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Where refactoring meetsBig $$$First steps

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RULES ;)REFACTORING

3CONFIDENTIALBy The U.S. Army

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Contact informationContact information

@michalgruca

michal.gruca@gmail.com

www.rits.pl

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WHO REFACTORS CODE QUESTION

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ON A DAILY BASIS

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WHO PLANS REFACTORINGS?QUESTION

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ACADEMIA TIMEREFACTORING

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What is refactoringWhat is refactoring

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That is very true, but to simplify discussion, I’m going to refer to changes as refactorings as well

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Meanwhile in perfect worldMeanwhile in perfect world

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• It’s hard to maintain

• Changes in domain are coming

– New requirements are impossible to implement

• There are no tests (sic!)

• Development of new features is so slow

• System is slow

• You just don’t want to go to work anymore

– (nor your colleagues)

Why to refactorWhy to refactor

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EVERYDAY REFACTORINGSREFACTORING TYPES

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Everyday refactoring :: DefinitionEveryday refactoring :: Definition

• Rename variable / method / class names

• Extract class / method / variable / parameter

• Move code around

• Removing duplication (DRY)

• Removing dead code

• Cleaning up comments

• Improving encapsulation

• etc

http://www.infoq.com/articles/natural-course-refactoring

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• Increases readability of code

• Enables understanding of code

• Introduces patterns

• Simplifies/allows testing

• Cleans up potential, simple, programming mistakes

• Fully supported by IDE in any language

• Is fast, does not need to be planned

• Does not require process, can be done on a go

• Is safe and non-intrusive

– But not always!

Everyday refactoring :: ProsEveryday refactoring :: Pros

By MazeNL77

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• In big ball of mud is not always safe!

– Watch out for reflection!

• Without tests and tools (IDE) can be very dangerous

• May be source of funky bugs

• No process, not all developers will adapt

• If backed with restrictive tools, can be

counterproductive

– Pre-hooks anyone?

Everyday refactoring :: ConsEveryday refactoring :: Cons

By Indi Samarajiva

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• Quarter of development followed by phase 2 with up to 6 months of work for team

– And short break between them

• Funky structure of domain model

– TreeMap<Integer, Map<TabelType, Map<RecordType, List<TableId>>>>

• Only creator understood the design

Everyday refactoring :: Example -> Planned refactoringsEveryday refactoring :: Example -> Planned refactorings

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BIG BANGREFACTORING TYPES

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Big Bang :: DefinitionBig Bang :: Definition

By Xtraterestrial

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• Allows for a fresh start

– New technology stack

– Clean architecture

– Better domain model

• Can be a serious contributor for finding a new job ;)

ProsPros

By MazeNL77

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ConsCons

By Indi Samarajiva

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ConsCons

• We don’t deliver anything for many, many sprints

• World moves forward, our application does not

• Business is unhappy

• Success of the new project is not guaranteed

By Indi Samarajiva

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ConsCons

By Indi Samarajiva

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Big Bang :: When to do itBig Bang :: When to do it

By Wayne Ray

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• ~5 year old system

• Build on top of 5+ year old code base

• Sudden plan to change business model

Big Bang :: Real world example -> Domain changeBig Bang :: Real world example -> Domain change

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SPROUTINGREFACTORING TYPES

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• Proposed by Michael Feathers in

“Working Effectively with Legacy Code”

– To refactor methods– And classes

• Can be used with whole packages, modules,

components, applications

Sprouting :: DefinitionSprouting :: Definition

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• Introducing new code in testable manner

• Separate abstractions

• Prevents rooting of new functionalities

• Enables change of architecture

• Allows to update technology stack

• Allows to build independent modules and applications

ProsPros

By MazeNL77

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• Requires much more work, people and resources than

standard feature release

• May add serious latency to functions and slow down the

whole system

• Adds more abstraction layers to the project

ConsCons

By Indi Samarajiva

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Sprouting :: Real world exampleSprouting :: Real world example

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Sprouting :: Real world exampleSprouting :: Real world example

By Crochetbug

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Sprouting :: Real world exampleSprouting :: Real world example

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GET PERMISSIONREFACTORING

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Decide what to measureDecide what to measure

• How many commits / sprint

• How many commits / file (how often it changes)

– By different users/ In one sprint• Cyclomatic complexity

• Code coverage

• LOC per sprint

• Findbugs issues

• Requests / second

• Resource (Memory/CPU) usage

• Lead time (how long its on board)

By Martinvl

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Measure!Measure!

• Velocity

• Build time

• Number of failing builds

• Number of merges

– +time of each merge• ROI / sprint

• Code quality

• Freeze time

• Response time

• Maximum load

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HOW TO MEASUREREFACTORING

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Show & discussShow & discuss

• Business like numbers

– Even if they don’t understand them

• Setup goals / milestones

• Try to use work time

• Setup day / sprint of excellence

• Organize hackathon / code retreat

• Share knowledge and train colleagues

• Set standards

– And enforce them with pre-commit hooks ;)

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Read list :: Build a book clubRead list :: Build a book club

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I love your feedback! I love your feedback!

@michalgruca

michal.gruca@gmail.com

www.rits.pl