Download or read book Toward an Understanding of Software Code Cloning as a Development Practice written by Cory J. Kapser and published by . This book was released on 2009 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: Code cloning is the practice of duplicating existing source code for use elsewhere within a software system. Within the research community, conventional wisdom has asserted that code cloning is generally a bad practice, and that code clones should be removed or refactored where possible. While there is significant anecdotal evidence that code cloning can lead to a variety of maintenance headaches -- such as code bloat, duplication of bugs, and inconsistent bug fixing -- there has been little empirical study on the frequency, severity, and costs of code cloning with respect to software maintenance. This dissertation seeks to improve our understanding of code cloning as a common development practice through the study of several widely adopted, medium-sized open source software systems. We have explored the motivations behind the use of code cloning as a development practice by addressing several fundamental questions: For what reasons do developers choose to clone code? Are there distinct identifiable patterns of cloning? What are the possible short- and long-term term risks of cloning? What management strategies are appropriate for the maintenance and evolution of clones? When is the ``cure'' (refactoring) likely to cause more harm than the ``disease'' (cloning)? There are three major research contributions of this dissertation. First, we propose a set of requirements for an effective clone analysis tool based on our experiences in clone analysis of large software systems. These requirements are demonstrated in an example implementation which we used to perform the case studies prior to and included in this thesis. Second, we present an annotated catalogue of common code cloning patterns that we observed in our studies. Third, we present an empirical study of the relative frequencies and likely harmfulness of instances of these cloning patterns as observed in two medium-sized open source software systems, the Apache web server and the Gnumeric spreadsheet application. In summary, it appears that code cloning is often used as a principled engineering technique for a variety of reasons, and that as many as 71% of the clones in our study could be considered to have a positive impact on the maintainability of the software system. These results suggest that the conventional wisdom that code clones are generally harmful to the quality of a software system has been proven wrong.
Download or read book Code Clone Analysis written by Katsuro Inoue and published by Springer Nature. This book was released on 2021-08-03 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first book organized around code clone analysis. To cover the broad studies of code clone analysis, this book selects past research results that are important to the progress of the field and updates them with new results and future directions. The first chapter provides an introduction for readers who are inexperienced in the foundation of code clone analysis, defines clones and related terms, and discusses the classification of clones. The chapters that follow are categorized into three main parts to present 1) major tools for code clone analysis, 2) fundamental topics such as evaluation benchmarks, clone visualization, code clone searches, and code similarities, and 3) applications to actual problems. Each chapter includes a valuable reference list that will help readers to achieve a comprehensive understanding of this diverse field and to catch up with the latest research results. Code clone analysis relies heavily on computer science theories such as pattern matching algorithms, computer language, and software metrics. Consequently, code clone analysis can be applied to a variety of real-world tasks in software development and maintenance such as bug finding and program refactoring. This book will also be useful in designing an effective curriculum that combines theory and application of code clone analysis in university software engineering courses.
Download or read book Toward Improved Understanding and Management of Software Clones written by Wei Wang and published by . This book was released on 2012 with total page 85 pages. Available in PDF, EPUB and Kindle. Book excerpt: The cloning of code is controversial as a development practice. Empirical studies on the long-term effects of cloning on software quality and maintainability have produced mixed results. Some studies have found that cloning has a negative impact on code readability, bug propagation, and the presence of cloning may indicate wider problems in software design and management. At the same time, other studies have found that cloned code is less likely to have defects, and thus is arguably more stable, better designed, and better maintained. These results suggest that the effect of cloning on software quality and maintainability may be determinable only on a case-by-case basis, and this only aggravates the challenge of establishing a principled framework of clone management and understanding. This thesis aims to improve the understanding and management of clones within software systems.
Download or read book Empirical Research towards a Relevance Assessment of Software Clones written by Saman Bazrafshan and published by Logos Verlag Berlin GmbH. This book was released on 2017-06-30 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: Redundancies in program source code - software clones - are a common phenomenon. Although it is often claimed that software clones decrease the maintainability of software systems and need to be managed, research in the last couple of years showed that not all clones can be considered harmful. A sophisticated assessment of the relevance of software clones and a cost-benefit analysis of clone management is needed to gain a better understanding of cloning and whether it is truly a harmful phenomenon. This thesis introduces techniques to model, analyze, and evaluate versatile aspects of software clone evolution within the history of a system. We present a mapping of non-identical clones across multiple versions of a system, that avoids possible ambiguities of previous approaches. Though processing more data to determine the context of each clone to avoid an ambiguous mapping, the approach is shown to be efficient and applicable to large systems for a retrospective analysis of software clone evolution. The approach has been used in several studies to gain insights into the phenomenon of cloning in open-source as well as industrial software systems. Our results show that non-identical clones require more attention regarding clone management compared to identical clones as they are the dominating clone type for the main share of our subject systems. Using the evolution model to investigate costs and benefits of refactorings that remove clones, we conclude that clone removals could not reduce maintenance costs for most systems under study.
Download or read book Analyzing Similarity of Cloned Software Variants Using Hierarchical Set Models written by Slawomir Duszynski and published by . This book was released on 2015-03-18 with total page 227 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Your Code as a Crime Scene written by Adam Tornhill and published by Pragmatic Bookshelf. This book was released on 2015-03-30 with total page 289 pages. Available in PDF, EPUB and Kindle. Book excerpt: Jack the Ripper and legacy codebases have more in common than you'd think. Inspired by forensic psychology methods, you'll learn strategies to predict the future of your codebase, assess refactoring direction, and understand how your team influences the design. With its unique blend of forensic psychology and code analysis, this book arms you with the strategies you need, no matter what programming language you use. Software is a living entity that's constantly changing. To understand software systems, we need to know where they came from and how they evolved. By mining commit data and analyzing the history of your code, you can start fixes ahead of time to eliminate broken designs, maintenance issues, and team productivity bottlenecks. In this book, you'll learn forensic psychology techniques to successfully maintain your software. You'll create a geographic profile from your commit data to find hotspots, and apply temporal coupling concepts to uncover hidden relationships between unrelated areas in your code. You'll also measure the effectiveness of your code improvements. You'll learn how to apply these techniques on projects both large and small. For small projects, you'll get new insights into your design and how well the code fits your ideas. For large projects, you'll identify the good and the fragile parts. Large-scale development is also a social activity, and the team's dynamics influence code quality. That's why this book shows you how to uncover social biases when analyzing the evolution of your system. You'll use commit messages as eyewitness accounts to what is really happening in your code. Finally, you'll put it all together by tracking organizational problems in the code and finding out how to fix them. Come join the hunt for better code! What You Need: You need Java 6 and Python 2.7 to run the accompanying analysis tools. You also need Git to follow along with the examples.
Download or read book Visualizing and Understanding Code Duplication in Large Software Systems written by Zhen Ming Jiang and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Software Clones Guilty Until Proven Innocent written by Jan Harder and published by Logos Verlag Berlin GmbH. This book was released on 2017 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt: Software systems contain redundant code that originated from the use of copy and paste. While such cloning may be beneficial in the short term as it accelerates development, it is frequently despised as a risk to maintainability and quality in the long term. Code clones are said to cause extra change effort, because changes have to be propagated to all copies. They are also suspected to cause bugs when the copied code fragments are changed inconsistently. These accusations may be plausible but are not based on empirical facts. Indeed, they are prejudice. In the recent past, science has started the endeavor to find empirical evidence to support the alleged effects of clones. In this thesis, we analyze the effects of clones from three different perspectives. First, we investigate whether clones do indeed increase the maintenance effort in real and long lived software systems. Second, we analyze potential reasons for the cases where clones do cause bugs. Third, we take a new perspective to the problem by measuring the effects of clones in a controlled experiment. This allows us to gather new insights by observing software developers during their work, whereas previous studies were based on historical data. With our work we aim to empirically find advice for practitioners how to deal with clones and, if necessary, to provide an empirical basis for tools that help developers to manage clones.
Download or read book HTML and CSS written by Jon Duckett and published by John Wiley & Sons. This book was released on 2011-11-08 with total page 514 pages. Available in PDF, EPUB and Kindle. Book excerpt: A full-color introduction to the basics of HTML and CSS! Every day, more and more people want to learn some HTML and CSS. Joining the professional web designers and programmers are new audiences who need to know a little bit of code at work (update a content management system or e-commerce store) and those who want to make their personal blogs more attractive. Many books teaching HTML and CSS are dry and only written for those who want to become programmers, which is why this book takes an entirely new approach. Introduces HTML and CSS in a way that makes them accessible to everyone—hobbyists, students, and professionals—and it’s full-color throughout Utilizes information graphics and lifestyle photography to explain the topics in a simple way that is engaging Boasts a unique structure that allows you to progress through the chapters from beginning to end or just dip into topics of particular interest at your leisure This educational book is one that you will enjoy picking up, reading, then referring back to. It will make you wish other technical topics were presented in such a simple, attractive and engaging way! This book is also available as part of a set in hardcover - Web Design with HTML, CSS, JavaScript and jQuery, 9781119038634; and in softcover - Web Design with HTML, CSS, JavaScript and jQuery, 9781118907443.
Download or read book Making Software written by Andy Oram and published by "O'Reilly Media, Inc.". This book was released on 2010-10-14 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many claims are made about how certain tools, technologies, and practices improve software development. But which claims are verifiable, and which are merely wishful thinking? In this book, leading thinkers such as Steve McConnell, Barry Boehm, and Barbara Kitchenham offer essays that uncover the truth and unmask myths commonly held among the software development community. Their insights may surprise you. Are some programmers really ten times more productive than others? Does writing tests first help you develop better code faster? Can code metrics predict the number of bugs in a piece of software? Do design patterns actually make better software? What effect does personality have on pair programming? What matters more: how far apart people are geographically, or how far apart they are in the org chart? Contributors include: Jorge Aranda Tom Ball Victor R. Basili Andrew Begel Christian Bird Barry Boehm Marcelo Cataldo Steven Clarke Jason Cohen Robert DeLine Madeline Diep Hakan Erdogmus Michael Godfrey Mark Guzdial Jo E. Hannay Ahmed E. Hassan Israel Herraiz Kim Sebastian Herzig Cory Kapser Barbara Kitchenham Andrew Ko Lucas Layman Steve McConnell Tim Menzies Gail Murphy Nachi Nagappan Thomas J. Ostrand Dewayne Perry Marian Petre Lutz Prechelt Rahul Premraj Forrest Shull Beth Simon Diomidis Spinellis Neil Thomas Walter Tichy Burak Turhan Elaine J. Weyuker Michele A. Whitecraft Laurie Williams Wendy M. Williams Andreas Zeller Thomas Zimmermann
Download or read book Bayesian Methods for Hackers written by Cameron Davidson-Pilon and published by Addison-Wesley Professional. This book was released on 2015-09-30 with total page 551 pages. Available in PDF, EPUB and Kindle. Book excerpt: Master Bayesian Inference through Practical Examples and Computation–Without Advanced Mathematical Analysis Bayesian methods of inference are deeply natural and extremely powerful. However, most discussions of Bayesian inference rely on intensely complex mathematical analyses and artificial examples, making it inaccessible to anyone without a strong mathematical background. Now, though, Cameron Davidson-Pilon introduces Bayesian inference from a computational perspective, bridging theory to practice–freeing you to get results using computing power. Bayesian Methods for Hackers illuminates Bayesian inference through probabilistic programming with the powerful PyMC language and the closely related Python tools NumPy, SciPy, and Matplotlib. Using this approach, you can reach effective solutions in small increments, without extensive mathematical intervention. Davidson-Pilon begins by introducing the concepts underlying Bayesian inference, comparing it with other techniques and guiding you through building and training your first Bayesian model. Next, he introduces PyMC through a series of detailed examples and intuitive explanations that have been refined after extensive user feedback. You’ll learn how to use the Markov Chain Monte Carlo algorithm, choose appropriate sample sizes and priors, work with loss functions, and apply Bayesian inference in domains ranging from finance to marketing. Once you’ve mastered these techniques, you’ll constantly turn to this guide for the working PyMC code you need to jumpstart future projects. Coverage includes • Learning the Bayesian “state of mind” and its practical implications • Understanding how computers perform Bayesian inference • Using the PyMC Python library to program Bayesian analyses • Building and debugging models with PyMC • Testing your model’s “goodness of fit” • Opening the “black box” of the Markov Chain Monte Carlo algorithm to see how and why it works • Leveraging the power of the “Law of Large Numbers” • Mastering key concepts, such as clustering, convergence, autocorrelation, and thinning • Using loss functions to measure an estimate’s weaknesses based on your goals and desired outcomes • Selecting appropriate priors and understanding how their influence changes with dataset size • Overcoming the “exploration versus exploitation” dilemma: deciding when “pretty good” is good enough • Using Bayesian inference to improve A/B testing • Solving data science problems when only small amounts of data are available Cameron Davidson-Pilon has worked in many areas of applied mathematics, from the evolutionary dynamics of genes and diseases to stochastic modeling of financial prices. His contributions to the open source community include lifelines, an implementation of survival analysis in Python. Educated at the University of Waterloo and at the Independent University of Moscow, he currently works with the online commerce leader Shopify.
Download or read book Remix and Reuse of Source Code in Software Production written by M. Cameron Jones and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The means of producing information and the infrastructure for disseminating it are constantly changing. The web mobilizes information in electronic formats, making it easier to copy, modify, remix, and redistribute. This has changed how information is produced, distributed, and used. People are not just consuming information; they are actively producing, remixing, and sharing information, using the web as a platform for creativity and production. This is true of software development as well. It is frequently commented by programmers and researchers who study software development, that programmers frequently copy and paste code. Although this practice is widely acknowledged, it is rarely studied directly, or explicitly accounted for in models of software development. However, this attitude is changing as software becomes more ubiquitous, and software development practice shifts away from the formal models of software engineering, towards a post-modernist perspective. This study explores how source code snippets in programming books and on the web are changing software development practice. By examining program source code using clone detection algorithms, this study provides a comprehensive view of code copying across 6,190 PHP-language applications. These data are used to explore the concept of a "remix" method of software production, where software and systems are built out of copied and pasted snippets of code. These findings are contrasted against both traditional models of information production coming from informetrics (e.g., authorship, citation analysis), and models from software engineering (e.g., the Lego Hypothesis). Explanations for observed phenomena are discussed borrowing metaphors from linguistics, which provide a richer explanation of copy-paste programming than offered by the Lego Hypothesis. The focus and findings of this study ultimately point to a pressing demand for further research centered on the notion of software as information. Software and software repositories hold a large amount of information about how it was produced, and how it is used, adapted, and maintained. Software informatics is proposed as an organizing label to study the science of information, practice, and communication around software. It studies the individual, collaborative, and social aspects of software production and use, spanning multiple representations of software from design, to source code, to application.
Download or read book Code Clone Discovery Based on Functional Behavior written by Ronald M. Krawitz and published by . This book was released on 2012 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: Legacy programs are used for many years and experience many cycles of use-maintenance-use-maintenance-use-etc. Source code or source code functionality is frequently replicated within these programs when it is written, as well as when it is maintained. Over time many different developers with greater or lesser understanding of the source code maintain the source code. Maintenance developers, when they have limited time or lack understanding of the program, frequently resort to short cuts that include cutting and pasting existing code and re-implementing functionality instead of refactoring. This means a specific functionality is often repeated several times, sometimes using different source code. Blocks of replicated source code or source code functionality are called code clones. Removing code clones improves extensibility, maintainability, and reusability of a program in addition to making the program more easily understood. It is generally accepted that four types of code clones exist. Type-1 and Type-2 code clones are comparatively straightforward to locate and tools exist to locate them. However, Type-3 and Type-4 code clones are very difficult to locate with only a few specialized tools capable of locating them with a lower level of precision. This dissertation presents a new methodology that discovered code clones by studying the functional behavior of blocks of code. Code Clone Discovery based on Functional Behavior (FCD) located code clone by comparing how the blocks of code reacted to various inputs. FCD stimulated the code blocks with the same input patterns and compared the resulting outputs. When a significant portion of the outputs matched, those blocks were declared to be a code clone candidate. Manual analysis confirmed that those blocks of code were code clones. Since FCD discovered code clones based on their black-box behavior, the actual source code syntax was irrelevant and manual inspection further confirmed FCD located code clones that included Type-3 and Type-4 code clones which are frequently excluded from code clone detection tools. FCD recognized the code clones regardless of whether or not they use identical code, similar code, or totally dissimilar code. This new technique allows for an improvement in software quality and has the potential to significantly reduce the cost of software over its lifetime.
Download or read book Advances in Software Engineering written by Hakan Erdogmus and published by Springer Science & Business Media. This book was released on 2013-03-20 with total page 481 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains both relevant real-world research, as well as reviews of different areas of interest in the software engineering literature, such as clone identification. The contents of the various sections will provide a better understanding of known problems and detailed treatment of advanced topics. Consequently, the book consolidates the work and findings from leading researchers in the software research community in key areas such as maintainability, architectural recovery, code analysis, software migration, and tool support.
Download or read book Producing Open Source Software written by Karl Fogel and published by "O'Reilly Media, Inc.". This book was released on 2005-10-07 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: The corporate market is now embracing free, "open source" software like never before, as evidenced by the recent success of the technologies underlying LAMP (Linux, Apache, MySQL, and PHP). Each is the result of a publicly collaborative process among numerous developers who volunteer their time and energy to create better software. The truth is, however, that the overwhelming majority of free software projects fail. To help you beat the odds, O'Reilly has put together Producing Open Source Software, a guide that recommends tried and true steps to help free software developers work together toward a common goal. Not just for developers who are considering starting their own free software project, this book will also help those who want to participate in the process at any level. The book tackles this very complex topic by distilling it down into easily understandable parts. Starting with the basics of project management, it details specific tools used in free software projects, including version control, IRC, bug tracking, and Wikis. Author Karl Fogel, known for his work on CVS and Subversion, offers practical advice on how to set up and use a range of tools in combination with open mailing lists and archives. He also provides several chapters on the essentials of recruiting and motivating developers, as well as how to gain much-needed publicity for your project. While managing a team of enthusiastic developers -- most of whom you've never even met -- can be challenging, it can also be fun. Producing Open Source Software takes this into account, too, as it speaks of the sheer pleasure to be had from working with a motivated team of free software developers.
Download or read book Software Product Quality Control written by Stefan Wagner and published by Springer Science & Business Media. This book was released on 2013-07-25 with total page 219 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quality is not a fixed or universal property of software; it depends on the context and goals of its stakeholders. Hence, when you want to develop a high-quality software system, the first step must be a clear and precise specification of quality. Yet even if you get it right and complete, you can be sure that it will become invalid over time. So the only solution is continuous quality control: the steady and explicit evaluation of a product’s properties with respect to its updated quality goals. This book guides you in setting up and running continuous quality control in your environment. Starting with a general introduction on the notion of quality, it elaborates what the differences between process and product quality are and provides definitions for quality-related terms often used without the required level of precision. On this basis, the work then discusses quality models as the foundation of quality control, explaining how to plan desired product qualities and how to ensure they are delivered throughout the entire lifecycle. Next it presents the main concepts and techniques of continuous quality control, discussing the quality control loop and its main techniques such as reviews or testing. In addition to sample scenarios in all chapters, the book is rounded out by a dedicated chapter highlighting several applications of different subsets of the presented quality control techniques in an industrial setting. The book is primarily intended for practitioners working in software engineering or quality assurance, who will benefit by learning how to improve their current processes, how to plan for quality, and how to apply state-of-the-art quality control techniques. Students and lecturers in computer science and specializing in software engineering will also profit from this book, which they can use in practice-oriented courses on software quality, software maintenance and quality assurance.
Download or read book Understanding the Evolution of Code Clones in Software Systems written by Avigit Saha and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
