A presentation I gave for the Capgemini Microsoft Group on principles and patterns to use in order to avoid code duplication.

1. Avoid Code Duplication!
Principles & Patterns
Lars-Erik Kindblad
Senior Consultant
Blog: kindblad.com

2. Agenda
 Why avoid code duplication?
 Principles and patterns:
 Extract Method Principle
 Inheritance Principle
 Execute Around Method Pattern

3. Why avoid code duplication?
 “The way you get programmer productivity is by eliminating the lines of
code you have to write” – Steve Jobs
 How? Stop duplicating and repeating code! Less Code to Write = Less
Code to Maintain = More features delivered = More productive
 We normalize databases – should also normalize our code
 DRY – Don’t repeat yourself – Single Source of Truth

4. Extract Method Principle: Example
Duplicated Code

5. Extract Method Principle: Example
Extract the code to a new method

6. Extract Method Principle: Example
Refactored to call the new method

7. Inheritance Principle: Example
Duplicated Code

8. Inheritance Principle: Example
Refactored to a common base class

9. Execute Around Method Pattern: Example
Duplicated Code

10. Execute Around Method Pattern: Example
Refactored to a new execute around method

11. Execute Around Method Pattern: Example
Refactored to use the new method

12. Execute Around Method Pattern: Example
Or:

14. About Capgemini
With more than 120,000 people in 40 countries, Capgemini is one
of the world's foremost providers of consulting, technology and
outsourcing services. The Group reported 2011 global revenues
of EUR 9.7 billion.
Together with its clients, Capgemini creates and delivers
business and technology solutions that fit their needs and drive
the results they want. A deeply multicultural organization,
Capgemini has developed its own way of working, the
Collaborative Business ExperienceTM, and draws on Rightshore ®,
its worldwide delivery model.
Rightshore® is a trademark belonging to Capgemini
www.capgemini.com
The information contained in this presentation is proprietary.
© 2012 Capgemini. All rights reserved.