Java- Using a constructor to place in values for a method?

Question

I have two classes here:

public class Invoice {

    ArrayList<Double> ItemPrices= new ArrayList<Double>();
    ArrayList<Boolean> ItemIsPet = new ArrayList<Boolean>();
    ArrayList<Integer> ItemQuantitys = new ArrayList<Integer>();

    public void add(Item anItem){

    }


    public static void main(String args[]){

        int counter = 0;
        boolean pet;
        Scanner s = new Scanner(System.in);

        do {

            System.out.println();
            System.out.print("Item " + counter+1 + ":");
            System.out.println();

            System.out.print("Please enter the item's price: ");
            double inputprice = s.nextDouble();

            System.out.println();
            System.out.print("Is this item a pet? (Y/N): ");
            String inputIsPet = s.next();
            if (inputIsPet.equals('Y')){
                pet = true;
            }
            else {
                pet = false;
            }
            System.out.println();

            System.out.print("What is the quantity of this item?: ");
            int inputquantity = s.nextInt();


            Item newItem = new Item(inputprice, pet, inputquantity);

            counter += 1;

        } while (true);

    }
}

And here is the second class:

public class Item {

    Invoice Inv = new Invoice();

    public Item(double price, boolean isPet, int quantity){

    }

}

My question is for this line right here:

Item newItem = new Item(inputprice, pet, inputquantity);

So I have those 3 necessary arguments from the user input so that I can make a new object newItem of type item, but my question is once I have object newItem, how can I access those inputted arguments? My assignment is forcing me to implement this particular "add" method:

public void add(Item anItem)

Basically, the way I want to use this method is to take the inputted arguments from here:

Item newItem = new Item(inputprice, pet, inputquantity);

and have the "add" method access them, and from there put them into these arrays:

ArrayList<Double> ItemPrices= new ArrayList<Double>();
ArrayList<Boolean> ItemIsPet = new ArrayList<Boolean>();
ArrayList<Integer> ItemQuantitys = new ArrayList<Integer>();

But how do I access the parts of the object newItem? Do I have to modify my constructor in some way?

Add instance fields and getters to the Item class and you are good to go — Jack Flamp
– Jack Flamp, Commented Apr 16, 2018 at 7:03
Are those arrays part of your assignment? I'd guess not, because they look very clunky and un-OO. — Robby Cornelissen
– Robby Cornelissen, Commented Apr 16, 2018 at 7:03

Andrew · Accepted Answer · 2018-04-16 07:15:08Z

3

Do I have to modify my constructor in some way?

Yes, you need to save incoming values into instance fields.

public class Item {

    private final double price;
    private final boolean isPet;
    private final int quantity;

    public Item(double price, boolean isPet, int quantity) {
        this.price = price;
        this.isPet = isPet;
        this.quantity = quantity;
    }

}

How can I access those inputted arguments?

Then you can write a getter for each field you want to access to.

public double getPrice() {
    return price;
}

How do I access the parts of the object newItem?

Now you can.

double price = newItem.getPrice();

edited Apr 16, 2018 at 7:15

answered Apr 16, 2018 at 7:07

Andrew

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1 Comment

Andrew Over a year ago

@MatthewButner, you may accept the answer if it was helpful

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