Refactoring: Improving the Design of Existing Code

Chapter 3Bad Smells in Code

by Kent Beck and Martin Fowler

“If it stinks, change it.”— Grandma Beck, discussing child-rearing philosophy

By now you have a good idea of how refactoring works. But just because you know how doesn’t mean you know when. Deciding when to start refactoring—and when to stop—is just as important to refactoring as knowing how to operate the mechanics of it.

Now comes the dilemma. It is easy to explain how to delete an instance variable or create a hierarchy. These are simple matters. Trying to explain when you should do these things is not so cut-and-dried. Instead of appealing to some vague notion of programming aesthetics (which, frankly, is what we consultants usually do), I wanted something a bit more solid.

When ...