Refactoring
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The document discusses refactoring code to improve its design without changing its external behavior. It defines refactoring as improving the code's internal structure to make it easier to understand and modify. The goals of refactoring are to remove duplication, simplify complex logic, clarify unclear code, and make the code easier to maintain without adding new functionality. It recommends refactoring when adding features, fixing bugs, or during code reviews. It also lists common "bad smells" in code and examples of refactoring techniques like extracting methods, moving methods, encapsulating fields, using interfaces, removing unused parameters, and replacing nested conditionals with guard clauses.
Refactoring
- 2. RefactoringAny fool can write code that a computer can understand. Good programmers write code that humans can understand.2
- 3. RefactoringWhat is Refactoring?Martin Fowler : "a change made to the internal structure of software to make it easier to understand and cheaper to modify without changing its observable behavior“.William C. Wake : "Refactoring is the art of safely improving the design of existing code“.3
- 4. RefactoringThe process of refactoring involves the removal of duplication, the simplification of complex logic, and the clarification of unclear code.The goal of refactoring is NOT to add new functionalityThe goal is refactoring is to make code easier to maintain in the future4
- 5. RefactoringWhen Should You Refactor?Refactor When You Add Function
- 6. Refactor When You Need to Fix a Bug
- 7. Refactor As You Do a Code Review5
- 8. RefactoringThe Refactoring CycleChoose the worst smellSelect a refactoring that will address the smellApply the refactoring6
- 9. RefactoringBad Smells in Code Duplicated Code
- 10. Long Method
- 11. Large Class
- 12. Long Parameter List
- 13. Divergent Change
- 14. Shotgun Surgery
- 15. Feature Envy
- 16. Data Clumps
- 19. Parallel Inheritance Hierarchies
- 20. Lazy Class
- 22. Temporary Field
- 23. Message Chains
- 24. Middle Man7
- 25. RefactoringBad Smells in Code Inappropriate Intimacy
- 26. Alternative Classes with Different Interfaces
- 27. Incomplete Library Class
- 28. Data Class
- 29. Refused Bequest
- 30. Comments8
- 31. void printOwing() { printBanner(); //print details System.out.println ("name: " + _name); System.out.println ("amount " + getOutstanding()); }RefactoringExtract Methodvoid printOwing() { printBanner(); //print details System.out.println ("name: " + _name); System.out.println ("amount " + getOutstanding()); }ReusabilityHigh CohesionReadabilityvoid printOwing() { printBanner(); printDetails(getOutstanding()); } Void printDetails (double outstanding) { System.out.println ("name: " + _name); System.out.println ("amount " + outstanding); }Polymorphism9
- 33. RefactoringMove Methodlow CouplingHigh Cohesion11
- 34. RefactoringEncapsulate Fieldyou should never make your data public. When you make data public, other objects can change and access data values without the owning object's knowing about it.12
- 36. RefactoringRemove ParameterA parameter is no longer used by the method body. Remove it.14
- 37. RefactoringReplace Nested Conditional with Guard ClausesA method has conditional behavior that does not make clear the normal path of execution.Use guard clauses for all the special cases.Readability15
- 38. RefactoringVisit our Page on Facebook!16