INFO2005 Requirements Analysis CASE Computer Aided Software Engineering

1. INFO2005Requirements Analysis CASE Computer Aided Software Engineering Department of Information Systems

2. Learning Objectives • Understand the use of various types of CASE in systems development • Describe the components of CASE tools and understand the relationships between them • Understand the use of CASE in Organisations • Understand the advantages and disadvantages of the use of CASE tools

3. Documentation Standards • We need to record facts about the organisation we are studying and its requirements. • Records of interviews and observations. • Details of problems. • Existing documents and where they are used. • Details of requirements. • Details of users. • Minutes of meetings. • Visual modeling helps represent requirements

4. Visual Modeling • ‘Visual modeling is the process of graphically depicting the system to be developed. Visual modeling allows you to present essential details of a complex problem and filter out the nonessential details. It also provides a mechanism for viewing the system to be developed from different perspectives.’ • Rational Rose 2000

5. Visual Modeling • identify requirements and communicate information • focus on how system components interact, without getting bogged down in specific details • allow you to see relationships among design components • improve communication across your team through the use of a common, graphical language

6. What is CASE? “Computer Aided Software Engineering (CASE) are the software tools that provide automated support for some portion of the systems development process” (Hoffer,1999) • Includes: • Cross lifecycle CASE & I-CASE • Upper CASE & Lower CASE

7. Categories of CASE Tools • Cross Lifecycle CASE • I-CASE (Integrated CASE) • Upper CASE • Lower CASE • Distinction much less with modern CASE

8. Organisational use of CASE • Depending on the CASE tool, the following system development activities may be covered:

9. Organisational use of CASE • Objectives of CASE • improve quality of developed systems • increase speed of systems development • improve testing process through automatic checking • integrate development activities (common methods) • improve documentation (quality and completeness) • standardise the development process • simplify program maintenance • promote reusability of modules & documentation • improve software portability across environments

10. CASE Tool Components • Vary depending on which CASE tool is considered but in general will include: • diagramming facilities • means of describing/defining functional and data objects • means of identifying relationships between system components • central repository of system information • error checking facilities (syntax errors)

11. CASE Tool Components • consistency and completeness checks • user interface generators • database specification • code generators • project management aids • documentation generators • May also provide features for group working, version control, interfacing facilities and security features

12. CASE Diagramming Tools • Diagramming facilities include: • checks for syntactic correctness • consistency & completeness checks • navigation to linked diagrams • data dictionary support • layering of system components • traceability of requirements • report generation • system simulation/performance analysis (models)

13. Rational Suite Development Studio Rational Unified Process - development framework Rational Rose 2000 Enterprise - graphical component modeling and development tool Rational ClearQuest - defect tracking/change request management system. Rational Pure Coverage - pinpoints areas of code that have not been exercised during testing

14. Rational Suite Development Studio • Rational Purify - pinpoints hard-to-find run-time errors in your applications • Rational Visual Quantify - advanced performance profiling tool • Rational RequisitePro - organize, prioritize, track and control changing requirements of a system or application. • Rational SoDA - automatic generation of software documentation

15. Rational Rose • Rational Rose provides • Use Case • Class Diagrams • Activity Diagrams • Interaction Diagram (Both forms) • State Machine Diagram • Component Diagram • Deployment Diagram

16. CASE Diagramming Tools

17. Rational Rose • Rose uses these diagrams in 4 views of the system • Use Case View • Logical View

18. Rational Rose • Component View • Deployment View

19. CASE Repository • A repository is a centralised database containing all models (diagrams), data dictionary entries, form & report definitions and system & organisational information • Holds complete information to develop a system from initiation to maintenance • It is the nucleus of an I-CASE environment

20. CASE Repository Diagrams Forms and Reports Documentation Project Information Analysis & Testing Results CASE Repository Source and Object Code Standard Libraries

21. CASE Repository Use Case Specifications Specifying an Actor

22. CASE Form/Report Generators • Automated generation of • data entry screens • reports • program code (eg Java, C++) • also reverse engineering of code • database schema

23. Benefits of using CASE Tools • Automation of tedious tasks • Syntax/completeness checks ensure consistency • Amending/updating achieved far more easily • More rapid development

24. Benefits of using CASE Tools • Capture of system data for reuse • particularly important for OO development • May guide the use of a methodology • Clearer communication with users • Continuity of development with changing staff • Standardised quality assurance/test procedures • Improvements in system quality • Reduction in defects increases morale

25. Role of CASE in QA • CASE can help with: • adherence to standards, • integrity of documentation, • centrally held data dictionary, • fast capture of requirements, • quick modification to designs, • trace requirements from model to code, • guide the development process, • easy, consistent code-generation. • All important in maintaining quality

26. Limitations of CASE • Limited flexibility in documentation • Development approach limited to fit capabilities of the CASE tool • Training and experience required • CASE prepared models may be more convincing but not reflect requirements

27. Limitations of CASE • Front loaded cost of installation of CASE tool & training • Incomplete coverage of syntax/ consistency checks • Limited intelligence - no checks on overall quality or correctness

28. Summary • Understand the use of various types of CASE in systems development • Describe the components of CASE tools and understand the relationships between them • Consider Rational Rose as an exemplar CASE tool • Understand the use of CASE in Organisations • Understand the advantages and disadvantages of the use of CASE tools

29. References • Hoffer, J.A. et.al. “Modern Systems Analysis & Design” 2nd Ed. Addison-Wesley 1999 Ch4 pp107-136 • Bennett, S. et. al. “Object-Oriented Systems Analysis & Design using UML” McGraw-Hill 1999 Ch3 pp55-60 • Rational Rose Tutorial (In folder RoseTutorial) • Rational Rose Enterprise Edition • Rational Unified Process 2000