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Abstract Classes

I have created an Abstract Class 'Vehicle' to cover Cars, Minibuses and Trucks. Unfortunatley I have no experience with using Abstract classes and can't get the code to function.

Any assistance would be greatly appreciated!

import javax.swing.JOptionPane;
public abstract class Vehicle{

//instance variables
public String make, colour, registration, motDue;

// Constructor
public Vehicle(String make, String colour, String registration, String motDue){
      setMake(make);
      setColour(colour);
      setRegistration(registration);
      setMot(motDue);
}

// Create Text for Output
public String toString() {
String output;

output = "Description: Car\n";
output = output + "Make: " + make + "\n";
output = output + "Colour: " + colour + "\n";
output = output + "Registration: " + registration + "\n";
output = output + "MOT Due: " + motDue + "\n";

return output;
}

public void printDetails(){
String output;

output = toString();
JOptionPane.showMessageDialog(null,output,"Details",JOptionPane.INFORMATION_MESSAGE);
}

//Set methods for properties

public void setMake(String aMake){
make = aMake;
}

public void setColour(String aColour){
colour = aColour;
}

public void setRegistration(String aRegistration){
registration = aRegistration;
}

public void setMot(String aMot){
motDue = aMot;
}

} //end class

import javax.swing.JOptionPane;
public class Car extends Vehicle{

//instance variables
private String make, colour, registration, motDue;

// Constructor
public Car(String make, String colour, String registration, String motDue){
      setMake(make);
      setColour(colour);
      setRegistration(registration);
      setMot(motDue);
}

// Create Text for Output
public String toString() {
String output;

output = "Description: Car\n";
output = output + "Make: " + make + "\n";
output = output + "Colour: " + colour + "\n";
output = output + "Registration: " + registration + "\n";
output = output + "MOT Due: " + motDue + "\n";

return output;
}

public void printDetails(){
String output;

output = toString();
JOptionPane.showMessageDialog(null,output,"Details",JOptionPane.INFORMATION_MESSAGE);
}

//Set methods for properties

public void setMake(String aMake){
make = aMake;
}

public void setColour(String aColour){
colour = aColour;
}

public void setRegistration(String aRegistration){
registration = aRegistration;
}

public void setMot(String aMot){
motDue = aMot;
}

} //end class

public class Main {
public static void main (String args[]){

VehicleHireCompany vhc = new VehicleHireCompany("Vehicle Hire Ltd.");
Vehicle v1 = new Car("Vauxhall", "Red", "MD03 PUV", "12th March 2009");
Vehicle v2 = new Car("Subaru", "Silver", "ST05 HNX", "14th January 2007");
Vehicle v1 = new Minibus("Ford", "White", "ST03 HGF", "14th January 2007", 15);
Vehicle v4 = new Minibus("Mercedes", "Blue", "GH05 HKL", "27th July 2008", 13);
Truck v5 = new Truck("Iveco", "Green", "SK05 GDL", "21st August 2008", 3);

// Make Association
vhc.ownsVehicle(v1);
vhc.ownsVehicle(v2);
vhc.ownsVehicle(v3);
vhc.ownsVehicle(v4);
vhc.ownsVehicle(v5);

// Print List of Cars
vhc.printDetails();

System.exit(0);
}
}

Mick Barry

Looks like your Car class can just be:

public class Car extends Vehicle{
// Constructor
public Car(String make, String colour, String registration, String motDue){
setMake(make);
setColour(colour);
setRegistration(registration);
setMot(motDue);
}
}

There appears to be no difference between a Car and a Vehicle so I don't see why you need a Vehicle class.

You'll also need to define your Minibus and Truck classes.

helpmeoot

ASKER

Objects. This is a continuation from some help you gave me last week.

I have classes for Minibus and Truck but didnt post the code. I felt if I got the car class working I could amend the rest.

If i take the code out for creating the output text in each vehicle, how can I print the different attributes?

There isnt a difference between Car and a 'Standard Vehicle'. However, I have to set the hierarchy up to be able to add different vehicle types in the future.

I had the code working with Car as the superclass and truck/minibus as subclasses. It was pointed out to me though that this was incorrect.

import javax.swing.JOptionPane;

public class Truck extends Vehicle{

//instance variables
private String make, colour, registration, motDue;
private int payload;

// Constructor
public Truck(String make, String colour, String registration, String motDue, int payload){
super(make, colour, registration, motDue);
setPayload(payload);

}

// Create Text for Output
public String toString() {
String output;

output = "Make: " + make + "\n";
output = output + "Colour: " + colour + "\n";
output = output + "Registration: " + registration + "\n";
output = output + "MOT Due: " + motDue + "\n";
output = output + "Max Payload (t): " + payload + "\n";

return output;
}

public void printDetails(){
String output;

output = toString();
JOptionPane.showMessageDialog(null,output,"Vehicle Hire - Truck Details",JOptionPane.INFORMATION_MESSAGE);
}

//Set methods for properties

public void setMake(String aMake){
make = aMake;
}

public void setColour(String aColour){
colour = aColour;
}

public void setRegistration(String aRegistration){
registration = aRegistration;
}

public void setMot(String aMot){
motDue = aMot;
}

public void setPayload(int aPayload){
payload = aPayload;
}

//Get methods for properties

public String getMake(){
return make;
}

ASKER CERTIFIED SOLUTION

Mick Barry

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