Reading in a data file into an array of objects?

Question

I'm having problems reading in my file into an array of objects. I created an if statement so that the lines of data get separated into two different subgroups one is produce and the other is cleaning. But when I run the program the objects that are created are empty. How do I connect the file into the objects? I'm missing something crucial.

import java.util.Scanner;
import java.io.File;
import java.io.FileNotFoundException;

public class Inventory{

    public static void main(String[] args){
         int i=0;
         Product[] pr=new Product[16];
         File InventoryFile=new File("inventory.csv");
         Scanner in=null;
         try{
            in=new Scanner(InventoryFile);
            while(in.hasNext()){
               String line=in.nextLine();
               String[]fields=line.split(",");
               if(fields[0].equals("produce"))
                    pr[i]= new Produce();
               else 
                    pr[i]=new Cleaning();
               i++;
            }
            System.out.println(pr[6]);  
           }catch(FileNotFoundException e){
             System.out.println("Arrgggg"+e.getMessage());
           }    
      }
  }

What is the output/exception you are getting? Why do you feel the objects are empty? — Juned Ahsan
– Juned Ahsan, Commented Jul 16, 2013 at 17:11
You are creating the Produce and Cleaning objects, but you are not filling them — amaurs
– amaurs, Commented Jul 16, 2013 at 17:23

Eric Eugene Herring · Accepted Answer · 2013-07-24 18:33:58Z

3

Your problem stems from not even setting your varibles in your objects all you haven been doing is making them produce and cleaning but not filled in their fields.

I can not answer further without knowing how you set up your produce, product, and cleaning classes and how they get their varibles filled.

answered Jul 24, 2013 at 18:33

Eric Eugene Herring

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Comments

amaurs · Accepted Answer · 2013-07-16 17:30:10Z

0

You are not filling your Objects, you are creating, but not filling them. You can create a constructor like this:

public Product(String a, int b, int c, String, d, int e)
{
     this.a = a;
     this.b = b;
     this.c = c;
     this.d = d;
     this.e = e;
}

and in the extended classes you just call the super constructor.

public Produce(String a, int b, int c, String, d, int e)
{
    super(a,b,c,d,e);
}

and when you create them call:

new Produce(fields[0],Integer.parseInt(fields[1]),Integer.parseInt(fields[2]),fields[3],Integer.parseInt(fields[4]));

answered Jul 16, 2013 at 17:30

amaurs

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Comments

Tracy Kennedy · Accepted Answer · 2013-07-16 18:22:44Z

When you're adding your Produce/Cleaning objects in your while loop here

if(fields[0].equals("produce"))
                pr[i]= new Produce();
           else 
                pr[i]=new Cleaning();

you're just adding new, blank Produce/Cleaning objects into your array.

To fix this, you need to have some getters and setters in your Produce/Cleaning objects classes, so that you can set the values of whatever variables it is you're trying to set (Strings for names of produce/cleaning items? doubles for prices? ints for # in-stock?).

Once you have that, you can give your Produce/Cleaning objects values that will mean something when you try to pull them up again, i.e.

if(fields[0].equals("produce"))
                pr[i]= new Produce(fields[1], fields[2], fields[3]); //assuming you make a constructor that takes these values
           else 
                pr[i]=new Cleaning(fields[1], fields[2], fields[3]);
.
.
.
if(pr[i] instanceOf Produce)
                String vegName = pr[i].getName();
                int stock = pr[i].getStock();
                double price = pr[i].getPrice();

I'd need to know more about what is in the csv and what you're trying to create with enter code hereyour array to give you more help, but hopefully this is a start.

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