Tài liệu Software engineering for students, 4th edition

Douglas Bell A Programming Approach fourth edition for Students Engineering for Students Software Software “Bell covers the main areas of software engineering with accuracy and authority, and without getting bogged down in superfluous detail. My students actually like this book; it's very readable.” Engineering Software Engineering Martin Bush, South Bank University ● Pragmatic, non-mathematical approach ● Self-test questions within each chapter help the reader to fully understand the concepts ● Numerous exercises are provided at the end of each chapter ● Consistent use of the UML as a design notation ● Software Engineering for Students for Students A Programming Approach fourth edition Case studies used throughout ● fourth edition Features A Programming Approach This fully revised version of Douglas Bell’s Software Engineering: A Programming Approach continues to use the successful formula of the previous editions. The author’s approach is to present the main principles, techniques and tools used in software engineering, one by one, chapter by chapter. He provides the reader with the knowledge to select the appropriate techniques for the project in hand. He builds on the reader’s experience of coding small-scale applications, and examines everything they will need to begin programming large-scale software systems. This book is a unique introduction to software engineering for all students of computer science and its related disciplines. It is also ideal for practitioners wishing to remain current with new developments in the area. Douglas Bell An accompanying website with even more teaching and learning resources Douglas Bell is a lecturer at Sheffield Hallam University in the UK. He has authored and co-authored a number of texts, including the best-selling Java for Students. Douglas Bell an imprint of www.pearson-books.com www.it-ebooks.info BELL_A01.QXD 2/2/05 3:20 PM Page i Software Engineering for Students www.it-ebooks.info BELL_A01.QXD 2/2/05 3:20 PM Page ii We work with leading authors to develop the strongest educational materials in computing, bringing cutting-edge thinking and best learning practice to a global market. Under a range of well-known imprints, including Addison-Wesley, we craft high quality print and electronic publications which help readers to understand and apply their content, whether studying or at work. To find out more about the complete range of our publishing, please visit us on the World Wide Web at: www.pearsoned.co.uk www.it-ebooks.info BELL_A01.QXD 2/2/05 3:20 PM Page iii Software Engineering for Students A Programming Approach Fourth Edition DOUGLAS BELL www.it-ebooks.info BELL_A01.QXD 2/2/05 3:20 PM Page iv Pearson Education Limited Edinburgh Gate Harlow Essex CM20 2JE England and Associated Companies throughout the world Visit us on the World Wide Web at: www.pearsoned.co.uk First published under the Prentice Hall imprint 1987 Second edition 1992 Third edition 2000 Fourth edition 2005 © Prentice Hall International 1987, 1992 © Pearson Education Limited 2000, 2005 The right of Douglas Bell to be identified as author of this work has been asserted by him in accordance with the Copyright, Designs and Patents Act 1988. All rights reserved. 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 or otherwise, without either the prior written permission of the publisher or a licence permitting restricted copying in the United Kingdom issued by the Copyright Licensing Agency Ltd, 90 Tottenham Court Road, London W1T 4LP. The programs in this book have been included for their instructional value. They have been tested with care but are not guaranteed for any particular purpose. The publisher does not offer any warranties or representations nor does it accept any liabilities with respect to the programs. All trademarks used herein are the property of their respective owners. The use of any trademark in this text does not vest in the author or publisher any trademark ownership rights in such trademarks, nor does the use of such trademarks imply any affiliation with or endorsement of this book by such owners. ISBN 0 321 26127 5 British Library Cataloguing-in-Publication Data A catalogue record for this book is available from the British Library Library of Congress Cataloging-in-Publication Data Bell, Doug, 1944Software engineering for student/Douglas Bell. -- 4th ed. p. cm. Rev. ed. of: Software engineering. 2000. ISBN 0-321-26127-5 1. Software engineering. 2. Computer programming. I. Bell, Doug, 1944Software engineering. II. Title. QA76.758.B45 2005 005.1--dc22 2004062346 10 9 8 7 6 5 4 3 2 1 09 08 07 06 05 Typeset in 9.75/12pt Galliard by 71 Printed in Great Britain by Henry Ling Ltd, at the Dorset Press, Dorchester, Dorset The publisher’s policy is to use paper manufactured from sustainable forests. www.it-ebooks.info BELL_A01.QXD 2/2/05 3:20 PM Page v Contents Preface xix Part A G 1. 2. 3. 4. Part B G 5. 6. 7. 8. 9. 10. 11. 12. 13. Part C G 14. 15. 16. 17. 18. Preliminaries 1 Software – problems and prospects The tasks of software development The feasibility study Requirements engineering 3 22 30 36 Design 51 User interface design Modularity Structured programming Functional decomposition Data flow design Data structure design Object-oriented design Design patterns Refactoring 53 67 87 102 111 121 139 151 165 Programming languages The basics Object-oriented programming Programming in the large Software robustness Scripting 173 175 200 221 237 259 v www.it-ebooks.info BELL_A01.QXD 2/2/05 3:20 PM Page vi vi Contents Part D G Verification 265 19. Testing 20. Groups Part E G 21. 22. 23. 24. 25. 26. 27. Part F G 267 283 Process models 289 The waterfall model The spiral model Prototyping Incremental development Open source software development Agile methods and extreme programming The unified process Project management 28. Teams 29. Software metrics and quality assurance 30. Project management Part G G Review 291 297 303 314 322 330 337 345 347 357 370 383 31. Assessing methods 32. Conclusion 385 392 Appendices 405 A. Case studies B. Glossary C. UML summary 407 411 412 Bibliography Index 417 419 www.it-ebooks.info BELL_A01.QXD 2/2/05 3:20 PM Page vii Detailed contents Preface xix Part A 1 G 1 Software – problems and prospects 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 1.10 1.11 2 Preliminaries Introduction Meeting users’ needs The cost of software production Meeting deadlines Software performance Portability Maintenance Reliability Human–computer interaction A software crisis? A remedy – software engineering? Summary Exercises Answers to self-test questions Further reading 3 3 4 5 10 10 11 11 13 16 16 17 18 19 20 20 The tasks of software development 22 2.1 2.2 2.3 2.4 2.5 22 23 26 27 28 28 28 29 Introduction The tasks Process models Methodology Hacking Summary Exercises Answer to self-test question vii www.it-ebooks.info BELL_A01.QXD 2/2/05 3:20 PM Page viii viii Detailed contents 3 30 3.1 3.2 3.3 3.4 3.5 3.6 4 The feasibility study 30 31 31 32 32 34 34 34 35 35 Introduction Technical feasibility Cost-benefit analysis Other criteria Case study Discussion Summary Exercises Answers to self-test questions Further reading Requirements engineering 36 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 36 37 38 40 41 42 45 46 47 47 48 49 Part B 5 G Introduction The concept of a requirement The qualities of a specification How to elicit requirements The requirements specification The structure of a specification Use cases Use case diagrams Summary Exercises Answers to self-test questions Further reading Design 51 User interface design 53 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 53 54 54 56 57 60 62 63 64 64 Introduction An inter-disciplinary field Styles of human–computer interface Different perspectives on user interface design Design principles and guidelines Interface design Case study Help systems Summary Exercises www.it-ebooks.info BELL_A01.QXD 2/2/05 3:20 PM Page ix Detailed contents Answers to self-test questions Further reading 6 ix 65 65 67 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 6.10 6.11 7 Modularity 67 68 70 70 73 74 76 77 79 82 84 84 85 85 86 Structured programming 7.1 7.2 7.3 7.4 7.5 8 Introduction Why modularity? Component types Component size and complexity Global data is harmful Information hiding Coupling and cohesion Coupling Cohesion Object-oriented programming Discussion Summary Exercises Answers to self-test questions Further reading 87 Introduction Arguments against goto Arguments in favor of goto Selecting control structures What is structured programming? Summary Exercises Answer to self-test question Further reading 87 89 92 94 96 98 99 100 101 Functional decomposition 102 8.1 8.2 8.3 102 103 107 109 109 110 110 Introduction Case study Discussion Summary Exercises Answer to self-test question Further reading www.it-ebooks.info BELL_A01.QXD 2/2/05 3:20 PM Page x x Detailed contents 9 111 9.1 9.2 9.3 9.4 10 Data flow design 111 113 115 117 118 119 120 120 Introduction Identifying data flows Creation of a structure chart Discussion Summary Exercises Answers to self-test questions Further reading 121 10.1 10.2 10.3 10.4 10.5 10.6 11 Data structure design 121 122 126 127 130 134 136 136 138 138 Introduction A simple example Processing input files Multiple input and output streams Structure clashes Discussion Summary Exercises Answers to self-test questions Further reading 139 11.1 11.2 11.3 11.4 11.5 11.6 11.7 12 Object-oriented design 139 140 144 145 145 146 147 147 148 149 149 Introduction Design Looking for reuse Using the library Class–responsibility–collaborator cards Iteration Discussion Summary Exercises Answers to self-test questions Further reading Design patterns 151 12.1 12.2 12.3 151 152 153 Introduction Inheritance Delegation www.it-ebooks.info BELL_A01.QXD 2/2/05 3:20 PM Page xi Detailed contents 12.4 12.5 12.6 12.7 12.8 12.9 12.10 12.11 12.12 12.13 12.14 13 Singleton Factory method Façade Immutable Model, view controller (observer, observable) Mediator Pipe and Filter Proxy Layers Blob – an anti-pattern Discussion Summary Exercises Answers to self-test questions Further reading 154 155 156 157 157 158 158 159 159 161 161 162 163 163 164 Refactoring 165 13.1 13.2 13.3 13.4 13.5 13.6 13.7 13.8 13.9 165 166 167 167 167 167 168 170 171 171 172 172 Part C 14 G Introduction Encapsulate data Move method Move data Extract class Inline class Identify composition or inheritance Use polymorphism Discussion Summary Exercises Answers to self-test questions Programming languages 173 The basics 175 14.1 14.2 14.3 14.4 14.5 14.6 175 176 176 178 179 180 Introduction Classifying programming languages and features Design principles Language syntax Control structures Selection www.it-ebooks.info xi BELL_A01.QXD 2/2/05 3:20 PM Page xii xii Detailed contents 14.7 14.8 14.9 14.10 14.11 14.12 14.13 14.14 14.15 15 Repetition Methods Parameter-passing mechanisms Primitive data types Data typing Strong versus weak typing User-defined data types (enumerations) Arrays Records (structures) Summary Exercises Answers to self-test questions Further reading 183 186 188 190 190 191 193 194 195 196 197 198 199 200 15.1 15.2 15.3 15.4 15.5 15.6 15.7 15.8 15.9 16 Object-oriented programming 200 200 206 207 209 212 212 213 215 217 217 218 220 Introduction Encapsulation Library classes Inheritance Polymorphism Single versus multiple inheritance Generics Dynamic data structures and pointers Garbage collection Summary Exercises Answers to self-test questions Further reading Programming in the large 221 16.1 16.2 16.3 16.4 16.5 16.6 16.7 16.8 16.9 221 223 224 226 226 227 229 230 232 Introduction Packages Using packages Creating packages Scoping in large programs Interfaces Interfaces and interoperability Multiple interfaces Separate compilation www.it-ebooks.info BELL_A01.QXD 2/2/05 3:20 PM Page xiii Detailed contents Summary Exercises Answers to self-test questions Further reading 17 233 233 234 235 237 17.1 17.2 17.3 17.4 17.5 17.6 17.7 17.8 17.9 18 Software robustness 237 239 242 244 245 249 252 253 254 255 255 257 258 Introduction Fault detection by software Fault detection by hardware Dealing with damage Exceptions and exception handlers Recovery blocks n-version programming Assertions Discussion Summary Exercises Answers to self-test questions Further reading Scripting 259 18.1 18.2 18.3 259 259 262 263 263 263 263 Part D 19 G Introduction Unix Discussion Summary Exercises Answers to self-test questions Further reading Verification 265 Testing 19.1 19.2 19.3 19.4 19.5 19.6 267 Introduction The nature of errors The problem of testing Black box (functional) testing White box (structural) testing Other testing methods www.it-ebooks.info 267 268 269 269 272 274 xiii BELL_A01.QXD 2/2/05 3:20 PM Page xiv xiv Detailed contents 19.7 19.8 19.9 20 Groups 20.1 20.2 20.3 20.4 20.5 20.6 Part E 21 Unit testing System (integration) testing Discussion Summary Exercises Answers to self-test questions Further reading G 276 277 278 278 279 281 282 283 Introduction The individual and the error Structured walkthroughs Inspections Pair programming Discussion Summary Exercises Further reading Process models 283 283 284 286 286 287 287 288 288 289 291 21.1 21.2 21.3 21.4 22 The waterfall model 291 291 293 294 295 295 296 Introduction Principles of the model Feedback between stages Discussion Summary Exercises Answers to self-test questions The spiral model 297 22.1 22.2 22.3 22.4 297 297 300 301 301 301 302 302 Introduction The spiral model Case study Discussion Summary Exercises Answer to self-test question Further reading www.it-ebooks.info BELL_A01.QXD 2/2/05 3:20 PM Page xv Detailed contents 23 303 23.1 23.2 23.3 23.4 23.5 23.6 23.7 24 Prototyping 303 303 304 305 307 308 310 312 312 313 Introduction Definition Throwaway or evolutionary? Throwaway prototyping Evolutionary prototyping Rapid prototyping techniques Discussion Summary Exercises Answers to self-test questions 314 24.1 24.2 24.3 24.4 24.5 24.6 24.7 24.8 25 Incremental development 314 315 315 316 317 318 319 319 320 320 321 321 Introduction Big-bang implementation Test beds Top-down implementation Bottom-up implementation Middle-out implementation Use case driven implementation Discussion Summary Exercises Answers to self-test questions Further reading Open source software development 322 25.1 25.2 25.3 25.4 25.5 25.6 322 322 323 324 325 326 327 328 328 328 Introduction The principles of open source development The schism within open source development Techniques of open source development Case Study: the GNU/Linux operating system Discussion Summary Exercises Answers to self-test questions Further reading www.it-ebooks.info xv BELL_A01.QXD 2/2/05 3:20 PM Page xvi xvi Detailed contents 26 330 26.1 26.2 26.3 27 Agile methods and extreme programming 330 330 332 335 336 336 336 Introduction The agile manifesto Extreme programming Summary Exercises Answers to self-test questions Further reading The unified process 337 27.1 27.2 27.3 27.4 27.5 27.6 27.7 337 337 338 339 341 341 343 343 344 344 Part F 28 G Project management Teams 28.1 28.2 28.3 28.4 28.5 28.6 28.7 29 Introduction Overview Phases of the UP Techniques Iteration Case study Discussion Summary Exercises Further reading 345 347 Introduction The principles of teams The functional team The project team The chief programmer team The object-oriented team Discussion Summary Exercises Answer To self-test question Further reading 347 347 351 351 351 353 354 355 355 355 356 Software metrics and quality assurance 357 29.1 29.2 29.3 357 358 358 Introduction Basic metrics Complexity metrics www.it-ebooks.info BELL_A01.QXD 2/2/05 3:20 PM Page xvii Detailed contents 29.4 29.5 29.6 29.7 29.8 30 Faults and reliability – estimating bugs Software quality Quality assurance Process improvement The Capability Maturity Model Summary Exercises Answers to self-test questions Further Reading 361 362 364 365 366 367 367 368 368 Project management 370 30.1 30.2 30.3 30.4 30.5 30.6 30.7 370 371 372 375 376 377 378 380 380 381 381 Part G 31 G Introduction Project inception Cost estimation Selecting tools and methods The project plan In the heat of the project Managing people Summary Exercises Answers to self-test questions Further reading Review 383 385 31.1 31.2 31.3 31.4 31.5 31.6 32 Assessing methods 385 386 387 388 389 390 390 390 391 Introduction How to assess methods Case study – assessing verification techniques The current state of methods A single development method? Introducing new methods Summary Exercises Further reading Conclusion 392 32.1 32.2 32.3 392 392 393 Introduction Software tools The world of programming languages www.it-ebooks.info xvii BELL_A01.QXD 2/2/05 3:20 PM Page xviii xviii Detailed contents 32.4 32.5 32.6 32.7 32.8 32.9 Software reuse The real world of software engineering Control versus skill Future methods and tools History The future of software engineering Summary Exercises Further reading Appendices A 394 395 397 398 400 400 401 402 402 405 Case studies 407 A.1 A.2 A.3 A.4 A.5 407 408 408 409 410 The ATM The word processor Computer game The library Patient monitoring system B Glossary 411 C UML Summary 412 C.1 C.2 C.3 C.4 412 413 414 414 416 Use case diagrams Class diagrams Package diagrams Activity diagrams Further reading Bibliography Index 417 419 www.it-ebooks.info BELL_A01.QXD 2/2/05 3:20 PM Page xix Preface What is software engineering? Software engineering is about the creation of large pieces of software that consist of thousands of lines of code and involve many person months of human effort. One of the attractions of software engineering is that there is no one single best method for doing it, but instead a whole variety of different approaches. Consequently the software engineer needs a knowledge of many different techniques and tools. This diversity is one of the delights of software engineering, and this book celebrates this by presenting the range of current techniques and tools. We shall see that some software engineering methods are well-defined while others are ill-defined. And the processes of software development are always under debate. Challenge and creativity Software engineering is about imagination and creativity – the process of creating something apparently tangible from nothing. Software engineering methods have not yet been completely analyzed and systematized. Thus there is still great scope for using imagination and creativity. The exercise of skill and flair is one of the joys of software engineering. Who is this book for? Ideally you, the reader, will have savored the joy of devising an elegant solution to a programming problem. You will also have experienced the intense frustration of trying to find an elusive bug – and the satisfaction of subsequently tracking it down and eliminating it. This book is for people who have experienced the pleasures of writing programs and who want to see how things change in the scale up to large programs and software systems. This book provides an introduction to software engineering for students in undergraduate programs in Computer Science, Computer Studies, Information Technology, xix www.it-ebooks.info