Emergent Design The Evolutionary Nature of Professional Software Development (paperback)

by Bain, Scott

• ISBN13: 9780321889065
• ISBN10: 0321889061
• Edition: 1st
• Format: Paperback
• Copyright: 2008-02-27
• Publisher: Addison-Wesley Professional

Summary

For software to consistently deliver promised results, software development must mature into a true profession. Emergent Designpoints the way. As software continues to evolve and mature, software development processes become more complicated, relying on a variety of methodologies and approaches. This book illuminates the path to building the next generation of software. Author Scott L. Bain integrates the best of today's most important development disciplines into a unified, streamlined, realistic, and fully actionable approach to developing software. Drawing on patterns, refactoring, and test-driven development, Bain offers a blueprint for moving efficiently through the entire software lifecycle, smoothly managing change, and consistently delivering systems that are robust, reliable, and cost-effective. Reflecting a deep understanding of the natural flow of system development, Emergent Designhelps developers work with the flow, instead of against it. Bain introduces the principles and practices of emergent design one step at a time, showing how to promote the natural evolution of software systems over time, making systems work better and provide greater value. To illuminate his approach, Bain presents code examples wherever necessary and concludes with a complete project case study. This book provides developers, project leads, and testers powerful new ways to collaborate, achieve immediate goals, and build systems that improve in quality with each iteration. Coverage includes How to design software in a more natural, evolutionary, and professional way How to use the "open-closed" principle to mitigate risks and eliminate waste How and when to test your design throughout the development process How to translate design principles into practices that actually lead to better code How to determine how much design is enough How refactoring can help you reduce over-design and manage change more effectively The book's companion Web site,www.netobjectives.com/resources, provides updates, links to related materials, and support for discussions of the book's content.

Author Biography

Scott L. Bain is a thirty-year veteran in computer technology, with a background in development, engineering, and design. He has also designed, delivered, and managed training programs for certification and end-user skills, both in traditional classrooms and via distance learning. For the past eight years, Scott has been working for Net Objectives in Puget Sound, teaching courses and consulting on design patterns, refactoring, unit testing, and test-driven development. Along with Net Objectives CEO Alan Shalloway, he has contributed significantly to the integration of design patterns in Agile environments. Scott is a frequent speaker at developer conferences such as JavaOne and SDWest.

Table of Contents

Series Foreword xvii

Preface xxiii

Acknowledgments xxix

About the Author xxxi

 

Chapter 1: Software as a Profession 1

How Long Have Human Beings Been Making Software? 1

What Sort of Activity Is Software Development? 2

What Is Missing? 6

Who Is Responsible? 8

Uniqueness 9

 

Chapter 2: Out of the Closet, Off to the Moon 11

Patterns and Professionalism in Software Development 11

Andrea’s Closet 12

Off to the Moon 18

The Value of Patterns 26

Summary 27

 

Chapter 3: The Nature of Software Development 29

We Fail Too Much 30

Definitions of Success 31

The Standish Group 32

Doing the Wrong Things 34

Doing the Things Wrong 35

Time Goes By, Things Improve 38

One Reason: The Civil Engineering Analogy 38

Giving Up Hope 41

Ignoring Your Mother 42

Bridges Are Hard, Software Is Soft 43

We Swim in an Ocean of Change 43

Accept Change 44

Embrace Change 45

Capitalize on Change 46

A Better Analogy: Evolving Systems 49

Summary 52

 

Chapter 4: Evolution in Code: Stage 1 55

Procedural Logic Replaced with Object Structure 56

The Origins of Object Orientations and Patterns 56

An Example: Simple Conditionals and the Proxy Pattern 58

The Next Step: Either This or That 62

Why Bother? 65

One Among Many66

Summary 67

 

Chapter 5: Using and Discovering Patterns 69

Design from Context: More Carpentry from Scott 70

Patterns Lead to Another Cognitive Perspective 79

Patterns Help Give Us a Language for Discussing Design 79

Patterns in This Book 80

Summary 81

 

Chapter 6: Building a Pyramid 83

Elements of the Profession 83

A Visual Representation 85

Summary 86

 

Chapter 7: Paying Attention to Qualities and Pathologies 89

Encapsulation 91

Cohesion 91

Coupling 99

Redundancy 106

Testability 112

Readability 114

Pathologies 114

Summary 119

 

Chapter 8: Paying Attention to Principles and Wisdom 121

Separating Use from Creation 122

The Open-Closed Principle 129

The Dependency Inversion Principle 133

Advice from the Gang of Four 135

GoF: Consider What Should Be Variable in Your Design and Encapsulate the Concept That Varies 143

Summary 146

 

Chapter 9: Paying Attention to Practices 147

Consistent Coding Style 148

Programming by Intention 153

Encapsulating the Constructor 155

Commonality-Variability Analysis 161

Practices and Freedom 166

Summary 167

 

Chapter 10: Paying Attention to Disciplines: Unit Testing 169

Economies of Testing 169

JUnit Framework 175

Mock Objects 204

Summary 212

 

Chapter 11: Paying Attention to Disciplines: Refactoring 213

Refactoring Bad Code 215

Refactoring Good Code 216

Structural Changes Versus Functional Changes 218

Refactoring Helps You Choose Your Battles 219

Patterns Can Be Targets of Refactoring 220

Avoiding Refactoring: Prefactoring 220

The Mechanics of Refactoring 221

Refactoring Legacy Code 231

Summary 233

 

Chapter 12: Test-Driven Development 235

What Makes Development Test-Driven? 235

Testing and Quality 238

Test-Driven Development and Patterns 241

Mock Objects 244

Mock Turtles 248

Testing the Decorator Pattern 248

Summary 253

 

Chapter 13: Patterns and Forces 255

Making Decisions in an Evolving Design 255

Christopher Alexander and Forces 256

More Choices, More Forces 266

Summary 271

 

Chapter 14: Emergent Design: A Case Study 273

The Problem Domain: The MWave Corporation 273

The Teams 275

The Simplest Thing That Could Possibly Work 277

A New Requirement: Complex Machines 281

Oh, By the Way 283

More Good News 285

Summary: What a Long, Strange Trip It Has Been 287

 

Chapter 15: A Conclusion: 2020 289

 

Appendix A: Evolutionary Paths 291

 

Appendix B: Overview of Patterns Used in the Examples 301

 

Appendix C: The Principle of the Useful Illusion 385

 

Bibliography 393

Index 395