Code quality

1. Aglobalviewontheproblem
IOurgoalistobuildanassistantfor
automaticcodetransformation
ITransformprogramtoimprove:
–architecture
–memoryusage
–speed
–readability

2. Three+waystotransform
IFromcodetocode
IFromaHLAto
anotherHLA
IFromcodetocode
throughHLA*
CodeCode’
CodeCode’
HLAHLA’
Language
Model
CodeCode’
HLAHLA’
Language
Model
*Higherlevelabstracion

3. Fromcodetocode
IRefactoring:
“achangemadetotheinternalstructureof
softwaretomakeoteasiertounderstand
andcheapertomodifywithoutchangingits
observablebehavior”[MF99]
IThisincludes:
–Useofpre-/post-conditions[WFO92]
–Definitionofhighlevelrefactorings
[MÓC00]

4. Fromcodetocode:examples
ILow-levelrefactorings:
refactoring[code]Åcode’
–renameSuperclass
–deleteMethod
IHigh-levelrefactorings:
–hierarchyLinearization
–convertHierarchyToAggregation

5. FromHLAtoHLA
IProjectUMLAUT[UMLAUT]:
“UMLAUTisaframeworkthatfacilitates
thetransformationofUMLmodel.Oncethe
modelhasbeenlinearized,map,filterand
reducefunctionscanbecomposedand
appliedonit.Butsomeproblemsof
semanticremain.”

6. FromcodetocodethroughHLA
IProjectFAMOOSandtheirFAMIX
Model[FAMOOS]:
“theFAMIXmodelprovidesfora
language-independentrepresentationof
object-orientedsourcesandcontainsthe
requiredinformationofthereengineering
tasksperformed[byourpresenttools].”

7. Anarrowviewontheproblem
ISofarresearchfocusesonrefactorings:
–Whatrefactoringsareinteresting?[MF99]
–Howtoprovetheydon’tchangethe
behaviouroftheprogram?[WFO92,DBR99]
–Howtocomposethem?[MÓC00]
–Howtosupportthem
[DR97,JREFACTORY,IJRENAMER,XREFACTORY]
IBUT...

8. Aglobalviewonourproblem
IBUTlittlehasbeendoneondetecting
thespotswheretoapplytherefactoring
IThisinvolvesformalizing:
–Therefactorings
–The“badsmells”[BFWFO94,WJB98]
–The“refactoringpatterns”
IAND...

9. Anarrowviewonourproblem
IANDhowtoautomatizerefactoring?
–Howtoautomaticallydetectspotsthat
shouldberefactored?[IRM96,MMF99]
–Whatrefactoringsshouldbeapplied?
–Howtoprovetheappliedrefactoringsdo
notchangethebehavioroftheprogram?
–Whatimprovementsareexpected?

10. Anexample
IImagineatoolthat:
–Takesasetofcodeasinput(codeor
bytecodealike)
–Analyzesit
–Noticesaspotthatisbadlydesigned
–Appliessomerefactoringstoimproveit

11. Needs
IHowtodothat?
–Formalizetheinputatahigherlevel:HLA
–Formalizetherefactoringpatternsusing
thesameHLA
–MatcharefactoringpatternwiththeHLA
–Formalizethesetofrefactoringstoapply
–Appplytherefactorings
–Provetheydonotchangethebehaviourof
theprogram

12. Relatedworks
IDesignpatternsformalizationand
detection[KB97,OPD99,GARFLC98]
IDesigndefectformalizationand
detection[SGWAEQQY98,WJB98,MMF99]
IStaticanddynamicanalysis
[JVRNHJSU92,JH90]
IConstraints/Logicprograming[JESS]

13. Someopenquestions
IQuestions:
–Dorefactoringsneedtopreserve
behaviourorjustbehaviourwithina
specifieddomain?
–WhatHLAshouldbeused
[HAAYGG00],AOL[GARFLC98],UML,FAMIX?
–Howtodetect“badsmells”inthisHLA?

14. Andsomemore
IQuestions:
–Howtoobtaindynamicinformationfrom
thesystem?
–Howtoformalizecreationaland
behaviouraldesignpatterns?

15. Ourinterest(inanutshell)
IOurinterest:
IThreedirections:
–Howtodetect?
–WhatHLAisneeded?
–Whatrefactorings,high-leverefactorings
andrefactoringpatterns?
CodeCode’
HLAHLA’
Language
Model

16. Ananswer(inanutshell)
Code
Meta-model
HLAPatterns
Refactorings
Code’
Constraints
Static/dynamicanalysis
Constraints
?

17. Wherearewegoingsofar?
IDefinitionofameta-modelforstructural
patternswithahintofbehaviour
[HAAYGG00]
IDifferencebetweenassociation,
aggregationandcomposition[YGG00]
(plusdelegation[GARFLC98])
IMixrefactoringandtests
IUseofexplicativeconstraints?

18. Didyousayconstraints?
ITwopossibilities:
CodeCode’
HLAHLA’
Language
Model
Constraintstodetect
Constraintsorlogic
programmingtoexpress,
checktransformations...

19. Howcome?Someexamples...
IConstraintstodetect:
–Expressadesignpatternwithconstraints
–Representthecodeasadomain
–Applytheconstraintsonthedomain
IConstraintstoexpressandtocheck
–Expressthetransformationwithconstraints
–Expressthepre-/post-conditions