02 - Use Case (2).pdf

UML 1 UNIFIED MODELING LANGUAGE Chapter 2: Use Case  Table of Content 2 ¨ 2.1 Use Case Components ¨ 2.2 Use Case Relationships  Modeling Requirements: Use Cases 3 ¨ A use case is a case (or situation) where your system...

UML 1 UNIFIED MODELING LANGUAGE Chapter 2: Use Case  Table of Content 2 ¨ 2.1 Use Case Components ¨ 2.2 Use Case Relationships  Modeling Requirements: Use Cases 3 ¨ A use case is a case (or situation) where your system is used to fulfill one or more of your user's requirements ¨ a use case captures a piece of functionality that the system provides ¨ Use cases are at the heart of your model since they affect and guide all of the other elements within your system's design  Example: Weblog CMS 4 ¨ Requirement A.1: The content management system shall allow an administrator to create a new blog account, provided the personal details of the new blogger are verified using the author credentials database. ¨ Requirement A.2: The content management system shall allow an administrator to create a new personal Wiki, provided the personal details of the applying author are verified using the Author Credentials Database.  2.1 Use Case Components 5 ¨ Actors: things that interact with your system ¤ Notation: a stick man or a labeled box ¤ Actors should be given appropriate names  2.1 Use Case Components 6 ¨ Identifying an actor ¤ Actors don’t have to be actual people ¤ An actor can also be a third party’s system ¤ Tricky actors Ex: System clock  2.1 Use Case Components 7 ¨ Refining actors ¤ Some actors are related to each other (generalization) ¤ If user1 is the general actor of user2, it means that user2 can do whatever user1 can do ¤ Notation of generalization arrow  2.1 Use Case Components 8 ¨ Use cases: interactions or cases where the system is being used to complete a specific job ¤ Notation: an oval with a name that describes the interaction that it represents ¤ What makes a good use case?  2.1 Use Case Components 9 ¨ Communication Lines ¤ Acommunication line connects an actor and a use case to show the actor participating in the use case  2.1 Use Case Components 10 ¨ System Boundaries: are used as a separation between actors (external) and use cases (internal) ¤ Notation: a box ¤ It is a good practice to name your boundary box  2.1 Use Case Components 11 ¨ Use Case Descriptions ¤ Related requirements ¤ Goal in context ¤ Preconditions ¤ Successful end condition ¤ Failed end condition ¤ Primary actors ¤ Secondary actors ¤ Trigger ¤ Main flow ¤ Extension  2.2 Use Case Relationships 12 ¨ The Relationship: is used to represent a use case that can be reused by other use cases ¤ Notation: a dotted arrow labeled with  2.2 Use Case Relationships 13 ¨ Special cases: one use case is a special type of another use case (use case generalization or use case inheritance) ¤ Notation: generalization arrow  2.2 Use Case Relationships 14 ¨ The Relationship: is used to represent a reusable behavior that is optional. ¤ Notation: a dotted arrow labeled with  References 15 ¨ Miles, R. (2006). Learning UML 2.0. O’Reilly. ¨ Chonoles, M. & Schardt, J. (2003). UML 2 for Dummies. Wiley Publishing.