On PHPMaster.com today there's a new tutorial posted that wants to provide a guide to walk you through a trio of ideas to help with code/idea reuse in your applications - inheritance, composition and delegation.
The popular belief is that reusing implementation, thus producing DRYer code, boils down to exploiting the benefits that Inheritance provides, right? Well, I wish it was that easy! [...] If you don’t know what path to travel when it comes to reusing implementation, in this article I’ll be doing a humble walk-through on the Inheritance/Composition/Delegation trio in an attempt to showcase, side by side, some of their most appealing virtues and clunky drawbacks.
He starts off with a look at Inheritance, showing with a small code sample showing the creation of an interface and a resulting PDO adapter class implementing it. He also shows the concept of composition, following the ideas of the Adapter pattern. In his Delegation example he shows how to implement the creation of the connection object as a part of the class' creation.