My presentation on code smells at ICSME 2016 in Raleigh.

1. A Validated Set of Smells
in MVC Architectures
Maurício Aniche, Gabriele Bavota, Christoph Treude, Arie van Deursen, Marco Gerosa
@mauricioaniche, @gbavota, @ctreude, @avandeursen, @gerosa_marco

2. ICSME 2016 2
Let’s improve
that feature … Oh no! Code there
sucks!

3. ICSME 2016 3
Look for code smells,
young padawan!

4. ICSME 2016 4
Take a look at
this God Class!
Nah…

5. ICSME 2016 5
What about this
Controller with
many routes?
Yeah, this is
a problem!!!!

6. Interviews +
surveys with
50 developers
ICSME 2016 6

7. ICSME 2016 7
1. Layer-focused survey
2. Role-focused survey
3. Interviews with developers
4. Expert review

8. Result: A catalogue
of smells
ICSME 2016 8

9. Promiscuous
Controller
Offers too many actions
ICSME 2016 9

10. Brain
Controller
Too much business logic
ICSME 2016 10

11. Meddling Service
Queries the database
ICSME 2016 11

12. Brain Repository
Complex logic (SQL or code)
ICSME 2016 12

13. Laborious Repository
Method
Many queries in a single method
ICSME 2016 13

14. Fat Repository
Manages many entities
ICSME 2016 14

15. Spring MVC in github
ICSME 2016 15

16. Detection strategies
ICSME 2016 16
3Q + 1.5IRQ

17. Smelly classes exist!
ICSME 2016 17

18. Our studyICSME 2016 18

19. RQ1. What is the impact of the proposed
code smells on change-proneness of
classes?
ICSME 2016 19

20. RQ2. What is the impact of the proposed
code smells on defect-proneness of
classes?
ICSME 2016 20

21. Smelly classes
ICSME 2016 21
Clean classes
have
changed
have not
changed
have
changed
have not
changed
Is this difference significant?

22. Are they smells?
ICSME 2016 22

23. RQ3. Do developers perceive classes
affected by the proposed code smells as
problematic?
ICSME 2016 23

24. • We collected perceptions of 17 developers
• 6 random classes of existing systems
(2 T-smelly, 2 non smelly, 2 MVC smelly)
• Evaluate from 0 to 5 the severity of the problem
ICSME 2016 24

25. Developers’ perceptions
Significantly different
ICSME 2016 25

26. SCAM 2016 + ICSME 2016 =
SCAM 2016 26

27. • Developers do care about other types of
smells (contextual smells)
• By means of a 4-step approach, we coined a
catalogue of smells for MVC apps.
• Classes affected by these smells tend to be
prone to change and to defects.
• Developers clearly perceive these smells.
SCAM 2016 27

28. A Validated Set of Smells
in MVC Architectures
Maurício Aniche, Gabriele Bavota, Christoph Treude, Arie van Deursen, Marco Gerosa
@mauricioaniche, @gbavota, @ctreude, @avandeursen, @gerosa_marco