Question

Im learning Java and having a problem with ArrayList.

Firstly I have a class called Item, with which I create various item objects.
Then I have a class Catalogue which is an array list and should hold a list of the item objects I create.
At the moment I can manually add the items to the catalogue by invoking an addItem method on the Catalogue object and manually entering the name of the item object I want to add (item1 item2 item3 etc)
But I wanted to know if there is a way to add the items to the ArrayList automatically each time I create an item object?

I should mention, my list needs to hold an infinite amount of items, so I have not specified a size in my code.
Any help would be greatly appreciated 🙂
Thanks

import java.util.ArrayList;

public class Catalogue
{
   private ArrayList<Item> catalogue;

    public Catalogue ()
    { 
      catalogue = new ArrayList<Item>();
    }


    public void addAnItem(Item item)
    {
      catalogue.add(item);
    }
}

Answer 1

One way you could do this, is if you passed the Catalogue into the constructor of the Item class, and once the item is set up, add the item to the catalogue at that point.

It may look something like this

public Item(Catalogue catalogue) {
   // set up item here

   // finally add item to the catalogue
   catalogue.addAnItem(this);
}