Use Cases: Requirements in Context

Use Cases: Requirements in Context describes how to gather and define software requirements using a process based on use cases. It shows systems analysts and designers how use cases can provide solutions to the most challenging requirements issues, resulting in effective, quality systems that meet the needs of users. Specifically, with use cases, you can:

Reduce the incidence of duplicate and inconsistent requirements; Communicate requirements that are understandable to both users and developers; Prototype the right system well before the design phase is underway; Document the entire requirements process clearly and efficiently.

Use Cases: Requirements in Context first examines the difficulties of requirements gathering and briefly introduces both use cases and the Unified Modeling Language (UML). Using detailed examples that run through the book, it then elaborates a four–step method for establishing requirements––an iterative process that produces increasingly refined requirements. Drawing on their own extensive experience, the authors offer practical advice on how to manage this process, including guidance on planning, scheduling and estimating. They also reveal common mistakes and pitfalls to avoid.

This detailed, hands–on book shows you how to:

Describe object relationships and interactions with use case diagrams and scenarios Specify functional and non–functional requirements Create the candidate use case list Break out detailed use cases and add detail to use case diagrams Add triggers, preconditions, basic course of events, and exceptions to use cases

Other topics include stakeholder interviews, use case name filters, the context matrix, user interface requirements, team organization, and quality assurance.

From the Inside Flap

Use Cases: Requirements in Context came about, as most books probably

do, as the result of a complaint. We felt that there weren‘t any good books

that addressed use cases for requirements gathering. It seemed that a lot of

people agreed that use cases were a perfectly good tool to solve the requirements

problem, but no one had put down on paper any detailed process to help people

understand how to use them this way. In fact, even as we write today, in late

1999, there is no book of this sort that we know of.

Requirements gathering has been a problem on almost every project we‘ve been

involved with. The fuzzy nature of requirements makes working with them slippery

and unintuitive for most software analysts. Use cases are the first tool we‘ve

seen that addresses the specification and communication concerns usually associated

with requirements gathering.

Although use cases in themselves are quite intuitive, the process around them

is often done poorly. The questions that people have––How many iterations do

I do? How fine–grained should a use case be?––are not answered or even addressed

in most texts. This is probably because they are hard questions and the answers

can vary greatly from one situation to another. However, they are important

questions, and we decided to describe our own best practices as a first volley

in what we hope will become a spirited industry dialog on how to generate requirements

that will address user needs.

Use Cases: Requirements in Context is a practical book for the everyday

practitioner. As consultants in the information technology industry, we employ

use cases to specify business systems as part of our daily lives. We think we

understand the issues facing people when they deliver software using tools such

as the Unified Modeling Language and use cases. Our main intent is not to describe

use case notation, although we do address that. Instead, we show a requirements

process that addresses requirements gathering in a way that produces quality

results.

While writing, we considered the factors that cause problems in requirements

gathering, and we developed a use case method for delivering a requirements–oriented

set of deliverables. The methodology breaks down the activity of producing requirements

into a series of steps, and it answers the questions that usually come up when

people employ use cases. This book relates directly to the real work of delivering

a specification, managing that effort with a team, and getting the most bang

for your buck.

The sample use cases and use case diagrams that appear throughout the book

are also presented in Appendixes B and C. These appendixes demonstrate the development

of the use cases and other requirements analysis artifacts through each phase

of their development. Appendix B documents a business system for real estate,

and Appendix C documents a business system for the garment industry.

We hope you enjoy this book. It was a labor of love for us. This is a process

that works well for us. If it works for you, too, that‘s great. If it doesn‘t,

perhaps you can adapt some of the tools, ideas, or suggestions to your own way

of addressing the requirements problem.

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From the back cover:

Backcover Copy

Use Cases: Requirements in Context describes how to gather and define software requirements using a process based on use cases. It shows systems analysts and designers how use cases can provide solutions to the most challenging requirements issues, resulting in effective, quality systems that meet the needs of users. Specifically, with use cases, you can:

• Reduce the incidence of duplicate and inconsistent requirements;
• Communicate requirements that are understandable to both users and developers;
• Communicate a vision of what the application needs to do without the distractions inherent in a coded prototype;
• Document the entire requirements process clearly and efficiently.

Use Cases: Requirements in Context first examines the difficulties of requirements gathering and briefly introduces both use cases and the Unified Modeling Language (UML). Using detailed examples that run through the book, it then elaborates a four–step method for establishing requirements––an iterative process that produces increasingly refined requirements. Drawing on their own extensive experience, the authors offer practical advice on how to manage this process, including guidance on planning, scheduling, and estimating. They also dedicate an entire chapter to the common mistakes made during requirements capture and specification, particularly those related to use case creation.

This detailed, hands–on book shows you how to:

• Describe the context of relationships and interactions between actors and applications using use case diagrams and scenarios;
• Specify functional and non–functional requirements;
• Create the candidate use case list;
• Break out detailed use cases and add detail to use case diagrams;
• Add triggers, preconditions, basic course of events, and exceptions to use cases.

Other tools examined in this book include the stakeholder interview, use case name filters, the context matrix, user interface requirements, team organization, and quality assurance.

0201657678B04062001

About the Author:

Author Bios

Daryl Kulak is the president and CEO of Water–Logic Software (www.water–logic.com), an Internet business and technology consulting firm based in Columbus, Ohio. He is a graduate of the Northern Alberta Institute of Technology (NAIT) in Edmonton, Alberta. During much of his seventeen–year career managing software development projects in the United States and Canada, Daryl has focused on use cases, iterative/incremental development, and component design. Eamonn Guiney is a consultant at NewtonPartners (www.newtonpartners.com), a company that provides management consulting and system integration services to the money management industry. He is based in Sacramento, California. Eamonn creates business systems using a variety of tools, particularly object–oriented methodologies and use cases.

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