This the content that I shared at DevNot Summit 2017 conference. It mentions my ideas about clean software design.

1. CLEAN
DESIGN
SOFTWARE
LEMi ORHAN ERGiN
agile software craftsman @ iyzico

11. codedesign processteam
management
organization
tests customer
ux & ui culture office
architecture infrastructure
ux & uimeetingssecurity

12. things smell…
and if something smells bad, it means it is not clean

13. LEMi ORHAN ERGiN
agile software craftsman @ iyzico
/lemiorhan
lemiorhanergin.com
@lemiorhan
agile practice lead at iyzico
developing software since 2001
worked at Sony, eBay/GittiGidiyor, ACM
consultant, architect, mentor, developer
founder of Software Craftsmanship Turkey
ex community leader of Agile Turkey
meetup.scturkey.org
agileturkey.org
dev.iyzipay.com

14. Jack W. Reeves
The C++ JournalVol. 2, No. 2. 1992
http://user.it.uu.se/~carle/softcraft/notes/Reeve_SourceCodeIsTheDesign.pdf
What is So"ware Design?

15. Source code is the real
so"ware design
Designing so!ware is an exercise in managing complexity
Jack W. Reeves
What is Software Design? The C++ JournalVol. 2, No. 2. 1992
http://user.it.uu.se/~carle/softcraft/notes/Reeve_SourceCodeIsTheDesign.pdf

16. The so"ware design is
not complete until it has
been coded and tested
Testing is part of the process of refining the design
Jack W. Reeves
What is Software Design? The C++ JournalVol. 2, No. 2. 1992
http://user.it.uu.se/~carle/softcraft/notes/Reeve_SourceCodeIsTheDesign.pdf

17. Programming
Source Code
SOFTWARE DESIGN
Automated Testing
(Unit, Functional, etc.)

18. The very first value of
so"ware is
Robert C. Martin
Author of Clean Code and Clean Coder
Owner of cleancoders.com training site
…

19. to tolerate and
facilitate on-going changes
Robert C. Martin
Author of Clean Code and Clean Coder
Owner of cleancoders.com training site
The very first value of
so"ware is

20. Each city has to be renewed in order to
meet the needs of its populace.
So!ware-intensive systems are like that.
Grady Booch
Developed UML
Wrote foreword to
“Design Patterns” and
“Technical Debt” books
Istanbul, TurkeyCredit: European Space Imaging

21. Programming
Source Code
SOFTWARE DESIGN
Refactoring
Automated Testing
(Unit, Functional, etc.)

22. Programming
Source Code
SOFTWARE DESIGN
Refactoring
Automated Testing
(Unit, Functional, etc.)
Testing and
Refactoring
are first class
citizens of
so"ware design
Tests should pass
Refactoring should be continuous

23. Programming
Source Code
SOFTWARE DESIGN
Refactoring
Automated Testing
(Unit, Functional, etc.)

24. Programming
Source Code
SOFTWARE DESIGN
Refactoring
clean?
Automated Testing
(Unit, Functional, etc.)

25. COUPLING
When readfile() is changed, do you change writeFile() too?
It shows how many places we need to change

26. Two elements are loosely
coupled if they are not
shown in the same diff
Kent Beck
The creator of extreme programming
One of the signatories of the Agile Manifesto
Pioneered software design patterns and TDD

27. COHESION
Do you search a lot where to change?
It shows how easy to find the places we need to change

28. How many files at any
one time is still open for
edit shows the level of
cohesion
Nat Pryce
Co-Author of Growing Object-Oriented Software Guided by Tests
Early adopter of XP

29. Programming
Source Code
SOFTWARE DESIGN
Refactoring
Low Coupling High Cohesion
Automated Testing
(Unit, Functional, etc.)

30. Programming
Source Code
SOFTWARE DESIGN
Refactoring
Automated Testing
(Unit, Functional, etc.)
Low Coupling High Cohesion
Refactor
namings
(how) mailer.useGmailSmtpSendEmail
(what) mailer.sendEmail
(why) mailer.sendActivationEmail
Reveal what you are doing or
why you are doing, not how
you are doing

31. Refactor
namings
Programming
Source Code
SOFTWARE DESIGN
Refactoring
Automated Testing
(Unit, Functional, etc.)
Low Coupling High Cohesion
manager
handler
helper
utils
facade
service
validator
converter
repository
wrapper
interceptor
controller
parser
gateway
generator
dto, vo, entity
Know what these
really means

32. Split
methods,
Create new
abstractions,
Re-organize
code
Programming
Source Code
SOFTWARE DESIGN
Refactoring
Automated Testing
(Unit, Functional, etc.)
Low Coupling High Cohesion
Be aware of leaky abstractions.
Do not expose details and
limitations of its underlying
implementation to its users that
should ideally be hidden away.

34. Programming
Source Code
Refactoring
Low Coupling High Cohesion
Automated Testing
(Unit, Functional, etc.)
and Code Review
Pair Programming

35. When code
is reviewed,
the design
will be cleaner.
Programming
Source Code
Refactoring
Automated Testing
(Unit, Functional, etc.)
Low Coupling High Cohesion
and Code Review
Pair Programming
Pair prog makes you code cheaper
due to spending less time in
decision taking, bug fixing and
debugging.

36. Find and
remove
duplications
Programming
Source Code
Refactoring
Automated Testing
(Unit, Functional, etc.)
Low Coupling High Cohesion
and Code Review
Pair Programming
It’s not about code duplication,
it’s about knowledge duplication.
Don’t repeat yourself. Every piece
of knowledge should have one and
only one representation.

37. Programming
Source Code
Refactoring
Automated Testing
(Unit, Functional, etc.)
Low Coupling High Cohesion
and Code Review
Pair Programming
Keep it
SMALLclasses, interfaces, responsibilities,
methods, modules, components…
use design pa!erns wisely

38. Programming
Source Code
Refactoring
Automated Testing
(Unit, Functional, etc.)
Low Coupling High Cohesion
and Code Review
Pair Programming
these
STOP
Singletons?
Sharing state
Static & new keywords
Framework slave coding
Premature optimization
Primitive obssession
Huge upfront design
Controling flows with exceptions
or use them wisely

39. Programming
Source Code
Refactoring
Low Coupling High Cohesion
Automated Testing
(Unit, Functional, etc.)
and Code Review
Pair Programming

40. LEMi ORHAN ERGiN
agile software craftsman @ iyzico
/lemiorhan
lemiorhanergin.com
@lemiorhan