1. IS550: Software requirements engineering Dr. Azeddine Chikh 5. Special interfaces - combined styles

2. Soren Lauesen, "Software Requirements: Styles & Techniques" Addison-Wesley Professional 2002, 608 pp, ISBN- 10: 0201745704 - ISBN-13: 9780201745702 Text

3. 0. Introduction 3 The most important product interfaces is usually the interactive interface to the user. The discussions in the previous chapter were primarily related to the user interface Many of the requirements styles could deal with other product interfaces (reports, platform, external technical systems) as well.

4. 1. Reports 4 Highlights Often hundreds of reports Specify the clearly necessary reports Postpone the rest, but specify the framework for making them

5. External reports R1:Product shall produce pay slips with layout as in app. xx. Specific purpose Existing reports - vague purpose Reports on demand R2:Product shall print forecasts of room occupation for monthly roster planning. Format for instance as xx. R3:Supplier shall provide a list of built-in reports. R4:Supplier shall develop up to 200 simple reports (like yy) at a price of $_____ per report and up to 50 complex reports (like zz) at a price of $_____ per report. R5:Product shall include a report generator. Reports like yy can be developed by: ordinary user?yes/no super user?yes/no customer’s IT dept?yes/no 1. Reports

6. 2. Platform requirements 6 Highlights What the product shall run on, now and in the future. Dealing with existing and planned platforms

7. We have a platform R1:Product shall run on Pentíum PC’s with 128 MB. Many older PC’s still used, so tasks 2.1 to 2.5 must be supported on 80486 with 64 MB. R2:Our IT staff have expertice in Oracle. Product must use same database platform. R3:Product shall run on MS Windows release xx.yy. Supplier shall for 3 years port his product to new releases within ___ months from release date. We want a new platform anyway R4:Customer expects to switch to client-server running OS zz. Supplier shall specify server memory and server speed needed to obtain capacity and response time for Rxx. We want software and hardware (maybe) R5:Supplier shall deliver hardware + software. Supplier shall upgrade if capacity becomes inadequate for the load specified in xx. R6:Product shall run on Pentium PC’s with 128 MB. As an option, total delivery may include the PC’s and hardware support. 2. Platform requirements

8. 3. Product integration – non technical customers 8 Highlights Find someone else to integrate the products Specify the user to be supported, or specify the desired commercial products

9. Who can integrate? Hotel system Account system Customer ??? Customer’s IT dept Product supplier Main contractor ? ? 3. Product integration – non technical customers

10. Integration reqs, domain-level Sub-tasks: 1.Get guest invoices 2.Post on accounts Problem: Same posted twice or forgotten. 3.Send invoices... Variants: 1a.We have several hotels and want shared accounting. Example solution: Automatic transfer from hotel system to Wonder-Account xx.yy. Account numbers defined in a database table. Unbroken sequence of numbers. Data transmission. Task:5.1 Daily accounting Purpose:Balance with bank account... Send out invoices to company customers Frequency:Daily R1:The product shall support task 5.1. 3. Product integration – non technical customers

11. Integration reqs, product-level We have a commercial product R2:Customer uses WonderAccount xx.yy. Hotel system shall ensure transfer within next day. Shall transfer... once and only once. We want a new commercial product R3:Customer wants new account system. Supplier shall specify the systems he integrates with and the degree of transfer reliability. R4:Supplier shall specify detailed interface for chosen account system. Consortium model R5:Supplier shall deliver hotel system plus account system. Account system shall provide standard account facilities. We have a tailor-made system R6:Customer uses old mainframe system YY for accounting. Hotel system must ensure daily transfers, once and only once. Let the supplier study YY documentation? Document the interface? Let YY developer be main contractor? 3. Product integration – non technical customers

12. 12 Highlights Product integration is a main contractor’s job Technical interfaces are a design issue Divide total product into sub-products, using what is available 4. Product integration – main contractor

13. Hotel system Account system Telephone system Sub-contractor Joint design work The optimal split. Exists? Willing? Cost vs. market DB sys Embedded 3rd party product Main contractor Visible 3rd party product 4. Product integration – main contractor

14. 5. Technical interfaces 14 Highlights Many ways to specify the technical interface Prototype and test the communication early

15. Hotel system Account system Communication channel Physical channel: File, TCP/IP, object calls... Message formats: Data descr, call params Protocol: State diagram, sequence diagram formal data descr, SDL... Semantics: about what? E/R, tasks, activity diagrams Verify early: Functional prototypes 5. Technical interfaces