Cocoa design patterns

457 Pages·2010·3.994 MB·English

by  Yacktman, Donald A.;Buck, Erik M

Praise for Cocoa Design Patterns
“This long-needed book is a great resource for Cocoa newcomers and veterans who
want to get the why behind the what.The list of patterns gives historical perspective and
answers many developer questions and the last three chapters—covering Core Data,
AppKit,and Bindings—are a must-read;they reveal insights that might otherwise
require hours of discussion with Apple engineers or access to source code.”
—Tim Burks,Software Developer and Creator of the Nu Programming Language,
www.programming.nu
“This book is a comprehensive and authoritative treatment of design patterns and their
practical applications in Cocoa projects.I recommend this book to anyone who wants
to advance from intermediate to expert proficiency as a Macintosh developer.”
—John C.Randolph,Vice President Engineering,Stealth Imaging,Inc.
“Cocoa Design Patterns is a fantastic book that will show you the ins and outs of software
design patterns,how Cocoa makes use of them,and how to apply them to your own
applications for better,more robust,and more maintainable software.”
—August Trometer,Owner of FoggyNoggin Software
“Cocoa Design Patterns is superb! It is highly readable,thoroughly enjoyable,and filled to
the brim with wisdom that will make you a more efficient and effective programmer.
The authors utilize a consistent and self-contained approach to each chapter,making it
easy to return to use as a reference.However,the material is so interesting and vital to
Cocoa programmers that you’ll want to read it from cover to cover.”
—David Mandell,Independent Developer
“Erik and Donald’s book really helped me out with the conceptual side of program-
ming.It caused me to realize where I was going wrong in my code and helped me sort
out my design issues.”
—Eoin Houlihan
“This book is recommended for any programmer interested in a deeper understanding
of Cocoa.Reading it might have helped me become a better software engineer in any
object-oriented language.I’ll keep it handy as a constant reference and look forward to
reading it again more carefully.”
—Daryl Spitzer
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Cocoa Design
Patterns
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Cocoa Design
Patterns
Erik M. Buck
Donald A. Yacktman
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Library of Congress Cataloging-in-Publication Data: Publishing
Coordinator
Buck,Erik M. Romny French
Cocoa design patterns / Erik M. Buck,Donald A. Yacktman. Cover Designer
Gary Adair
p. cm.
Compositor
Includes bibliographical references and index. Jake McFarland
ISBN 978-0-321-53502-3 (pbk. : alk. paper) 1. Cocoa (Application development environ-
ment) 2. Object-oriented programming (Computer science) 3. Software patterns. 4. Mac
OS. I. Yacktman,Donald A. II. Title.
QA76.64.B82 2009
005.26’8—dc22
2009023288
Copyright © 2010 Pearson Education,Inc.
All rights reserved. Printed in the United States of America. This publication is protected by
copyright,and permission must be obtained from the publisher prior to any prohibited repro-
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sions,write to:
Pearson Education,Inc.
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Fax [phone]
ISBN-13: 978-0-321-53502-3
ISBN-10: 0-321-53502-2
Text printed in the United States on recycled paper at R.R. Donnelley in Crawfordsville,
Indiana.
First printing September 2009
❖
To my beloved wife,Michelle,who makes my life
and every accomplishment possible,and to my children,
Joshua,Emma,and Jacob,for their tireless support
and understanding.
—Erik M.Buck
❖
Dedicated to my wife Marcie for her patience and
support and my boys,Joseph and William,for their
never-ending curiosity about how and why things
work the way they do.
—Donald A.Yacktman
❖
Table of Contents
I: One Pattern to Rule Them All 1
1 Model View Controller 2
MVC in Cocoa 4
Core Data Support for Model Subsystems 5
Application Kit Support for View Subsystems 6
Application Kit Support for Controller Subsystems 8
Cocoa’s Text Architecture 9
Cocoa’s Document Architecture 10
Cocoa Scriptability 13
Cocoa’s Preference Pane Architecture 14
Quartz Composer’s Architecture 15
The QTKit Architecture 15
Summary 15
2 MVC Analyzed and Applied 17
Non-MVC Design 17
Analysis of the Non-MVC Pay Calculator Design 21
MVC Design 22
Analysis of the MVC Pay Calculator Design 26
Summary 27
II: Fundamental Patterns 28
3 Two-Stage Creation 29
Motivation 29
Solution 31
Zones 31
Initializing Allocated Memory 32
Implementing the Designated Initializer 33
Using Zones in Initializers 35
Creating Temporary Instances 37
Examples in Cocoa 38
Consequences 42
Contents ix
4 Template Method 43
Motivation 43
Solution 44
Default Template Methods 45
Designing with Template Methods 46
Examples in Cocoa 47
Using the –drawRect: Template Method 47
Other Cocoa Template Methods 47
Consequences 51
5 Dynamic Creation 53
Motivation 53
Solution 53
Using Dynamic Creation 54
Dynamic Creation to Implement Plug-In
Architectures 60
Examples in Cocoa 61
Consequences 62
6 Category 63
Motivation 63
Solution 64
Informal Protocols 67
The Anonymous Category 68
Code Organization 69
When to Use Categories Versus Subclassing 69
Examples in Cocoa 70
Using Categories for Organization 70
Using Categories for Informal Protocols 71
Using Categories for Framework Division 74
Consequences 74
The Clash of Methods 74
Replacing Methods 75
Software Maintenance 76