Use Case Modeling
Writing Effective Use Cases
Writing Effective Use Cases
Alistair Cockburn Humans and Technology in preparation for Addison-Wesley Longman, Q3 2000.
©A.Cockburn 1999
Page 1 of 204
Writing Effective Use Cases Prologue
There are still no trusted guides about how to write (or review) use cases, even though it is now nearly a decade since use cases have become the "norm" for writing functional requirements for object-oriented software systems, and are gaining acceptance for embedded software and business process reengineering work. I can say from firsthand attempts that is very difficult to articulate what makes a use case "good", let alone how to write them so they will come out being "good". This view is shared by many teachers of use case writing. The problem is that writing use cases is fundamentally an exercise in writing natural language essays, with all the difficulties in articulating "good" that comes with natural language prose writing in general. These are the guidelines I use in writing and coaching. The ideas came from listening to my on the fly inventions, describing to beginners what is going wrong, how to think and observe to get the writing to improve. This book has those guidelines, examples of use cases, variations that make sense - - and best of all, the reassurance that a use case need not be "best" to be "useful". Even mediocre use cases are useful, more useful than many of the competing requirements files being written. So relax, write something readable, and you will have done your organization a service already. Audience This book is predominantly aimed at the professional practitioners who read and study alone. For these people, the book is organized as a self-study guide. There are introductory, intermediate and advanced concepts, reminders and rules, examples, test questions with answers, and a set of discussions around frequently asked questions. The second group of people for whom this book is intended are consultants and
Writing Effective Use Cases
Alistair Cockburn Humans and Technology in preparation for Addison-Wesley Longman, Q3 2000.
©A.Cockburn 1999
Page 1 of 204
Writing Effective Use Cases Prologue
There are still no trusted guides about how to write (or review) use cases, even though it is now nearly a decade since use cases have become the "norm" for writing functional requirements for object-oriented software systems, and are gaining acceptance for embedded software and business process reengineering work. I can say from firsthand attempts that is very difficult to articulate what makes a use case "good", let alone how to write them so they will come out being "good". This view is shared by many teachers of use case writing. The problem is that writing use cases is fundamentally an exercise in writing natural language essays, with all the difficulties in articulating "good" that comes with natural language prose writing in general. These are the guidelines I use in writing and coaching. The ideas came from listening to my on the fly inventions, describing to beginners what is going wrong, how to think and observe to get the writing to improve. This book has those guidelines, examples of use cases, variations that make sense - - and best of all, the reassurance that a use case need not be "best" to be "useful". Even mediocre use cases are useful, more useful than many of the competing requirements files being written. So relax, write something readable, and you will have done your organization a service already. Audience This book is predominantly aimed at the professional practitioners who read and study alone. For these people, the book is organized as a self-study guide. There are introductory, intermediate and advanced concepts, reminders and rules, examples, test questions with answers, and a set of discussions around frequently asked questions. The second group of people for whom this book is intended are consultants and