Advice on working with legacy code

Question

I need some advice on how to work with legacy code.

A while ago, I was given the task to add a few reports to a reporting app. written in Struts 1, back in 2005. No big

Answer 1

I agree with other comments. If you don't have to, then don't do it. It usually cost far more then it's worth if the code base is more or less dead any way.

On the other hand, if you feel that you cannot get your head around the code then a refactor is probably unavoidable. If this is the case then, since it's a web application, can you create a solid suite of functional tests using selenium? If so this is the fastest and most rewarding test approach for such code and will catch most bugs for the buck.

Second, start with the extract method refactoring to create compose methods of the big difficult methods. Every time you think to your self "This should have a comment to explain what it does" you should extract it to a method with a name that replaces the comment.

Once this has been done, if you still can't add the functionality required, you can go for more advanced refactorings, and perhaps even adding some unit tests. But I usually find that I can add what is required/fix the bug in legacy code by just creating self documenting code.