JAVA adding object to ArrayList of different Class,constantly replace 0 index and doesnt get bigger

Question

I am trying to finish my home assignment for programming class, unfortunately getting stuck through half of it ,due to my stupidity. ArrayList that I have created overwrites 0 index constantly.

Here are my classes for creating invoices:

import java.util.ArrayList;

public class Order 
{
    private String customerName;
    private ArrayList<LineItem> items = new ArrayList<LineItem>();

    public Order(String customerName)
    {
        this.customerName = customerName;
    }

    public String getCustomerName()
    {
        return customerName;
    }

    public ArrayList<LineItem> getItems()
    {   
        return this.items;
    }

    public double getOrderTotal()
    {

        double totalOrder = items.get(0).getTotalPrice();
        return totalOrder;
    }

    public void addItem(String description,double unitPrice, int quantity)
    {
        LineItem object = new LineItem(description,unitPrice,quantity);
        items.add(object);
    }

    public String toString()
    {
        String.format("%n%-20s%-15s%-15f%-15f",items.get(0).getDescription(),
    items.get(0).getQuantity(),items.get(0).getUnitPrice(),getOrderTotal());

        return p;`                           

    }

}

public class LineItem
{
    private String description;
    private double unitPrice;
    private int quantity;

    public LineItem(String description,double unitPrice, int quantity)
    {
        this.description = description;
        this.unitPrice = unitPrice;
        this.quantity = quantity;
    }
    public String getDescription()
    {
        return this.description;
    }

    public double getUnitPrice()
    {
        return this.unitPrice;
    }

    public int getQuantity()
    {
        return this.quantity;
    }

    public double getTotalPrice()
    {
        return this.unitPrice * this.quantity;
    }
    public String toString()
    {
        return  String(this.description,this.unitPrice,this.quantity)     
    }
}

AND a part of ... while LOOP for main class

do
{

    customerName = AssignmentHelper.getRequiredStringInput("Please enterthe customer's name: ","A customer name must be entered!");

    newOrder = new Order(customerName);
    newOrder.addItem(description,unitPrice,quantity);

} while(Character.toString(userAnswer).equalsIgnoreCase ("Y"));

Eran · Accepted Answer · 2016-04-12 05:44:55Z

4

Your loop creates a new Order object in each iteration :

newOrder = new Order(customerName);

Each Order object has a new empty ArrayList, which is why it seems the first index is always overwritten.

If you want a single ArrayList to hold all the items, you should create a single Order object prior to the do-while loop.

newOrder = new Order(customerName);
do {
    ...
    newOrder.addItem(description,unitPrice,quantity);
} while(Character.toString(userAnswer).equalsIgnoreCase ("Y"));

answered Apr 12, 2016 at 5:44

Eran

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3 Comments

Denys Fiialko Over a year ago

do you know how can i itirate through ArrayList insie the toString().Ideally i guess it suppose to override the TO String method from LineItem.

Eran Over a year ago

@DenysFiialko What exactly do you want to do? Print the contents of the ArrayList?

Denys Fiialko Over a year ago

Program should display conents of Array using Order class with template from LineItem class. Customer: Name ORDER ITEMS -------------------------------------------------------------------------------- Item Description 000 00,000.00 000,000.00 {...} --------------------------------------------------------------------------------

annu · Accepted Answer · 2016-04-12 07:03:13Z

0

In the loop, a new order object is created which has two fields (customer name and an Arraylist of line items). Initially the ArrayList will be empty.The call to addItem object creates a new Lineitem object and add its to the ArrayList items. Therefore the lineItem object will always be added to index zero.

Create a new object only when a new customer is added.You can have a HashMap where key is the customer name. If the key already exists add to the same object else create a new order object and it to the Map.

answered Apr 12, 2016 at 7:03

annu

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1 Comment

Denys Fiialko Over a year ago

Thank you!!Appreciate fast response

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