Clean Legacy CodeVictor Chircu @YonderSilviu Eigel @Ness

10th of May 2014

Legacy Code

“Source code inherited from someone else and source code inherited from an older version of the software”

Wikipedia

Legacy Code

“Code without tests” Michael Feathers

So What?

Refactoring

“A controlled technique for improving the design of an existing code base, without changing external behavior”

Martin Fowler

Refactoring

Refactoring requires unit testsEspecially refactoring legacy code

Daily Standup

Yesterday I’ve…Today I’ll fix a bug inside BookOverview page

Nothing is blocking me

What Is BookOverview Page

Demo

Cleaning Legacy Code

Cleaning Legacy Code Algorithm

1. Identify change points.2. Find test points.3. Break dependencies.4. Write tests.5. Make changes and refactor.

Dependency Breaking Techniques

Extract method under testParameterize methodBreak encapsulationExtract and override callSubclass and override method

Refactorings

Extract Method, Inline Method, Inline Temp, Move Method, Extract Class, Self Encapsulate Field, Consolidate Duplicate Conditional Fragments, Replace Nested Conditional With Guard Clauses, Invert Conditional, Replace If With Switch, Rename Method, Change Signature, Add Parameter, Remove Parameter, Separate Query From Modifier, Pull Up Field, Pull Up Method, Extract Interface, Replace Constructor With Factory Method

Our Legacy

Github Repo: http://tinyurl.com/CleanLegacyCode

Stay tuned: iasidevelopers.net

Q&A

Clean Legacy Code

Victor Chircu @YonderSilviu Eigel @Ness

10th of May 2014

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