Object-Oriented Analysis and Design Understanding System Development with UML 2.0 Mike O’Docherty Object-Oriented Analysis and Design Object-Oriented Analysis and Design Understanding System Development with UML 2.0 Mike O’Docherty Copyright  2005 John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex PO19 8SQ, England Telephone (+44) 1243 779777 Email (for orders and customer service enquiries): cs-books@wiley.co.uk Visit our Home Page on www.wiley.com 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, scanning or otherwise, except under the terms of the Copyright, Designs and Patents Act 1988 or under the terms of a licence issued by the Copyright Licensing Agency Ltd, 90 Tottenham Court Road, London W1T 4LP, UK, without the permission in writing of the Publisher Requests to the Publisher should be addressed to the Permissions Department, John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex PO19 8SQ, England, or emailed to permreq@wiley.co.uk, or faxed to (+44) 1243 770620 This publication is designed to provide accurate and authoritative information in regard to the subject matter covered It is sold on the understanding that the Publisher is not engaged in rendering professional services If professional advice or other expert assistance is required, the services of a competent professional should be sought Other Wiley Editorial Offices John Wiley & Sons Inc., 111 River Street, Hoboken, NJ 07030, USA Jossey-Bass, 989 Market Street, San Francisco, CA 94103-1741, USA Wiley-VCH Verlag GmbH, Boschstr 12, D-69469 Weinheim, Germany John Wiley & Sons Australia Ltd, 33 Park Road, Milton, Queensland 4064, Australia John Wiley & Sons (Asia) Pte Ltd, Clementi Loop #02-01, Jin Xing Distripark, Singapore 129809 John Wiley & Sons Canada Ltd, 22 Worcester Road, Etobicoke, Ontario, Canada M9W 1L1 Wiley also publishes its books in a variety of electronic formats Some content that appears in print may not be available in electronic books Library of Congress Cataloging-in-Publication Data O’Docherty, Mike Object-oriented analysis and design : understanding system development with UML 2.0 / Mike O’Docherty p cm Includes bibliographical references and index ISBN-13 978-0-470-09240-8 ISBN-10 0-470-09240-8 (pbk : alk paper) Object-oriented programming (Computer science) Computer software–Development I Title QA76.64.O35 2005 005.1
17 – dc22 2005004182 British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library ISBN-13 978-0-470-09240-8 ISBN-10 0-470-09240-8 Typeset in 10/14 Berkeley-Medium by Laserwords Private Limited, Chennai, India Printed and bound in Great Britain by Biddles Ltd, King’s Lynn This book is printed on acid-free paper responsibly manufactured from sustainable forestry in which at least two trees are planted for each one used for paper production For Alice and George Contents Introduction 1.1 Background 1.2 A Brief History of Programming 1.3 Methodologies 1.4 About this Book 1.4.1 Content Overview 1.4.2 Case Studies 1.4.3 Navigation 4 5 7 Part I Setting the Scene Object Concepts 2.1 Introduction 2.2 What Is an Object? 2.3 Identical or Equal? 2.4 Depicting Objects 2.5 Encapsulation 2.6 Association and Aggregation 2.7 Graphs and Trees 2.8 Links and Navigability 2.9 Messages 2.10 Invoking an Operation 2.11 An Example Collaboration 2.12 How an Object-Oriented Program Works 2.13 Garbage Collection 2.14 Classes 2.15 What Does a Class Define? 2.16 Shared Data and Shared Operations 2.17 Types 2.18 Terminology 2.19 Reusing Code 10 12 13 16 19 20 21 23 25 27 28 30 32 32 34 37 39 40 41 43 ... Questions 20 4 20 6 20 7 20 7 20 8 20 8 21 0 21 2 21 3 21 4 21 5 21 5 21 6 21 8 22 0 22 2 22 3 22 5 22 5 22 6 22 7 23 0 23 3 23 7 23 8 23 8 23 9 Choosing Technologies 9.1 Introduction 24 0 24 2 xi xii Contents 9 .2 9.3 9.4... 10. 5.1 Using Proxies and Copies 10. 5 .2 Classifying Business Services 24 2 24 4 24 6 24 7 24 8 25 0 25 0 25 2 25 4 25 5 25 6 25 8 25 8 26 2 26 7 26 7 26 7 26 8 27 0 27 2 27 3 27 3 27 4 27 4 27 5 27 6 27 7 28 2 28 4 28 5 28 6... Introduction 6 .2 The Birth of a System 98 100 1 02 1 02 1 02 103 103 104 104 104 104 105 106 1 10 1 10 111 1 12 113 114 115 116 117 1 20 121 122 123 124 125 126 126 127 128 129 1 30 1 32 133 ix x Contents 6.3