasting with or without minor modiflcations. One of the major shortcomings of such duplicated fragments is that if a bug is detected in a code fragment, all the other fragments similar to it should be investigated to check the possible existence of the same bug in the similar fragments. Refactoring of the duplicated code is another prime issue in software maintenance although several studies claim that refactoring of certain clones are not desirable and there is a risk of removing them. However, it is also widely agreed that clones should at least be detected. In this paper, we survey the state of the art in clone detection research. First, we describe the clone terms commonly used in the literature along with their corresponding mappings to the commonly used clone types. Second, we provide a review of the existing clone taxonomies, detection approaches and experimental evaluations of clone detection tools. Applications of clone detection research to other domains of software engineering and in the same time how other domain can assist clone detection research have also been pointed out. Finally, this paper concludes by pointing out several open problems related to clone detection research.

Abstract: Code and design smells are poor solutions to recurring implementation and design problems. They may hinder the evolution of a system by making it hard for software engineers to carry out changes. We propose three contributions to the research field related to code and design smells: (1) DECOR, a method that embodies and defines all the steps necessary for the specification and detection of code and design smells, (2) DETEX, a detection technique that instantiates this method, and (3) an empirical validation in terms of precision and recall of DETEX. The originality of DETEX stems from the ability for software engineers to specify smells at a high level of abstraction using a consistent vocabulary and domain-specific language for automatically generating detection algorithms. Using DETEX, we specify four well-known design smells: the antipatterns Blob, Functional Decomposition, Spaghetti Code, and Swiss Army Knife, and their 15 underlying code smells, and we automatically generate their detection algorithms. We apply and validate the detection algorithms in terms of precision and recall on XERCES v2.7.0, and discuss the precision of these algorithms on 11 open-source systems.

Abstract: Even bad code can function. But if code isnt clean, it can bring a development organization to its knees. Every year, countless hours and significant resources are lost because of poorly written code. But it doesnt have to be that way.Noted software expert Robert C. Martin, presents a revolutionary paradigm with Clean Code: A Handbook of Agile Software Craftsmanship. Martin, who has helped bring agile principles from a practitioners point of view to tens of thousands of programmers, has teamed up with his colleagues from Object Mentor to distill their best agile practice of cleaning code on the fly into a book that will instill within you the values of software craftsman, and make you a better programmerbut only if you work at it.What kind of work will you be doing? Youll be reading codelots of code. And you will be challenged to think about whats right about that code, and whats wrong with it. More importantly you will be challenged to reassess your professional values and your commitment to your craft. Clean Code is divided into three parts. The first describes the principles, patterns, and practices of writing clean code. The second part consists of several case studies of increasing complexity. Each case study is an exercise in cleaning up codeof transforming a code base that has some problems into one that is sound and efficient. The third part is the payoff: a single chapter containing a list of heuristics and smells gathered while creating the case studies. The result is a knowledge base that describes the way we think when we write, read, and clean code.Readers will come away from this book understandingHow to tell the difference between good and bad codeHow to write good code and how to transform bad code into good codeHow to create good names, good functions, good objects, and good classesHow to format code for maximum readability How to implement complete error handling without obscuring code logicHow to unit test and practice test-driven developmentWhat smells and heuristics can help you identify bad codeThis book is a must for any developer, software engineer, project manager, team lead, or systems analyst with an interest in producing better code.