Adapter pattern

• What problem does Adapter pattern solve?

Suppose we have a common PriceCalculator interface for:

- CarPriceCalculator 

- TruckPriceCalculator 

in order to call printVehiclePrice() for both of them:

At some point, we may want to add an extra UKPriceCalculator, that doesn't/shouldn't belong (e.g. a third party calculator) to above hierarchy, and thus cannot implement PriceCalculator, and cannot call printVehiclePrice()

• How does Adapter pattern solve this?

1. Create an Adapter class implementing PriceCalculator interface
2. Add a UKCarPriceCalculator class property

3. Override PriceCalculator's calculatePrice(), referring UKCarPriceCalculator methods

4. Finally, use the new Adapter class in main method