Working Effectively with Legacy Code

Chapter 20: This Class Is Too Big and I Don’t Want It to Get Any Bigger

Many of the features that people add to systems are little tweaks. They require the addition of a little code and maybe a few more methods. It’s tempting to just make these changes to an existing class. Chances are, the code that you need to add must use data from some existing class, and the easiest thing is to just add code to it. Unfortunately, this easy way of making changes can lead to some serious trouble. When we keep adding code to existing classes, we end up with long methods and large classes. Our software turns into a swamp, and it takes more time to understand how to add new features or even just understand how old features work.

I visited a team once that had ...