Slides Part 2 (OOA, pages 1-128, pdf, 4 slides per page)

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Sends = BankClerk: {give money(amount), no cover} Pre = accountnr is a valid account number, account.balance ≥ 0 Post = If account.balance − amount ≥ 0: account.balance ′ = account.balance − amount is sent{give money(amount)} If account.balance − amount < 0: account.balance ′ = account.balance is sent{no cover} account.balance ′ ≥ 0 =⇒ The class Account has the attribute balance. account.balance ≥ 0: Invariant. Contained in pre- and in postcondition. Note: the output event give money gets a parameter (These are not contained in the scenarios ). MORE EXAMPLES sd OpenAccountS1 : Bank BankClerk Schufa open_new_customer_account alt [ClientKnown] customer_already_known [else] alt [queryOK] account_opened [else] account_not_opened ref 85 87 SchufaQuery REMARK The precondition of the operation must be consistent with the scenarios. If it cannot be taken for granted that only valid account numbers can be given as a parameter of the operation withdraw money, then a scenario must be added that states how to treat the case of an invalid account number. Once such a scenario is added, the precondition “accountnr is a valid account number” may be dropped. Assumption: cd is sufficient to distinguish different customers 86 Operation = open new customer account Description = A new customer wants to open an account. A query is sent to the Schufa before the account can be opened. Reads = supplied cd : Customer data Changes = — Sends = BankClerk: {customer already known}, Schufa: {schufa query(cd))} Pre = — Post = If exists account : Account with account.customer data = cd: is sent{customer already known} Otherwise: is sent{schufa query(cd)} =⇒ The class Account has the attribute customer data. 88
SCHUFA QUERY REMARKS sd SchufaQuery alt [creditWorthinessOK] [else] : Bank schufa_query credit_worthiness_ok credit_worthiness_not_ok 89 Schufa • Associations are sets of tuples (in case of binary associations: sets of pairs). • When a new object is created, all associations of the corresponding class must be considered, and new tuples involving the new object have to be added if appropriate. • In the example, the new account is added to the Keeps association which holds between the bank and its accounts. • The scenario OpenAccountS1 guarantees that the precondition of the system operation credit worthiness ok is fulfilled. • It is not stated how the new account number is determined. • We abstract from details of the customer data. 91 Operation = credit worthiness ok Description = Schufa confirms credit-worthiness of the new customer. The account can be opened. Reads = supplied cd : Customer data bank : Bank Changes = Keeps, new account : Account Sends = BankClerk: {account opened(accountnr)}, Pre = exists no account : Account with account.customer data = cd Post = Keeps ′ = Keeps ∪{(bank, account)} UML NOTATION account.customer data ′ = cd, account.balance ′ =0 account.number ′ = accountnr, where accountnr is a new account number is sent{account opened(accountnr)} 90 Sequence of tagged values, i. e., sequence of pairs consisting of keyword and value. sd operation Actor operation {Description = ..., Reads = ..., Changes = ..., Sends = ..., Pre = ..., Post = ... } 92 : System
Page 1 and 2: LITERATURE The Fusion Method using
Page 3 and 4: 5. System class model Borderline be
Page 5 and 6: MEANING OF THE CLASS DIAGRAM ➠ Ea
Page 7 and 8: STRUCTURING CLASS MODELS In general
Page 9 and 10: ACTORS ➠ are outside of the syste
Page 11 and 12: ➠ extend-relation extension point
Page 13 and 14: EXAMPLE: OPENING AN ACCOUNT • Nor
Page 15 and 16: PATTERN FOR MODELING “” REMARKS
Page 17 and 18: OBJECT-ORIENTED ANALYSIS ➠ Class
Page 19 and 20: Excursion: Design by Contract What
Page 21: APPLICATION OF THE DESIGN-BY-CONTRA
Page 25 and 26: USE CASE “PREPARE APPLICATION/CON
Page 27 and 28: Operation = application not accepte
Page 29 and 30: LIFE-CYCLE EXPRESSIONS The Life-Cyc
Page 31 and 32: Canc = cancel contract;#confirm can

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