301AA-AdvancedProgramming[AP-2017]

Lecturer:AndreaCorradiniandrea@di.unipi.itAssistant:LilloGalleBagalleBa@di.unipi.it

DepartmentofComputerScience,PisaAcademicYear2017/18

AP-2017-02:Mo%va%onsandIntroduc%on

SoJwareisEverywhere

SoJwareasCompeOOveAdvantage

MostAdmiredCompaniesMakingITaCompe44veAdvantage(Forbes)•  Accenture•  Amazon•  Apple•  ClevelandClinic•  GeneralElectric•  GoldmanSachs•  Google•  HospitalCorporaOonof

America•  IBM•  IntermountainHealthcare

•  JP Morgan Chase •  Kaiser Permanente •  Mayo Clinic •  Microsoft •  Nestle •  Procter & Gamble •  Progressive Insurance •  Schlumberger •  Target •  Toyota •  Wells Fargo

Programminginthe21century •  SoJwareascomplexasever•  Commandlineinterfacenotenough•  DatacomesfrommulOplesources:structured(DB)andunstructured

•  Singlecomputernotenough•  SoJwaredevelopmentisagroupacOvity•  DeploymentonWebormobiledevices

ComplexityPromptsforInnovaOon

•  Object-OrientedProgrammingallowseverlargerapplicaOonstobebuilt

•  Butlimitedsupportforreuse•  OS+librariesnotenough•  Reusablecomponentsareneeded•  MulO-OerapplicaOonsdevelopmentincreasesthechoicesonhowtobuildapplicaOons

KeyIngredientsforComplexSoJware

•  Advancedfeaturesextendingprogramminglanguages

•  Componentmodelstoensurereusability•  Frameworkstosupportefficientdevelopmentof(componentbased)applicaOons

•  Execu4onenvironmentsprovidingrunOmesupportforeverdynamicsoJwaresystems

6

TheSoJwareArchitect

•  Anewroleisneeded:SoBwareArchitect•  tocreate,defineorchooseanapplica4onframework•  tocreatethecomponentdesignaccordingtoacomponentmodel

•  tostructureacomplexapplicaOonintopieces•  tounderstandtheinteracOonsanddependenciesamongcomponents

•  toselecttheexecu4onenvironment/plaEormbasedoncost/performancecriteria

•  toorganizeandsupervisethedevelopmentprocess

WhatareFrameworks?

•  SoBwareFramework:AcollecOonofcommoncodeprovidinggenericfunc%onalitythatcanbeselec%velyoverriddenorspecializedbyusercodeprovidingspecificfunc%onality

•  Applica4onFramework:AsoJwareframeworkusedtoimplementthestandardstructureofanapplicaOonforaspecificdevelopmentenvironment

FrameworkFeatures•  Frameworks,likeso*warelibraries,providereusableabstrac6onsofcodewrappedinawell-definedAPI

•  But:Inversionofcontrol–  unlikeinlibraries,theoverallprogram'sflowofcontrolisnotdictatedbythecaller,butbytheframework

•  Helpssolvingrecurringdesignproblems•  DrivessoluOon

–  Providesadefaultbehavior–  Dictateshowtofill-in-the-blanks

•  Non-modifiableframeworkcode–  Extensibility:usuallybyselecOveoverriding

OOSoJwareFramework

•  Object-orientedprogrammingframeworksconsistsofasetofabstractclasses

•  AnapplicaOoncanbebuiltsimplyinheriOngfrompre-exisOngclassesintheframework

•  InstanOaOonofaframeworkconsistsofcomposingandsubclassingtheexisOngclasses

ExamplesofFrameworks

•  GeneralsoJwareframeworks–  .NET–Windowsplajorm.Provideslanguageinteroperability

– AndroidSDK–SupportsdevelopmentofappsinJava(butdoesnotuseaJVM!)

–  Spring–Cross-plajorm,forJavaapplicaOons–  Cocoa–Apple’snaOveOOAPIformacOS.IncludesCstandardlibraryandtheObjecOve-CrunOme.

–  Eclipse–Cross-plajorm,easilyextensibleIDEwithplugins

ExamplesofFrameworks

•  FrameworksforApplicaOonwithGUI– MFC-MicrosoJFoundaOonClassLibrary.C++object-orientedlibraryforWindows.

– Gnome–WriBeninC;mainlyforLinux

– Qt-Cross-plajorm;wriBeninC++

ExamplesofFrameworks

•  WebApplicaOonFrameworks[basedonModel-View-ControllerdesignpaBern]– ASP.NETbyMicrosoJforwebsites,webapplicaOonsandwebservices

– GWT-GoogleWebToolkit(GWT)– Rails-WriBeninRuby-Providesdefaultstructuresfordatabases,webservicesandwebpages.

ExamplesofFrameworks

•  Concurrency– HadoopMap/Reduce-soJwareframeworkforapplicaOonswhichprocessbigamountsofdatain-parallelonlargeclusters(thousandsofnodes)inafault-tolerantmanner.

• Map:Takesinputdataandconvertsitintoasetoftuples(key/valuepairs).

•  Reduce:TakestheoutputfromMapandcombinesthedatatuplesintoasmallersetoftuples.

FrameworkDesign

•  IntellectualChallengingTask•  Requiresadeepunderstandingoftheproblemdomain

•  RequiresmasteringofsoBware(design)paQerns,OOmethodsandpolymorphisminparOcular

DesignPaBerns•  Generalconceptualsolu%onstorecurrentdesignproblems

•  Moreabstractthanframeworks –  Frameworkscanbeembodiedincode,butonlyexamplesofpaBernscanbeembodiedincode

–  DesignpaBernsexplaintheintent,trade-offs,andconsequencesofadesign

•  Smallerarchitecturalelementsthanframeworks –  AtypicalframeworkcontainsseveraldesignpaBernsbutthereverseisnevertrue.

•  Lessspecializedthanframeworks–  FrameworksalwayshaveaparOcularapplicaOondomain–  DesignpaBernscanbeusedinnearlyanykindofapplicaOon

The23DesignPaBernsoftheGangofFour

173

Tabella dei pattern GoF

comportamentali

creazionali strutturali

Behavioural

CreaOonal Structural

ErichGamma,RichardHelm,RalphJohnsonandJohnVlissidesDesignPa:erns:ElementsofReusable

Object-OrientedSo*ware[1995]

CourseobjecOvesandSyllabus

CourseObjecOves•  Understandprogramminglanguagetechnology:

–  ExecuOonModels–  Run-Ome

•  Analyzeprogrammingmetaphors:– Objects–  Components–  PaBerns

•  Learnadvancedprogrammingtechniques•  Presentstate-of-the-artframeworksincorporaOngthesetechniques

•  PracOcewithalltheseconceptsthroughsmallprojects

Run-OmeSystems•  VirtualExecuOonEnvironment

– MemoryManagement–  ThreadManagement–  ExcepOonHandling–  Security– DebuggingSupport– AOTandJITCompilaOon– DynamicLink/Load–  ReflecOon–  VerificaOon

•  Aconcreteexample:theJVM

SelectedAdvancedConceptsinProgrammingLanguage

•  OverloadingandTypeClassesinHaskell•  LambdaexpressionsandStreamsinJava8•  ClosuresvsDelegatesinCLI•  AlgebraicdatatypesandAcOvepaBernsinF#•  AssociaOvearraysinscripOnglanguages•  ExtensionsinSwiJ

AdvancedProgrammingTechniques

•  GenericProgramming–  JavaGenerics–  C++templates–  C#Generics–  Scalagenerics

•  GeneraOveProgramming– Metaprogramming–  ReflecOon–  Template– Generators

•  Actorbasedprogramming–  ScalaandAkka

ComponentModelsandFrameworks

•  Component-orientedProgramming•  JavaBeansandNetBeans•  SpringandSpringBeans•  COM•  CLRand.NET•  OSGiandEclipse•  HadoopMap/Reduce

IEEESpectrumRanking2017-2014

Top10Frameworks