Question

Please help me with this code. Thank you

Implement the following Java class: Vehicle

Class should contain next instance variables:

• Integer numberOfWheels;
• Double engineCapacity;
• Boolean isElectric,
• String manufacturer;
• Array of integers productionYears;

Supply your class with:

1. Default constructor (which sets all variables to their respective default values)
2. Constructor which accepts all the variables
3. All the appropriate getters and setters (you may skip comments for this methods. Also, make sure that for engineCapacity setter method you check first if the vehicle is electric. If it is not – set engineCapacity to the new value, but if it is electric – leave the value at 0 and display an error message);

Your class will implement following methods:

1. Public void addProductionYear(int year); *
2. Public Boolean isSameManufacturer(Vehicle v); **
3. Public String toString(); ***

* - this method will expand array productionYears by 1 element and place argument int as the last subscript

** - this method will compare two objects by checking whether or not the manufacturer variables are the same

*** - this method will output all the information with a neat formatting

Write a driver program which will creates at least 2 object of this Class and tests all the methods

Answer 1

Here is the completed code for this problem. Comments are included, go through it, learn how things work and let me know if you have any doubts or if you need anything to change. If you are satisfied with the solution, please rate the answer. Thanks

// Vehicle.java

import java.util.Arrays;

public class Vehicle {

              // attributes

              private int numberOfWheels;

              private double engineCapacity;

              private boolean isElectric;

              private String manufacturer;

              private int[] productionYears;

              // default constructor

              public Vehicle() {

                           numberOfWheels = 0;

                           engineCapacity = 0;

                           isElectric = false;

                           manufacturer = "";

                           productionYears = new int[0];

              }

              // constructor taking initial values for all elements

              public Vehicle(int numberOfWheels, double engineCapacity,

                                         boolean isElectric, String manufacturer, int[] productionYears) {

                           this.numberOfWheels = numberOfWheels;

                           this.isElectric = isElectric;

                           // validating and setting engine capacity

                           if(!isElectric){

                                         setEngineCapacity(engineCapacity);

                           }

                           this.manufacturer = manufacturer;

                           this.productionYears = productionYears;

              }

              // getters and setters

              public int getNumberOfWheels() {

                           return numberOfWheels;

              }

              public void setNumberOfWheels(int numberOfWheels) {

                           this.numberOfWheels = numberOfWheels;

              }

              public double getEngineCapacity() {

                           return engineCapacity;

              }

              public void setEngineCapacity(double engineCapacity) {

                           // checking if vehicle is electric

                           if (isElectric) {

                                         // error

                                         System.out.println("Error: can't set engine capacity"

                                                                    + " for an electric vehicle");

                                         engineCapacity = 0;

                           } else {

                                         // setting the value

                                         this.engineCapacity = engineCapacity;

                           }

              }

              public boolean isElectric() {

                           return isElectric;

              }

              public void setElectric(boolean isElectric) {

                           this.isElectric = isElectric;

              }

              public String getManufacturer() {

                           return manufacturer;

              }

              public void setManufacturer(String manufacturer) {

                           this.manufacturer = manufacturer;

              }

              public int[] getProductionYears() {

                           return productionYears;

              }

              public void setProductionYears(int[] productionYears) {

                           this.productionYears = productionYears;

              }

              // method to add production year to the array

              public void addProductionYear(int year) {

                           // creating a new array with one size more than productionYears

                           int[] newArray = new int[productionYears.length + 1];

                           // copying all elements from productionYears to newArray

                           for (int i = 0; i < productionYears.length; i++) {

                                         newArray[i] = productionYears[i];

                           }

                           // adding year at the end of newArray

                           newArray[productionYears.length] = year;

                           // replacing productionYears with newArray

                           productionYears = newArray;

              }

              // returns true if two vehicles have same manufacturer

              public boolean isSameManufacturer(Vehicle v) {

                           return this.manufacturer.equalsIgnoreCase(v.manufacturer);

              }

              @Override

              public String toString() {

                           // creating and returning a properly formatted String containing all

                           // info

                           String data = "Number of wheels: " + numberOfWheels

                                                       + ", Engine capacity: " + engineCapacity + "\n";

                           data += "Is electric: " + isElectric + "\n";

                           data += "Manufacturer: " + manufacturer + "\n";

                           data += "Production years: " + Arrays.toString(productionYears);

                           return data;

              }

}

// Test.java

public class Test {

              public static void main(String[] args) {

                           // Testing Vehicle class and methods

                           Vehicle v1 = new Vehicle();

                           System.out.println("V1\n" + v1);

                           v1.setManufacturer("Ford");

                           v1.setNumberOfWheels(4);

                           v1.setEngineCapacity(200);

                           v1.addProductionYear(1994);

                           v1.addProductionYear(1996);

                           v1.addProductionYear(1997);

                           v1.addProductionYear(1999);

                           System.out.println("V1 updated: \n" + v1);

                           Vehicle v2 = new Vehicle(4, 0, true, "Tesla", new int[] { 2016, 2017 });

                            System.out.println("V2\n" + v2);

                           v2.setEngineCapacity(299);

                           System.out.println("V2\n" + v2);

                           System.out.println("V1 and V2 have same manufacturers? "+v1.isSameManufacturer(v2));

                           v1.setManufacturer("Tesla");

                           System.out.println("now V1 and V2 have same manufacturers? "+v1.isSameManufacturer(v2));

              }

}

/*OUTPUT*/

V1

Number of wheels: 0, Engine capacity: 0.0

Is electric: false

Manufacturer:

Production years: []

V1 updated:

Number of wheels: 4, Engine capacity: 200.0

Is electric: false

Manufacturer: Ford

Production years: [1994, 1996, 1997, 1999]

V2

Number of wheels: 4, Engine capacity: 0.0

Is electric: true

Manufacturer: Tesla

Production years: [2016, 2017]

Error: can't set engine capacity for an electric vehicle

V2

Number of wheels: 4, Engine capacity: 0.0

Is electric: true

Manufacturer: Tesla

Production years: [2016, 2017]

V1 and V2 have same manufacturers? false

now V1 and V2 have same manufacturers? true