created March 13, 2009

1.   Better encapsulation of the Goods class would call making instance variables private and using getter and setter methods to access them. A further refinement would be to make the class abstract and to define additional child classes. Here is a revised Goods class:

public abstract class GoodsSGA
{
  private String description;
  private double price;
  private int quantity;

  public GoodsSGA( String des, double pr, int quant )
  {
    description = des;
    price       = pr;
    quantity    = quant;
  }

  double getPrice()
  {
    return price;
  }

  void setPrice( double newPrice)
  {
    price =  newPrice;
  }

  int getQuantity()
  {
    return quantity;
  }

  void setQuantity ( int newQuantity )
  {
    quantity =  newQuantity;
  }
       
  public String toString()
  {
    return "item: " + description + " quantity: " + quantity + " price: " + price ;
  }
}

Revise the source code for the classes Food, Toy, and Book. (Perhaps call the revised classes FoodSG, ToySG, and BookSG.) create a new class ToiletrySG for things like bubble bath. Create a new testing class, StoreSG to test your revised classes.

Note: the child classes will need to use the getter and setter methods to access the instance variables that are declared as private in GoodsSG.

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