ASE '15 XTREE

XTREESDiscoveringUsefulChanges

forSoftwareProjectsRahulKrishna([email protected]),

TimMenzies,CS@NcState

29 November 2015

NoConsensus!

• Thereseemstobecontradictingconclusionsontheimpactofcodesmellsonsystems[1]

39 November 2015

[1] Dag I.K. Sjoberg, Aiko Yamashita, Bente C.D. Anda, Audris Mockus, Tore Dyba, "Quantifying the Effect of Code Smells on Maintenance Effort," IEEE Transactions on Software Engineering, vol. 39, no. 8, pp. 1144-1156, Aug., 2013

NoConsensus!


CodeSmell Study Findings

Duplicate CodeJürgensetal. Duplicate codecontained morefaultsthanaverage

Rahmanetal. Mostdefectivecodewerenotsignificantlyassociatedwith duplicatecode

49 November 2015


NoConsensus!





GodClassDeligiannisetal. GodClasseshavedetrimental effect

Olbrich etal. GodClasseshavepositiveeffects

59 November 2015


NoConsensus!





GodClassDeligiannisetal. GodClasseshavedetrimental effect

Olbrich etal. GodClasseshavepositiveeffects

ShotgunsurgeryLietal. ShotgunSurgerywaspositivelyassociatedwithsoftwarefaults

D'Ambrosetal. ShotgunSurgerywasnot consistent withdefectsacrosssystems

69 November 2015


NoConsensus!


• Thiscontradictioncanalsobeseeninseveralwidelyusedtools

79 November 2015


NoConsensus!


• Thiscontradictioncanalsobeseeninseveralwidelyusedtools

CodeSmell SonarQube Rank[13] JeffAtwood[14] OurclientsLazyClass/Freeloader L M HMessage Chains H HSpeculativeGenerality H LSwitchStatements L L

89 November 2015


99 November 2015

109 November 2015

Howtoplanchanges…Sanely

119 November 2015


129 November 2015


139 November 2015


149 November 2015


159 November 2015

Roadmap

• WhyPlan?• CommentsonPlanningAgents• WhatarePlans?• XTREE• Doesthiswork?

• Canwereducedefects?• Canweoptimizeruntimes?

• FutureWork• Summary

169 November 2015

CommentsonPlanningAgents

AGoodPlanner

1. IdentifyBadOptions

2. Discoverpossiblesetofgoodoptions

3. Offereffectiveandsuccinctsummaries

179 November 2015

Scope

189 November 2015

Roadmap




199 November 2015

WhatarePlans?

209 November 2015

WhatarePlans?

• Plansarechangestospecificproblems• Specifically,foreverytestexample inZ,aplan∆ isusedtoadjustZj

• Itcan,forinstance,beusedtoreducethenumberofdefects

219 November 2015

WhatarePlans?



229 November 2015

WhatarePlans?



∀δ j ∈Δ :Z j =Z j +δ j if Z j is numeric

δ j otherwise

⎧⎨⎪

⎩⎪

239 November 2015

WhatarePlans?



∀δ j ∈Δ :Z j =Z j +δ j if Z j is numeric

δ j otherwise

⎧⎨⎪

⎩⎪

249 November 2015

BTW:Planningisnotoptimization

259 November 2015

• Wewishtotreatallmembersofthepopulation

• Notelect foranelite few

• Sowewon’tuseNSGA-II,SPEA2,NSGA-III,MOEA/D,DE,etc.


269 November 2015








279 November 2015

Roadmap




289 November 2015

XTREE

299 November 2015

XTREE

309 November 2015

XTREE

319 November 2015

XTREE

329 November 2015

XTREE

339 November 2015

XTREE

349 November 2015

Ensure a class only contains methods that interact with each other

XTREE

359 November 2015

Ensure a class only contains methods that interact with each other

Refactor such that cohesion among methods improves

Roadmap




369 November 2015

Doesthiswork?Canwereducedefects?

• 5SampleprojectsfromJureczkoOOdataset[17] — Ant,Ivy,Lucene,Poi,andJedit

• Datasetcontainsacollectionof20OOmeasures,andabugcount.

Canwereduceruntimes?• 6systemsfromSiegmund etal.[18]— Apache,SQLite,LLVM,x264andtwoversionsoftheBerkeleydatabase(onewrittenin“C”andoneinJava)

• Thedatasetrecordstheruntimesofcompiledsystemsmeasuredusingstandardbenchmarking tools.

379 November 2015

Doesthiswork?Canwereducedefects?

• 5SampleprojectsfromJureczkoOOdataset[17] — Ant,Ivy,Lucene,Poi,andJedit

• Datasetcontainsacollectionof20OOmeasures,andabugcount.

Canwereduceruntimes?• 6systemsfromSiegmund etal.[18]— Apache,SQLite,LLVM,x264andtwoversionsoftheBerkeleydatabase(onewrittenin“C”andoneinJava)

• Thedatasetrecordstheruntimesofcompiledsystemsmeasuredusingstandardbenchmarking tools.

389 November 2015

AnalysisMethods

Performancecanbeassessedusing3criteria1. Effectiveness:Measuredas%Improvement.Denoted

byR,

2. Succinctness:Howmanyattributesneed tomodified togetadesiredresult

3. Stability:Resultsmustberepeatable.

399 November 2015

AnalysisMethods


byR,



409 November 2015

AnalysisMethods


byR,



419 November 2015

Jureczko:EffectivePlans(20Repeats)

429 November 2015

PriorworkPROMISE’12:Deltabetweenclustercentroids

Jureczko:EffectivePlans(20Repeats)

439 November 2015

PriorworkPROMISE’12:Deltabetweenclustercentroids

% Improvements in 20 repeats

Jureczko:SuccinctChanges

449 November 2015

Seigmund:EffectiveandSuccinct

• XTREEworked(again..)

• Stableacrossmanyruns

459 November 2015

Roadmap

• WhyPlan?• CommentsonPlanningAgents• WhatarePlans?• XTREE• ExperimentalResults

• JureczkoDefectDatasets• Seigmund Datasets


469 November 2015

Scope

479 November 2015

Roadmap

• WhyPlan?• CommentsonPlanningAgents• WhatarePlans?• XTREE• ExperimentalResults

• JureczkoDefectDatasets• Seigmund Datasets


489 November 2015

499 November 2015