Erich Gamma - Design Patterns: Elements of Reusable Object-Oriented Software

Brian W. Kernighan, Consulting Editor

Matthew H. Austern, Generic Programming and the STL: Using and Extending the C++ Standard Template Library

David R. Butenhof, Programming with POSIX Threads

Brent Callaghan, NFS Illustrated

Tom Cargill, C++ Programming Style

William R. Cheswick/Steven M. Bellovin/Aviel D. Rubin, Firewalls and Internet Security, Second Edition: Repelling the Wily Hacker

David A. Curry, UNIX System Security: A Guide for Users and System Administrators

Stephen C. Dewhurst, C++ Gotchas: Avoiding Common Problems in Coding and Design

Dan Farmer/Wietse Venema, Forensic Discovery

Erich Gamma/Richard Helm/Ralph Johnson/John Vlissides, Design Patterns: Elements of Reusable Object-Oriented Software

Erich Gamma/Richard Helm/Ralph Johnson/John Vlissides, Design Patterns CD: Elements of Reusable Object-Oriented Software

Peter Haggar, Practical Java Programming Language Guide

David R. Hanson, C Interfaces and Implementations: Techniques for Creating Reusable Software

Mark Harrison/Michael McLennan, Effective Tcl/Tk Programming: Writing Better Programs with Tcl and Tk

Michi Henning/Steve Vinoski, Advanced CORBA Programming with C++

Brian W. Kernighan/Rob Pike, The Practice of Programming

S. Keshav, An Engineering Approach to Computer Networking: ATM Networks, the Internet, and the Telephone Network

John Lakos, Large-Scale C++ Software Design

Scott Meyers, Effective C++ CD: 85 Specific Ways to Improve Your Programs and Designs

Scott Meyers, Effective C++, Third Edition: 55 Specific Ways to Improve Your Programs and Designs

Scott Meyers, More Effective C++: 35 New Ways to Improve Your Programs and Designs

Scott Meyers, Effective STL: 50 Specific Ways to Improve Your Use of the Standard Template Library

Robert B. Murray, C++ Strategies and Tactics

David R. Musser/Gillmer J. Derge/Atul Saini, STL Tutorial and Reference Guide, Second Edition: C++ Programming with the Standard Template Library

John K. Ousterhout, Tel and the Tk Toolkit

Craig Partridge, Gigabit Networking

Radia Perlman, Interconnections, Second Edition: Bridges, Routers, Switches, and Internetworking Protocols

Stephen A. Rago, UNIX System V Network Programming

Eric S. Raymond, The Art of UNIX Programming

Marc J. Rochkind, Advanced UNIX Programming, Second Edition

Curt Schimmel, UNIX Systems for Modern Architectures: Symmetric Multiprocessing and Caching for Kernel Programmers

W. Richard Stevens, TCP/IP Illustrated, Volume 1: The Protocols

W. Richard Stevens, TCP/IP Illustrated, Volume 3: TCP for Transactions, HTTP, NNTP, and the UNIX Domain Protocols

W. Richard Stevens/Bill Fenner/Andrew M. Rudoff, UNIX Network Programming Volume 1, Third Edition: The Sockets Networking API

W. Richard Stevens/Stephen A. Rago, Advanced Programming in the UNIX Environment, Second Edition

W. Richard Stevens/Gary R. Wright, TCP/IP Illustrated Volumes 1-3 Boxed Set

John Viega/Gary McGraw, Building Secure Software: How to Avoid Security Problems the Right Way

Gary R. Wright/W. Richard Stevens, TCP/IP Illustrated, Volume 2: The Implementation

Ruixi Yuan/W. Timothy Strayer, Virtual Private Networks: Technologies and Solutions

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Elements of Reusable Object-Oriented Software

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Material from A Pattern Language: Towns/Buildings/Construction by Christopher Alexander, copyright 1977 by Christopher Alexander is reprinted by permission of Oxford University Press, Inc.

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Library of Congress Cataloging-in-Publication Data
Design Patterns : elements of reusable object-oriented software / Erich Gamma ... [et al.].
p. cm.(Addison-Wesley professional computing series)
Includes bibliographical references and index.
ISBN 0-201-63361-2
1. Object-oriented programming (Computer science) 2. Computer softwareReusability.
I. Gamma, Erich. II. Series.
QA76.64.D47 1994
005.1'2dc20
94-34264
CIP

Copyright 1995 by Addison-Wesley

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 the prior consent of the publisher. Printed in the United States of America. Published simultaneously in Canada.

Cover art M.C. Escher/Cordon Art - Baarn - Holland. All rights reserved.

ISBN 0-201-63361-2
Text printed in the United States on recycled paper at Courier Westford in Westford, Massachusetts.
37th Printing March 2009

To Karin

E.G.

To Sylvie

R.H.

To Faith

R.J.

To Dru Ann and Matthew Joshua 24:15b

J.V.

This is one of the best written and wonderfully insightful books that I have read in a great long while...this book establishes the legitimacy of patterns in the best way: not by argument but by example.

Stan Lippman, C++ Report

...this new book by Gamma, Helm, Johnson, and Vlissides promises to have an important and lasting impact on the discipline of software design. Because Design Patterns bills itself as being concerned with object-oriented software alone, I fear that software developers outside the object community may ignore it. This would be a shame. This book has something for everyone who designs software. All software designers use patterns; understanding better the reusable abstractions of our work can only make us better at it.

Tom DeMarco, IEEE Software

Overall, I think this book represents an extremely valuable and unique contribution to the field because it captures a wealth of object-oriented design experience in a compact and reusable form. This book is certainly one that I shall turn to often in search of powerful object-oriented design ideas; after all, thats what reuse is all about, isnt it?