Question

This question is designed to test your understanding and application of inheritance,composition, polymorphism, exceptions and file handling. You are required to write classes
representing a taxi fleet made up of cars and vans.
Section A
You are to write three classes named Fleet, Car and Van, to represent the fleet of a taxi company. An Fleet object is composed of upto 5 Car objects and 2 Van objects. In addition to the methods specified below you are free to place any necessary methods to promote code reuse. The Car class has three attributes ID, age and cost. It has two methods: …. It should also have a constructor ….. Assume age is always an integer. The Van is the subclass of Car, in addition to the attributes and methods of the Car class, has a surchargeRate attribute and the calculateSurcharge () method. …..This class should also have a constructor …
The Fleet class has four methods:
(1) to add a car
(2) to add a van
(3) calculate the total cost, and
(4) calculate the total surcharge.
Section B
In this section you are required to read the data from a file fleet.txt and then perform the following tasks.
…….
You may omit extra getter and setter methods for simplicity during exam conditions unless otherwise stated.
You do not need to consider imports or packaging. You may make use of the Scanner class to read from a file which as the format:
Scanner scan = new Scanner(new File(“fleet.txt”);

Answer 1

Car.java

public class Car {
private String id;
private int age;
private double cost;
  
public Car()
{
this.id = "";
this.age = 0;
this.cost = 0;
}

public Car(String id, int age, double cost)
{
this.id = id;
this.age = age;
this.cost = cost;
}

public String getId() {
return id;
}

public int getAge() {
return age;
}

public double getCost() {
return cost;
}
  
@Override
public String toString()
{
return ("Id: " + getId() + ", Age: " + getAge() + ", Cost: $" + String.format("%.2f", getCost()));
}
}

Van.java

public class Van extends Car{
private double surchargeRate;
  
public Van()
{
super();
this.surchargeRate = 0;
}
  
public Van(String id, int age, double cost)
{
super(id, age, cost);
}
  
public Van(String id, int age, double cost, double surchargeRate)
{
super(id, age, cost);
this.surchargeRate = surchargeRate;
}

public double getSurchargeRate() {
return surchargeRate;
}
  
public double calculateSurcharge()
{
return (getCost() * (getSurchargeRate() / 100));
}
  
@Override
public String toString()
{
return(super.toString() + ", Surcharge rate: " + String.format("%.2f", getSurchargeRate())
+ ", Surcharge amount: $" + String.format("%.2f", calculateSurcharge()));
}
}

Fleet.java

import java.io.File;
import java.io.FileNotFoundException;
import java.util.ArrayList;
import java.util.Scanner;

public class Fleet {
  
private ArrayList<Van> fleet = new ArrayList<>();
  
public void readFile(String fileName)
{
File file = new File(fileName);
Scanner scan;
try
{
scan = new Scanner(file);
while(scan.hasNextLine())
{
String line = scan.nextLine().trim();
if(line.contains("C")) // it's a Car
{
String[] data1 = line.split(" ");
String id = data1[0];
int age = Integer.parseInt(data1[1]);
double cost = Double.parseDouble(data1[2]);
addCar(new Van(id, age, cost));
}
else if(line.contains("V")) // it's a Van
{
String[] data2 = line.split(" ");
String id = data2[0];
int age = Integer.parseInt(data2[1]);
double cost = Double.parseDouble(data2[2]);
double surchargeRate = Double.parseDouble(data2[3]);
addCar(new Van(id, age, cost, surchargeRate));
}
}
}catch(FileNotFoundException fnfe){
System.out.println("Could not find file: " + fileName);
}
}
  
public void addCar(Van van)
{
this.fleet.add(van);
}
  
public ArrayList<Van> getFleet(){ return this.fleet; }
  
public double calculateTotalCost()
{
double totalCost = 0;
for(int i = 0; i < getFleet().size(); i++)
{
totalCost += getFleet().get(i).getCost();
}
return totalCost;
}
  
public double calculateTotalSurcharge()
{
double totalSurcharge = 0;
for(int i = 0; i < getFleet().size(); i++)
{
totalSurcharge += getFleet().get(i).calculateSurcharge();
}
return totalSurcharge;
}
  
public void printAllCars()
{
System.out.println("===== ALL CARS =====\n--------------------");
for(int i = 0; i < getFleet().size(); i++)
{
if(getFleet().get(i).getId().contains("C"))
System.out.println(getFleet().get(i).toString());
}
}
  
public void printAllVans()
{
System.out.println("===== ALL VANS =====\n--------------------");
for(int i = 0; i < getFleet().size(); i++)
{
if(getFleet().get(i).getId().contains("V"))
System.out.println(getFleet().get(i).toString());
}
}
}

FleetDemo.java (Main class)

public class FleetDemo {

private static final String FILENAME = "fleet.txt";
  
public static void main(String[]args)
{
Fleet fleet = new Fleet();
fleet.readFile(FILENAME);
  
fleet.printAllCars();
System.out.println();
fleet.printAllVans();
System.out.println();
  
System.out.println("Total Cost: $" + String.format("%.2f", fleet.calculateTotalCost()));
System.out.println("Total Surcharge: $" + String.format("%.2f", fleet.calculateTotalSurcharge()) + "\n");
}
}

********************************************************************* SCREENSHOT ******************************************************

fleet.txt (below):

Sample Output: