AbstractListModel, DefaultListModel

• ListModel is an interface, which means you must provide an implementation for each of the four methods.
• But it is actually not that bad - Java provides a default implementation for two of the methods for you in the AbstractListModel.  All you have to do is implement the getSize() and getElementAt(int i) methods.
• DefaultListModel goes one step further.  It is an implementation of ListModel that allows you to dynamically add and remove elements.
• Internally, DefaultListModel holds the items in a Vector.
• The only trick is, you can't pass in a vector to a constructor.  You must use the empty constructor of the DefaultListModel, the only constructor provided, and then add each element individually via the addElement(Object o) method.
• Let's rebuild our JList example with a DefaultListModel.  Further, let's add another JFrame that permits the user to add his or her own buildings and definitions.
• As an added bonus, let's get rid of the Array all together.  Why use that when we can just use the DefaultListModel?  We can access this directly for our purposes, just as the JList can.

Created by:  Brandan Jones December 17, 2001