An abstract class is a class that cannot (or should not) be instantiated. They are surprisingly useful for certain purposes. In this article, you will learn the important concepts related to abstract classes in PHP 4, and see many hands-on examples that will allow you to make use of them in your own applications.
The article looks at the creation of these classes in PHP4, then moves on to the creation of one a bit more "clever" and keeps even subclasses from instantiating it. Once that's done, they show how to use a get_class() call to pull in its functionality...
