Use Case Description
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- Use Case name: Select Destination
- Summary: The user in the elevator presses an up or down elevator button to select a destination floor to which move
- Dependency
- Actor: Elevator User (primary), Arrival Sensor
- Precondition: User in the elevator
- Description:
- 1.User presses an up elevator button. The elevator button sensor sends the elevator button request to the system, identifying the destination floor the user wishes to visit.
- 2.The new request is added to the list of floors to visit. If the elevator is stationary, The system determines in which direction the system should move in order to service the next request. The system commands the elevator door to close. When the door has closed, the system commands the motor to start moving the elevator, either up or down.
- 3.As the elevator moves between floors, the arrival sensor detects that the elevator is approaching a floor and notifies the system. The system checks whether the elevator should stop at this floor. If so, the system commands the motor to stop. When the elevator has stopped, the system commands the elevator door to open.
- If there are other outstanding requests, the elevator visits these floors on the way to the floor requested by the user. Eventually, the elevator arrives at the destination floor selected by the user.
- Alternatives:
- 1.User presses down elevator button to move down. System response is the same as for the main sequence.
- 2.If the elevator is at a floor and there is no new floor to move to, the elevator stays at the current floor, with the door open.
- Postcondition: Elevator has arrived at the destination floor selected by the user.