Activity Diagram for the Elevator System

An activity diagram is a great way to visualize the flow of messages from one activity to the other in the system. There can be different activity diagrams that we can create for our elevator system. In this lesson, we will create activity diagrams for the following two activities:

• The passenger arrives at the desired floor.

• Activity challenge: The passenger calls for the elevator.

The passenger arrives at the desired floor

The following are the states and actions that will be involved in this activity diagram.

States

Initial state: The passenger enters the elevator car.

Final state: There are two final states present in this activity diagram. These are shown below:

• The passenger arrives at the destination floor.

• The passenger is not allowed due to max load/capacity issues.

Actions

The passenger enters the elevator car. The elevator car checks if the safety limits are met. The elevator car stops at other passengers’ floors. Finally, the elevator car reaches the passenger’s desired floor.

Based on the order above, the activity diagram of a passenger arriving at their desired floor is given below.

Note: Here, the passenger is just entering the elevator, so either the up or the down button can be pressed.