You wish your software is able to survive its environment changes and its users requests for change? Four pillars are needed for long lasting software: a good organization, a good development team, good tools and good practices (clean code and clean architecture). This talk is a synthesis of my own experience with a focus on the key points and ideas to be successful in the long term.

1. The four pillars of
Long Lasting Software
François Lorioux,
a guy with f… (strong) french accent

2. About me
●
30 years experience in software
●
Software editors Oil E&P and Bank
●
Currently Team leader and Architect

3. Why this session?
Experience with Long Lasting Software
Key ideas for long term success

4. Long Lasting Software?
Software successfully delivered
Software with long active
maintenance
Not zombie software

5. Keys for Long Lasting Software
- Knowing software evolution “laws”
- Applying the four pillars
Source: https://allomarcel.com/blog/artisanat/la-cle-de-la-securite.html

6. Lehman's “laws”
●
Changes are needed
– Improvements and added features
– Technical environment
●
Complexity increases (technical debt)
– Quality decreases
– Cost of change increases

7. Software is under pressure!
source: http://www.symbols-n-emoticons.com/2013/09/emoticon-under-pressure.html
Exogenous factors
- User requirements
- Technology changes
Endogenous factors
- Design/coding practices
- Schedule

8. Result is technical debt
source: http://blog.castsoftware.com/
the-financial-implications-of-technical-debt/
Technical Debt
is the cost
of missing
quality

9. How to keep your
software healthy?
source: http://fitlife.tv/5-minutes-and-5-dollars-to-a-happier-healthier-you_original/

10. Healthy software: how?
Genetic: software DNA
Things to do
→ Continuous improvement
Things not to do
→ Software killer practices

11. 1- Good Practices

12. Let's imagine...
source: http://www.fitnetmanager.com/le-blog/le-role-du-manager-en-synthese/
No more open source third-party!

13. Software boundaries?
Outside world
- Operating System
- Third-party libraries
-...
Inside world
(code under VCS)
Connection?

14. Bottom/Up versus Top/Down
Outside world
as foundations
Outside world
as resources
Inside world
Isolation layer
Inside world

15. Solution?
source: https://8thlight.com/blog/uncle-bob/2012/08/13/the-clean-architecture.html

16. Design...
●
There is no ideal design
●
Design must be only good enough
●
Emergent design

17. Clean code...
Simplicity
Testability Alignment
Readable
Maintainable
Reliable
Transferable
Robust
SRP
Top/Down
Intention
revealing
Understandable
Good names
Separation
of
concerns
“What” vs.
“How”
Low
coupling
Boyscout
rule
DDD
Extensible
Continuous
improvement
Dependency
Injection
Secure
Entity
Ubiquitous
Language Value
Object
Modular
Automaticity
Dependency
Management

18. Software killer: dependencies...
source: http://www.saalonmuyo.com/wp-content/uploads/2008/05/syscalliis.jpg

19. Dependencies...
Dependencies on third-party
Dependency inter components

20. Easy to kill a software!
public MyFrame extends JFrame

21. 2- Good Team

22. Communication inside the team
• Humility
• Respect
• Trust

23. Willing to learn?

24. Develop the culture
●
Design Patterns (Command, Factory,...)
●
Coding/Design Smells (Data Clumps,...
●
Acronyms (DRY, YAGNI, SOLID, KISS,…)
●
DDD (Entity, Value Object, UL,...
●
TDD, Emergent design,
●
...

25. No knowledge island!
http://www.canalbd.net/img/couvpage/36/9782800136363_cg.jpg

26. 3- Good Tools

27. Tools: key ideas
• Quality
• Productivity (time is money)
• Automation wherever possible

28. Software factory...
SVN Build

29. More tools...
Dependencies management
JDepend, STAN, CDA
Performance/Memory analysis
JVisualVM
→ Wish list: JRebel...

30. Tools: productivity trap
interface builder case
https://fr.fotolia.com/tag/balance
Long term Short term

31. 4- Good Organization

32. Risk management
Software
investment
Debt risk
Team risk
Supplier risk

33. Everything's ok...
Source: http://3.bp.blogspot.com/-mfAJxfANVOQ/T0MOzCeRfkI/AAAAAAAAAGA/
ckzXX0ZzvrE/s1600/grenouiille_boueLentement.jpg

34. Supplier risk
Know dependencies/suppliers
Have contractual clauses
Be aware
- technical solutions exist...
- .. but must be applied early

35. Tackling the Technical Debt
source : https://twitter.com/carnage4life

36. Technical Debt: when?
source: http://www.justaddgoodstuff.com/

37. Thanks !
Any question ?
@fldev
francois.lorioux@free.fr