Java

OOP GUIDE / WORK

VEHICLE SUPERCLASS

Topics

• Intro to Inheritance
• Using extends
• Superconstructors
• Testing inheritance

TASK – PART 1 – SETUP & EXAMINATION – THE VEHICLE CLASS

Copy and paste the following Vehicle and VehicleTester classes. Examine them to make sure you understand how they work.

public class Vehicle

{

public String owner;

public int registrationNumber;

public Vehicle(String o, int r)

{

owner = o;

registrationNumber = r;

}

public String toString()

{

return "Vehicle (Owner:" + owner + ", Reg#" + registrationNumber + ")";

}

}

public class VehicleTester

{

public static void main(String[] args)

{

Vehicle v = new Vehicle("Jimmy Twoshoes", 123456);

System.out.println(v);

}

}

TASK – PART 2 – SETUP – VEHICLE CLASS

Copy and paste the following Truck class that inherits from Vehicle. Examine it closely.

public class Truck extends Vehicle

{

public boolean hasExtendedCab;

public int payloadCapacity; //usually 1000lbs, 1500lbs or 2000lbs

public int towingCapacity; //usually between 8000 and 14000lbs

public Truck(String ow, int rn, boolean cab, int pc, int tc)

{

super(ow, rn);

hasExtendedCab = cab;

payloadCapacity = pc;

towingCapacity = tc;

}

public String requiredHitch()

{

if (towingCapacity <= 2000)

return "Class I";

else if (towingCapacity <= 3500)

return "Class II";

else if (towingCapacity <= 8000)

return "Class III";

else

return "Class IV";

}

}

TASK – PART 3 – TESTING TRUCK

Inside the Vehicle tester class, inside main, create a Truck object. You determine the parameters for your truck.

Call the requiredHitch() method from the Truck class.

Call the toString() method that is inherited from the Vehicle class.

TASK – PART 4 - TOSTRING

Create a toString() method inside truck that incorporates all instance variables from Truck and Vehicle.

Now run your tester class again. Notice that the new toString() method is called.

TASK – PART 5 – CAR CLASS

Create the Car class with the following specifications:

· It extends the Vehicle class.

· It has the following instance variables:

public int seatingSpots;

public boolean hasLeatherInterior;

public double fuelEfficiencyPer100km; //usually 5L to 10L per 100km

· It has a constructor that gets a parameter for each of the instance variables.

· It has the following method that returns true is the fullEfficiencyPer100km is 6L or less. Otherwise, it returns false.

public boolean isFullEfficient()

· It has a toString method that incorporates all instance variables from Car and Vehicle.

TASK – PART 6 – TESTING

Inside the Vehicle tester class, inside main, create a Car object. You determine the parameters for your truck.

Call the isFullEfficient() method from the Car class.

Call the toString() method.