CodequalityinMVCsystems

Maurício Aniche@mauricioaniche

60kand110klinesofJavacode!

Me beautifulcode

5

Sugarlevel150[70,120]

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Coupling10<15

Howtofindthisnumber?

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Benchmarking

Benchmarkin Controllers

8

Why? theirownconcernseachpartofthearchitecture

has!

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Quantiles

Coup

ling(CBO

)

Aniche, M., Treude, C., Zaidman, A., van Deursen, A., Gerosa, M.A., “SATT: Tailoring Code Metric Thresholds for Different Software Architectures”. 16th IEEE International Working Conference on Source Code Analysis and Manipulation, 2016.

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Expertsexplained to us

SATT for the rescue12

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Talktodevelopersyoushould,youngpadawan!

A catalogueof smells

specific to MVC(after talking to 50 developers)

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Grrrrrr…Controllers that offer many

servicesGrrrr…

Repositories that deal with many Entities

Grrrrr…

Aniche, Maurício, Bavota, Gabriele, Treude, Christoph, van Deursen, Arie, Gerosa, Marco.“A Validated Set of Smells in Model-View-Controller Architecture”. Software Maintenance and Evolution (ICSME), 2016, 32th International Conference, IEEE, 2016.

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Theyareindeedbad…(pronetochangeandtodefects)

Itindeedbecameatool!

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Bettercodehub likeit!J

Database-centriccodeBecauseinthewrong

place,theyare!It’sveryhardtofindsomeSQLqueriesinmycodebase…

Project #ofclasses

#ofcommits

#ofDAOs #ofmethods

Gnarus 924 10451 39 233

Caelumweb 1321 12077 81 590

There aremany queries!

Queriescan get complicated!SELECT

p.name as project,c.id as commitId,a.name as artifactName,a.path as artifactPath

FROMProjects p

JOIN Commits c ON c.project_id = p.id

JOIN Artifacts a ON a.commit_id = c.id

WHEREp.repository = ’Apache’;

WhereshouldIput

it?

public class InvoiceDAO {public Invoice findById(int id) { … }public ShoppingCart find(User u) { … })public List<Invoice> getAll() { … }public void save(Invoice inv) { ...}

}

Bythemethodsignatureswe

should!

Whereshouldwestart?

Project #ofDAOmethods

#of”correct”methods

#of”wrong”methods

%ofwrongmethods

Caelumweb 590 511 79 13.38%

Gnarus 233 200 33 14.16%

Project #ofinspectedmethods

#ofagreement

%ofagreement

Caelumweb 79 59 74.68%

Gnarus 33 16 48.48%

Aniche, Maurício F., Gustavo A. Oliva, and Marco A. Gerosa. “Are the Methods in Your Data Access Objects (DAOs) in the Right Place? A Preliminary Study.”. 6th Workshop on Managing Technical Debt, in conjunction with ICSME2014, Canada. Short paper.

PhilCalçado just(re-)bloggedaboutit!

http://philcalcado.com/2010/12/23/how_to_write_a_repository.html

TestcodestabilityNothappenitshould!

Wehatesystemtestingbecausewehavetorewritethem

often!

Largeseleniumcodeis!

A catalogueof patterns

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Fixture APIID in HTML

Move Fast, Move Slow…

Aniche, M., Guerra, E., Gerosa, M. “A Set of Patterns to Improve Code Quality of Automated Functional Tests of Web Applications”. 21th Conference on Pattern Languages of Programs. 2014.

Thanks!@mauricioaniche

YoungmeworkingonalowqualitycodethatIwrotemyselfat

myfirstinternationalproject(DominicanRepublic,2006).

Sorryaboutmyhair.

Mybossesdoingpeerpress…oops,pairprogramming!