Modelling Web Navigation by Statechart(7)

UML,OOP,面向对象

productA.html

(a)

(b)

Figure9.Intra-pageModeling

forsimplicity.Everyhyperlinkfromonepagetotheotherisrepresentedbyastatetransitionarrow,thehyperlinkac-tivationistheeventthattriggersthetransition.Ifmulti-plehyperlinksonawebpagepointtothesametarget,theyareconsideredequivalentandonlyonetransitionarrowisneededtorepresentthem.Thehyperlinkscanbeavailablefromallpagesub-states(Figure10a)oronlyavailablefromsomeofthem(Figure10b).Targetofthehyperlinkisal-waysoneofthesub-statesofthetargetwebpage,sothiscanberepresentedbydefaultingtotheselectconnective(Figure10c).Thechangeofstaterepresentsthechangeofdisplayingcurrentwebpagetothetargetwebpageofthehyperlink.

TheXORdecompositionofStatechartplaysanimpor-tantroleheretosimplifythediagram.Webpageshav-inghyperlinksofcommontargetcanbegrouped.Themodelofacommontree-likemenustructureofwebpagesisshowninFigure11atoillustratethis.jp(menu,pos)ofproductA.htmlandproductB.htmlaregroupedtogethertoberepresentedbyonetransitionarrow.

Theselectconnectivecanalsobeusedtogroupallhy-perlinktargetsofapage.In gure11b,menu.jpeventfromstatemenu.htmlisde nedasthedisjunctionofthetwolowerleveleventsjp(productA,pos)andjp(productB,pos)in gure11a.Thisde nitionshouldaccompanythestate-chartsoexpansionbacktoFigure11aispossibleifdesired.4.2.3Frame-based

AwebpagewithframesismodeledastheorthogonalANDofthestateofitsframes(Figure12).Anoptionalstatename,suchasframe1,frame2andframe3inthe gurecanbegiventoeachframe.frame2andframe3,havingtwoormorepossiblesub-states,hasadefaultstatetoindicatethedefaultwebpageloadedinthatframe.ThisisindicatedbythedefaultarrowintheStatechart.Thesub-statescanbeasimplewebpageoranotherframedpage,Navigationfromaframedwebpagetoanotherpagecanbemodeledasthe

Figure10.Inter-pageHyperlinks

Figure11.Inter-pageModeling