Use Case Explanation:
1. What are Use Cases?
- They describe how a system interacts with external users (called actors).
- Each use case represents a specific function the system provides to users.
- They help capture informal requirements.
2. Actors:
- Actors are external users that interact with the system but aren’t part of it.
3. Example:
- Imagine a vending machine system.
- Actors: Customers and Repair Technicians.
4. Use Case Examples:
- Buy a Beverage:
- Customer inserts money, selects a drink, and gets the beverage.
- Perform Scheduled Maintenance:
- Technician does routine service to keep the machine in good condition.
- Make Repairs:
- Technician fixes unexpected issues in the vending machine.
- Load Items:
- Stock clerk adds items to replenish the machine’s stock.
5. Use Case Diagrams:
- Diagrams visually represent use cases and actors.
- For our vending machine:
- 3 use cases (Buy, Maintenance, Repairs) and 1 actor (Customer).
- Extended Relationships: Maintenance and Repairs extend from the main ‘Order’ use case.
- Customer is an external actor.
In a Simpler Way:
Imagine a Vending Machine:
- Customers can buy drinks, Technicians do maintenance and repairs, and a Stock Clerk loads items.
Picture This as a Diagram:
- There’s a box (system) with 3 labeled sections (Buy, Maintenance, Repairs) and an actor (Customer) outside the box.
- Maintenance and Repairs are like special types of ordering (extended from the main order).
Why Diagrams?
- It’s like drawing a map so everyone understands how the vending machine system works without a lot of words.