Analysis & Design

  1. Get Requirements
  2. Describe the app
  3. Identify Main Objects
  4. Describe Interactions
  5. Create Class Diagram

 

Requirements Analysis

 

  • Functional
    • Features
    • Capabilities
  • Non-Func
    • Help
    • Legal
    • Performance
    • Support
    • Security
  • FURPS
    • Functional
    • Usability
    • Reliability
    • Performance
    • Supportability

Expect Requirements to Change!

 

Expect something documented

 

 

Use Cases

 

User focus

 

Specify how user interacts with app

 

Use Case

  • Title What’s the goal? Keep it short
  • Actor Who wants it? Different people types or computers / data
  • Steps How do you achieve it? Single Paragraph, or Numbered List

Max of 1 or 2 days. Anything else is focussing on use cases, not the product!

 

Remember, requirements will change, stuff will have to be revisited / redone!

 

Actors

 

Can be user, application, system

 

ID Actors

  • External Systems / Organisations
  • Roles / Security Groups
  • Job Titles / Departments

Focus should be on the goal that the actor wants to achieve

 

 

Scenarios

 

  • Describes a goal that an actor can accomplish in a single encounter
  • Focus on the actors goal, not what they need to do to achieve that goal
  • Can have multiple scenarios
  • Go for simplicity
  • Use active voice
  • Omit needless words / detail
  • Not pseudo code / too much detail
  • Focus on intention
  • Use Case Prompts
    • Who does Sys admin?
    • Who Managers users & security?
    • What happens if system fails?
    • Is anyone looking at performance metrics / logs?

 

Use Case Diagrams

 

Diagram of several use cases, looked at the same time

 

To get the bigger picture

 

  • List the goals, the use cases – draw ellipse around each
  • Draw box around all the goals
  • List the actors – use stick figures
  • Draw line from actor to goals
  • Add any non-human systems, on the other side

  • Primary actors on the LHS. These are the actors that initiate
  • Secondary actors on the RHS. These actors take more of a reactive role
  • No order / sequence

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