Program slicing for refactoring book

Software under evolution is modified and enhanced to accommodate new requirements. It also transforms a program to improve its internal structure, design, simplicity understandability or other features without affecting its external behavior. As program slicing is a technique for computing a subprogram that preserves a subset of the original programs functionality, program sliding is a new technique for computing two such. These ideas are being implemented through the eclipse refactoring infrastructure. Using software metrics and program slicing for refactoring. Deriving extract method refactoring suggestions for long methods 3. Having read it, i would have called the book something like the refactoring toolset or refactoring pearls. It is not intended to be an standalone substitution of the book so if you really want to learn the concepts here presented, buy and read the book and use this repository as a reference and guide. In addition to discussing the various techniques of refactoring, the author provides a detailed catalog of. When i updated it eighteen years later, refactoring had become a regular tool for any skilled programmer. Refactoring can improve the quality of a software system as measured by coupling, cohesion, and cyclomatic complexity, but knowing which refactoring choices should be implemented is key. Program slicing and refactoring as program reengineering approaches, makes software systems maintainable. Refactoring may involve moving a field from one class to. Refactoring is meant as an improvement of the internal structure of a software system.

Each refactoring step is simpleseemingly too simple to be worth doing. The following section describes our approach for guiding the refactoring process through the use of program slicing and software metrics. The vagaries of code inside these methods conceal the execution logic and make the method extremely hard to understand and even harder to change. A slice extraction refactoring acm digital library. Refactoring consists of improving the internal structure of an existing programs source code, while preserving its external behavior. A data slice is the set of methods that access to a particular attribute field in a class. Program slicing sliding coslicing reuse refactoring. Keywords differencing and integration, software maintenance, testing, aspect mining using program slicing, refactoring to aspects, program slicing for refactoring, untangling.

Everyday low prices and free delivery on eligible orders. Pdf program slicing tool for effective software evolution using. Although refactoring code has been done informally for decades, william griswolds 1991 ph. If you add or change the interface, you are rewriting the code. Refactoring is not just any restructuring intended to improve the code refactoring. Application of program slicing for aspect mining and. He claimed a slice to be the mental abstraction people make when they are debugging a program. Ieee transactions on software engineering 178, 751.

Given each failed asserts, rit helps developers focus their attention on logically related program statements by applying program slicing for minimizing each test. Furthermore, we show how a generalization of such slice extraction. Identifying extract class and extract method refactoring opportunities through analysis of variable declarations and uses. With this book he brings the benefits of refactoring into the html world. Elliotte rusty harold has long had a permanent place on my bookshelf for his work on xml technologies, and a place in my libraries for his open source software for xml processing. Program slicing and refactoring as program reengineering approaches, makes. Typically, this is done by applying series of refactorings, each of which is a usually tiny change in a computer program s source code that does not modify its functional requirements. As program slicing is a technique for computing a subprogram that preserves a subset of the original program s functionality, program sliding is a new technique for computing two such subprograms, a slice and its complement, the coslice. On choosing program refactoring and slicing reengineering.

By amogh katti, gulbarga karnataka india and sujatha terdal. To learn more about refactoring, the natural starting point is my refactoring book, now in its second edition. Jan 01, 1999 the book is well written, provides samples, examples, diagrams, steps to follow, sidenotes, commentary, and basically everything you would need to fully understand a refactoring method. There are more than 20 refactoring steps in the refactor menu. This catalog is organized into several categories of database refactoring.

Refactoring is the process of changing the internal structure of a program, while preserving its behaviour. The proposed methodology aims at automatically identifying extract method refactoring opportunities. With refactoring you can take a bad design, chaos even, and rework it into welldesigned code. Improving the design of existing code is one of those amazing books that every professional developer should have on their book shelf. Refactoring legacy code can actually fix bugs sometimes. The concept of program slicing was originally introduced by mark weiser. Common to all slicing related refactorings, as explored in this thesis, is the goal of improving reusabilit. Program slicing was invented, by mark weiser, for times when only a portion of a program s behavior is of interest 61, and with the observation that programmers use slices when debug ging 62. Method extraction is the process of separating out a. This paper proposes a mechanism that automatically refactors methods of object oriented programs by using program slicing. Effective slicing and refactoring requires proper metrics to quantitatively establish the improvement in the quality. However, for political reasons, you still might want to call it refactoring. Genetic programming for reverse engineering invited paper.

In computer programming, program slicing is the computation of the set of program statements, the program slice, that may affect the values at some point of interest, referred to as a slicing criterion. The term refactoring specifically refers to a common activity in programming and software maintenance. Part of the communications in computer and information science book series. Chamillard university of colorado at colorado springs refactoring can improve the quality of a software system as measured by coupling, cohesion, and cyclomatic complexity, but knowing which refactoring choices should be implemented is key. This is the book that im proudest of, in that its had a high impact on the world of software development. The bulk of this book is a catalog of refactorings, but there is more to it as i will explain below. Whether youre focused on legacy or greenfield development, this book will make you a better software designer by helping you learn. Without refactoring you accrue technical debt, forget what portions of code do and create code that is resistant to any form of testing. Improving the design of existing code addisonwesley object technology series book online at best prices in india on. Code refactoring is a disciplined way to restructure code, undertaken in order to improve some of the nonfunctional attributes of the software.

We use cookies to offer you a better experience, personalize content, tailor advertising, provide social media features, and better understand the use of our services. Today, refactoring requires considerable design knowhow, but once tools become available, all programmers should be able to improve their code using refactoring techniques. Refactoring is the controllable process of systematically improving your code without writing new functionality. The idea of using slicing for refactoring has been suggested by maruyama 42. Automated methodextraction refactoring by using blockbased slicing. As you can see below, eclipse comes with much more refactoring steps available out of the box. Ill start by saying the book refactoring typescript paperback, ebook by james hickey was named incorrectly. In this book, martin fowler shows you where opportunities for refactoring typically can be found, and how to go about reworking a bad design into a good one.

Refactoring does not include any change to the system. Refactoring has become a fullfledged part of the software development lexicon sadly also leading to misuse. To this end, it employs and extends a blockbased slicing technique 20 in order to suggest slice. Improving the design of existing code addisonwesley signature series fowler 2 by fowler, martin isbn. Refactoring can, of course, be done with other languages, and i hope this book will be useful to those working with other languages. As we wanted to have an approach that is able to nd extract method refactorings automatically, we did not rely on a program slicer. Program slicing and dependence analysis has been widely studied in. The mantra of refactoring is clean code and simple design. When refactoring met slicing refactoring is a discipline of change of the internal structure of a software system through small and welldefined sourcecode transformations that preserve the observable behavior of the original system program demo 1. Even before i started work on the refactoring book. With proper training a skilled system designer can take a bad design and rework it into welldesigned, robust code.

Transformation of centralized software components into. Christoph reichenbach from university of colorado visited us, to talk about refactoring ml programs. Part of the lecture notes in computer science book series lncs, volume 73. Refactoring in eclipse slicing is the study of meaningful subprograms. Citeseerx transformation, refactoring, program slicing. Sep 08, 2009 the refactoring tool provides pretty basic refactoring steps. Ive always respected him as a fine programmer and writer.

It seems that refactoring is just editing your code or what. Automated improvement of software design by searchbased. Clearly, as stated above, this is a very simplistic refactoring tool, especially when comparing to eclipse. Several development environments now automate many of the refactorings described in the book. Strictly speaking, when you do both together, you are rewriting. Some other software engineering tasks, such as refactoring, can also be improved with the use of automatic slicing. Visaggioextracting reusable functions by flow graphbased program slicing. Refactoring interprocedural dynamic slicing for handling pointers. Implementing a refactoring tool is a real challenge and even todays the most mature tool implementations are far from being bugfree. The ultimate question of programming, refactoring, and everything by andrey karpov, published on february 19, 2017 yes, youve guessed correctly the answer is 42. It is sometimes easier to fix a bug by refactoring the code its in than by tracking it down. Refactoring via program slicing and sliding ibm research. Improving the design of existing code shows how refactoring can make objectoriented code simpler and easier to maintain.

Improving the design of existing code is focused on oo programming lots of java examples and agile practices. Improving the design of existing code, martin fowler. On choosing program refactoring and slicing reengineering practice towards. We apply aop to develop a program debugging tool using program slicing. Sep 12, 2017 this is my summary of the refactoring. The concept of program slicing was originally introduced by mark weiser in 1981. A direct application of program slicing in the field of refactoring is slice extraction, which has been formally defined by ettinger 2007 as the extraction of the computation of a set of variables v from a program s as a reusable program entity, and the update of the original program. It then uses the semantic impact of a set of identified refactoring changes to detect tests whose behavior may have been affected and modified by refactoring edits. The noun refactoring refers to one particular behaviorpreserving transformation, such as extract method or introduce parameter.

No one actually writes plain old javascript nowadays. A change which improves andor ensures the consistency and usage. Program slicing for refactoring nate slicing based refactoring tool. Genetic programming for reverse engineering mark harman. Code refactoring is a disciplined technique for restructuring an existing body of code, altering its internal structure without changing its external behavior,1 undertaken in order to improve some of the nonfunctional attributes of the software. While the book doesnt provide revolutionary solutions to perform refactoring you shouldnt perform major refactoring in one step anyway, a. Introduction to software engineeringtestingrefactoring. Preserving behaviour guarantees that refactoring does not introduce or remove any bugs. Transformation of centralized software components into distributed ones by code refactoring. Notkin, automated support for program refactoring using invariants, in. Ppt program slicing powerpoint presentation free to.

Refactoring is an effective way to quickly uncover problematic code and fix it. Refactoring is the process of improving the design of existing programs without changing their external behaviour. Deriving extract method refactoring suggestions for long. A database refactoring is a small change to your database schema which improves its design without changing its semantics. Refactoring is a proven way to prevent software decay. However, i felt it would be best to focus this book on java because it is the language i. A change to the table structure of your database schema. Today refactoring requires considerable design knowhow, but once tools become available, all programmers should be able to improve their code using refactoring techniques. A definition of an extract slice mini refactoring given a program and a variable at a point of interest, extract the slice of the program on that variable as a reusable method, and update the original program to reuse the extracted slice. Common to all slicing related refactorings, as explored in this thesis, is the goal of improving reusability, comprehensibility and hence maintainability of existing code. Fine slicing proceedings of the 15th international. I wrote the original edition in 2000 when refactoring was a littleknown technique.

Net, youll discover to apply refactoring techniques to manage and modify your code. In this paper, we examine how method extraction can be improved through program slicing. The bulk of the book is around seventy refactorings described in detail. A survey of software refactoring software engineering, ieee. Improving the design of existing code by martin fowler. As a result, the software becomes more complex and deviates from its original design, in turn lowering the quality. Fine slicing has proved useful in capturing meaningful subprograms and has enabled the creation of an advanced computationextraction algorithm and its implementation in a prototype refactoring tool. This article presents an approach that guides the refactoring. Over the last years, a great deal of ontologies of many different kinds and describing different domains has been created, and new methods and prototypes have. There are then some introductory chapters that discuss broader issues around refactoring, the code smells that suggest refactoring, and the role of testing. Abstract as program slicing is a technique for computing a subprogram that preserves a subset of the original programs functionality, program sliding is a new technique for computing two such subprograms, a slice and its complement, the coslice. Moreover, a set of rules regarding the preservation of existing dependences is proposed that exclude refactoring opportunities corresponding to slices whose extraction could possibly cause a change in program behavior.

Software maintenance, design quality, antipatterns, refactoring, searchbased. Much of refactoring is devoted to correctly composing methods. Refactoring is a change to the code that has no effect on the codes behavior. The course covers 21 smells of bad code and 66 refactoring techniques to fix them. Even if that had been correct, the paper is of the cheapest possible quality which means you can see the text of the next page through the page you are reading, something that makes reading source code, where punctuation really matters, much more difficult. Refactoring programs to secure information flows scott f. In most cases, excessively long methods are the root of all evil. However, i felt it would be best to focus this book on java because it is the language i know best.

The example concerns a piece of software for run ning a video store, focusing on the. Ssbse to the problems of remodularisation, refactoring, regression testing, slicing, and concept assignment in particular. Program slicing, metrics, and refactoring when considering options for refactoring, a technique known as program slicing can be used to isolate. The behaviour preservation is crucial so that refactor. This article presents an approach that guides the refactoring of software systems by combining the use of software metrics and a technique called program slicing. Refactoring to patterns reflects three years of refinement and the insights of more than sixty software engineering thought leaders in the global patterns, refactoring, and agile development communities. Identification of extract method refactoring opportunities. To go the full extent into refactoring you actually have to analyze and manipulate the parse tree of the program, as john and don describe in the book. Chris gave a talk at the fp group refactoring functional programs and program slicing.

If refactoring code fixes a bug, wasnt what you did, by definition, not refactoring. Refactoring can make a program easier to understand or modify if applied appropriately. The ultimate question of programming, refactoring, and. Decoupling a slice of code from its original context and making it into a. Program slicing is a technique which extracts all state ments that may possibly. This book arrived this morning and i was disappointed. This paper presents a interprocedural dynamic slicing for handling pointers in. The goal of refactoring is to pay off technical debt. Code refactoring is the process of restructuring existing computer codechanging the factoringwithout changing its external behavior. A book has been written on the subject by martin fowler. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext.

Tool support for refactoring haskell programs a thesis submitted to. We then briefly explain the automation of these techniques in section 6, based on a program slicing tool developed by the second author. Over time the code will be modified, and the integrity of the system, its structure according to that design, gradually fades. The content of the book is in plain old javascript, which was surprising for a 2018 book. Program slicing can be used in debugging to locate source of errors more easily. Refactoring is intended to improve the design, structure, andor implementation of the software its nonfunctional attributes, while preserving the functionality of the software. A slice extraction refactoring ran ettinger and mathieu verbaere programming tools group. Refactoring is the process of changing the code of the software such that its internal design is improved without altering its observable behavior. Our updated entry in the 9th edition of the haskell communities report. Keywordsprogram slicing, decomposition slicing, dead code. As program slicing is a technique for computing a subprogram that preserves a subset of the original programs functionality, program sliding is a new technique for computing two such subprograms, a slice and its complement, the coslice. Dive into refactoring teaches you how to properly deal with legacy code, how to identify ugly code and how to clean it safely.