There are a few ways to modify the UML class diagram in Figure 6.21 to accommodate the new automated car washing system service. Here is one possible approach:
- Add a new class called “CarWash” to represent the automated car washing system.
- Add an association between CarWash and ServiceStation, indicating that the car wash is part of the service station.
- Add attributes to CarWash, such as “typeOfWash” (string) and “fee” (float), which represent the type of wash chosen by the customer and the fee for that wash.
- Add a method to CarWash called “computeFee”, which takes as input the type of wash and type of car, computes the fee based on some algorithm, and returns it.
- Add a control panel object to CarWash that displays the amount due and accepts payment from customers.
- Add an attribute to CarWash called “isBusy” (boolean), which indicates whether or not there is currently a car being washed.
- Modify the ServiceStation class to include a reference to the CarWash object, allowing customers to access this new service when they visit.
The resulting UML diagram might look something like this:
+------------------+ +------------------+
| ServiceStation | | CarWash |
+------------------+ +------------------+
| -name: string |<>---->| -typeOfWash: string |
| -address: string | | -fee: float |
| -phone: string | | +computeFee(): float|
| -carCount: int | | -controlPanel |
+------------------+ | -isBusy: boolean |
+------------------+
