Generalizations Much like superclasses in a class diagram a generalized use case represents several similar use cases One or more specializations provides details of the similar use cases www.oseng.com O Lethbridge/Laganiere 2001 Chapter 7: Focusing on Users and Their Tasks
© Lethbridge/Laganière 2001 Chapter 7: Focusing on Users and Their Tasks 11 Generalizations • Much like superclasses in a class diagram. • A generalized use case represents several similar use cases. • One or more specializations provides details of the similar use cases
Inclusions Allow one to express commonality between several different use cases Are included in other use cases even very different use cases can share sequence of actions -Enable you to avoid repeating details in multiple use cases Represent the performing of a lower-level task with a lower-level goal www.oseng.com O Lethbridge/Laganiere 2001 Chapter 7: Focusing on Users and Their Tasks
© Lethbridge/Laganière 2001 Chapter 7: Focusing on Users and Their Tasks 12 Inclusions • Allow one to express commonality between several different use cases. • Are included in other use cases —Even very different use cases can share sequence of actions. —Enable you to avoid repeating details in multiple use cases. • Represent the performing of a lower-level task with a lower-level goal
EXample of generalization, extension and nclusion Open file Ordinary User Open file by Open file by typing name browsing 玡 xtend? 玦 nclude? Attempt to open file System that does not exist Browse for file Administrator www.oseng.com O Lethbridge/Laganiere 2001 Chapter 7: Focusing on Users and Their Tasks 13
© Lethbridge/Laganière 2001 Chapter 7: Focusing on Users and Their Tasks 13 Example of generalization, extension and inclusion Open file by typing name Open file by browsing Open file System Administrator Browse for file Ordinary User Attempt to open file that does not exist 玡xtend? 玦nclude?
Example description of a use case Use case: Open file Related use cases: Generalization of Open file by typing name Open file by browsing Steps Actor actions System responses 1.Choose'Open.'command 2 File open dialog appears 3. Specify filename 4. Confirm selection 5. Dialog disappears www.oseng.com O Lethbridge/Laganiere 2001 Chapter 7: Focusing on Users and Their Tasks 14
© Lethbridge/Laganière 2001 Chapter 7: Focusing on Users and Their Tasks 14 Example description of a use case Use case: Open file Related use cases: Generalization of: • Open file by typing name • Open file by browsing Steps: Actor actions System responses 1. Choose ‘Open…’ command 2. File open dialog appears 3. Specify filename 4. Confirm selection 5. Dialog disappears
EXample(continued) Use case: Open file by typing name Related use cases: Specialization of: Open file Ste Actor actions System responses Choose'Open. 'command i 2. File open dialog appears 3a. Select text field 3b. Type file name 4. Click Open 5. Dialog disappears www.oseng.com O Lethbridge/Laganiere 2001 Chapter 7: Focusing on Users and Their Tasks 15
© Lethbridge/Laganière 2001 Chapter 7: Focusing on Users and Their Tasks 15 Use case: Open file by typing name Related use cases: Specialization of: Open file Steps: Actor actions System responses 1. Choose ‘Open…’ command 2. File open dialog appears 3a. Select text field 3b. Type file name 4. Click ‘Open’ 5. Dialog disappears Example (continued)