inheritance, extended class.

[Mohamed Suood]

I am trying to complete my exercise but I have issues in it. I would be very grateful if you help me.

Here is my abstract Boat class.

public abstract class Boat{
	private int height;
	private int length;
	private int width;
	private double boatValue;
	private double chargeRate;
	private Owner owner;
	public Owner getOwner() {
		return owner;
	}
	
	public void setOwner(Owner owner) {
		this.owner = owner;
	}
	
	public Boat(){
		height=0;
		length=0;
		width=0;
		boatValue=0.0;
		chargeRate=0.0;
	}
	
	public int getHeight() {
		return height;
	}
	
	public void setHeight(int height) {
		this.height = height;
	}
	
	public int getLength() {
		return length;
	}
	
	public void setLength(int length) {
		this.length = length;
	}
	
	public int getWidth() {
		return width;
	}
	
	public void setWidth(int width) {
		this.width = width;
	}
	
	public double getBoatValue() {
		return boatValue;
	}
	
	public void setBoatValue(double boatValue) {
		this.boatValue = boatValue;
	}
	
	public double getChargeRate() {
		return chargeRate;
	}
	
	public void setChargeRate(double chargeRate) {
		this.chargeRate = chargeRate;
	}
	
	public Boat(int height,int length,int width, double boatValue, double chargeRate){
		setHeight(height);	
		setLength(length);
		setWidth(width);
		setBoatValue(boatValue);
		setChargeRate(chargeRate);
	}
	
	public abstract double totalMonthlyCharge();
	
	@Override
	public String toString() {
		return "BOAT height=" + height + ", length=" + length + ", width="
				+ width + ", boatValue=" + boatValue + ", chargeRate="
				+ chargeRate;
	}
}

Here is my extended class SailBoat.

public class SailBoat extends Boat {
	private int mastHeight;
	private int sailArea;
	
	@Override
	public double totalMonthlyCharge() {
		// TODO Auto-generated method stub
		return 0;
	}
	
	public SailBoat(){
		mastHeight = 0;
		sailArea = 0;
	}
	
	public SailBoat(int height,
					int length,
					int width, 
					double boatValue, 
					double chargeRate, 
					int mastHeight, 
					int sailArea){
		super();
		this.mastHeight = mastHeight;
		this.sailArea = sailArea;
	}
	
	
	public int getMastHeight() {
		return mastHeight;
	}

	public void setMastHeight(int mastHeight) {
		this.mastHeight = mastHeight;
	}

	public int getSailArea() {
		return sailArea;
	}

	public void setSailArea(int sailArea) {
		this.sailArea = sailArea;
	}

	public int  sailArea(int mastHeight, int length ){
		sailArea = mastHeight * length;
		return sailArea;
	}
	
	public double sailRate(){
		double sailRate = sailArea * 0.01;
		return sailRate;
	}
	
	public String toString(){
		return super.toString() + ", Mast Height="
				+ mastHeight + ", Sail Area=" + sailArea;
	}
}

and here is my driver class.

public class BoatStorage  {
	
	public static void main(String[] args){
		Boat[] boatList = new Boat[20];
		boatList[0] = new SailBoat();
		
		boatList[0].setHeight(12);
		boatList[0].setLength(12);
		boatList[0].setWidth(12);
		boatList[0].setBoatValue(250);
		boatList[0].setChargeRate(12);
		boatList[0].setMastHeight(12);   // <<=== something is woring here in this line.
		
		boatList[1] = new MotorBoat(33,33,33,130.0,13.0);
		
		System.out.println(boatList[0].toString());
		System.out.println(boatList[1].toString());
		Owner[] ownersList = new Owner[20];
	}
}

[Joanne Neal]

Did you have an actual question ?
TellTheDetails

[Paweł Baczyński]

And the question / problem is?

Welcome to the Ranch!

[Prabhakar Reddy Bokka]

Mohamed Suood wrote:
boatList[0].setMastHeight(12); // <<=== something is woring here in this line.

The issue is... setMastHeight(12) method is not a method of Boat class, and your instance is of a Boat class. Hence the issue.
If you want to set setMastHeight, you need to use the instace of SailBoat class.

[Campbell Ritchie]

Welcome to the Ranch
Consider adding a setMastHeight method to the Boat class. If Boat is abstract, the method can be abstract, too.

[Joanne Neal]

Prabhakar Reddy Bokka wrote:and your instance is of a Boat class.

To be more precise the reference variable is of type Boat and that is what is used to determine what methods can be called.
The instance is actually a SailBoat object.

[Joanne Neal]

Campbell Ritchie wrote:Consider adding a setMastHeight method to the Boat class. If Boat is abstract, the method can be abstract, too.

But not all boats have masts, so that would not be a good design.

If you want to add a SailBoat instance to the array, you need to create it separately and then add it
e.g.

SailBoat sb = new SailBoat();  
sb.setHeight(12);  
sb.setLength(12);  
sb.setWidth(12);  
sb.setBoatValue(250);  
sb.setChargeRate(12);  
sb.setMastHeight(12);
boatList[0] = sb;

Alternatively you could have a constructor that sets all the variables as you appear to have with your MotorBoat class.

Or a third alternative is to use the Builder pattern.