In an object oriented application each object you create should have well defined and narrow focused responsibilities. Ideally in your application each of your objects should have just a single responsibility. If you have an object that performs calculations, database updates, sends emails, imports data and performs logging, then this is a good candidate for breaking down into separate objects each with more narrow focused responsibilities. However, once you have separated your objects in this way you still need a nice way of combining these separate objects so they can work together.
Dependency injection is a complicated word for a fairly simple technique of getting objects to work together. It also provides a good technique to increase the maintainability of your applications.
Continued here: Dependency Injection
Christian Ready · August 23, 2009 at 9:01 pm
Thank you for your very clear, concise Wiki article on Dependency Injection! Although it may be a little outside the scope of the article, could you explain how a framework like ColdSpring simplifies dependency injection? I ask because a number of newcomers have probably heard of ColdSpring but aren’t sure what problem it solves or how it solves this particular problem.
Kevan Stannard · August 23, 2009 at 9:38 pm
Thanks Christian. Next entry for the wiki will describe writing a simple object factory and I’ll follow this with a brief introduction to ColdSpring. Actually I’ll be looking for some nice introductory tutorials for ColdSpring (and LightWire) that I can refer to, so if anyone knows of any, please leave a comment about them.