Matthew Setter has a new post today looking at setter injection of dependencies in a Zend Framework v2 based application. He shows how to do it via ServiceManager-aware interfaces.

For configuring objects, reused throughout the application, I’ve found it to be nothing short of amazing. With next to no code, one Module configuration setting, along with the magic of OOP, classes are suitably initialized throughout the application, without any hands-on configuration on my part. Whilst Zend Framework 2 is great without this. When you start using setter injection, it becomes so much more. In today’s post, I’ll take you through an example which uses setter injection to ensure that the AuthService, or authenticated user object is always available to a class and any of its descendants.

He walks you through a basic implementation, showing the creation of the "AuthAwareInterface" interface class and an implementation of it, the "CacheableTable". In the "CacheableTable" there's a setter and getter for the currently authenticated user. Using these he's able to configure the ServiceManager to get the AuthService instance from the service locator and inject it into the class. He also includes a word of warning to be careful with the injection you do use, pointing out that it can lead to difficult to track bugs and issues down the line.