Product Description

After more than ten years, object technology pioneer Rebecca Wirfs-Brock teams with expert Alan McKean to present a thoroughly updated, modern, and proven method for the design of software. The book is packed with practical design techniques that enable the practitioner to get the job done. Like many human endeavors, design is part art, part engineering, part guesswork, and part experimentation. Discipline, hard work, inspiration, and sound technique all play their part as well. For any given problem, there are many reasonable, but only a few very good solutions. The authors' goal is to help readers learn to make those very good design decisions on their own. The book explores challenges that software developers will face as they build their design, and shows how design patterns can be used to solve design problems. Long awaited and eagerly anticipated, this book represents the first great software design book of the century. A FUTURE CLASSIC!

Product Details

• Amazon Sales Rank: #450350 in Books
• Published on: 2002-11-18
• Original language: English
• Number of items: 1
• Binding: Paperback
• 416 pages

From the Back Cover

If you create software using object-oriented languages and tools, then Responsibility-Driven Design has likely influenced your work. For over ten years Responsibility-Driven Design methodology has been the standard bearer of the behavioral approach to designing object-oriented software. Object Design: Roles, Responsibilities, and Collaborations focuses on the practice of designing objects as integral members of a community where each object has specific roles and responsibilities. The authors present the latest practices and techniques of Responsibility-Driven Design and show how you can apply them as you develop modern object-based applications.

Working within this conceptual framework, Rebecca Wirfs-Brock and Alan McKean present how user requirements, system architecture, and design patterns all contribute to the design of an effective object model. They introduce a rich vocabulary that designers can use to discuss aspects of their designs, discuss design trade-offs, and offer practical guidelines for enhancing the reliability and flexibility of applications. In addition, case studies and real-world examples demonstrate how the principles and techniques of Responsibility-Driven Design apply to real-world software designs.

You'll find coverage of such topics as:

As all experienced designers know, software design is part art and inspiration and part consistent effort and solid technique. Object Design: Roles, Responsibilities, and Collaborations will help all software designers--from students to seasoned professionals--develop both the concrete reasoning skills and the design expertise necessary to produce responsible software designs.

About the Author

Rebecca Wirfs-Brock is founder of Wirfs-Brock Associates. She consults with clients on actual architecture and design projects as well as development practices and methods. She is the originator of the set of development practices known as Responsibility-Driven Design. Among her widely used inventions are use case conversations and object role stereotypes. She was lead author of the classic work Designing Object-Oriented Software (Prentice-Hall, 1990).

Alan McKean is a respected object technology educator and cofounder of Wirfs-Brock Associates. His classes have introduced thousands of developers to object-oriented design and programming and his instructional techniques have been widely adopted by other educators. An experienced programmer, speaker, and instructor, Alan has developed curricula in object-oriented design, programming, and distributed object systems.

0201379430AB08292002

Excerpt. © Reprinted by permission. All rights reserved.

This book is about designing object software. Like many human endeavors, design is part art, part engineering, and part guesswork and experimentation. Discipline, hard work, inspiration, and sound technique all play their parts. Although software design is a highly creative activity, the fundamentals can be easily learned. Strategies and techniques exist for developing a design solution, and this book is packed with practical design techniques that help you get the job done. We hope you will become adept at thinking in objects and excited about devising solutions that exploit object technology.

You can consider design choices only in light of what you know to be relevant and important. To achieve good results, you need to learn how to discriminate important choices from mundane ones and how to acquire a good set of techniques that you intelligently practice. The informal tools and techniques in this book that don't require much more than a white board, a stack of index cards, a big sheet of paper, and chairs around a table. Oh yeah, be sure to bring your brain, too!

But more important than a grab bag of techniques are the fundamental ways you view a design. Although the techniques we present in this book are independent of any particular implementation technology or modeling language or design method, our approach to object design requires a specific perspective: Objects are not just simple bundles of logic and data. They are responsible members of an object community. This approach, called Responsibility-Driven Design, gives you the basis for reasoning about objects.

Most novice designers are searching for the right set of techniques to rigidly follow in order to produce the correct design. In practice, things are never that straightforward. For any given problem there are many reasonable solutions, and a few very good solutions. People don't produce identical designs even if they follow similar practices or apply identical design heuristics. For each problem you approach, you make a different set of tactical decisions. The effects of each small decision accumulate. Your current design as well as your current lines of reasoning shape and limit subsequent possibilities. Given the potential impact of seemingly inconsequential decisions, designers need to thoughtfully exercise good judgment.

Your primary tool as a designer is your power of abstraction--forming objects that represent the essence of a working application. In a design, objects play specific roles and occupy well-known positions in an application's architecture. Each object is accountable for a specific portion of the work. Each has specific responsibilities. Objects collaborate in clearly defined ways, contracting with each other to fulfill the larger goals of the application.

Design is both a collaborative and a solo effort. To work effectively you need not only a rich vocabulary for describing your design but also strategies for finding objects, recipes for developing a collaborative model, and a framework for discussing design trade-offs. You will find these tools in this book. We also explore how design patterns can be used to solve a particular design problem and demonstrate their effects on a design. We present you with strategies for increasing your software's reliability and flexibility. We discuss different types of design problems and effective ways to approach them. This book presents many tools and techniques for reasoning about a design's qualities and effectively communicating design ideas. Whether you're a student or a seasoned programmer, a senior developer or a newcomer to objects, you can take away many practical things from this book. How to Read This Book

This book is organized into two major parts. The first six chapters--Chapter 1, Design Concepts, Chapter 2, Responsibility-Driven Design, Chapter 3, Finding Objects, Chapter 4, Responsibilities, Chapter 5, Collaborations, and Chapter 6, Control Style--form the core of Responsibility-Driven Design principles and techniques. You should get a good grounding by reading these chapters.

Chapter 1, Design Concepts, introduces fundamental views of object technology and explains how each element contributes to a coherent way of designing an application. Even if you are a veteran designer, a quick read will set the stage for thinking about object design in terms of objects' roles and responsibilities. Chapter 2, Responsibility-Driven Design, provides a brief tour of Responsibility-Driven Design in practice. Chapter 3, Finding Objects, presents strategies for selecting and, equally important, rejecting candidate objects in an emerging design model. Chapter 4, Responsibilities presents many techniques for defining responsibilities and intelligently allocating them to objects. Chapter 5, Collaborations, gives many practical tips and examples of how to develop a collaboration model. Chapter 6, Control Style, describes strategies for developing your application's control centers and options for allocating decision-making and control responsibilities.

Chapters 7-10 explore challenges you may encounter as you develop your design. Each chapter covers a specific topic that builds on the design concepts and techniques presented in the first part of the book. Chapter 7, Describing Collaborations, explores options for documenting and describing your design. Chapter 8, Reliable Collaborations, presents strategies for handling exceptions, recovering from errors, and collaborating within and across a "trusted region." Chapter 9, Flexibility, discusses how to characterize software variations and design to support them. Chapter 10, On Design, discusses how to sort design problems into one of three buckets--the core, the revealing, and the rest--and treat each accordingly.

0201379430P10212002

Customer Reviews

Very Good Text on Object Design
I think I finally have a handle on object modeling-- 'Object Design' deserves a lot of the credit.

I have a shelf full of books on UML, uses cases, patterns, and modeling. I spent almost a year struggling through UML, trying to understand the nuances of sequence diagrams versus collaboration diagrams. Meanwhile, I felt no closer to being able to create serviceable object models for my projects.

Rebecca Wirfs-Brock and Alan McKean dispense with much of the tedious diagramming one usually associates with object modeling. Instead of charts and relationships, the book focuses on the roles, responsibilities, and behaviors that define an object. If you have ever assembled and managed employee teams, the framework will be very fmailiar. And that's where I found my breakthrough.

The book offers a good introduction to object modeling for those new to the area, and a solid reference for those looking to stremline their current methodology. The processes suggested by the authors are simple and flexible. But they are powerful enough to handle even complex designs.

One of the strongest pieces of advice in the book is to avoid rushing into UML software--stick with index cards until the design is fairly well developed. That's what got me out of a morass of charts and diagrams that looked nice, but did relatively little. I'd paraphrase the book's theme as "Forget the formalism and focus on your application's responsibilities, and how those responsibilities can be allocated among cohesive, well-organized team players.:

The book is language neutral--it's focus is design, rather than programming. The design methodology taught in the book should be easily adaptable to nearly any object-oriented programming language.

I have no hesitation recommending Object Design to novice and intermediate object modelers. I rate is as the best book I have read on the design and modeling of object-oriented systems.

A great first text on OO design
Wirfs-Brock and McKean have written an oustanding introductory book on object-oriented design. This is definitely a book for beginning OO programmers, the ones who aren't sure how to assign functions to objects and who aren't ready for design patterns yet. More experienced developers won't get much out of it, but that's OK. Every level needs its own reference books.

The book's layout and illustrations present its content well. UML diagrams, for example, use one color and typeface for the actual UML notation. The same diagrams use a different color and typeface for notes that explain the UML. Unlike other books, there's no confusion about which is the tool and which describes the tool. The text is gentle and reasonably jargon-free, but I think it over-does the friendliness in places. In discussing a program's normal and exception handling behavior, the term "happy path" described the execution in the absence of errors. The term may be evocative, but is just a bit hard to take seriously.

The sequence of topics makes good sense. It starts with the idea of a "responsibility," the basic unit of application logic. The authors develop this into strategies for defining objects, defining relationships between objects, and defining the control strategies that implement those relationships. They continue on through error handling (reliability) and extensibility - handling of future features. Throughout, the authors keep a moderate, pragmatic tone, free of name-brand methodology. That's a good thing, since the real focus is on basic skills and decision criteria.

One aspect of this book is just a little confusing. It's definitely aimed at educating a new OO designer, but it doesn't lay out its educational objectives or plan very clearly. It certainly lacks the didactic rigor of a textbook. It would make a good supplementary text, though, and it might be very helpful to a novice working with more experienced developers. Best of all, it refers to additional texts (including Strunk and White!) that will help claify the programs as well as communication with other members of the programming team.

This book is great for anyone starting OO design on their own. It's also good for classroom students who just aren't getting it from their regular instructor and text. Experienced developers won't find much new here, except very clear descriptions of how much error handling or flexibility is enough.

//wiredweird

Definitive guide to Object Oriented Design
I've always believed the best approach to object-oriented design is Responsibility Driven Design (RDD), and this is the best book on the subject-written by the inventor of RDD.

I recently showed Mike Rosen, of Cutter Consortium, Object Design. Before I could say it had great chapters on RDD plus work on design for reliability and flexibility plus pages of references to related books and papers, he said 'Great! This will be my next book purchase'.

So, why is Object Design: Roles, Responsibilities, and Collaborations (OD) a really great book? These folks have years of design consulting and teaching experience, know what they are talking about, and are good at telling the story.

OD is a great read from cover to cover. Their two-chapter review of object design concepts was energetic, insightful, and comprehensive. From the beginning they are mixing in CRC cards (Thanks Kent, Ward!), architecture styles, patterns, and stereotypes into the discussion. This is the place to start for novices and intermediate students, and professionals now have the definitive reference book on object oriented design.

The authors understand we all have different learning styles. Along with their conversation, the first two chapters also illustrate concepts and examples with over 20 figures, a couple of UML diagrams, three (short) Java code blocks, and eight CRC card drawings. Concrete examples are provided throughout the book, from computer speech to finance and telecommunications.

The Chapter titles are: 1 Design Concepts, 2 Responsibility Driven Design, 3 Finding Objects, 4 Responsibilities, 5 Collaborations, 6 Control Style, 7 Describing Collaborations, 8 Reliable Collaborations, 9 Flexibility, and 10 On Design. Each chapter includes a summary. The recommendations for further reading provide a guided tour of related works in software engineering, design, and general literature.

The authors share how they think about the critical areas of design for flexibility and reliability. So how do you build reliable systems? What are some experience-based guidelines for dealing with error conditions? What about all those exceptions anyway?! The chapter on flexibility is for me the heart of object technology. They show how you can apply object technology to give users control over their world. The analysis of hot spots or flex points guides the focused introduction of added flexibility. Then you can actually deliver on the promise of object oriented software.

Practitioners will find this book "spot on" for the treatment of UML and Patterns. So, yes, with three or more UML books on the shelf, I am sure you can draw all those diagrams - right? With OD you are learning to think in objects and to communicate your story. Your learning how to tell your story with UML, what to say visually and what not to say. OD is a pretty good source for UML notation guidance too, as the text and the diagrams are meticulously accurate, down to the arrow head styles. OD provides a good introduction to patterns and weaves a number of the more interesting GOF patterns into the design examples. Patterns are also emphasized in the chapter on flexibility.

Paraphrasing Ivar Jacobson's words from the forward: "this higher-level view of design, which focuses on responsibilities...helps you step away from implementation details and focus on what the appropriate software machinery should be..." In closing he writes: "Whether you are new to object technology or an experienced developer, this book is a rich source of practical advice."

These common sense lessons are essential for practitioners of design and systems architecting in all fields.