Practice_Interface

Instruction

In this assignment you are going to learn how to create an interface, how to implement that interface using a class. You will also learn the benefits of using interface. For this assignment you are given two packages with the starter code which you have to use for two different tasks as described below.

Task 1

• We have a package named interface1 that includes two simple classes named Vehicle and FixedProperty.
• Create two classes Bus and House where, Bus specializes (extends) the class Vehicle and House specializes the class FixedProperty.
• Bus class needs to have the following:
  • an instance variable numberOfSeats that keeps record for number of seats in the bus.
  • a getter function to return the number of seats.
  • a constructor that sets values for all member variables.
• The House class should have
  • an instance variable area that stores the area of the house.
  • a getter function to return the area.
  • a constructor that sets values for all member variables.
• Now, write an interface ITaxable with a parameterless operation TaxValue as double TaxValue(). The operation should return the tax amount as a decimal number .
• Create the variations of class House and class Bus which implement the interface Itaxable as TaxableHouse and TaxableBus.

  • The tax for a bus is calculated as:

    -- Tax=0.01% of the price value for each seat

  • The tax for a house is calculated as

    -- If the house is located within the city : Tax=0.005% of the estimated price of the house for each square foot.

    -- Else Tax=0.001% of the price for each square foot.

• Use the given Main class to show that your program works. You may make changes in Main if you want.
• Notice that both class House and Bus have a superclass, namely FixedProperty and Vehicle, respectively. Therefore it is essential that taxation is introduced via an interface.

Task 2

• Within the package interface2 you are given an interface called Measurable which contains the single abstract method double getMeasure();.
• Create two classes named Student and Item that implements the interface Measurable such that:
  • For Student the getMeasure() returns the tution fees for a student.
  • For Item the getMeasure() returns the price of the item.
• In your Main class
  • Create a list of Student objects and a list of Item objects with different tution fees and prices.
  • Add necessary constructors, instance varibles and setter/getter functions for your classes.
  • Define a method call public static returnAverage(ArrayList list) that returns the average of any list of objects that are Measurable.
  • Now calculate and print the average tution fees for a student and the average price of an item.

Grading

• You will get 2 marks for submitting during tutorial class.
• Another 2 marks for completing all tasks.