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CLEAN CODE
IN PRACTICE
/
Antoine Vernois @avernois
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a.b.c.d
THANKS
ITAKE ORGANIZERS
JÉRÔME AVOUSTIN
YOU !
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ANTOINE VERNOIS
Journeyman
@avernois
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DISCLAIMER
Object Oriented Language
I won't go into details
Some points will look stupidly simple
I will repeat myself
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AGILE & QUALITY
Continuous attention to technical excellence
and good design enhances agility.
Agile Manifesto, 9th principle
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WHY QUALITY ?
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AGILE & QUALITY (AGAIN)
Responding to change over following a plan.
Agile Manifesto, 4th value
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WHAT IS QUALITY ?
A software is of good quality if the cost to add
a feature does not change over time.
Jérôme Avoustin
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WHAT IS A CLEAN CODE ?
Clean code is not about beautifullness,
it's about goodness.
Rebecca Wirfs-Brock
tested !
no duplication
reveals its intention
easy to read
B. Stroustrup, R. Jeffries, K. Beck, M.
Feathers, W. Cunningham, ...
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ABOUT TESTS
When I hear tests are for those who don't know how to code
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SMELLS
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SMELLS
Singleton
Tight coupling
Untestable
Premature Optimisation
Indescriptive naming
Duplication
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GOOD PRACTICES
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GOOD PRACTICES
Single Responsability
Open-closed principle
Liskov substitution principle
Interface segregation principle
Dependency inversion principle
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GOOD NAMING
names should reveal the intent
alt+shift+r is your friend (in eclipse)
...
LET'S SEE FOR REAL.
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DUPLICATION
DON'T REPEAT YOURSELF !
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ABSTRACTION
1 LEVEL BY METHOD
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ABSTRACTION
DEMETER'S LAW
DON'T TALK TO STRANGER
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TIGHT COUPLING
IT'S BAD !
Tests
Reuse
...
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DEPENDANCY INJECTION
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METHODS
SHORT
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COMMENTS
Comments are always failure
Uncle Bob
Don't comment bad code. Rewrite it.
Brian W. Kernighan, P.J. Plaugher
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COMMENTS FROM REAL LIFE
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COMMENTS : THE EXCEPTION
EXPLAIN THE WHY !
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COMMENTS
TEST TELLS ME WHAT
CODE TELLS ME HOW
COMMENT, IF NEEDED, TELLS ME WHY
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HANDLING EXCEPTION
FAIL FAST
1. Do not check exception
2. Manage exception as high as possible
3. Never ever return null !
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TESTS
The give you confidence to change the code.
one test, one assert
readibility
tests document your code
A TEST SHOULD TELL YOU A STORY
TESTS ARE FIRST CLASS CITIZEN !
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SOME MORE ADVICES
Don't think inheritance, think polymorphism
Don't think if/switch, think polymorphism
AVOID SINGLETONS
Did i warn you i will repeat myself ?
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READ LIST
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QUOTES
Any fool can write code that a computer can
understand. Good programmers write code
that human can understand.
Martin Fowler
Always code as if the guy who ends up
maintaining your code will be a violent
psychopath who knows where you live.
Martin Golding
...if you're afraid to change something it is
clearly poorly designed.
Martin Fowler
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AND ALL OF THIS, IT
STARTS NEXT TIME
YOU'LL READ OR WRITE
CODE
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THANK YOU !
ANY QUESTION ?