自动售货机-需求报告.doc

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1、VendingMachine1-ObjectivesTheobjectivesofthisexerciseareto:·BasedonTOODdesignapproach,propose2solutionsforthedesignarchitectureoftheVendingMachinepresentedinspecificationmodule:·Firstsolution:sequential-withoutprocess.Usingasequentialsolution,itisinterestingtoshowthanonemodeofth

2、eStateTransitionDiagram(STD)cannotbereached:“DispensingProduct”.·Secondsolution:concurrent-withprocess(es).Hypothesismustbemadeonthehardware.2-ProblemOverviewThisexampleisanextensionoftheproblempresentedattheForum”StructuredDevelopment”inSanFrancisco,inFebruary1986.Theproblemsta

3、tementandtheresultingmodelswereinteractivelydevelopedanddescribedasadialoguebetweenthecustomerandtheanalyst.Thecustomerstartedbyoutliningtotheanalystthatheisfacedwithcrooksascustomerswhotryputtingjunkintothecoinslotsofhisvendingmachineshopingtogetsomethingfornothing.Someeventryt

4、oentercoin-likeslugstofoolthemachines.Theyalsotrytovandalizetheselectionregistertogetproductsfree.Thesearemajorproblemsforthevendingmachineoperatorsbecausetheydobusinessonanarrowmargin,whichdisappearsveryquickly.Themachineistodothefollowing:-Acceptobjectsfromthecustomerinpayment

5、forhis/herpurchase.-Checkeachobjecttomakesurethatitisnotaslug.Thisistobedonebyvalidatingthesize,weightandthickness.-Acceptnickels,dimesandquarters.Anyothercoinsaretobetreatedasslugsandreturnedtothecustomer.-Onlyinitiatepaymentcomputationorproductselectionprocessafteravalidatedco

6、inisdetected.-Acceptproductselectionfromthecustomer.-Checktoseewhethertheselectedproductisavailable,ifnotavailable,returncoinsautomaticallyandnotifycustomer.-Acceptavarietyofproducts,whichwillchangefromtimetotime.Hence,theproductpricesshouldbechangeable.-Returnthecustomer’spayme

7、ntonrequestifheorshedecidesnottomakeaselection.-Dispensetheproducttothecustomerifitisavailableandtheamountissufficient.-Returnthecorrectchangetothecustomeriftheamountdepositisgreaterthantheproductprice(initialconditions?).-Disabletheproductselectionaftertheproductisdispensedandu

8、ntilthenextvalidatedcoinisreceived.Severalextra