Tài liệu Beginning software engineering

www.it-ebooks.info www.it-ebooks.info BEGINNING SOFTWARE ENGINEERING INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxi ▸ PART I SOFTWARE ENGINEERING STEP‐BY‐STEP CHAPTER 1 Software Engineering from 20,000 Feet. . . . . . . . . . . . . . . . . . . . . . . 3 CHAPTER 2 Before the Beginning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 CHAPTER 3 Project Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 CHAPTER 4 Requirement Gathering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 CHAPTER 5 High‐Level Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 CHAPTER 6 Low‐Level Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 CHAPTER 7 Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143 CHAPTER 8 Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173 CHAPTER 9 Deployment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203 CHAPTER 10 Metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215 CHAPTER 11 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241 ▸ PART II PROCESS MODELS CHAPTER 12 Predictive Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 265 CHAPTER 13 Iterative Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283 CHAPTER 14 RAD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303 APPENDIX Solutions to Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 361 GLOSSARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417 INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 437 www.it-ebooks.info www.it-ebooks.info BEGINNING I Software Engineering Rod Stephens www.it-ebooks.info Beginning Software Engineering Published by John Wiley & Sons, Inc. 10475 Crosspoint Boulevard Indianapolis, IN 46256 www.wiley.com Copyright © 2015 by John Wiley & Sons, Inc., Indianapolis, Indiana Published simultaneously in Canada ISBN: 978-1-118-96914-4 ISBN: 978-1-118-96916-8 (ebk) ISBN: 978-1-118-96917-5 (ebk) Manufactured in the United States of America 10 9 8 7 6 5 4 3 2 1 No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except as permitted under Sections 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, (978) 750-8400, fax (978) 646-8600. 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If this book refers to media such as a CD or DVD that is not included in the version you purchased, you may download this material at http://booksupport.wiley.com. For more information about Wiley products, visit www.wiley.com. Library of Congress Control Number: 2015930533 Trademarks: Wiley, the Wiley logo, Wrox, the Wrox logo, Programmer to Programmer, and related trade dress are trademarks or registered trademarks of John Wiley & Sons, Inc. and/or its affi liates, in the United States and other countries, and may not be used without written permission. All other trademarks are the property of their respective owners. John Wiley & Sons, Inc., is not associated with any product or vendor mentioned in this book. www.it-ebooks.info ABOUT THE AUTHOR ROD STEPHENS started out as a mathematician, but while studying at MIT, he discovered how much fun programming is and he’s been programming professionally ever since. During his career, he has worked on an eclectic assortment of applications in such fields as telephone switching, billing, repair dispatching, tax processing, wastewater treatment, concert ticket sales, cartography, and training for professional football players. Rod has been a Microsoft Visual Basic Most Valuable Professional (MVP) for more than a decade and has taught introductory programming courses. He has written more than two dozen books that have been translated into languages from all over the world, and he’s written more than 250 magazine articles covering Visual Basic, C#, Visual Basic for Applications, Delphi, and Java. Rod’s popular VB Helper website (www.vb-helper.com) receives several million hits per month and contains thousands of pages of tips, tricks, and example programs for Visual Basic programmers. His C# Helper website (www.csharphelper.com) contains similar material for C# programmers. You can contact Rod at [email protected] or [email protected]. ABOUT THE TECHNICAL EDITOR BRIAN HOCHGURTEL has been doing .NET development for over ten years, and actually started his .NET experience with Rod Stephens when they wrote the Wiley book, Visual Basic.NET and XML, in 2002. Currently Brian works with C#, SQL Server, and SharePoint in Fort Collins, CO. www.it-ebooks.info www.it-ebooks.info CREDITS EXECUTIVE EDITOR PROFESSIONAL TECHNOLOGY & STRATEGY DIRECTOR Robert Elliott Barry Pruett PROJECT EDITOR Adaobi Obi Tuiton BUSINESS MANAGER Amy Knies TECHNICAL EDITOR Brian Hochgurtel ASSOCIATE PUBLISHER Jim Minatel PRODUCTION MANAGER Kathleen Wisor PROJECT COORDINATOR, COVER Brent Savage COPY EDITOR San Dee Phillips PROOFREADER Sarah Kaikini, Word One MANAGER OF CONTENT DEVELOPMENT & ASSEMBLY INDEXER Mary Beth Wakefield Johnna VanHoose Dinse MARKETING DIRECTOR COVER DESIGNER David Mayhew Wiley MARKETING MANAGER COVER IMAGE Carrie Sherrill ©iStock.com/Chris Hepburn p www.it-ebooks.info www.it-ebooks.info ACKNOWLEDGMENTS THANKS TO BOB ELLIOTT, Adaobi Obi Tulton, San Dee Phillips, Katie Wisor, and all the others who worked so hard to make this book possible. (Adaobi was this book’s project manager. You’ll learn what a project manager does in Chapter 3. It’s a bit different for writing a book but not as different as you might think. As always, many thanks for your hard work, Adaobi!) Thanks also to technical editor Brian Hochgurtel for giving me the benefit of his valuable experience. Special thanks to Mary Brodie at gearmark.blogs.com for letting me use her quote in Chapter 13, “Iterative Models.” www.it-ebooks.info www.it-ebooks.info CONTENTS INTRODUCTION xxi PART I: SOFTWARE ENGINEERING STEP‐BY‐STEP CHAPTER 1: SOFTWARE ENGINEERING FROM 20,000 FEET Requirements Gathering High‐Level Design Low‐Level Design Development Testing Deployment Maintenance Wrap‐up Everything All at Once Summary 3 4 5 6 6 6 8 9 9 10 11 CHAPTER 2: BEFORE THE BEGINNING Document Management Historical Documents E‐mail Code Code Documentation Application Documentation Summary 15 16 18 19 21 22 25 25 CHAPTER 3: PROJECT MANAGEMENT Executive Support Project Management 29 30 31 PERT Charts Critical Path Methods Gantt Charts Scheduling Software Predicting Times Get Experience Break Unknown Tasks into Simpler Pieces www.it-ebooks.info 33 38 41 42 42 44 44 CONTENTS Look for Similarities Expect the Unexpected Track Progress Risk Management Summary 45 45 46 47 49 CHAPTER 4: REQUIREMENT GATHERING Requirements Defined 53 54 Clear Unambiguous Consistent Prioritized Verifiable Words to Avoid 54 55 56 56 60 60 Requirement Categories 61 Audience‐Oriented Requirements Business Requirements User Requirements Functional Requirements Nonfunctional Requirements Implementation Requirements FURPS FURPS+ Common Requirements Gathering Requirements 61 61 62 63 63 63 64 64 66 67 Listen to Customers (and Users) Use the Five Ws (and One H) Who What When Where Why How Study Users 67 68 68 68 69 69 69 69 70 Refining Requirements 71 Copy Existing Systems Clairvoyance Brainstorm 71 73 74 Recording Requirements 76 UML User Stories 77 77 xii www.it-ebooks.info CONTENTS Use Cases Prototypes Requirements Specification 78 78 80 Validation and Verification Changing Requirements Summary 80 80 81 CHAPTER 5: HIGH‐LEVEL DESIGN The Big Picture What to Specify 87 88 89 Security Hardware User Interface Internal Interfaces External Interfaces Architecture Monolithic Client/Server Component‐Based Service‐Oriented Data‐Centric Event‐Driven Rule‐Based Distributed Mix and Match Reports Other Outputs Database Audit Trails User Access Database Maintenance Configuration Data Data Flows and States Training 89 90 91 92 93 94 94 95 96 97 97 97 98 98 99 101 102 102 103 103 104 104 105 105 UML 105 Structure Diagrams Behavior Diagrams Activity Diagrams Use Case Diagram State Machine Diagram Interaction Diagrams 107 109 110 111 112 113 xiii www.it-ebooks.info CONTENTS Sequence Diagram Communication Diagram Timing Diagram Interaction Overview Diagram Summary 113 114 115 115 116 CHAPTER 6: LOW‐LEVEL DESIGN OO Design 119 120 Identifying Classes Building Inheritance Hierarchies Refinement Generalization Hierarchy Warning Signs Object Composition Database Design 121 122 123 125 126 127 127 Relational Databases First Normal Form Second Normal Form Third Normal Form Higher Levels of Normalization Summary 128 130 134 135 137 138 CHAPTER 7: DEVELOPMENT Use the Right Tools 143 144 Hardware Network Development Environment Source Code Control Profilers Static Analysis Tools Testing Tools Source Code Formatters Refactoring Tools Training Selecting Algorithms 144 145 146 147 147 147 147 147 148 148 148 Effective Efficient Predictable Simple Prepackaged 149 149 151 152 152 Top‐Down Design 153 xiv www.it-ebooks.info CONTENTS Programming Tips and Tricks Be Alert Write for People, Not the Computer Comment First Write Self‐Documenting Code Keep It Small Stay Focused Avoid Side Effects Validate Results Practice Offensive Programming Use Exceptions Write Exception Handers First Don’t Repeat Code Defer Optimization Summary 155 155 156 157 159 160 161 162 163 165 166 167 167 167 169 CHAPTER 8: TESTING 173 Testing Goals Reasons Bugs Never Die 175 175 Diminishing Returns Deadlines Consequences It’s Too Soon Usefulness Obsolescence It’s Not a Bug It Never Ends It’s Better Than Nothing Fixing Bugs Is Dangerous Which Bugs to Fix 175 175 176 176 176 177 177 177 178 178 179 Levels of Testing 179 Unit Testing Integration Testing Automated Testing Component Interface Testing System Testing Acceptance Testing Other Testing Categories 179 181 182 183 184 185 185 Testing Techniques 186 Exhaustive Testing Black‐Box Testing 186 187 xv www.it-ebooks.info CONTENTS White‐Box Testing Gray‐Box Testing 188 188 Testing Habits 189 Test and Debug When Alert Test Your Own Code Have Someone Else Test Your Code Fix Your Own Bugs Think Before You Change Don’t Believe in Magic See What Changed Fix Bugs, Not Symptoms Test Your Tests How to Fix a Bug Estimating Number of Bugs Tracking Bugs Found Seeding The Lincoln Index 189 189 190 192 193 193 193 194 194 194 195 195 197 197 Summary 198 CHAPTER 9: DEPLOYMENT Scope The Plan Cutover 203 204 204 206 Staged Deployment Gradual Cutover Incremental Deployment Parallel Testing 206 206 208 209 Deployment Tasks Deployment Mistakes Summary 209 210 211 CHAPTER 10: METRICS 215 Wrap Party Defect Analysis 216 216 Kinds of Bugs Discoverer Severity Time Created Age at Fix Task Type Ishikawa Diagrams 217 217 217 218 218 218 219 xvi www.it-ebooks.info CONTENTS Software Metrics 222 Qualities of Good Attributes and Metrics Using Metrics Process Metrics Project Metrics Things to Measure Size Normalization Function Point Normalization Count Function Point Metrics Multiply by Complexity Factors Calculate Complexity Adjustment Value Calculate Adjusted FP Summary 223 224 226 226 227 229 231 232 232 233 235 235 CHAPTER 11: MAINTENANCE Maintenance Costs Task Categories 241 242 243 Perfective Tasks Feature Improvements New Features The Second System Effect Adaptive Tasks Corrective Tasks Preventive Tasks Clarification Code Reuse Improved Flexibility Bug Swarms Bad Programming Practices Individual Bugs Not Invented Here Task Execution Summary 244 245 245 245 247 248 251 252 253 254 254 255 256 256 256 257 PART II: PROCESS MODELS CHAPTER 12: PREDICTIVE MODELS Model Approaches Prerequisites Predictive and Adaptive 265 266 267 267 Success and Failure Indicators 268 xvii www.it-ebooks.info CONTENTS Advantages and Disadvantages 268 Waterfall Waterfall with Feedback Sashimi Incremental Waterfall V‐Model Systems Development Life Cycle Summary 270 271 272 273 275 276 280 CHAPTER 13: ITERATIVE MODELS 283 Iterative Versus Predictive Iterative Versus Incremental Prototypes Types of Prototypes Pros and Cons 284 286 287 288 289 Spiral 290 Clarifications Pros and Cons 293 294 Unified Process 295 Pros and Cons Rational Unified Process 296 297 Cleanroom Summary 298 299 CHAPTER 14: RAD 303 RAD Principles James Martin RAD Agile 305 308 309 Self‐Organizing Teams Agile Techniques Communication Incremental Development Focus on Quality XP 311 313 313 314 316 317 XP Roles XP Values XP Practices Have a Customer On Site Play the Planning Game Use Standup Meetings Make Frequent Small Releases xviii www.it-ebooks.info 318 319 319 320 320 321 322