Professional refactoring in Visual Basic

527 Pages·2008·4.028 MB·English

by  Danijel Arsenovski

Arsenovski ffirs.tex V3-03/20/2009 9:12am Pageiii
Professional
Refactoring in C# & ASP.NET
Danijel Arsenovski
WileyPublishing,Inc.
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Professional Refactoring in C# & ASP.NET
Publishedby
WileyPublishing,Inc.
10475CrosspointBoulevard
Indianapolis,IN46256
www.wiley.com
Copyright©2009byWileyPublishing,Inc.,Indianapolis,Indiana
PublishedsimultaneouslyinCanada
ISBN:978-0-470-43452-9
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Contents
Introduction xvii
Chapter 1: Refactoring: What’s All the Fuss About? 1
AQuickRefactoringOverview 1
TheRefactoringProcess 2
ALookattheSoftwareSituation 3
TheRefactoringProcess:ACloserLook 5
UsingCodeSmells 6
TransformingtheCode 6
AutomatingRefactoringTransformations 6
TheBenefitsofRefactoring 8
DebunkingCommonMisconceptions 10
NoProgrammerIsanIsland 19
RefactoringforBusinessPeople 20
C#andRefactoring 21
Summary 21
Chapter 2: A First Taste of Refactoring 23
SampleApplication:CaloriesCalculator 23
CaloriesCalculatorApplicationwithRecommendedDailyCaloriesAmountCalculation 24
GrowingRequirements:CalculatingIdealWeight 27
GrowingRequirements:PersistingPatientData 30
RefactoringinAction 31
DecomposingthebtnCalculate_ClickMethod 32
TheCalculateandDisplayDistancefromIdealWeightSegment 33
CalculatingCaloriesandIdealWeightbyGender 33
ThebtnCalculate_ClickMethodafterMethodExtraction 34
DiscoveringNewClasses 35
NarrowingthePatientClassInterface 38
RestructuringtheDistanceFromIdealWeightMethod 41
CreatingthePatientClassHierarchy 43
ImplementingthePersistenceFunctionality 48
SavingtheData 49
ImplementingPatient-HistoryDisplayFunctionality 57
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Contents
CaloriesCalculator,RefactoredVersion 61
Summary 63
Chapter 3: Assembling a Refactoring Toolkit 65
UsinganAutomatedRefactoringTool 66
ReSharperfromJetBrains 66
Refactor!ProfromDeveloperExpress 67
Refactor!forASPfromDeveloperExpress 68
VisualStudioRefactoringFeatures 68
Unit-TestingBasics:TheTestingHarness 70
WhyaUnitTestingFramework? 71
YourFirstTasteofNUnit 73
InstallingNUnit 74
WorkingwiththeSamples 74
ImplementingYourFirstTest 76
TheTest-DrivenApproach 84
OtherTestToolstoConsider 85
AboutVersionControl 87
VersionControlAsaBackupSystem 87
VersionControlandConcurrency 87
Summary 88
Chapter 4: Application Prototype: Rent-a-Wheels 89
InterviewingtheClient 90
InterviewingtheManager 90
InterviewingtheDeskReceptionist 91
InterviewingtheParkingLotAttendant 91
InterviewingMaintenancePersonnel 92
TakingtheInitialStepsintheRent-a-WheelsProject 93
ActorsandUseCases 93
VehicleStates 95
FirstSketchoftheMainApplicationWindow 97
Rent-a-WheelsTeamMeeting 97
MakingthePrototypeWork 98
ExaminingtheDatabaseModel 98
ExaminingtheC#Code 100
FastandFuriousApproachtoProgramming 104
Database-DrivenDesign 104
GUI-BasedApplication 104
Event-DrivenProgramming 105
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Contents
RapidApplicationDevelopment(RAD) 105
CopyandPasteAsaCodeReuseMechanism 106
FromPrototypetoDeliveryThroughtheRefactoringProcess 106
Summary 106
Chapter 5: Basic Hygiene 109
EliminatingDeadCode 109
TypesofDeadCode 111
CommonSourcesofDeadCode 112
ReducingtheScopeandAccessLevelofUndulyExposedElements 116
ScopeandAccessLevel 118
CommonSourcesofOverexposure 119
DealingwithOverexposure 122
UsingExplicitImports 123
UsingSectionDepictsDependenciesinYourSystem 124
RemovingUnusedAssemblyReferences 126
BasicHygieneintheRent-a-WheelsApplication 127
Summary 128
Chapter 6: From Problem Domain to Code: Closing the Gap 129
UnderstandingtheProblemDomain 130
StepOne:GatheringtheInformation 131
StepTwo:AgreeingontheVocabulary 131
StepThree:DescribingtheInteractions 132
StepFour:BuildingthePrototype 133
NamingGuidelines 133
CapitalizationStyles 134
SimpleNamingGuidelines 135
GoodCommunication:ChoosingtheRightWords 136
RenameRefactoring 140
RenameRefactoringinVisualStudio 142
PublishedandPublicInterfaces 144
Self-ContainedApplicationsversusReusableModules 144
ModifyingthePublishedInterfaces 148
RenameandSafeRenameRefactoringintheRent-a-WheelsApplication 153
Summary 154
Chapter 7: The Method Extraction Remedy for Duplicated Code 155
EncapsulatingCodeandHidingtheDetails 155
InformationandImplementationHiding 156
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Contents
DecomposingMethods 159
CircumferenceCalculation—LongMethodExample 159
ExtractingCircumferenceLengthCalculationCode 162
ExtractingtheRadiusCalculationCode 165
Extractingthe‘‘WaitforUsertoClose’’Code 166
ExtractingtheReadCoordinatesCode 166
ExtractMethodRefactoringinVisualStudio 169
InliningMethods 171
TheDuplicatedCodeSmell 175
SourcesofDuplicatedCode 176
Copy-PasteProgramming 177
MagicLiterals 178
Extract Method and Replace Magic Literal Refactoring in the Rent-a-Wheels
Application 179
Summary 180
Chapter 8: Method Consolidation and Extraction Techniques 183
DealingwithTemporaryVariables 183
MoveDeclarationNearReferenceRefactoring 184
MoveInitializationtoDeclarationRefactoring 187
SplitTemporaryVariableRefactoring 188
InlineTempRefactoring 192
ReplaceTempwithQueryRefactoring 194
IntroducingExplainingTemporaryVariables 197
DealingwithLongandNestedConditionals 198
MethodReorganizationandRent-a-Wheels 201
RemovingDuplicationinRent-a-Wheels 203
Summary 211
Chapter 9: Discovering Objects 213
ABriefObject-OrientedProgrammingOverview 214
ObjectsinOOP 214
EncapsulationandObjects 214
EncapsulateFieldRefactoringinVisualStudio 216
ObjectStateRetention 218
Classes 218
ObjectIdentity 219
ObjectsAsBasicBuildingBlocks 220
RootObject 221
ObjectLifetimeandGarbageCollection 221
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DesigningClasses 223
UsingAnalysisArtifacts 223
ClassesAreNouns,OperationsAreVerbs 226
Classes,Responsibilities,andCollaborators 231
EmployingCardsinBrainstormingSessions 235
EntitiesandRelationships 239
DiscoveringHiddenClasses 240
DealingwithDatabase-DrivenDesign 241
MovingfromProceduraltoObject-OrientedDesign 244
SeparatingDomain,Presentation,andPersistence 252
DiscoveringObjectsandtheRent-a-WheelsApplication 257
Summary 265
Chapter 10: Advanced Object-Oriented Concepts and Related Refactorings 267
Inheritance,Polymorphism,andGenericity 268
Inheritance 268
ClassversusInterfaceInheritance 271
Polymorphism 273
Genericity 276
InheritanceAbuseandRefactoringSolutions 277
CompositionMistakenforInheritanceandOtherMisuses 281
RefactoringforInheritance—Print-SystemExample 288
DelegationInsteadofInheritanceInsidethePrintSystem 294
MakingUseofGenerics 308
InheritanceandGenericTypesintheRent-a-WheelsApplication 312
ExtractingSuper 312
EmployingGenerics 313
ExtractingtheDataObjectsProviderClass 314
Summary 318
Chapter 11: Code Organization on a Large Scale 319
Namespaces 319
NamingGuidelinesandNamespaceOrganization 320
NestedNamespaces 320
ChangingtheDefaultNamespaceName 321
EmployingUsingDirectives 321
Assemblies 323
BinaryReuse 323
NamespaceOrganizationGuidelines 325
DependencyConsiderations 330
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Contents
C#ProjectFileStructureOrganization 338
PartialClasses 339
NamespaceOrganizationandWindowsFormsInheritanceinRent-a-Wheels 345
ExtractingtheParentAdministrationFormUsingtheAbstractFormHelperPattern 345
NamespaceandAssemblyReorganization 353
Summary 355
Chapter 12: Refactoring to Patterns 357
DesignPatterns:What’sAlltheFussAbout? 358
DefiningDesignPatterns 358
ClassifyingPatterns 359
PatternElements 359
WeighingtheBenefitsofDesignPatterns 360
UsingPatterns 360
ExampleDesignPattern:AbstractFactory 361
UsingAbstractFactory 361
Solution 371
Consequences 374
DependencyInjectionPattern 376
ProblemUsingDependencyInjection 376
Solution 379
Constructor-BasedInjectionvs.Property-BasedInjection 380
WhatServiceImplementationtoInject 380
BenefitsoftheDIPattern 382
RefactoringtoDI 385
RefactoringtoPatternsandtheRent-a-WheelsApplication 385
EliminatingCodeThatDuplicates.NETFrameworkFunctionality 385
InjectingDataClassestoGUIClassesviaDependencyInjection 386
CRUDPersistencePattern 389
Summary 389
Chapter 13: LINQ and Other C# 3.0 Enhancements 391
TypeInferenceforLocalVariables 391
Auto-implementedProperties 393
ExtensionMethods 395
ObjectandCollectionInitializers 402
QueryingObjectswithLINQ 404
OldExampleinNewRobes 407
Object-RelationalMappingwithLINQtoSQL 414
LINQandtheRent-a-WheelsApplication 418
Summary 427
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Contents
Chapter 14: A Short History of the Web for Developers
and ASP.NET Tooling 429
Refactor!forASP.NET 430
InvokingRefactor!forASP.NET 431
ExploringtheRefactor!forASP.NETUserInterface 433
HTMLHistoryandItsLegacy 438
HTMLHistory 438
CatchingUpwiththeWeb 446
VisualStudioandXHTML 446
XMLandEncoding 447
VisualStudioDTDValidationforHTML 448
ServingStrictXHTML 449
Summary 451
Chapter 15: Refactoring ASP.NET Applications 453
RefactoringHTML 454
Well-FormedXHTMLDocuments 454
XHTMLValidity 456
ToolSupportforUpgradingLegacy,XHTMLNon-CompliantMarkup 458
Pretty-PrintingYourHTMLDocuments 459
SeparatingStructurefromPresentation 460
UsingHTTPtoYourAdvantagewithREST 467
RefactoringASP.NETCode 472
ASP.NETCodeModel:Single-filevs.Code-behind 472
MasterPages 476
WebUserandCustomServerControls 480
Rent-a-WheelsandASP.NETRefactorings 486
Summary 489
Appendix A: Rent-a-Wheels Prototype Internals and Intricacies 491
HandOverButtonClickEvent-HandlingCode 491
ReceiveButtonClickEvent-HandlingCode 492
ChargeButtonClickEvent-HandlingCode 492
ChangeBranchButtonClickEvent-HandlingCode 493
ToMaintenanceandFromMaintenance 497
AdministerFleetForm 498
DeleteButtonClickEvent-HandlingRoutine 498
NewButtonClickEvent-HandlingRoutine 499
ReloadButtonClickEvent-HandlingRoutine 499
FormLoadEvent-HandlingRoutine 499
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Contents
AdministerFleetFormClassCode:Fields 501
NavigationButtonsClickEvent-HandlingRoutine 502
SaveButtonClickEvent-HandlingRoutine 503
DisplayButtonClickEvent-HandlingRoutine 505
Summary 509
Appendix B: Unleash Refactor! for ASP.NET 511
Index 515
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