Description
Incorrect or incomplete application of object-oriented programming principles can result in issues that damage system functionality and performance.
All such issues are called Object-Oriented Abusers.
Here is a list of such observations.
- Alternative Classes with Different Interfaces
- Switch Statements
- Temporary Field
- Refused Bequest
Alternative Classes with Different Interfaces
Problem: Two classes perform identical functions but have different method names.
Solution: Use the mentioned refactoring techniques to avoid these kinds of code smells.
- Rename Method
- Move Method
- Add Parameter
- Parameterize Method
- Extract Superclass
Switch Statements
Problem: You have a complex switch operator or sequence of if statements.
Solution: Use the mentioned refactoring techniques to avoid these kinds of code smells.
- Extract Method
- Move Method
- Replace Type Code with Subclasses
- Replace Type Code with State/Strategy
- Replace Conditional with Polymorphism
- Replace Parameter with Explicit Methods
- Introduce Null Object
Temporary Field
Problem: Temporary fields get their values (and thus are needed by objects) only under certain circumstances. Outside of these circumstances, they’re empty.
Solution: Use the mentioned refactoring techniques to avoid these kinds of code smells.
- Extract Class
- Replace Method with Method Object
- Introduce Null Object
Refused Bequest
Problem: If a subclass uses only some of the methods and properties inherited from its parents, the hierarchy is off-kilter. The unneeded methods may simply go unused or be redefined and give off exceptions.
Solution: Use the mentioned refactoring techniques to avoid these kinds of code smells.
- Replace Inheritance with Delegation
- Extract Superclass
Overall
We now know how to find and resolve object-oriented abusers in the code to improve the code quality.