Question

Using your Barrel class and Temperature class create a VacuumBarrel class that extends the Barrel class and incorporates a Temperature as the private data of the VacuumBarrel. Provide constructors, add(VacuumBarrel), subtract(VacuumBarrel), divide(int), equals(VacuumBarrel), greaterThan(VacuumBarrel) (that has one parameter and returns true if the this is greater than the parameter), toKelvin(), toFahrenheit(), toCelsius(), and toString() methods. Use a similar demo to the one you used with the Temperature class. This demo will put instances of VacuumBarrel in three arrays and manipulates them.

The VacuumBarrel class extends Barrel so it is a Barrel. The data of the Barrel class should be private so the code answer.marbles = this.marbles + other.marbles; will not compile. The Barrel methods are inherited however and they can be used to make the addition. The Barrel class should have method set(int) that can be used to set the value of marbles to the integer parameter. The Barrel class should have method get() that will return the value of a Barrel. If the values of the two Barrels can be found then an addition is easy. It is also possible that the Barrel class has method set(Barrel) that will set the value of marbles to the parameter’s value. The method add(Barrel) of the Barrel class returns a Barrel. Using these two methods will also give the value for VacuumBarrel answer.

The VacuumBarrel has a private Temperature that can use the methods from the Temperature class. In the VacuumBarrel the private data degree and scale of the Temperature class cannot be used. If the private data in the VacuumBarrel is called temp then this value can be accessed with this code: answer.temp, this.temp and other.temp.

Answer 1

Here is the code,

The question is not completely clear, but I have tried to what I understood, If you feel there need some changes required then let me know I will try to fix that as well.

One thing that was not mentioned was the return types of the given method to be implemented like: add(VacuumBarrel), subtract(VacuumBarrel), divide(int), equals(VacuumBarrel), etc.

Barrel.java

public class Barrel {
    private int marbles;

    public void setMarbles(int marbles) {
        this.marbles = marbles;
    }

    public int getMarbles() {
        return marbles;
    }

    public void set(Barrel barrel){
        this.marbles = barrel.getMarbles();
    }

    public Barrel add(Barrel barrel){
        Barrel addBarrel = new Barrel();
        addBarrel.setMarbles(this.marbles + barrel.getMarbles());
        return addBarrel;
    }
}

Temperature.java

public class Temperature {
    private double degree;
    private String scale;

    public Temperature(double degree, String scale) {
        this.degree = degree;
        this.scale = scale;
    }

    public double getDegree() {
        return degree;
    }

    public void setDegree(double degree) {
        this.degree = degree;
    }

    public String getScale() {
        return scale;
    }

    public void setScale(String scale) {
        this.scale = scale;
    }
}

VacuumBarrel.java

public class VacuumBarrel extends Barrel{
    private Temperature temperature;

    public VacuumBarrel(Temperature temperature){
        this.temperature = temperature;
        if(!this.temperature.getScale().equals("celsius")){
            this.temperature = toCelsius();
            this.temperature.setScale("celsius");
        }
    }

    public VacuumBarrel add(VacuumBarrel obj){
        VacuumBarrel additionBarrel = new VacuumBarrel(this.temperature);
        if(!obj.temperature.getScale().equalsIgnoreCase("celsius")){
            obj.temperature = obj.toCelsius();
            obj.temperature.setScale("celsius");
        }
        additionBarrel.temperature.setDegree(additionBarrel.temperature.getDegree() + obj.temperature.getDegree());
        additionBarrel.temperature.setScale("celsius");
        return additionBarrel;
    }

    public VacuumBarrel subtract(VacuumBarrel obj){
        VacuumBarrel additionBarrel = new VacuumBarrel(this.temperature);
        if(!obj.temperature.getScale().equalsIgnoreCase("celsius")){
            obj.temperature = obj.toCelsius();
            obj.temperature.setScale("celsius");
        }
        additionBarrel.temperature.setDegree(additionBarrel.temperature.getDegree() - obj.temperature.getDegree());
        additionBarrel.temperature.setScale("celsius");
        return additionBarrel;
    }

    public VacuumBarrel divide(VacuumBarrel obj){
        VacuumBarrel additionBarrel = new VacuumBarrel(this.temperature);
        if(!obj.temperature.getScale().equalsIgnoreCase("celsius")){
            obj.temperature = obj.toCelsius();
            obj.temperature.setScale("celsius");
        }
        additionBarrel.temperature.setDegree(additionBarrel.temperature.getDegree() / obj.temperature.getDegree());
        return additionBarrel;
    }

    public boolean equals(VacuumBarrel obj){
        return this.temperature == obj.temperature;
    }

    public boolean greaterThan(VacuumBarrel obj){
        if(!obj.temperature.getScale().equalsIgnoreCase("celsius")){
            obj.temperature = obj.toCelsius();
            obj.temperature.setScale("celsius");
        }
        return this.temperature.getDegree() > obj.temperature.getDegree();
    }

    public Temperature toKelvin(){
        Temperature mTemp;
        if(this.temperature.getScale().equalsIgnoreCase("celsius")){
            double tempInKelvin = this.temperature.getDegree() + 273.15;
            return new Temperature(tempInKelvin, "kelvin");
        }
        else{
            double tempInKelvin = 273.5f + ((this.temperature.getDegree() - 32.0f) * (5.0f/9.0f));
            return new Temperature(tempInKelvin, "kelvin");
        }
    }

    public Temperature toFahrenheit(){
        Temperature mTemp;
        if(this.temperature.getScale().equalsIgnoreCase("celsius")){
            double tempInFahrenheit = this.temperature.getDegree() * (9f / 5) + 32;
            return new Temperature(tempInFahrenheit, "fahrenheit");
        }
        else{
            double tempInFahrenheit = ((this.temperature.getDegree() - 273.15) * 1.8) + 32;
            return new Temperature(tempInFahrenheit, "fahrenheit");
        }
    }

    public Temperature toCelsius(){
        Temperature mTemp;
        if(this.temperature.getScale().equalsIgnoreCase("fahrenheit")){
            double tempInCelsius =(( 5 *(this.temperature.getDegree() - 32.0)) / 9.0);
            return new Temperature(tempInCelsius, "celsius");
        }
        else{
            double kelvin = this.temperature.getDegree();
            double tempInCelsius = kelvin - 273.15F;
            return new Temperature(tempInCelsius, "celsius");
        }
    }

    @Override
    public String toString() {
        return "VacuumBarrel{" +
                "temperature=" + temperature +
                '}';
    }
}

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