Use Cases & User flows

• It's a methodology for gathering requirements
• Explicits the situations/scenarios in which the system would be used

• A user flow is a detailed as a sequence diagram (part of the UML standard)

• Identify the actors/users of the system

• Identify and describe all the possible use cases
• Expand each use case in form of user flows

• Detail the actions and data of each event

• Example: "allow people to join drivers on a route, who are willing to take passengers for a fee"

• Actors
  • Driver and Rider
• Use Cases
  • Rider first time registration
  • Driver registration
  • Rider login
  • Driver login
  • Successful match and ride
  • Unsuccessful ride
• User flow ("Successful match and ride" expanded)

%% Start a ride
sequenceDiagram

autonumber

participant Rider
participant Phone
participant Driver

Driver->>Phone: Ready for pick up

Rider->>Phone: Look for a driver
activate Phone
  Phone->>Phone: Match rider to a driver

  Phone-->>Rider: Driver is found
  Phone-->>Driver: Rider is found
deactivate Phone

Driver->Phone: Start Ride
activate Phone
  Phone->Rider: Ride started
deactivate Phone

%% Ride completion
sequenceDiagram

autonumber

participant Rider
participant Phone
participant Driver

Driver->>Phone: Finish Ride
activate Phone
  Phone->>Phone: Charge rider
  Phone->>Rider: Show Receipt
  Phone->>Phone: Take service fee
  Phone->>Phone: Pay driver
  Phone-->>Driver: Show driver earnings

deactivate Phone