- Duplicated Code
- Long Method
- Large Class
- Long Parameter List
- Divergent Change
- Shotgun Surgery
- Feature Envy
- Data Clumps
- Primitive Obsession
- Case Statements
- Parallel Inheritance Hierarchies
- Lazy Class
- Speculative Generality
- Temporary Field
- Message Chains
- Middle Man
- Inappropriate Intimacy
- Alternative Classes with Different Interfaces
- Incomplete Library Class
- Data Class
- Refused Bequest
- Comments
- Metaprogramming Madness
- Disjointed API
- Repetitive Boilerplate
This chapter is from the book
This chapter is from the book
This chapter is from the book
Speculative Generality
Speculative generality is a smell to which we are very sensitive. You get it when people say, "Oh, I think we need the ability to do this kind of thing someday" and thus want all sorts of hooks and special cases to handle things that aren't required. The result often is harder to understand and maintain. If all this machinery were being used, it would be worth it. But if it isn't, it isn't. The machinery just gets in the way, so get rid of it.
If you have classes or modules that aren't doing much, use Collapse Hierarchy. Unnecessary delegation can be removed with Inline Class. Methods with unused parameters should be subject to Remove Parameter. Methods named with odd names should be brought down to earth with Rename Method.
Speculative generality can be spotted when the only users of a method, a code branch, or an entire class are test cases. If you find this type of code, delete it and the test case that exercises it. If you have a method or class that is a helper for a test case that exercises legitimate functionality, you have to leave it in, of course.