Java, reference to an object of a class?

You state:

If I wanted to take the class StoreInventory and its attributes and use those attributes in a new class how do I include the StoreInventory in my new class Snacks?

Your logic doesn't smell right to me. Wouldn't it be the other way around -- StoreInventory should hold Snack objects and not be Snack objects holding StoreInventory objects?

Note that whatever you do, and no matter what folks suggest, inheritance is not the solution you want. Use composition, and likely your StoreInventory object should hold either an array of Snack or a collection such as an array list of Snack -- ArrayList<Snack>.

e.g.,

public class StoreInventory {
   private List<Snack> snackList = new ArrayList<Snack>();
   // ... etc...

  public void addSnack(Snack snack) {
     snackList.add(snack);
  }
}

Two standard ways:

• Aggregation: You have a StoreInventory data member within your class definition and use it. E.g.:

  class Snacks {
      private StoreInventory inventory;
  
      Snacks() {
          this.inventory = new StoreInventory();
      }
  }
  

• Inheritance: You derive from StoreInventory, e.g.:

  class Snacks extends StoreInventory {
  
      Snacks() {
          super(); // <== Initialize the base class
      }
  }
  

  Note that the call to super(); doesn't have to be explicit if there are no arguments; if you leave it out, the compiler will add it for you. But if StoreInventory needs construction arguments, that's how you would supply them.

Now you have the terminology, you shouldn't have much trouble finding tutorials for those two concepts.

You can use either inheritance

class Snacks extends StoreInventory

or composition (most likely this one in your case):

class Snacks {
    private final StoreInventory storeInventory = new StoreInventory();
}

Although without more information, it's hard to say which would be better, but those are basically your two choices.

You can either extend the StoreInventory class or include it as a field in the new class.

These techniques are called inheritance and composition respectively.

See this: http://www.artima.com/objectsandjava/webuscript/CompoInherit1.html

You can either

• subclass it e.g. class MyClass extends StoreInventory

• or a better option would be use delegation e.g.

  private final StoreInventory inventory = ....