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Requirements Gathering Technique: Use Case Diagrams with Latinitas Project example. By Gretel Paronzini-Fredette. Agenda. Use Case Definitions Value of Use Cases Brief Overview of Use Case Core Components and Structure New Approach for Gathering Latinitas’ Requirements
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Requirements Gathering Technique: Use Case Diagramswith Latinitas Project example By Gretel Paronzini-Fredette
Agenda • Use Case Definitions • Value of Use Cases • Brief Overview of Use Case Core Components and Structure • New Approach for Gathering Latinitas’ Requirements • Use Case Diagram vs. DFD • Use Case Specification: Login and Authenticate • Tips on requirements gathering • Questions
Use Case Definitions • Use Case Diagram • Use Case Model • Use Case Specification/ Definition/Description
Use Case Definitions • Use Case Model: • “A view of a system that emphasizes the behavior as it appears to outside users. A use case model partitions system functionality into transactions ‘use cases’ that are meaningful to users ‘actors.’ There are two kinds: 1- Use Case Diagrams, and 2- Use Case Descriptions” (Kobryn) • “Use cases and use case diagrams are the Unified Modeling Language (UML) features that support the gathering and analysis of user-centric requirements by starting with your user’s goals.” (Chonoles, Schardt) • Use Case Diagrams Definition: • “A use case diagram is a graphic representation of the key features of the written use case reports that comprise a system.” (McLeod, Jordan) • “High-level visual representation of the user requirements.” (Weigers)
Value of Use Cases • Use cases help the analyst focus on what the users need to accomplish vs. on what the users want the system to do. • Use cases help focus on user’s goals. Thus, you can provide systems that deliver value to your customer. • Use cases help the requirements analyst with the organization of requirements: • They allow descriptions of sequences of events for what the actor does with the system. • They help with requirements prioritization. The highest priority functional requirements are those that originated in the top priority use cases.
Value of Use Cases – Part 2 • Use cases help bridge the gap between business requirements and the application of technology. • Use cases are a “road map” for developers and testers. Programming code and test cases are traced back to each one of the functional requirements described in the use case descriptions. • Use cases also allow the requirements analyst to discover business rules, and data exchanged between the actor and the system. • Use case diagrams provide visibility to the system internals unlike the DFD and Context Diagram.
Visio Software – UML Options Use Case Symbols
Basic Structure and Components Use Case: Name Brief Description Actors Pre-Conditions Post-Conditions Basic Flow Alternate Flows Exception Flows Additional Components Special Requirements Data Sources * Dependencies Assumptions Open Issues * It is advisable to keep data sources in the use case until they are signed off by the user. After that, it is recommended to have them in a data dictionary instead. (One place to make modifications) Brief Overview of Use Case Core Components and Structure – Use Case Description
New Approach for Gathering Latinitas’ Requirements – Login and Authenticate UCS • Latinitas - Login and Authenticate UCS.DOC
Tips for requirements gathering • Use as many tools as you need to understand your client’s problems/needs. • Ask questions, be a detective, perform your client’s job. • Find out what your client’s business processes are. • Find out functional and non-functional requirements, constraints, data to be used, and business rules. • Document EVERYTHING! • Encourage feedback from your client, make him/her be part of the requirements gathering process. • Ask the client to sign-off requirements.
Works Cited • Chonoles, Michael J., and James A. Schardt. UML 2 for Dummies. Hoboken: Wiley, Inc., 2003. • Kobryn, Cris. "Introduction to UML: Structural and Use Case Modeling." Telogic. Object Modeling with OMG UML Tutorial Series. 2001. 1 Oct. 2007 <www.omg.org/docs/omg/01-03-02.ppt>. • McLeod Jr., Raymond, and Eleanor Jordan. Systems Development a Project Management Approach. Danvers: John Wiley and Sons, 2002. • Reinhold, Christiane. Personal interview. 5 Oct. 2007. • Steinle, Randy. "Use Cases." Systems Evolution. Educational Briefing. Department of Information Resources, Austin. 07 Dec. 2005. • Weigers, Karl E. Software Requirements, Second Edition. Microsoft Press, 2003.