As an application developer, you can have a lifelong career without ever knowing what any of the patterns are called or how or when they're used. However, I've found that a good working knowledge of these patterns, as well as those introduced in the developerWorks article "Five common PHP design patterns" (see Resources), allows you to do two things: Enable high-bandwidth conversations and reduce painful lessons.

The patterns they talk about in this "five more" article of the series are:

• Adapter Pattern
• Iterator Pattern
• Decorator Pattern
• Delegate Pattern
• State Pattern

Diagrams are provided for each of them, showing how they flow along with brief code examples (structures really) to show how that transitions over to actual use.

You may have already encountered situations in coding PHP applications in which you would like to use inheritance, but could not for one reason or another. Fortunately, there is an alternative for these situations that can help you achieve the same result. In this first article in a two-part series, you'll learn about the adapter pattern.

They start off with the basics of the Adapter pattern and move quickly into the first definition of a class using them - a directory processor. Once that's built, they show how it all works with a more practical example.