tell a story. use case function and form first form: a narrative make a payment
Post on 18-Dec-2015
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TRANSCRIPT
Tell a Story
Use Case
Function and Form
First Form: A NarrativeMake a Payment
Narrative Form
Second Form: A ScenarioRegister Customer With Automatic Activation
Scenario Form
Third Form: A ConversationMake A Payment - General Flow
Conversation Form
Comparing the Three Forms
The Benefits of Use Cases
Use Cases Aid Understanding
Use Cases Vary by AbstractionLevel
Use Cases Vary in Scope
Use Cases Vary in Detail
What Use Cases Cannot Do
Finding Use Cases
Finding Use Cases
Naming Use Cases
Primary and Secondary Actors
Naming Actors
Group individuals according to their common use of the system. Identify the roles they take on when they use or are used by the system
Each role is a potential actor Name each role and define its distinguishing
characteristics. Add these definitions to your glossary
Don’t waste time debating actor names
Actor and Use Case Checklist
Glossary
Glossaries
Build Consensus
Defining Concepts
Identify a concept and its distinguishing characteristics
More than a synonym for a word Identifies a way of mentally dividing reality for
purpose of talking or thinking
Writing Glossary Entries
Why this concept is important Typical sizes or values Clarify likely misunderstandings Show an example Explain graphical symbols Relate entries
A Good Form for Definitions
Improving Glossary Definitions
Relating Definitions
Define Acronyms and Their Concepts
Avoid Using“Is When” or “Is Where”
Explain What Is Unclear
Setting the Stage for the Use Case
Level—summary, core, supporting, or internal use case?
Actor(s)—role names of people, objects or external systems initiating this use case
Context—the current state of the system and actor
Preconditions—what must be true before a use case can begin
Completing The Picture
Variations— different ways to accomplish use case steps Exceptions— errors that occur during the execution of a step Policies— specific rules that must be enforced by the use case Issues— questions about the use case Design notes— hints to implementers Post-conditions— what must be true about the system after a use
case completes Other requirements— what constraints must this use case conform
to Priority— how important is this use case? Frequency— how often is this performed?
Make Clear What You Don’t Know
Avoid Vague Words
Write General and Specific Cases
Actor Actions
Include System Actions
Describing Actions
Condense Information Entryand/or Validation Actions
State System Actions at aReasonably High Level
Showing Optional and Repeated Actions