Product Description

This book provides programmers with the ability to cost effectively handlecommon legacy code problems without having to go through the hugelyexpensive task of rewriting all existing code. It describes a series of practicalstrategies that developers can employ to bring their existing softwareapplications under control. The author provides useful guidance about how touse these strategies when refactoring or making functional changes to codebases. One of the book's key points is that it teaches developers to write teststhat can be used to make sure they are not unintentionally changing theapplication as they optimize it. Examples are provided in Java, C++, and Csharp,and the book assumes that the reader has some knowledge of UMLnotation. Strategies using UML and code in C++ and Java primarily whilelanguage independent advice will be delivered in side bars and appendices forlanguage specific users.

Product Details

• Amazon Sales Rank: #38112 in Books
• Published on: 2004-10-07
• Original language: English
• Number of items: 1
• Binding: Paperback
• 456 pages

From the Back Cover

Get more out of your legacy systems: more performance, functionality, reliability, and manageability

Is your code easy to change? Can you get nearly instantaneous feedback when you do change it? Do you understand it? If the answer to any of these questions is no, you have legacy code, and it is draining time and money away from your development efforts.

In this book, Michael Feathers offers start-to-finish strategies for working more effectively with large, untested legacy code bases. This book draws on material Michael created for his renowned Object Mentor seminars: techniques Michael has used in mentoring to help hundreds of developers, technical managers, and testers bring their legacy systems under control.

The topics covered include

• Understanding the mechanics of software change: adding features, fixing bugs, improving design, optimizing performance
• Getting legacy code into a test harness
• Writing tests that protect you against introducing new problems
• Techniques that can be used with any language or platform—with examples in Java, C++, C, and C#
• Accurately identifying where code changes need to be made
• Coping with legacy systems that aren't object-oriented
• Handling applications that don't seem to have any structure

This book also includes a catalog of twenty-four dependency-breaking techniques that help you work with program elements in isolation and make safer changes.

© Copyright Pearson Education. All rights reserved.

About the Author

MICHAEL C. FEATHERS works for Object Mentor, Inc., one of the world's top providers of mentoring, skill development, knowledge transfer, and leadership services in software development. He currently provides worldwide training and mentoring in Test-Driven Development (TDD), Refactoring, OO Design, Java, C#, C++, and Extreme Programming (XP). Michael is the original author of CppUnit, a C++ port of the JUnit testing framework, and FitCpp, a C++ port of the FIT integrated-testing framework. A member of ACM and IEEE, he has chaired CodeFest at three OOPSLA conferences.

© Copyright Pearson Education. All rights reserved.

Customer Reviews

practical and helpful advice on testing
This book focuses on how best to treat existing, large and probably poorly designed code, when needing to add features. This is most likely to happen when you have big old code that needs maintaining, but a lot of the advice is directly applicable to open source projects that lack tests and documentation. Therefore this can be considered as a valuable addition to the literature on testing and refactoring.

The advocated approach is rooted in writing unit tests and refactoring. Each chapter is themed around a problem (e.g. "Dependencies on Libraries is Killing Me", "I Don't Understand the Code Well Enough to Change It"), and then a series of techniques are suggested. At the back of the book are a series of refactorings, specifically for dealing with large classes, with some platform specific approaches, such as C++ forbidding the use of virtual functions that resolve to subclasses in constructors.

The code is mainly in Java, with a large number of examples in C++, and a handful in C and C#. You can probably get by with just knowing Java.

To get the most out of this book, I would suggest having read Martin Fowler's Refactoring first. It would also help to be familiar with the JUnit Java testing framework, which is used for the testing examples throughout. If you don't already know JUnit, you can pick up enough knowledge from the many articles on the web, and you certainly don't need to have read a book on Test Driven Development.

A reasonable measure of the quality of a book such as this is if it changes the way you code. It did so for me, and I recommend this as another high quality book in the Robert C. Martin series.

A very useful book
The biggest single problem I had when I moved from working for myself as a programmer back to the mainstream was dealing with other people's code. For nearly twenty years I only had to deal with my own code. Suddenly I had to understand and change other people's code. It was quite a culture shock, and one of the most difficult things I've done.

I wish I'd found Michael's book earlier, it would have helped ease the transition. Of course, not everyone else's code is legacy code, but even if you are not handling true 'legacy' code, this book will help you deal with the problems you face.

The book is in three parts. The first is a discussion of how you go about changing software that is badly structured and has complex interactions and side effects. Where do you start, and how do you make sure that you don't break things further down the convoluted chain of dependencies. The answer to the latter, of course, is testing, testing, testing, and the author makes a good enough case to persuade even the most sloth like to get into the testing mode.

The second part of the book is organised almost like an FAQ with chapters devoted to common problems like 'I don't understand the code well enough to change it'. This one crops up all too often, and is an excellent example of how the author doesn't avoid difficult questions. The final part of the book is a useful catalog of mostly pattern based techniques that can be used to break dependencies.

The book is well written and features clear examples that are written in either C++, Java, C and C#, and the problems caused by the different features, or lack of them, available to the different languages are discussed and work arounds suggested. I enjoyed reading this book.

Highly recommended!

A guide to retrofitting unit tests to existing code.
The books definiton of Legacy code is code not covered by unit tests.
This book covers adding unit tests to existing code.
It has a set of techniques for changing code so that it is more suitable to be covered by unit tests.