Description

Java Application Architecture lays the foundation you'll need to incorporate modular design thinking into your development initiatives. Before it walks you through eighteen patterns that will help you architect modular software, it lays a solid foundation that shows you why modularity is a critical weapon in your arsenal of design tools. Throughout, you'll find examples that illustrate the concepts. By designing modular applications today, you are positioning yourself for the platform and architecture of tomorrow.

Features

• Introduces 18 new modular patterns, identified by the author - the next logical step in the evolution of object-oriented programming
• These patterns help developers break up large software projects into smaller, more accessible chunks, or modules
• This modular structure makes the software system less complex to develop, and easier to maintain and update

Table of Contents

Foreword by Robert C. Martin xix

Foreword by Peter Kriens xxi

Acknowledgments xxv

About the Author xxvii

 

Introduction 1

Object-Oriented Design 2

Logical versus Physical Design 3

Modularity 4

Who This Book Is For 6

How This Book Is Organized 7

Pattern Form 10

Pattern Catalog 12

The Code 13

An Opening Thought on the Modularity Patterns 14

Reference 14

 

Part I: The Case for Modularity 15

 

Chapter 1: Module Defined 17

1.1 Defining a Module 17

1.2 Succinct Definition of a Software Module 20

1.3 Conclusion 20

 

Chapter 2: The Two Facets of Modularity 21

2.1 The Runtime Model 21

2.2 The Development Model 22

2.3 Modularity Today 25

2.4 Conclusion 27

 

Chapter 3: Architecture and Modularity 29

3.1 Defining Architecture 29

3.2 A Software Architecture Story 30

3.3 The Goal of Architecture 33

3.4 Modularity: The Missing Ingredient 36

3.5 Answering Our Questions 43

3.6 Conclusion 44

3.7 References 44

 

Chapter 4: Taming the Beast Named Complexity 45

4.1 Enterprise Complexity 46

4.2 Technical Debt 47

4.3 Design Rot 48

4.4 Cyclic Dependencies-The Death Knell 50

4.5 Joints, Modules, and SOLID 56

4.6 Managing Complexity 57

4.7 Benefits of Modularity 59

4.8 Conclusion 60

4.9 References 60

 

Chapter 5: Realizing Reuse 61

5.1 The Use/Reuse Paradox 62

5.2 The Reuse Disclaimer 63

5.3 Reuse or Use 64

5.4 Modular Tension 65

5.5 Modular Design 66

5.6 Conclusion 67

5.7 Reference 68

 

Chapter 6: Modularity and SOA 69

6.1 All the Way Down, Revisited 69

6.2 Granularity-Architecture's Nemesis 72

6.3 An Alternate View 79

6.4 Conclusion 80

 

Chapter 7: Reference Implementation 83

7.1 Why No OSGi? 83

7.2 Background on This Exercise: Building the System 84

7.3 Version 1 85

7.4 First Refactoring 87

7.5 Second Refactoring 90

7.6 Third Refactoring 93

7.7 Fourth Refactoring 95

7.8 Fifth Refactoring 98

7.9 Sixth Refactoring 99

7.10 Seventh Refactoring 102

7.11 The Postmortem 103

7.12 Conclusion 110

7.13 Reference 110

 

Part II: The Patterns 111

 

Chapter 8: Base Patterns 115

Manage Relationships 116

Module Reuse 125

Cohesive Modules 139

 

Chapter 9: Dependency Patterns 145

Acyclic Relationships 146

Levelize Modules 157

Physical Layers 162

Container Independence 170

Independent Deployment 178

Reference 185

 

Chapter 10: Usability Patterns 187

Published Interface 188

External Configuration 200

Default Implementation 206

Module Facade 212

 

Chapter 11: Extensibility Patterns 221

Abstract Modules 222

Implementation Factory 229

Separate Abstractions 237

Reference 244

 

Chapter 12: Utility Patterns 245

Colocate Exceptions 246

Levelize Build 253

Test Module 263

 

Part III: Poma and OSGi 271

 

Chapter 13: Introducing OSGi 273

13.1 Some History 273

13.2 Benefits of OSGi 274

13.3 Digesting OSGi 276

13.4 OSGi Bundle 277

13.5 OSGi Runtime Management 279

13.6 The Two Facets of Modularity, Revisited 279

13.7 OSGi and the Patterns 279

 

Chapter 14: The Loan Sample and OSGi 283

14.1 Getting Started 283

14.2 The Manifests 285

14.3 µServices 286

14.4 Installation and Execution 292

14.5 Conclusion 293

 

Chapter 15: OSGi and Scala 295

15.1 Getting Started 295

15.2 The Scala Code 296

15.3 Scala Bean Configuration 299

15.4 Scala µService Configuration 299

15.5 Building the Scala Module 300

15.6 Installation and Execution 300

15.7 Conclusion 301

 

Chapter 16: OSGi and Groovy 303

16.1 Getting Started 303

16.2 The Groovy Code 304

16.3 Groovy Bean Configuration 306

16.4 Groovy Service Configuration 307

16.5 Building the Groovy Module 307

16.6 Installation and Execution 308

16.7 Conclusion 309

 

Chapter 17: Future of OSGi 311

17.1 OSGi as an Enabler 312

17.2 The Disruption 312

17.3 The Power of Ecosystems 314

17.4 The Ecosystem 316

17.5 Conclusion 317

 

Appendix: SOLID Principles of Class Design 319

Single Responsibility Principle (SRP) 320

Open Closed Principle (OCP) 320

Liskov Substitution Principle (LSP) 323

Dependency Inversion Principle (DIP) 325

Interface Segregation Principle 327

Composite Reuse Principle (CRP) 329

References 335

 

Index 337

Author

Kirk Knoernschild is a software developer who has filled most roles on the software development team. Kirk is the author of Java Design: Objects, UML, and Process (Addison-Wesley, 2002), and he contributed to No Fluff Just Stuff 2006 Anthology (Pragmatic Bookshelf, 2006). Kirk is an open source contributor, has written numerous articles, and is a frequent conference speaker. He has trained and mentored thousands of software professionals on topics including Java/J2EE, modeling, software architecture and design, component-based development, service-oriented architecture, and software process. You can visit his website at techdistrict.kirkk.com.

Reader Review(s)

“The fundamentals never go out of style, and in this book Kirk returns us to the fundamentals of architecting economically interesting software-intensive systems of quality. You'll find this work to be well-written, timely, and full of pragmatic ideas.”

-Grady Booch, IBM Fellow

 

“Along with GOF's Design Patterns, Kirk Knoernschild's Java Application Architecture is a must-own for every enterprise developer and architect and on the required reading list for all Paremus engineers.”

-Richard Nicholson, Paremus CEO, President of the OSGi Alliance

 

“In writing this book, Kirk has done the software community a great service: He's captured much of the received wisdom about modularity in a form that can be understood by newcomers, taught in computer science courses, and referred to by experienced programmers. I hope this book finds the wide audience it deserves.”

-Glyn Normington, Eclipse Virgo Project Lead

 

“Our industry needs to start thinking in terms of modules-it needs this book!”

-Chris Chedgey, Founder and CEO, Structure 101

 

“In this book, Kirk Knoernschild provides us with the design patterns we need to make modular software development work in the real world. While it's true that modularity can help us manage complexity and create more maintainable software, there's no free lunch. If you want to achieve the benefits modularity has to offer, buy this book.”

-Patrick Paulin, Consultant and Trainer, Modular Mind

 

“Kirk has expertly documented the best practices for using OSGi and Eclipse runtime technology. A book any senior Java developer needs to read to better understand how to create great software.”

-Mike Milinkovich, Executive Director, Eclipse Foundation