3.1 Design a class hierarchy to model different types of trade tariffs. Your implementation should demonstrate understanding of inheritance and polymorphism.

Class Design

·         Create an abstract base class Tariff with these properties:

·         rate (double - represents percentage rate)

·         effectiveDate (String)

·         and one abstract method: double calculateDuty(double productValue)

Create three concrete subclasses that extend Tariff:

·         SteelTariff (adds property: steelType String)

·         AluminumTariff (adds property: countryOfOrigin String)

·         ChinaTariff (adds property: productCategory String)

Method Implementation

·         Implement the calculateDuty() method differently for each subclass:

·         Base calculation is productValue * rate

·         Add 5% surcharge if steelType is "stainless"

·         For AluminumTariff:

·         Base calculation is productValue * rate

·         Add 10% surcharge if countryOfOrigin is "Canada"

For ChinaTariff:

·         Flat $500 fee if productCategory is "electronics"

·         Otherwise productValue * rate

Demonstration

Create a main method that:

·         Creates an array of Tariff objects containing one instance of each subclass

·         Initializes each with appropriate values.

·         Iterates through the array, calling calculateDuty() for a sample product value of $10,000

·         Prints the calculated duty for each tariff

(25 MARKS)