Modelling Web Navigation by Statechart(10)

UML,OOP,面向对象

highlightCwillgiveadifferenttargettotheaction,andthisactionwillbereceivedbythedisplaystateasaeventtotriggertransition.Thenamedisplayisinsertedbeforethejp(target,pos)eventtopreventambiguity.

Regardingthescopeofsystemunderdescription,notethatsome,orallofA.html,B.htmlandC.htmlcanbeoutsidetheinterestset.ControlactionsfromtheJAVAprogrammakeitpossibleforthesystemtoreturnfromthosestatesevenifnohyperlinkleadingoutofthemismodeled.Thisshowsthattheyarenotterminalstates.

5Conclusion

Wehavepointedoutprevioushyperdocumentmodelingtechniquesofwebnavigationcannotmodeldynamicwebnavigation,whichisusedextensivelyincontemporarywebpages.Mostofthesepreviousmodelsonlyaddresshyper-media,withoutthesupportfordynamiccontent.Weana-lyzeddifferentkindsofwebnavigationmethods,andawebnavigationmodelingmethodusingstatechartisproposedtoprovideamorecomprehensivemodelingofwebnavigation.Thisnewmodelprovidesasimplewaytomodelcomplex,dynamicwebnavigation.Futureworkswillbecarriedoutonre nementofthemodelandtheanalysisofwebnaviga-tionusingthemodel.

Figure18.ClientSideDynamicPagesTheyareprogramstatesandeventsinstead.

Onthenavigationaspects,thesescriptsandprogramscanpostconstrains(enable/disable)onthehyperlinks,thisisnaturallymodeledasconstrainsonthetransitiontrigger-ingevents.Dynamicde nitionofhyperlinktargetismod-eledbyvariablesoftransitions.targetofahyperlinkisavariableinthemodel,whichthescriptsandprogramscanchangethevalueatruntimeandachievetheeffectofdy-namicallyde ningahyperlink.Notethatsomescriptsandprogramscanpostconstrainsonhyperlinksofpagesotherthanthehostingpage.

Figure18illustratesthis.Thesystemstartswiththestateagreement.JScriptisusedwithacheckboxtomaketheuseragreetosometermsandconditionsbeforeproceeding.Thisismodeledbytheconstrainontheeventjp(menu,pos).TheconditionJScript.in(agreed)istrueonlyifthesub-stateJScriptisinagree,andthetransitionisallowedonlyifthisconditionistrue.

Inmenu,aJAVAmenu,embeddedinmenu.html,isdis-playedinseparateframeswiththeinformationpagesA,BandC.TheJAVAmenuismodeledasanorthogonalsub-stateofthemenustate.Itwill rstshowanopeninganima-tionwheninitialized,andwillproceedtodisplaythemenuitemsaftertheanimationhasended,orwhentheuserclicksamousebutton.

ActionsinstatedisplaymenushowshowtheJAVApro-gramcontrolnavigationonanotherframe.WhenamouseclickeventisreceivedbytheJAVAprogram,itwillreplacethecurrentcontentofthedisplayframewiththepagethecurrentlyhighlighteditemrepresents.Thisismodeledbytheactiondisplay.jp(target,pos)oftheeventmouseClick.mouseClickindifferentstateshighlightA,highlightB,

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