Home > Store

Emergent Design: The Evolutionary Nature of Professional Software Development

eBook (Watermarked)

  • Your Price: $42.39
  • List Price: $52.99
  • Includes EPUB and PDF
  • About eBook Formats
  • This eBook includes the following formats, accessible from your Account page after purchase:

    ePub EPUB The open industry format known for its reflowable content and usability on supported mobile devices.

    Adobe Reader PDF The popular standard, used most often with the free Acrobat® Reader® software.

    This eBook requires no passwords or activation to read. We customize your eBook by discreetly watermarking it with your name, making it uniquely yours.

Also available in other formats.

Register your product to gain access to bonus material or receive a coupon.


  • Copyright 2008
  • Pages: 448
  • Edition: 1st
  • eBook (Watermarked)
  • ISBN-10: 0-13-279999-5
  • ISBN-13: 978-0-13-279999-7

For software to consistently deliver promised results, software development must mature into a true profession. Emergent Design points 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 Design helps 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.

Sample Content

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


Submit Errata

More Information

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020