![template method: reports
bad
code
class Report
def initialize
@title = 'Monthly Report'
@text = [ 'Things are going', 'really, really well.' ]
end
def output_report
...HTML specific stuff...
end
end](https://image.slidesharecdn.com/clean-code-130315223806-phpapp01/85/Clean-code-7-320.jpg)
![template method: reports bett
er co
class Report de
def initialize
@title = 'Monthly Report' def output_start; end
@text = ['Things are going', 'really, really
well.'] def output_head
end output_line(@title)
end
def output_report
output_start def output_line(line)
output_head raise 'Called abstract method: output_line'
@text.each do |line| end
output_line(line)
end def output_end; end
output_end end
end](https://image.slidesharecdn.com/clean-code-130315223806-phpapp01/85/Clean-code-8-320.jpg)
Clean code
- 1. clean code from theory to practice by Luís Zamith
- 2. @zamith
- 4. Clean Code TAKING YOUR PROGRAMS TO THE LAUNDRY
- 5. My d efin ition 1. Looks like you cared 2. Pretty much what you expected 3. Language looks as perfect fit for problem
- 6. circular friction reduction device = with central axis Design Patterns
- 7. template method: reports bad code class Report def initialize @title = 'Monthly Report' @text = [ 'Things are going', 'really, really well.' ] end def output_report ...HTML specific stuff... end end
- 8. template method: reports bett er co class Report de def initialize @title = 'Monthly Report' def output_start; end @text = ['Things are going', 'really, really well.'] def output_head end output_line(@title) end def output_report output_start def output_line(line) output_head raise 'Called abstract method: output_line' @text.each do |line| end output_line(line) end def output_end; end output_end end end
- 9. Design Principles THE THEORY BEHIND THE THEORY
- 10. Single responsibility Open closed Liskov substitution Interface segragation Uncle Bob Martin Dependency inversion
- 11. RECA P DESIGN PRINCIPLES + = CODE CLEAN DESIGN PATTERNS
- 12. Code Smells Sir, your issues have some code.
- 13. Smell number 1 long method
- 14. TOO LONG Can’t tell what it does at a glance, it’s TOOO T R LONG More than one level of C LONG nesting, probably E FATOO More than one level of R TOO LONG abstraction, may be Flog score greater than 15, may be
- 15. Solu tion #1 Extract Method: Split method into many auxiliary methods
- 16. Solu tion #2 Replace temp with query: Move local variables into methods
- 17. Smell number 2 large class
- 18. TOO BIG Need to scroll to know what it does, it’s O R TOO BIG T More private methods C BIG than public, it’s E FA TOO More than seven R TOO BIG methods, probably Flog score greater than 50, may be
- 19. Solu tion #1 Extract class: If the class has multiple responsibilities
- 20. Solu tion #2 Extract service object: If the class has many objects related to a single action
- 21. strategy pattern: reports report = Report.new(HTMLFormatter.new) report.output_report report.formatter = PlainTextFormatter.new report.output_report
- 22. beware of the god class
- 23. Smell number 3 feature envy All your features are mine
- 24. 4 Smelling feature envy: SYMPTOMS
- 25. Smelling feature envy: Many references to the same object
- 26. Smelling feature envy: Local variables or params that are used more than instance variables and methods
- 27. Smelling feature envy: Methods that include a class name in their name
- 28. Smelling feature envy: Private methods on the same class with the same parameter
- 29. Solu tion #1 Extract method: If possible move part of a method to the appropriate class
- 30. Solu tion #2 Move method: Move the entire method into the right class
- 31. DESIGN PRINCIPLES + = CODE CLEAN DESIGN PATTERNS
- 33. Learn the principles use the patterns Know the smells
- 34. thanks!
- 36. luís zamith blog.zamith.pt twitter+github: @zamith