Pattern Languages of Program Design 4

Description

Design patterns have moved into the mainstream of commercial software development as a highly effective means of improving the efficiency and quality of software engineering, system design, and development. Patterns capture many of the best practices of software design, making them available to all software engineers.

The fourth volume in a series of books documenting patterns for professional software developers, Pattern Languages of Program Design 4 represents the current and state-of-the-art practices in the patterns community. The 29 chapters of this book were each presented at recent PLoP conferences and have been explored and enhanced by leading experts in attendance. Representing the best of the conferences, these patterns provide effective, tested, and versatile software design solutions for solving real-world problems in a variety of domains.

This book covers a wide range of topics, with patterns in the areas of object-oriented infrastructure, programming strategies, temporal patterns, security, domain-oriented patterns, human-computer interaction, reviewing, and software management. Among them, you will find:

• The Role object
• Proactor
• C++ idioms
• Architectural patterns for security
• Reports
• Composing multimedia artifacts
• Customer interaction

As patterns evolve beyond the realm of research into the world of practical software development, more and more developers are discovering that reusable design patterns (such as those contained in this volume) can help them achieve faster, more cost-effective delivery of their applications.

Sample Content

Table of Contents

Preface.


Introduction I.


Introduction II.


1. Basic Object-Oriented Patterns.

Abstract Class, Bobby Woolf.

Role Object, Dirk Baumer, Dirk Riehle, Wolf Siberski and Martina Wulf.

Essence, Andy Carlson.

Object Recursion, Bobby Woolf.

Prototype-Based Object System, James Noble.

Basic Relationship Patterns, James Noble.

Abstract Session: An Object Structured Pattern, Nat Pryce.

Object Synchronizer, Antonio Rito Silva, Joao Pereira and Jose Alves Marques.

Proactor, Irfan Pyarali, Tim Harrison, Douglas C. Schmidt and Thomas D. Jordan.

C++ Idioms, James O. Coplien.

Smalltalk Scaffolding Patterns, Jim Doble and Ken Auer.

High-Level and Process Patterns from the Memory Preservation Society: Patterns for Managing Limited Memory, James Noble and Charles Weir.

Temporal Patterns, Andy Carlson, Sharon Estepp and Martin Fowler.

A Collection of History Patterns, Francis Anderson.

Architectural Patterns for Enabling Application Security, Joseph Yoder and Jeffrey Barcalow.

Tropyc: A Pattern Language for Cryptographic Object-Oriented Software, Alexandre Braga, Cecilia Rubira and Ricardo Dahab.

Creating Reports with Query Objects, John Brant and Joseph Yoder.

Feature Extraction: A Pattern for Information Retrieval, Dragos-Anton Manolescu.

Finite State Machine Patterns, Sherif M. Yacoub and Hany H. Ammar.

Patterns for Designing Navigable Information Spaces, Gustavo Rossi, Daniel Schwabe and Fernando Lyardet.

Composing Multimedia Artifacts for Reuse, Jacob L. Cybulski and Tanya Linden.

Display Maintenance: A Pattern Language, Dwayne Towell.

An Input and Output Pattern Language: Lessons from Telecommunications, Robert Hanmer and Greg Stymfal.

Identify the Champion: An Organizational Pattern Language for Program Committees, Oscar Nierstrasz.

A Pattern Language for Writers’ Workshops, James O. Coplien and Bobby Woolf.

Customer Interaction Patterns, Linda Rising.

Capable, Productive, and Satisfied: Some Organizational Patterns for Protecting Productive People, Paul Taylor.

SCRUM: A Pattern Language for Hyperproductive Software Development, Mike Beedle, Martine Devos, Yonat Sharon, Ken Schwaber and Jeff Sutherland.

Big Ball of Mud, Brian Foote and Joseph Yoder.

Preface

Of Phish and Phugues

The year is 1621; the place, Plymouth, in what will eventually become Massachusetts. A group of settlers from England arrived the previous November and are now setting out to plant crops. Before long a native named Squanto stops by. Evidently a gardening enthusiast, he offers to tutor the settlers in farming techniques, first by placing fish in the ground to enrich the soil. This and other tricks of farming in the New World contribute to a bountiful harvest. The settlers survive the ensuing winter, thanks in large part to Squanto and his sage advice.

An apocryphal story, no doubt, but modern horticulturists can corroborate Squanto's fishy insights. In fact, you can buy fish fertilizers in many gardening stores. Our agricultural forebears may not have had a deep knowledge of plant physiology, but they knew what worked. And they passed it along.

Over a hundred years later and half a world away, in what is now Germany, a master of a different sort plies his trade. According to legend, Johann Sebastian Bach pays a visit to Frederick the Great, King of Prussia. After exchanging pleasantries, the king asks Bach to play something for him. Dutifully and without hesitation, Bach sits down at the organ and improvises a five-part fugue. The king, an eminent composer himself, is awed.

Bach's work is the very essence of baroque music. And he passes that mastery along--several of his children also become important musicians and composers.

Lore flows from one generation to the next. Languages are vivid examples, perpetuating and evolving through oral tradition--words and concepts passing from person to person. A case in point is English, which traces its roots to numerous languages, including German, Greek, and Latin. Herein lies a problem: the multifaceted heritage of English creates a potpourri of spelling conventions that is downright bewildering. For example, we spell the "f" sound with the letters "ph" in "physics" but with "f" in "fish" and "fugue." There are historical and linguistic reasons for such anomalies, but they don't matter much to us. We just memorize that it's "fugue," not "phugue."

In software we don't have centuries of history to draw on. We didn't learn agriculture from ancient farmers, nor can we trace our roots through the Middle English of Chaucer. But we have been around long enough to learn a few things. The most important among them is this: We must share what we have learned. If we keep knowledge to ourselves, hoarding it like pack rats, then our field will surely stagnate. We doom colleague and successor alike to repeat our mistakes. Gradually, reinvention displaces innovation. Progress slows. The field goes fallow.

Patterns are conduits of knowledge, capturing and conveying time-proven practices. Patterns are more than tricks or seemingly arbitrary spelling rules--they impart understanding. They teach you not just what and how but also why and when. That's where their real power lies.

What can we reasonably expect of patterns? Maybe they will help other people develop better software than we have. Maybe they'll allow people to build on what we've done right. We certainly hope patterns will help others avoid the pitfalls we've experienced.

But we can expect more. The pervasiveness of computer technology exerts a strong influence on society. Influence of such magnitude must be exercised responsibly. While patterns won't force you to act responsibly, they can ease the grind of reinvention, freeing you to consider higher purposes. Ultimately, patterns make life better for everyone--software user and developer alike.

These are ambitious and humbling goals, to be sure. We dedicate this fourth volume in the Pattern Languages of Program Design series to their attainment.

ACKNOWLEDGMENTS

Now for a word about the contributors to this book. A compendium of this size won't come together without many people pulling together. We are hugely grateful for their work. Specifically, we thank the authors for making this book necessary, to paraphrase Yogi Berra. We're referring not just to the authors you find here but also to the 60 percent or so of submitters whose works were not accepted. The exceptionally high quality of the submissions guaranteed the quality of the book, although it also made our job more difficult!

We recruited a veritable army of reviewers to help sift through the submissions. We owe them our sanity: Francis Anderson, Brad Appleton, Jorge Arjona, Owen Astrannen, Ken Auer, Jeff Barcalow, Kent Beck, Mike Beedle, Steve Berczuk, Manish Bhatt, Rosana Braga, John Brant, Kyle Brown, Jose Burgos, Frank Buschmann, Andy Carlson, Ian Chai, Alistair Cockburn, Jens Coldewey, James Coplien, Ward Cunningham, David Cymbala, Fonda Daniels, Dennis DeBruler, Michel DeChamplain, David Delano, Dwight Deugo, Paul Dyson, Philip Eskelin, Javier Galve, Julio Garcia, Alejandra Garrido, John Goodsen, Robert Hanmer, Kevlin Henney, Robert Hirschfeld, Ralph Johnson, Wolfgang Keller, Elizabeth Kendall, Norm Kerth, Charles Knutson, Frederick Koh, Philippe Lalanda, Manfred Lange, Doug Lea, Mary Lynn Manns, Klaus Marquardt, Paulo Masiero, Skip McCormick, Regine Meunier, Oscar Nierstrasz, James Noble, Alan O'Callaghan, Don Olson, William Opdyke, Dorina Petriu, Irfan Pyarali, Andreas Rausch, Dirk Riehle, Linda Rising, Antonio Rito Silva, Don Roberts, Gustavo Rossi, Cecilia Rubira, Andreas Ruping, Doug Schmidt, Ari Schoenfeld, Dietmar Schutz, Christa Schwanninger, Joe Seda, Peter Sommerlad, Michael Stal, Paul Taylor, Jenifer Tidwell, Dwayne Towell, and David Ungar.

We would like to give special thanks to John Vlissides, the managing editor of the series. He has provided us with encouragement and, occasionally, a needed prod. Neil would like to especially thank his two coeditors. Working with you has been a joy.

Finally, we would like to give special thanks to our families, friends, and coworkers who have supported us through this process. We hope that by the time you read this, we will be back to our cheery selves.

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