Practical Object-Oriented Design
An Agile Primer Using Ruby
2nd Edition
Published on 21. November 2018
Book
Paperback/Softback
288 pages
978-0-13-445647-8 (ISBN)
Description
The Complete Guide to Writing Maintainable, Manageable, Pleasing, and Powerful Object-Oriented Applications
Object-oriented programming languages exist to help you create beautiful, straightforward applications that are easy to change and simple to extend. Unfortunately, the world is awash with object-oriented (OO) applications that are difficult to understand and expensive to change. Practical Object-Oriented Design, Second Edition, immerses you in an OO mindset and teaches you powerful, real-world, object-oriented design techniques with simple and practical examples.
Sandi Metz demonstrates how to build new applications that can "survive success" and repair existing applications that have become impossible to change. Each technique is illustrated with extended examples in the easy-to-understand Ruby programming language, all downloadable from the companion website, poodr.com. Fully updated for Ruby 2.5, this guide shows how to
Decide what belongs in a single class
Avoid entangling objects that should be kept separate
Define flexible interfaces among objects
Reduce programming overhead costs with duck typing
Successfully apply inheritance
Build objects via composition
Whatever your previous object-oriented experience, this concise guide will help you achieve the superior outcomes you're looking for.
Register your book for convenient access to downloads, updates, and/or corrections as they become available. See inside book for details.
Object-oriented programming languages exist to help you create beautiful, straightforward applications that are easy to change and simple to extend. Unfortunately, the world is awash with object-oriented (OO) applications that are difficult to understand and expensive to change. Practical Object-Oriented Design, Second Edition, immerses you in an OO mindset and teaches you powerful, real-world, object-oriented design techniques with simple and practical examples.
Sandi Metz demonstrates how to build new applications that can "survive success" and repair existing applications that have become impossible to change. Each technique is illustrated with extended examples in the easy-to-understand Ruby programming language, all downloadable from the companion website, poodr.com. Fully updated for Ruby 2.5, this guide shows how to
Decide what belongs in a single class
Avoid entangling objects that should be kept separate
Define flexible interfaces among objects
Reduce programming overhead costs with duck typing
Successfully apply inheritance
Build objects via composition
Whatever your previous object-oriented experience, this concise guide will help you achieve the superior outcomes you're looking for.
Register your book for convenient access to downloads, updates, and/or corrections as they become available. See inside book for details.
Reviews / Votes
Praise for the first edition of Practical Object-Oriented Design in Ruby"Meticulously pragmatic and exquisitely articulate, Practical Object Oriented Design in Ruby makes otherwise elusive knowledge available to an audience which desperately needs it. The prescriptions are appropriate both as rules for novices and as guidelines for experienced professionals."
-Katrina Owen, Creator, Exercism
"I do believe this will be the most important Ruby book of 2012. Not only is the book 100% on-point, Sandi has an easy writing style with lots of great analogies that drive every point home."
-Avdi Grimm, author of Exceptional Ruby and Objects on Rails
"While Ruby is an object-oriented language, little time is spent in the documentation on what OO truly means or how it should direct the way we build programs. Here Metz brings it to the fore, covering most of the key principles of OO development and design in an engaging, easy-to-understand manner. This is a must for any respectable Ruby bookshelf."
-Peter Cooper, editor, Ruby Weekly
"So good, I couldn't put it down! This is a must-read for anyone wanting to do object-oriented programming in any language, not to mention it has completely changed the way I approach testing."
-Charles Max Wood, Ruby Rogues Podcast co-host and CEO of Devchat.tv
"Distilling scary OO design practices with clear-cut examples and explanations makes this a book for novices and experts alike. It is well worth the study by anyone interested in OO design being done right and 'light.' I thoroughly enjoyed this book."
-Manuel Pais, DevOps and Continuous Delivery Consultant, Independent
"If you call yourself a Ruby programmer, you should read this book. It's jam-packed with great nuggets of practical advice and coding techniques that you can start applying immediately in your projects."
-Ylan Segal, San Diego Ruby User Group
"This is the best OO book I've ever read. It's short, sweet, but potent. It slowly moves from simple techniques to more advanced, each example improving on the last. The ideas it presents are useful not just in Ruby but in static languages like C# too. Highly recommended!"
-Kevin Berridge, software engineering manager, Pointe Blank Solutions, and organizer, Burning River Developers Meetup
"This is the best programming book I've read in ages. Sandi talks about basic principles, but these are things we're probably still doing wrong and she shows us why and how. The book has the perfect mix of code, diagrams, and words. I can't recommend it enough and if you're serious about being a better programmer, you'll read it and agree.
-Derick Hitchcock, software engineer, Cisco
"Metz's take on the subject is rooted strongly in theory, but the explanation always stays grounded in real world concerns, which helped me to internalize it. The book is clear and concise, yet achieves a tone that is more friendly than terse.&rdqu
More details
Other editions
Additional editions
E-Book
07/2018
2nd Edition
Addison Wesley
€47.49
Available for download
E-Book
07/2018
2nd Edition
Addison Wesley
from
€28.79
Available for download
Previous edition
Book
09/2012
Addison Wesley
€41.46
Article exhausted; check for reprint
Person
Sandi Metz is a programmer, teacher, author, and sometime consultant. In the past 30+ years she has written innumerable applications and creates practical solutions that produce working software that is easy to change. She has spoken about object-oriented design and refactoring at international Ruby conferences since 2009.
Content
Introduction xv
Acknowledgments xix
About the Author xxi
Chapter 1: Object-Oriented Design 1
1.1 In Praise of Design 2
1.2 The Tools of Design 4
1.3 The Act of Design 6
1.4 A Brief Introduction to Object-Oriented Programming 10
1.5 Summary 13
Chapter 2: Designing Classes with a Single Responsibility 15
2.1 Deciding What Belongs in a Class 16
2.2 Creating Classes That Have a Single Responsibility 17
2.3 Writing Code That Embraces Change 24
2.4 Finally, the Real Wheel 33
2.5 Summary 35
Chapter 3: Managing Dependencies 37
3.1 Understanding Dependencies 38
3.2 Writing Loosely Coupled Code 41
3.3 Managing Dependency Direction 53
3.4 Summary 59
Chapter 4: Creating Flexible Interfaces 61
4.1 Understanding Interfaces 61
4.2 Defining Interfaces 63
4.3 Finding the Public Interface 65
4.4 Writing Code That Puts Its Best (Inter)Face Forward 77
4.5 The Law of Demeter 80
4.6 Summary 84
Chapter 5: Reducing Costs with Duck Typing 85
5.1 Understanding Duck Typing 85
5.2 Writing Code That Relies on Ducks 95
5.3 Conquering a Fear of Duck Typing 100
5.4 Summary 103
Chapter 6: Acquiring Behavior through Inheritance 105
6.1 Understanding Classical Inheritance 105
6.2 Recognizing Where to Use Inheritance 106
6.3 Misapplying Inheritance 114
6.4 Finding the Abstraction 116
6.5 Managing Coupling between Superclasses and Subclasses 129
6.6 Summary 139
Chapter 7: Sharing Role Behavior with Modules 141
7.1 Understanding Roles 142
7.2 Writing Inheritable Code 158
7.3 Summary 161
Chapter 8: Combining Objects with Composition 163
8.1 Composing a Bicycle of Parts 163
8.2 Composing the Parts Object 168
8.3 Manufacturing Parts 176
8.4 The Composed Bicycle 181
8.5 Deciding between Inheritance and Composition 185
8.6 Summary 191
Chapter 9: Designing Cost-Effective Tests 193
9.1 Intentional Testing 194
9.2 Testing Incoming Messages 202
9.3 Testing Private Methods 215
9.4 Testing Outgoing Messages 217
9.5 Testing Duck Types 221
9.6 Testing Inherited Code 233
9.7 Summary 244
Afterword 245
Index 247
Acknowledgments xix
About the Author xxi
Chapter 1: Object-Oriented Design 1
1.1 In Praise of Design 2
1.2 The Tools of Design 4
1.3 The Act of Design 6
1.4 A Brief Introduction to Object-Oriented Programming 10
1.5 Summary 13
Chapter 2: Designing Classes with a Single Responsibility 15
2.1 Deciding What Belongs in a Class 16
2.2 Creating Classes That Have a Single Responsibility 17
2.3 Writing Code That Embraces Change 24
2.4 Finally, the Real Wheel 33
2.5 Summary 35
Chapter 3: Managing Dependencies 37
3.1 Understanding Dependencies 38
3.2 Writing Loosely Coupled Code 41
3.3 Managing Dependency Direction 53
3.4 Summary 59
Chapter 4: Creating Flexible Interfaces 61
4.1 Understanding Interfaces 61
4.2 Defining Interfaces 63
4.3 Finding the Public Interface 65
4.4 Writing Code That Puts Its Best (Inter)Face Forward 77
4.5 The Law of Demeter 80
4.6 Summary 84
Chapter 5: Reducing Costs with Duck Typing 85
5.1 Understanding Duck Typing 85
5.2 Writing Code That Relies on Ducks 95
5.3 Conquering a Fear of Duck Typing 100
5.4 Summary 103
Chapter 6: Acquiring Behavior through Inheritance 105
6.1 Understanding Classical Inheritance 105
6.2 Recognizing Where to Use Inheritance 106
6.3 Misapplying Inheritance 114
6.4 Finding the Abstraction 116
6.5 Managing Coupling between Superclasses and Subclasses 129
6.6 Summary 139
Chapter 7: Sharing Role Behavior with Modules 141
7.1 Understanding Roles 142
7.2 Writing Inheritable Code 158
7.3 Summary 161
Chapter 8: Combining Objects with Composition 163
8.1 Composing a Bicycle of Parts 163
8.2 Composing the Parts Object 168
8.3 Manufacturing Parts 176
8.4 The Composed Bicycle 181
8.5 Deciding between Inheritance and Composition 185
8.6 Summary 191
Chapter 9: Designing Cost-Effective Tests 193
9.1 Intentional Testing 194
9.2 Testing Incoming Messages 202
9.3 Testing Private Methods 215
9.4 Testing Outgoing Messages 217
9.5 Testing Duck Types 221
9.6 Testing Inherited Code 233
9.7 Summary 244
Afterword 245
Index 247