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SYS366 The Last Stage in Analysis: System Use Case Descriptions created through the Use Case Authoring Process.

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Presentation on theme: "SYS366 The Last Stage in Analysis: System Use Case Descriptions created through the Use Case Authoring Process."— Presentation transcript:

1 SYS366 The Last Stage in Analysis: System Use Case Descriptions created through the Use Case Authoring Process

2 Where did we come from? Identified Stakeholder categories/types Identified business areas & basic processes Completed interviews with stakeholder rep. Identified Business Use Cases Built a Business Use Case Diagram Wrote Business Use Case Descriptions Created Actor/Activity Tables from the Business Use Case Descriptions

3 System Use Cases Identify actors for System Use Cases look for an actor who specifically interacts with the system  humans, devices, other systems, etc Actors are not part of the system. They are just outside the system boundary and are visible to the system. Identify activities for System Use Cases Anything the system must do to achieve the use case result Happens only inside the system boundary Systems Use Case Diagram Systems Use Case Descriptions Systems Use Case Authoring Process

4 Systems Use Cases convert Business Use Cases to system requirements. How? B.U.C. description leads to B.U.C. actor/activity table leads to System Use Case Diagram & Description

5 Documenting Systems Use Cases Systems Use Case Diagram Shows the functionality that the system will provide and which users (actors) will communicate with the system Done using Rational Rose acts as a place holder for the Systems Use Case Description is a visual index, providing a context for the descriptions

6 Systems Use Cases Diagram Actors are represented by a ‘stick’ figure Systems Use Cases are shown as an oval Associations are a customer ID labeled arrow line —–—––– 

7 Designing Dialogs The process of designing the overall sequences that users follow to interact with an information system the sequence in which information is displayed to and obtained from the user

8 Sequence understanding how the user will interact with the system clear understanding of user, task, technological and environmental characteristics

9 Systems Use Case Descriptions The (systems) use case descriptions provide the substance of the (systems) use case model and they are the basis for most of the …modeling work…More than 90% of the (systems) use-case model lies beneath the surface, in the textual use-case descriptions themselves. * *Use Case Modeling, Kurt Bittner & Ian Spence, Addison-Wesley, 2003, p. 30

10 Systems Use Case Descriptions “(Systems) use cases are more than just a named ellipse and a brief description. For each (systems) use case there will also be a (systems) use- case description where the full story of the use case is told.”* *Use Case Modeling, Kurt Bittner & Ian Spence, Addison-Wesley, 2003, p. 30

11 Systems Use Case Descriptions “The use case description tells a story of how a system and its actors collaborate to achieve a specific goal This collaboration takes the form of a dialog between the system and its actors It is a step-by-step description of a particular way of using a system”* *Use Case Modeling, Kurt Bittner & Ian Spence, Addison-Wesley, 2003, p. 24

12 Systems Use Case Descriptions “Just like a story, every use case should have a clear beginning (how the actor starts the use case) Middle (how the system and actors work together) End how the use case is concluded”* *Use Case Modeling, Kurt Bittner & Ian Spence, Addison-Wesley, 2003, p. 24

13 Systems Use Case Description Describes typical ways (or cases) of using the system* with processing details Not a complete description of all possible ways that some task is performed by actor Does not say how the system is designed or implemented (e.g. J2EE or.NET) *Use Case Modeling, Kurt Bittner & Ian Spence, Addison-Wesley, 2003, pp

14 Systems Use Case Descriptions The systems use case description must include: Who the actors are and how many of them are interacting with the system at any point in time What data is used and how All normal logic: sequential, decision, looping All exception and error logic

15 Today Systems Use Case Descriptions Systems Use Cases Authoring

16 The Systems Use Cases and its description evolves through the authoring process.* * Systems Use Cases Modeling by Bittner & Spence, Page 152

17 The Authoring Life Cycle Discovered Briefly Described Bulleted Outline Essential Outline Detailed Description Systems Use Case Specification

18 The Authoring Life Cycle State 1: Discovered * Through Interviews with the Stakeholders Through experience Shown on a Systems Use Case diagram Place holder for the Systems Use Case description A visual index, providing a context for the descriptions * Systems Use Cases Modeling by Bittner & Spence, Pages

19 The Authoring Life Cycle State 2: Briefly Described Once the Systems Use Case has been identified, it should be described Example: Create Vehicle Reservation by Phone This Systems Use Cases describes how the actor, a Call Centre Employee, uses the system to reserve a vehicle for a specified period at a customer’s request.

20 The Authoring Life Cycle State 3: Bulleted Outline Captures the simple steps of the use case in short sentences organized sequentially

21 Bulleted Outline Example of a Systems Use Case

22 Bulleted Outline Let’s create a bulleted outline for one of your use cases


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