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!Smelly code - The origins
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Alexandru Simonescu
June 17, 2016
Programming
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!Smelly code - The origins
Some best practices we use to forget
Alexandru Simonescu
June 17, 2016
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Transcript
!smelly_code clean development @alexsimonescu
Coach better than teach
N-Layered Domain Oriented Architecture Guide
SOLID
what’s next?
GRASP
General Responsibility Assignment Software Patterns
(High cohesion) && (Low coupling)
Cohesion
High Cohesion - Methods of a class have much in
common
High Cohesion - Methods of a class have much in
common - Methods focus on same functionality
High Cohesion - Methods of a class have much in
common - Methods focus on same functionality - Higher cohesion between elements = better
High Cohesion - Methods of a class have much in
common - Methods focus on same functionality - Higher cohesion between elements = better - Lower cohesion can be disturbing; but not critical
Cohesion Types
Functional Cohesion Small units, work together and share same intention
/ function
Sequencial Cohesion Output of an element, serves as input for
another one
Informational Cohesion Different modules work with same data object
Procedural Cohesion Elements are grouped together in order to sequentially
execute a task
Temporal Cohesion Elements are executed at same moment of time
Logical Cohesion Logical elements are put together in same module
Loose Coupling
Loose coupling - Increase reusability
Loose coupling - Increase reusability - Low colateral effect when
changing collaborators
Patterns
Reuse / release equivalence - Libraries
Reuse / release equivalence - Libraries - You are the
consumer
Reuse / release equivalence - Libraries - You are the
consumer - You should not need to look at source code
Reuse / release equivalence - Libraries - You are the
consumer - You should not need to look at source code - Take care with semantic versioning
Common reuse principle - Tells how to organize packages
Common reuse principle - Tells how to organize packages -
The classes on a package are reused together
Common reuse principle - Tells how to organize packages -
The classes on a package are reused together - If you reuse one class from the package, you should reuse all
Acyclic dependencies - The dependency graph between packages should be
direct
Acyclic dependencies - The dependency graph between packages should be
direct - There must not be any cycles
Smells
Compound names
Long names
Comments
Long parameters list
Duplicated code
Conditional complexity
Large classes
Dead code
Temporary fields
Crime scene
Crime scene
Code Maat
Code Maat
None
None
None
Find the boss
Use cases
MVC
MVC
MVP
MVP
MVVM
MVVMP
Clean Architecture
None
None
None
None
Hexagonal
None
None
None
Thanks!