The J2EE Architect's Handbook

306 Pages·2004·1.4 MB·English

How to be a successful technical architect
™
for J2EE applications
Derek C. Ashmore
Derek Ashmore has assembled a “must-have” book for anyone working
with Java and/or J2EE applications. Mr. Ashmore covers all the bases in
this “how-to” approach to designing, developing, testing, and implement-
ing J2EE applications using Java with frequent references to XML, JDBC
libraries, SOAP, relational database access (using SQL), and references vari-
ous useful tools when relevant. This book clearly illustrates Derek’s exper-
tise in the Java world . . . thank you for sharing your knowledge to the IT
community with such a useful book.
— Dan Hotka, Author, Instructor, Oracle Expert
[Derek has written] an in-depth and comprehensive resource for the Java 2
architect! The book provides a concise road map for real-world J2EE devel-
opment. The approach is practical and straightforward, based on a wealth
of experience. All aspects of project management, application and data
design, and Java development are covered. This book avoids the “dry style”
and over-abstraction (over-simplification) common to so many books in
this subject area. An awesome book, I keep it on my “A” shelf!
— Jim Elliott, CTO, West Haven Systems, Inc.
Clear reading and bridges the gap between professionals and professors.
I’ve read many technical books in my thirty-year career where the author
spends more time tossing around the current buzz words and fails to get
the point across. Derek’s book really connects with the hard core devel-
oper. Practical, knowledgeable, excellent examples.
— John R. Mull, President, Systech Software Products, Inc.
I’m a junior J2EE technical architect, and I just finish reading your [book].
It’s really interesting and instructive. It helps me a lot on my project plan-
ning . . .
— Bruno Gagnon, Junior Technical Architect
J2EE™
The
Architect’s
Handbook
How to be a successful technical architect
for J2EE™ applications
Derek C. Ashmore
What readers are saying about The J2EE Architect’s Handbook:
I would highly recommend The J2EE Architect’s Handbook to anyone who
has struggled with how to practically apply all of the Objected Oriented
Design, Design Pattern, eXtreme Programming, and Data Modeling books
that line their shelves.
— D. Scott Wheeler, Partner, Open Foundation
This book is well crafted and explains everything you really need to know
in order to be a successful and productive J2EE architect. It is an excellent
book, which offers a full and detailed coverage of the topic of J2EE archi-
tecture and can be used as a handbook by the novice or as a reference tool
for the experienced architect. The straightforward writing style and good
visuals make for a quick and comprehensive learning experience. If Java is
your primary programming language, and you’re currently working as a
J2EE architect or considering it as a future career, this book should be in
your library.
— Ian Ellis, Senior Technical Architect
The J2EE Architect’s Handbook is a must have for experienced architects
and budding designers alike. It is concise, to the point, and packed with
real-world code examples that reinforce each concept. Today’s J2EE teams
would do well to keep a copy at each designer’s fingertips.
— Ross MacCharles, Lead Technical Architect
The Architect’s Handbook offers an excellent summary/detail look at what
comprises a mature J2EE application architecture. It helps the average de-
veloper to become a productive team member by providing an awareness
of the larger issues in development. And it transforms the more senior
technician into an insightful architect, now readily capable of making sound,
high-impact decisions. An unparalleled resource for the architect’s library.
— Jeffrey Hayes
© 2004 by Derek C. Ashmore
∆∆
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All rights reserved. No part of this book may be reproduced or transmitted in any form or by
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tion storage and retrieval system, without written permission from the author except for the
inclusion of brief quotations for a review.
The opinions and views expressed in this book are solely that of the author. This book does
not necessarily represent the opinions and views of the technical reviewers or the firms that
employ them.
TRADEMARKS: Java, J2EE, Java Development Kit, and Solaris are trademarks of Sun
Microsystems, Inc. All other products or services mentioned in this book are the trademarks
or service marks of their respective companies and organizations.
While every precaution has been taken in the preparation of this book, the author and pub-
lisher assume no responsibility for errors and omissions or for damages resulting from the use
of the information contained herein.
ISBN: 0972954899
Library of Congress Cataloging-in-Publication Data
Ashmore, Derek C.
The J2EE architect’s handbook : how to be a
successful technical architect for J2EE applications /
by Derek C. Ashmore.
p. cm.
Includes bibiliographical references and index.
ISBN 0972954899
1. Java (Computer program language) 2. Application
software--Development. 3. Web site development.
I. Title.
QA76.73.J38A84 2004 005.2'762
QB103-200953
Editor: Barbara McGowran
Cover Design: The Roberts Group
Interior Design: The Roberts Group
Indexer: The Roberts Group
Contents
Preface xi
How the Book Is Organized xii
Common Resources xiii
Feedback xiii
Acknowledgments xiii
1. Project Development Team and Project Life Cycle 1
Project Development Team: Roles and Responsibilities 1
Technical Architect 2
Project Manager 5
Business Analyst 5
Layout Designer 6
Presentation-Tier Developer 6
Business Logic Developer 7
Data Modeler 7
Database Administrator 7
Data Migration Specialist 8
Infrastructure Specialist 8
Testing Specialist 8
Project Life Cycle Approaches 9
Waterfall Approach 9
Iterative Approaches 9
Rational Unified Process 10
Which Approach Is Most Popular? 11
Consider a Hybrid Approach 11
Further Reading 12
SECTION 1: Planning J2EE Applications 13
2. Defining the Project 15
Identifying Project Scope 17
Identifying the Actors 17
Writing Use Cases 19
Common Mistakes 22
Architect’s Exercise: ProjectTrak 23
Prototyping 24
Further Reading 25
3. Scope Definition and Estimation 27
Defining Scope 27
Basics of Estimating 28
An Algorithm for Estimating 29
Architect’s Exercise: ProjectTrak 31
Further Reading 32 v
vi Contents
4. Designing External Application Interfaces 33
Selecting a Communication Method 34
Asynchronous Communication 35
Synchronous Communication 35
Comparing the Two Methods 37
Common Mistakes 39
Determining a Data Structure 39
Error-Handling Requirements 42
Error Notification Procedures 42
Retry Procedures 42
External Interface Guidelines 43
Architect’s Exercise 45
SECTION 2: Designing J2EE Applications 47
5. A Layered Approach to J2EE Design 49
Overview of the Layering Concept 49
Data Access Object Layer 52
Choosing a Database Persistence Method 53
Simplified Data Access Pattern 56
Supporting Multiple Databases 57
Value Object Layer 59
Common Patterns 59
Business Logic Layer 60
Common Patterns 61
Deployment Layer 63
Choosing Deployment Wrappers 63
Common Patterns 65
Presentation Layer 66
Architectural Component Layer 68
Further Reading 70
6. Creating the Object Model 71
Identifying Objects 72
Object Identification Example 73
Turning Objects into Classes 75
Determining Relationships 75
Identifying Attributes 77
Identifying Methods 78
Shortcuts 79
Architect’s Exercise: ProjectTrak 81
Further Reading 84
7. Creating the Data Model 85
Key Terms and Concepts 86
Design Practices and Normal Form 89
Architect’s Exercise: ProjectTrak 91
Contents vii
Creating Database Schema Definitions 93
Common Mistakes 94
Creating XML Document Formats 95
Common Mistakes 98
Further Reading 98
8. Network Architecture 99
Key Terms and Concepts 100
Networking Basics 102
Security 104
Architecting Application Security 105
Scalability and High Availability 105
Architecting Scalability and Availability 107
Network Diagram Example 108
Further Reading 108
9. Planning Construction 109
Task Order and Dependencies 110
Critical Path 115
Common Mistakes 116
Further Reading 117
SSSSSeeeeeccccctttttiiiiiooooonnnnn 33333::::: Building J2EE Applications 119
10. Building Value Objects 121
Implementation Tips and Techniques 123
Value Objects Made Easy 130
Common Mistakes 133
Architect’s Exercise: ProjectTrak 134
11. Building XML Access Objects 139
An XAO Example 140
Architectural Guidelines 145
Overview of JAXB 145
JAXB Usage Guidelines 149
Using XSLT Within Java 150
XSLT Usage Guidelines 151
Internet Resources 152
Further Reading 152
12. Building Database Access Objects 153
Data Access Object Coding Guidelines 154
Using Entity Beans 157
A Hibernate Example 159
JDBC Best Practices 163
Architect’s Exercise: ProjectTrak 169
viii Contents
Other Code Reduction Paradigms 173
Java Data Objects (JDO) 173
CocoBase 173
TopLink 173
OJB 173
Further Reading 174
13. Building Business Objects 175
Transaction Management 176
Business Object Coding Guidelines 180
Architect’s Exercise: ProjectTrak 182
Further Reading 184
14. Building Deployment Layer Objects 185
Session Beans 186
Message-Driven Beans 191
Web Services 194
Architect’s Exercise: ProjectTrak 195
Further Reading 197
15. Building the Presentation Layer 199
Presentation Components 201
Page Display 201
User Input Validation 204
Data Processing 206
Navigation 208
Security 208
Presentation Layer Coding Guidelines 209
Common Mistakes 210
Further Reading 210
16. Building Architectural Components 211
Component Quality 212
Making Components Easy to Use 213
Making Components Easy to Configure and Control 216
Open Source Alternatives 217
Resolving Technical Issues 218
Mitigating Political Risk 219
Component Usage Guidelines 219
17. Application Architecture Strategies 223
Logging Strategies 223
Sample Strategy 225
Exception-Handling Strategies 225
Sample Strategy 234
Threading Strategies 234
Sample Threading Guidelines 237
Contents ix
Configuration Management Strategies 237
Further Reading 240
SECTION 4: Testing and Maintaining J2EE Applications 241
18. Functional Testing Guidelines 243
Testing Assumptions 244
Testing Coverage 245
Test Case Coding Overview and Examples 246
Combining Test Cases into Suites 248
Testing Best Practices 249
19. Performance Tuning and Load Testing 251
Measuring Performance 252
Memory Leaks Defined 253
Testing for Memory Leaks 254
Diagnosing Performance Problems 256
Using HPROF to Measure CPU Usage 257
Using HPROF to Measure Memory Usage 260
Further Reading 262
20. Postimplementation Activities 263
Application-Monitoring Guidelines 264
Bug-Fighting Guidelines 265
Top Refactoring Indicators 266
Common Refactoring Techniques 267
Extract and Delegate 267
Extract and Extend 269
Extract and Decouple with Interface 270
Further Reading 271
Bibliography 273
The Apache Software License, Version 1.1 276
Index 277