The Role of Taxonomy and Ontology in Semantic Layers - Heather Hedden.pdf
Top 5 ways to improve your code
1. Top 5 Ways to Improve Your
Code
Eric De Carufel
Agile Coach
http://blog.decarufel.net
http://pyxis-tech.com
2. Introduction
• Legacy code is code without
tests
• Michael Feather in Working
effectively with legacy code
• Without continuous
maintenance the code will
degrade rapidly
• We need to detect and
remove code smell
3. My Top 5 Improvements
1. Simplify conditionals
2. Improve code documentation
3. Improve method calls
4. Manage scope
5. Remove dead code
5. 1. Simplify conditionals –When?
• There is more than one condition (and / or)
• There is too much code in the body
• The condition is based on type
• There are nested if statements
• There are many decisions based on the same info
(if else if chain / switch case)
13. Keep Conditional Statements Lean
• Do your best to have only one condition
• Use methods to combine multiple conditions
• Invert your conditions if most (or all) the code of
your method is inside the "true" block
• Make sure to avoid double negation
18. 2. Delete comments – When?
• Every time there is a comment that is not (useful)
information, intention, clarification, warning, TODO or
amplification.
• Comments are the only content of a code section
• Empty catch statements
• Your comments describe line by line what you are trying to
do
• Example:
// Getting connection string from configuration
// Opening connection
// Retrieving data
// Closing connection
19. 2. Delete comments – How?
• Replace comments with good naming
• Extract methods
• Use meaningful names
• Write useful comments
• Naming Conventions (MSDN: Guidelines for names)
• Properties
• Enums
• Events
• Methods
21. Use Meaningful Names
• Use Intention-Revealing names
• Avoid disinformation
• Make meaningful distinctions
• Use pronounceable names
• Avoid encoding
• Avoid mental mapping
• Class names -> nouns not verbs
• Method names -> verbs
• Don't be cute. Use standard names
• Solution Domain Names vs Problem Domain Names
22. Properties
• Do use PascalCase naming
• Do name properties with a noun, noun phrase or an
adjective
• Do Not use names that match Get method
• Do name booleans with Can, Is or Has prefix
23. Enums
• Consider the first element to be
the default value
• Do use PascalCasing naming
• Single choice enumerations should
be singular
• Bit fields enumerations should be
plural and have Flags attibute
• Value of bit fields enumeration
should be coherent (Read & Write
== ReadWrite)
24. Events
• Do use PascalCase naming
• Do name event using a verb, present progressive for pre-event and past for post-event
• Do provide a virtual version of the event to override
• Do provide a way to cancel pre-event
25. Methods
• Do give methods names that are verbs or verb
phrases
• ProcessPayment
• Do express the return value in method name
• CreateCustomer
• GetInvoice
• Use consistent naming (Get, Fetch or Retrieve but
not all in same context)
27. 3. Clarify contracts – When?
• There are too many parameters (how many is too
many?)
• A method does more than one thing
• A method uses out parameters
• You need default values
28. 3. Clarify contracts – How?
• Reduce number of parameters
• Introduce parameter object
• Create overloads with less parameters
• Use default values
• Function output
• Return type value
• Use out parameters
• Overload methods in proper order
33. 4. Reduce scope – When?
• A field is used in only a few methods
• Public members expose class behavior
34. 4. Reduce scope – How?
• Reduce visibility
• Use protected
• Use private
• Use Internal
• Reduce scope
• Move fields to method
• Split class
• Move local variable close to its use
• Reduce lifetime
• Initialize late
• Reduce references
• Free early
35. 5. Remove Dead Code – Why?
• Because you must
• Better maintainability
• Better performance
• Better readability
• 100% test coverage
36. 5.Remove Dead Code – When?
• You know the code is dead
• You think the code is dead
• You want that code to be dead
37. 5. Remove Dead Code – How?
• Identify and remove dead code
• Delete the code
• Compile
• Run the tests
• What is dead code?
• Commented code.
• Any line of code that is not covered by unit tests.
• Tools
• There are tools that delete all code not covered by unit tests.
38. Next Steps
• Improve your conditional code
• Improve your documentation
• Improve your method calls
39. Resources
• Refactoring – Improving the design of existing code
• Author: Martin Fowler
• Edition: Addison Wesley
• ISBN: 978-0-201-48567-7
• Refactoring to patterns (Martin Fowler signature)
• Author: Joshua Kerievsky
• Edition: Adison Wesley
• ISBN: 978-0-321-21335-1
• Clean code – a handbook of agile software craftsmanship
• Author: Robert C. Martin
• Edition: Prentice Hall
• ISBN: 978-0-132-35088-4
• Working effectively with legacy code
• Author: Michael C. Feather
• Edition: Prentice Hall
• ISBN: 978-0-13-117705-5
40. Related sessions
• Day 2 – 08h45 to 10h00
• DEV373 – Testing with Microsoft Visuals Studio Test
Professional and the new Team Lab 2010
by Etienne Tremblay
• Day 2 – 10h30 to 11h45
• ARC301 – Design by Contract (DbC) and Code
Contracts in Visual Studio 2010
by Joel Hebert
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