This document discusses refactoring code to improve its structure and quality. It defines refactoring as changing code without changing its external behavior to improve non-functional properties like readability. Code smells are hints that refactoring is needed, like duplicate code or large classes. Code smiles are aspects that make code easy to maintain, like clear naming. The document advocates identifying problems early through lessons learned and prefactoring to prevent issues.

1. Revisiting Refactoring Learning From the Past Improving the Future

2. What We Will Cover What is a Refactor What is a Refuctor What are Code Smells What are Code Smiles How does this change what we do

3. Defining Refactoring Code refactoring is the process of changing a computer program's internal structure without modifying its external functional behavior or existing functionality improve internal non-functional properties of the software improve code readability to simplify code

4. A List of Refactors http://www.refactoring.com/catalog/

5. Observations About Refactoring Refactoring improves the design of software – without refactoring, a design will “decay” as people make changes to a software system • Refactoring makes software easier to understand – because structure is improved, duplicated code is eliminated, etc. • Refactoring promotes a deep understanding of the code at hand by tearing it apart and putting it back together again

6. What We Will Cover What is a Refactor What is a Refuctor What are Code Smells What are Code Smiles How does this change what we do

7. Defining Refuctoring Refuctoring is the process of taking a well-designed piece of code and, through a series of small, reversible changes, making it completely unmaintainable by anybody except yourself. Often occurs when refactoring is not disciplined Occurs when changes are made at the last minute

8. A Sampling of Refuctors Inconsistent Naming Conventions Module Gravity Well Useless prefixes / suffixes “Pig Latin” Reusing names Often introduced accidentally in a rush

9. What We Will Cover What is a Refactor What is a Refuctor What are Code Smells What are Code Smiles How does this change what we do

10. Defining Code Smells A Code Smell is a hint that something has gone wrong somewhere in your code A Code Smell is a hint that something might be wrong, not a certainty. Calling something a CodeSmell is not an attack; it's simply a sign that a closer look is warranted.

11. A List of Code Smells Duplicate Code Large Method Marge Class Inappropriate Intimacy Feature Envy Switch Statements Comments

12. Observations About Code Smells Smells are guidelines Smells should not be dogmatic Smells should introduce a sense of humor to code reviews Code smells have associated Refactors to address specific smells

13. What We Will Cover What is a Refactor What is a Refuctor What are Code Smells What are Code Smiles How does this change what we do

14. Defining Code Smiles A code "smile" is some aspect of the code that makes other developers smile when they have to maintain it. Code Smiles add up to code that is easily maintained

15. A List of Code Smiles Common sense naming conventions Cohesive and loosely coupled modules Elegant abstractions Lack of duplication A close resemblance to the application domain

16. Observations About Code Smiles Code smiles do not happen by accident Code full of Smiles can deteriorate without careful attention Code smiles may also require supporting documentation or one on one training

17. What We Will Cover What is a Refactor What is a Refuctor What are Code Smells What are Code Smiles How does this change what we do

18. Defining Prefactoring Simple steps to take to prevent common problems before they arise Conduct “Lessons Learned” meetings from previous projects Identify common problems Take steps at every stage to avoid issues known to cause problems in the past

19. Towards a Catalog of Prefactors Identify a recurring issue Define a preventative measure Verify that the prevention is being followed Verify that the recurring issue is reduced Refine the preventative measure

20. Sample Prefactoring Inappropriate Intimacy Object model not resembling Business Model Separation By Interfaces Read code aloud to customers

21. Where to get More Information http ://www.refactoring.com/catalog/index.html http://www.waterfall2006.com/gorman.html http://www.simple-talk.com/dotnet/.net-framework/code-deodorants-for-code-smells/ http://www.simple-talk.com/author/nick-harrison/