In this fourth part of the series covering the Singleton and Factory Design Patterns in PHP, we will discuss issues stemming from the fact that PHP 4 does not have an abstract class. Since we found it useful in the previous article to define the form element factory class as an abstract class, in this article we will discuss the process for making the form element factory class a Singleton, and how this serves our purposes.
They walk you through the process of using the Singleton pattern, including how to make it all work in PHP4. They keep with the form creation example, and show how to interlace the pattern with it...
