The Examples of Documents to Be Read

Transcription

1 The Examples of Documets to Be Read Example : A use case for a automated system at a gas statio, describig how a customer purchases a parkig spot. Note that time of paymet is the same as purchase time is a coditio; it describes what must be true for the fuctioality to be executed. The ca oly wait for 30 secods for the authorizatio process imposes a costrait that must be always be true for system fuctioality. billig services Credit_Card System parkig Gas Statio Ower A customer, givig his accout_umber, asks the Gas Statio Ower for a available parkig spot to park his car. To get a available parkig spot Gas Statio Ower searches for the ext parkig place available. With this iformatio the customer ca cofirm the lease of the parkig place. The time of paymet (time of purchase or a mothly paper bill) ad how the service should be paid (by cash, persoal check or credit card). If the time of paymet is the same as the purchase time ad decides to pay by Credit Card the Credit Card system should be used. The ca oly wait for 30 secods for the authorizatio process otherwise this paymet should be made by cash or persoal check to avoid other s waitig o the lae. The Gas Statio Ower should ask the for a ew paymet type. It allows the Gas Statio Ower to mark a ew service purchase for this at this date.

2 Example 2: A sequece diagram for the automated gas statio system, capturig how classes collaborate to perform the fuctioality described i Example. Combiatios of messages that form system services have bee marked. Coditios ad costraits are icluded as aotatios o the diagram. Respose time < 30 secs represets a ofuctioal costrait o the way certai fuctioality has to be implemeted. Paymet : Gas Statio Ower : Gas Statio Ower Parkig Spot : Parkig_Spot Credit Card System : Credit_Card System Bill : Bill Purchase : Purchase parkig_spot_request( accout_umber) ext_available( ) where_to_park( available parkig_spot) [ Paymet type = Credit Card ad paymet time = ow] lease_parkig_spot(parkig_spot, paymet time, paymet type) ew_paymet_type_request() [ respose time => 30 secs or credit card ot authorized ad paymet time = ow] authorize_paymet(customer, amout, date) [ paymet time = mothly] [respose time < 30 secs] add_to_bill(customer, amout, date) ew_purchase(customer, parkig_spot, date) time = mothly is a example of a coditio that must be true for a particular message to be executed; i this case, the system variable paymet time must have the value mothly. Example 3: The class diagram for the classes described i Example 2. Note that costraits o system fuctioality are represeted as aotatios o classes. Purchase Tax : umber () taxes() ew_purchase(customer, parkig_spot)()..* Bill Issue_Date : Date Paymet_Date : Date () taxes() customer() purchases() add_to_bill(customer, amout, date)() (from s) - ame : text - address : text - SSN : umber - Birthday : Date - Accout_umber : umber Gas Statio Ower parkig_spot_request() Credit_Card System (from Exteral Systems) + authorize_paymet(customer, amout, date)() [ respose time should be less tha 30 secs for all Credit Card Systems ] + opame() + ew_paymet_type_request()()..* Parkig_Spot Place : text is_available() ext_available() 2

3 Example 4: Requiremets descriptios ad Class descriptios used to show how coditios ad costraits should be cosidered while readig both documets. Observe the relatioship betwee both documets show by the uderlied iformatio. Requiremet Descriptio A customer has the optio to be billed automatically at the time of purchase (of gas, car maiteace or parkig spots) or to be set a mothly paper bill. s ca pay via cash, credit card or persoal check. Gas Statio services have a fixed (gas: US$.09 gallo, car maiteace: US$ ad parkig spot: US$ 5.00 per day). The tax is 5% added to the fial of the purchase. Sometimes, the Gas Statio ower ca defie discouts to those s. Class Descriptio Class ame: Purchase Category: s Exteral Documets: Export Cotrol: Public Cardiality: Superclasses: oe Public Iterface: taxes Private Iterface: Tax : umber Service: Services Implemetatio: Tax : umber = 0.05 Operatio ame: Public member of: Purchase Cocurrecy: Sequetial Retur ( + tax) * service- > Operatio ame: taxes Public member of: Purchase Cocurrecy: Sequetial Retur tax * service-> Class ame: Category: Services Services Exteral Documets: Export Cotrol: Public Cardiality: Superclasses: oe Public Iterface: Private Iterface: Discout_Rate : umber Price : umber Implemetatio: Discout_Rate : umber Price: umber Operatio ame: Public member of: Services Cocurrecy: Sequetial Retur ( - discout_rate ) * Class ame: Car_Maiteace Category: Services Exteral Documets: Export Cotrol: Public Cardiality: Superclasses: Services Public Iterface: Private Iterface: 3

4 Price : umber Implemetatio: Price : umber =

5 Example 5: A state diagram for the gas statio ower class from the automated gas statio system. A associated sequece diagram is show i Example 2. [time <= 7] Authorizig [paymet ok] [paymet ot OK] Authorized Rejected Purchased 5