Object Oriented PHP Concepts Techniques and Code Jun 2006 (pdf document) download at fliiby.com

"® OBJEC T-ORIENTED CONCEPTS, TECHNIQUES, A ND CODE PETER LAVIN PHP OBJECT-ORIENTED PHP Concepts, Techniques, and Code by Peter L a vin ® San Francisco OBJECT-ORIENTED PHP. Copyright © 2006 by Peter Lavin. All rights reserved. No part of this work may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage or retrieval system, without the prior written permission of the copyright owner and the publisher. Printed on recycled paper in the United States of America 1 2 3 4 5 6 7 8 9 10 – 09 08 07 06 No Starch Press and the No Starch Press logo are registered trademarks of No Starch Press, Inc. Other product and company names mentioned herein may be the trademarks of their respective owners. Rather than use a trademark symbol with every occurrence of a trademarked name, we are using the names only in an editorial fashion and to the benefit of the trademark owner, with no intention of infringement of the trademark. Publisher: William Pollock Managing Editor: Elizabeth Campbell Associate Production Editor: Christina Samuell Cover and Interior Design: Octopod Studios Developmental Editor: William Pollock Technical Reviewer: Peter MacIntyre Copyeditors: Publication Services, Inc. and Sarah Lemaire Compositor: Riley Hoffman Proofreader: Stephanie Provines For information on book distributors or translations, please contact No Starch Press, Inc. directly: No Starch Press, Inc. 555 De Haro Street, Suite 250, San Francisco, CA 94107 phone: 415.863.9900; fax: 415.863.9950; info@nostarch.com; www.nostarch.com The information in this book is distributed on an “As Is” basis, without warranty. While every precaution has been taken in the preparation of this work, neither the author nor No Starch Press, Inc. shall have any liability to any person or entity with respect to any loss or damage caused or alleged to be caused directly or indirectly by the information contained in it. Librar y of Congress Cataloging-in-Publication Data Lavin, Peter. Object-oriented PHP : concepts, techniques, and code / Peter Lavin. p. cm. Includes index. ISBN 1-59327-077-1 1. PHP (Computer program language) 2. Object-oriented programming (Computer science) QA76.73.P224L38 2006 005.1'17--dc22 2006015309 I. Title. BRIEF CONTENTS Acknowledgments ........................................................................................................ xiii Introduction ...................................................................................................................xv Chapter 1: What a Tangled Web We Weave....................................................................1 Chapter 2: Basics of Object-Oriented Programming ............................................................5 Chapter 3: Object-Oriented Features New to PHP 5 ..........................................................11 Chapter 4: Show a Little Class ........................................................................................17 Chapter 5: Mod UR Class ..............................................................................................25 Chapter 6: The ThumbnailImage Class.............................................................................35 Chapter 7: Building the PageNavigator Class...................................................................47 Chapter 8: Using the PageNavigator Class ......................................................................57 Chapter 9: Database Classes .........................................................................................65 Chapter 10: Improvement Through Inheritance..................................................................75 Chapter 11: Advanced Object-Oriented Programming Concepts ........................................91 Chapter 12: Keeping It Fresh..........................................................................................99 Chapter 13: More Magic Methods................................................................................111 Chapter 14: Creating Documentation Using the Reflection Classes ....................................125 Chapter 15: Extending SQLite ......................................................................................139 Chapter 16: Using PDO...............................................................................................157 Appendix A: Setting Up PHP 5 .....................................................................................165 Appendix B: Conversion Table: PHP 4 and PHP 5 ...........................................................169 Glossary ....................................................................................................................173 Index .........................................................................................................................179 CONTENTS IN DETAIL A CK N O W LE D G M E N T S xiii I NT R O D UC T I O N xv What Does This Book Have to Offer? ....................................................................... xvi Who Should Read This Book? .................................................................................. xvi Requirements ......................................................................................................... xvi Software .................................................................................................. xvi Skills ........................................................................................................xvii Overview of Contents .............................................................................................xvii Companion Website .............................................................................................. xix Resources ............................................................................................................... xx Websites ................................................................................................... xx Books ....................................................................................................... xx 1 W HA T A T A N G L E D W E B W E W E A V E 1 Do We Really Need Objects? .................................................................................... 2 Just a Scripting Language ............................................................................. 2 Object Orientation Is for Large Software Shops ............................................... 3 Leave Well Enough Alone ............................................................................ 3 Increased Complexity .................................................................................. 3 The PHP Culture ....................................................................................................... 4 2 B A S IC S O F O B J E CT -O R IE NT E D PR O G R AM M IN G 5 Class ...................................................................................................................... 6 Classes Versus Records ................................................................................ 6 A Cohesive Whole ...................................................................................... 6 Objects Are Instances .................................................................................. 6 Objects Need Access Modifiers ................................................................................. 7 Object Reuse and Inheritance .................................................................................... 7 Multiple Inheritance ..................................................................................... 8 Having Your Cake and Eating It Too .............................................................. 8 Where to Go from Here ............................................................................................ 9 3 O B J E C T -O R I E N T E D F E AT U R E S N E W T O P H P 5 11 Access Modifiers .................................................................................................... 12 Built-in Classes ....................................................................................................... 12 Exceptions ................................................................................................ 12 Database Classes ...................................................................................... 13 Web Services ........................................................................................... 13 Reflection Classes ..................................................................................... 14 Iterator ..................................................................................................... 14 Backward Compatibility .......................................................................................... 14 Pass By Reference ..................................................................................... 14 Prognosis ................................................................................................. 15 Where to Go from Here .......................................................................................... 15 Adoption of PHP 5 .................................................................................... 16 Compromise ............................................................................................. 16 4 S HO W A LI TT L E C L AS S 17 Design .................................................................................................................. 18 Defining the Problem ................................................................................. 18 Not the Da Vinci Code ........................................................................................... 19 The Constructor ......................................................................................... 19 Referencing Instance Variables ................................................................... 20 Wrapper Methods ..................................................................................... 20 Creating an Instance .............................................................................................. 21 What Have You Accomplished? ............................................................................... 23 But Will It Fly? ....................................................................................................... 23 5 M O D U R CL A SS 25 Upgrading to PHP 5 ............................................................................................... 26 Access Modifiers ....................................................................................... 26 The Constructor ......................................................................................... 28 Modifying Your Class ............................................................................................. 29 Reconstructing the Constructor .................................................................... 29 Filtering Content ........................................................................................ 31 Resetting the Array .................................................................................... 32 Summary of Changes ............................................................................................. 33 6 T H E T HU M B N A I LI M A G E CL A SS 35 What Does a Designer Do? ..................................................................................... 36 Mimicking the Designer ............................................................................. 36 Help from PHP Functions ............................................................................ 36 The ThumbnailImage Class ...................................................................................... 37 Data Members .......................................................................................... 37 Deconstructing the Constructor .................................................................... 37 Two Ways to Construct an Object ............................................................... 38 Internal Behavior—Private Methods ............................................................. 39 Must It Be Private? ..................................................................................... 40 A Helper Method ...................................................................................... 40 Public Methods ......................................................................................... 41 Garbage Collection ................................................................................... 41 viii C on t en t s in D et ai l Displaying the Image ................................................................................. 41 Get and Set Methods ................................................................................. 42 Image Quality ........................................................................................... 42 When to Change the Quality ...................................................................... 43 Displaying a Thumbnail .......................................................................................... 44 Putting It All Together .............................................................................................. 44 Where to Go from Here .......................................................................................... 45 7 B U IL D IN G T H E P A G E N A VI G A T O R C L A SS 47 How Will the Navigator Behave? ............................................................................. 47 Different Kinds of Searches ......................................................................... 48 What Will It Look Like? ........................................................................................... 48 The Code .............................................................................................................. 49 The Constructor ......................................................................................... 51 Ain’t Misbehavin’ ...................................................................................... 52 Other Constructor Method Calls .................................................................. 52 The getNavigator Method ....................................................................................... 54 Move First and Move Previous .................................................................... 54 Main Body of the Navigator ....................................................................... 55 Move Next and Move Last ......................................................................... 56 Current and Total Number of Pages ............................................................ 56 Where to Go from Here .......................................................................................... 56 8 U S I N G T HE P AG E NA V I G A T O R C L AS S 57 DirectoryItems Change ............................................................................................ 58 CSS and Reusability ............................................................................................... 58 Paging with Class .................................................................................................. 60 Displaying an Array Slice ........................................................................... 61 Creating the PageNavigator Object ............................................................ 62 Where to Go from Here .......................................................................................... 63 9 D A T A B A S E C L A SS E S 65 Using What You Know ........................................................................................... 65 One Lump or Two? ................................................................................................. 66 The MySQLConnect Class ....................................................................................... 66 A Class-Conscious Variable ........................................................................ 67 Making Other Connections ......................................................................... 68 You Can Only Get There from Here ............................................................. 68 The MySQLResultSet Class ....................................................................................... 69 Using the Page Navigator ....................................................................................... 70 Ordering, Filtering, and Extracting .............................................................. 71 Traversing the Result Set ............................................................................. 72 Your Navigator Needs Directions ................................................................ 73 Where to Go After the Navigator ............................................................................. 74 C on t en ts in D et ail ix 10 I M PR O V E M E N T T H RO U G H I N HE R IT AN C E 75 The Standard PHP Library ........................................................................................ 76 Extending a Class Through Inheritance ...................................................................... 76 The Exception Class ................................................................................... 77 protected ................................................................................................. 77 final ......................................................................................................... 78 More Magic Methods ................................................................................ 78 Replacing Errors with Exceptions .............................................................................. 79 The MySQLException Class ..................................................................................... 80 Changes to the MySQLConnect Class ....................................................................... 81 Prodding Your Class into Action .................................................................. 82 Catching Exceptions ............................................................................................... 83 Implementing an Interface ....................................................................................... 84 Learning About the Iterator Interface ............................................................ 85 Implementation ......................................................................................... 86 Leaving a Method Undefined ...................................................................... 88 Implementation and Access ........................................................................ 88 Iterating Through a MySQLResultSet ............................................................ 89 Where to Go from Here .......................................................................................... 89 11 A D V A NC E D O B JE C T - O RI E N T E D P RO G RA M M I N G C O NC E P T S 91 Abstract Classes ..................................................................................................... 91 Private Methods Can’t Be Abstract .............................................................. 92 Interface or Pure Abstract Class? ................................................................. 92 Polymorphism ........................................................................................................ 93 Controlling How Functions Are Used ........................................................... 93 Static Classes ........................................................................................................ 94 Static Math Classes ......................................................................................"

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