计算与软件工程课件-uml state

UMLIIIStateDiagramOutlineTransitionStringStateSymbolCompartmentsCompositeStatesCompoundTransitionsHistoryStates3StateDiagram4StateTransitionStringFormatevent-signature—Theemptystringoraneventnamefollowedbyalistofevent-parametersenclosedinparenthesesparenthesesmaybeomittediftherearenoparametersparameter-name:typeparameter-nameisasimplenametypeisatypedescriptioninanarbitraryformattypemaybeomittedalongwiththecolonguard

—aBooleanexpressioninsquarebracketsFormatnotspecifiedinUMLaction-expression—descriptionofacomputationdonewhenthetransitionoccursFormatnotspecifiedinUMLOptional;ifomitted,soistheslashevent-signatureguard/action-expression5TransitionStringExamplesbuttonPressbuttonPress(modifiers:Modifer[*])buttonPress/closeWindowbuttonPress[enabled]buttonPress[enabled]/closeWindow[mode=active]/closeWindowbuttonPress[enabled],mouseClick6StateSymbolCompartmentsAsmanyasthreecompartmentsNamecompartmentOptional;maybeattachedtoatabPathnameInternaltransitionsInternaltransitionspecifications,oneperlineTransitionprocessedwithoutcausingastatechangeOptionalNesteddiagramOptional7InternalTransitionSpecificationsMaybeatransitionstringorastringofthefollowingform:action-label/action-expressionaction-label—oneoftheitemsfromthetableonthenextslideaction-expression—descriptionofacomputationinaformatnotspecifiedbyUML8InternalTransitionActionLabelsActionLabelMeaningentryExecutetheassociatedaction-expression(anentryaction)uponstateentry.exitExecutetheassociatedaction-expression(anexitaction)uponstateexit.doExecutetheassociatedaction-expression(adoactivity)uponstateentryandcontinueuntilstateexitoractioncompletion.includeTheaction-expressionmustnameafiniteautomaton.Thenamedautomatonisaplaceholderforanestedstatediagram(discussedbelow).9InternalTransitionExamplesbuttonPress/beepkeyPress(SPACE)/count++timeout[mode=alert]/displayAlertMsgentry/count:=0;sum:=0exit/ringbelldo/displayflashinglightinclude/OrderProcessing10StateDiagramwithInternalTransitionsExample11NestedStateDiagramsAstatewithoutanestedstatecompartmentisasimplestate;onewithanestedstatecompartmentisacompositestate12TypesofCompositeStatesSequentialcomposite

state—Thenestedstatecompartmentisasingleregionwithsub-statesorinnerstatesandtransitions.Concurrentcomposite

state—Thenestedstatecompartmentiscomprisedoftwoormoreregionsseparatedbyconcurrentregionboundarylines(dashedlines)containinginnerstatesandtransitions.13SequentialCompositeStatesExample14UsingSequentialCompositeStateAnyfiniteautomatoncanbedescribedbyastatediagramwithonlysimplestates.Sequentialcompositestatessimplifystatemodelsintwoways:OrganizestatesintohierarchiesConsolidatemanytransitions15ConcurrentCompositeStatesTheregionsinaconcurrentcompositestatenestedstatecompartmentcontainstatediagramsthatexecuteinparallel.Onestateineachregionisenteredwhentheconcurrentcompositestateisentered.Onestatefromeachregionisalwaysamongthejointconcurrentstatesuntiltheconcurrentcompositestateisexited.Eventscausetransitionsineachconcurrentregiontooccursimultaneously.16ConcurrentCompositeStateExample17EnteringSelectedConcurrentStates:Illustration18LeavingSelectedConcurrentStates:Illustration19UsingConcurrentCompositeStatesAnyconcurrentcompositestatecanberepresentedbyadiagramwithonlysimplestates,butitwillhavemanymorestatesthantheconcurrentcompositestate.Concurrentcompositestatesthussimplifydiagrams.Ontheotherhand,diagramswithconcurrentcompositestatesareoftenhardtounderstand.20CompoundTransitionsTransitionsfrommultiplesourcesortomultipletargetswithcommontransitionstringsTransitionarrowsfrommultiplesourcesmayconvergeonatransitionjunctionpointfromwhichasinglearrowgoestoatargetCommontransitionstringstatedonlyonceAtransitionarrowswithasingleeventstringmayendatajunctionpointfromwhichemergearrowswithmutuallyexclusiveguardstomultipletargetsSymbolisafilledcircle21CompoundTransitionExample22HistoryStatesAhistorystate

isapseudo-stateindicatingthatthesub-statelastactivewhenacompositestatewasexitedshouldbereentered.SymbolisacircledHManycommondeviceshavepersistentstate,sothisisausefulmodelingfeature.23HistoryStateExample24StateDiagramHeuristics1Checkthateverypletiontransitionarrowislabeled.Checkthatnoarrowleavesafinalstate.Checkforblackholes(deadstates)andwhiteholes(unreachablestates).Labelstateswithadjectives,gerundphrases,orverbphrases.25StateDiagramHeuristics2Nameeventswithverbphrasesorwithnounphrasesdescribingactions.Nameactionswithverbphrases.Combinearrowswiththesamesourceandtargetstates.Usestubsandtheincludeinternaltransitiontoposelargeandcomplicatedstatediagrams.26StateDiagramHeuristics3Makeoneinitialstateineverystatediagram(includingnestedstatediagrams).Checkthatnoeventlabelstwoormoretransitionsfromastate.Checkthatallguardsonthesameeventareexclusive.Use[