Mariusz Sieraczkiewicz - Natural course of refactoring
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The document discusses the concept of refactoring in software development, comparing it to a natural and iterative process akin to sex, emphasizing its complexities and the common challenges faced. It outlines two types of refactoring: everyday and strategic, along with steps to enhance code readability and overall architecture. Key practices and strategies for effective refactoring are highlighted, including the importance of understanding the code and aligning with team dynamics and business goals.
Mariusz Sieraczkiewicz - Natural course of refactoring
- 1. www.bnsit.pl Natural Course of Refactoring. A refactoring workflow. Mariusz Sieraczkiewicz @ms_bnsit_pl http://msieraczkiewicz.blogspot.com 1
- 2. www.bnsit.pl Why refactoring is like sex? NaturalCourse of Refactoring
- 3. www.bnsit.pl Once you get started, you’ll only stop because you’re exhausted. One mistake and the consequences may be really huge. Whyrefactoring is like sex? NaturalCourseofRefactoring2014 3 (adaptedfrom http://www.thealmightyguru.com/Humor/Docs/ProgrammingIsLikeSex.html)
- 4. www.bnsit.pl People more talk about it than actually do. You can do it for money or for fun. It’s not really an appropriate topic for dinner conversation. Whyrefactoring is like sex? NaturalCourseofRefactoring2014 4 (adaptedfrom http://www.thealmightyguru.com/Humor/Docs/ProgrammingIsLikeSex.html)
- 5. www.bnsit.pl Beginners do a lot of noise about it. Some people are just naturally good at it, .. but some people will never realize how bad they are, and you’re wasting your time trying to tell them. Whyrefactoring is like sex? NaturalCourseofRefactoring2014 5 (adaptedfrom http://www.thealmightyguru.com/Humor/Docs/ProgrammingIsLikeSex.html)
- 6. www.bnsit.pl It doesn’t go so well when you’re drunk, but you’re more likely to do it. You’ll miss it after a longer break. Whyrefactoring is like sex? NaturalCourseofRefactoring2014 6 (adaptedfrom http://www.thealmightyguru.com/Humor/Docs/ProgrammingIsLikeSex.html)
- 7. www.bnsit.pl Code readability NaturalCourse of Refactoring
- 8. www.bnsit.pl .so!changesIntroDuCinG!maYBe,softwaRe,TosO,cal LEdprOgRessIve,and.however.cHanGes!Modifies.us uallY,sTRucTureOFmaYbe,hoWEVeRtHecoDE,And!w HaTmaYbecumulatEdhowevEr.anD,mAkes.AnD,,and ,the.LeSs!rEAdAblE,aNd.cOdeMAybe.ANd,!and,!Th enumber!of,sO,HoWEvErsodepeNdeNCiES,And.MA ybeintErACtIOns!betWeenHoWevEr!differEntsySte m.moDules!inCreasESoThat,iTsO!morE.is.diffiCuLt,T o,AnDuNdErstandmodIFy Why is it difficulttounderstand software aftersome timeof its evolution? NaturalCourseofRefactoring2014 8
- 9. www.bnsit.pl Introducing changes to software (so called progressive changes) usually modifies structure of the code, what cumulated makes the code less readable. The number of dependencies and interactions between different system modules increase, so that it is more difficult to understand and modify. Why is it difficulttounderstand software aftersome timeof its evolution? NaturalCourseofRefactoring2014 9
- 10. www.bnsit.pl Even answers to easy questions are difficult to find. The problem lies more in a code readibility, than in the programmers reading skills. Even great reader will not perform good in such environment. What alters programmersproductivity in this case? NaturalCourseofRefactoring2014 10
- 11. www.bnsit.pl Flavoursof refactoring NaturalCourse of Refactoring NaturalCourseofRefactoring2014 11
- 13. www.bnsit.pl Everyday refactoring Within a reach of every programmer Can be done in minutes Mostly safe, IDE-base automatic refactorings For local health of the code Part of programming practice No excuse for not doing it Main practices Cleaning names Naming conditions Extracting methods Moving methods and extracting classes Everyday refactoring NaturalCourseofRefactoring2014 13
- 14. www.bnsit.pl Strategic refactoring A team longer term effort Requires aligning with iteration planning Generates items in backlog Risky activity that requires intensive testing (including good tests suite) Difficult and time-consuming Check carefully if refactoring gives you enough value (Feather’s Quadrant) Main practices Introducing high level design patterns Introducing architectural changes Strategic refactoring NaturalCourseofRefactoring2014 14
- 15. www.bnsit.pl When should I do strategic refactoring? NaturalCourse of Refactoring
- 16. www.bnsit.pl 1. complexity := 1 2. For every decision point (if, while, for, and, or, try, case, break, continue) complexity++ 3. if 6 <= complexity <= 10 – simplify a method 4. if complexity > 10 – compose method McCabe Metric (Cyclomatic Complexity) Simplifiedversion NaturalCourseofRefactoring2014 16
- 17. www.bnsit.pl High complexity/ Seldom changes Don’t touch it. High complexity/ Frequent changes Apply strategic refactoring Low complexity/ Seldom changes Utils, good for experiments Low complexity/Frequent changes Heaven Feather’sQuadrant NaturalCourseofRefactoring2014 17 Confront with: • team opinions • business strategy Frequency of changes Complexity
- 18. www.bnsit.pl Natural Course of Refactoring Theprocess
- 21. www.bnsit.pl Sometimes it is the most difficult point Try to… • find an author and ask for help • find somebody who worked with the code and ask for help • find somebody who knows the system (or module) and ask for help • Do it yourself if none of above are possible Understand NaturalCourseofRefactoring2014 21
- 22. www.bnsit.pl Mental tools Simple code cleaning Clean up the names Add temporary comments to the code Introduce lazy variables initialization Make optical cleanup (make more space) Scaffolding refactoring Do some exploratory refactoring to be thrown away The only goal is to gain more understanding of the code Done in Notepad or something similar Understand NaturalCourseofRefactoring2014 22
- 23. www.bnsit.pl They should be temporary. Delete them after refactoring. // SMELL it doesn’t look good, copy- paste antipattern // REFACTOR introduce factory // NOTE send a message // IDEA it can be modeled as a state machine Introducerefactoringcomments NaturalCourseofRefactoring2014 23
- 24. www.bnsit.pl Step 1. Express algorithm NaturalCourseofRefactoring2014 24
- 25. www.bnsit.pl Aim Code that speaks to you Mental tools • Compose method • Introduce Method Object Refactoring • Extract method Express algorithm NaturalCourseofRefactoring2014 25
- 27. www.bnsit.pl Move meaningful private methods to another classes. You can’t test private method without hacks so if it is worth testing, find another class where this method will be public. Extract responsibilities NaturalCourseofRefactoring2014 27
- 28. www.bnsit.pl Mental tools Single responsibility principle Move method refactoring Extract class refactoring Introduce Domain Object Introduce Value Object Extract responsibilities NaturalCourseofRefactoring2014 28
- 30. www.bnsit.pl Flexibility based on requirements eg. be prepared for many cripting algorithms, starting with 5 Flexibility which emerged from code eg. your team has written 8 reports with similar structure Never guess for flexibility Do you REALLY needflexibility? NaturalCourseofRefactoring2014 30
- 31. www.bnsit.pl Strategy, Template method – different versions of the same algorithm State – simple state machines Factory – polimorphic object creation Builder – creating complex object in multiple steps Decorator – flexibility in enhancing behaviour at runtime Observer – loosen dependencies by indirect communication (events) Some design patterns applications NaturalCourseofRefactoring2014 31
- 32. www.bnsit.pl Mental tools S.O.L.I.D. Design patterns Refactoring to patterns Apply designpatterns NaturalCourseofRefactoring2014 32
- 33. www.bnsit.pl Step 4. Evolve architecture NaturalCourseofRefactoring2014 33
- 34. www.bnsit.pl It is always a strategic decision. It is useful to have regular Design Retrospective meetings when such ideas are discussed. Evolve architecture NaturalCourseofRefactoring2014 34
- 35. www.bnsit.pl Mental tools Introducing/removing layers Introducing or replacing ORM/NoSQL/? Important change in building blocks Changing or introducing new framework Introducing events Introducing state machine Moving towords DDD, Microservices, CQRS Introducing Bounded-Context (DDD) Applying Anticorruption Layer Evolve architecture NaturalCourseofRefactoring2014 35
- 37. www.bnsit.pl NaturalCourseofRefactoring2014 37 Everyday refactoring Strategic refactoring
- 38. www.bnsit.pl It is just a model – neither true nor false Big classes and big methods has fragments of code in different NCR stages Quite seldom code is in Compose method step (which the most increases readability) The consecutive steps are done more seldom than preceding ones Some comments NaturalCourseofRefactoring2014 38
- 39. www.bnsit.pl Extracting responsibilities and Introducing flexibility should be attracted by current architecture vision (Architectural Mantra) Lack of the architecture vision may push you to local optimum NCR is an ongoing process and should be a part of whole software process. NCRand architecture NaturalCourseofRefactoring2014 39 Technikipracyz kodem
- 40. www.bnsit.pl Why NCR? Easy to teach Easy to understand and remeber Separates everyday and strategic refactoring Indicates the simplest (safe) possible step in the moment Gives hints what kind of refactorings can be applied in the moment NCRIN A TEAM NaturalCourseofRefactoring2014 40
- 41. www.bnsit.pl Natural Course of Refactoring. A refactoring workflow. Mariusz Sieraczkiewicz @ms_bnsit_pl http://msieraczkiewicz.blogspot.com 41