Is Declaration Ordering Refactoring
1 September 2004
Is it a refactoring to change the order of declarations, eg methods and fields in a Java program?
The order in which you declare features in modern programming languages doesn't alter the program at all. If you swap two methods around in your text file, the program doesn't care. Thus the argument against it being a refactoring is that it doesn't change how the program works, thus it doesn't change the design, thus it can't be a refactoring.
In my DefinitionOfRefactoring, I used the phrase "to make it easier to understand and cheaper to modify". Can changing declarations do this? In some cases I think it does. It can make sense to put related features in a class together. You can also order the features in such a way to help explain how the class works - this is particularly valuable when you writing test cases (although here, in some xunit implementations, the order might affect the execution). So since it improves the understandability of the code, I would count reordering declarations as a refactoring.
The fact that it doesn't alter the internal execution is a red-herring. Changing the name of a method doesn't alter the execution, yet renaming is a very important refactoring to improve the understandability of a program.