Use Case Diagrams

Question 1

Whatis the diagram kind for a use case diagram, and which model elements can the frame correspond?

Answer 1

(321)
diagram kind: uc
model element: package model, model library, block

Question 2

What does an actor represent?

Answer 2

(322)

the role of a human, organization, or any external system that participates in the use of some system

Question 3

How are actors represented on a use case diagram?

Answer 3

(322)

stick figure with actors name underneath or a rectangle containing the actor’s name below the keyword <>

Question 4

If 1 actor specializes another, what does that imply?

Answer 4

(322)

a specialized actor participates in all the use cases that the more general actor participates in.

Question 5

What does a use case represent?

Answer 5

(321)
Use cases describe the functionality of a sytem in terms of how it is used to achieve the forals of its various users.
(323)
a use case describes the goals of a system from the perspective of the users of the system.

Question 6

What is another term for the system under consideration?

Answer 6

(323)
system under consideration: The subject (represented as a block) is the system that provides functionality in support of use cases. often represents a system that is being developed.

Question 7

How does a scenario differ from a use case?

Answer 7

(323)
a use case may cover 1 or more scenarios that correspond to how the system interacts with its actors under different circumstances

Question 8

How is an inclusion relationship represented?

Answer 8

(326) inclusion and extension are shown using dashed lines with an open arrowhead at the included and extended ends, respectively. An inclusion line as keyword <> and an extension line has the keyword <>

Question 9

What 2 pieces of information might an extension relationship include (apart from a base and extending use case)?

Answer 9

(326)
attached note: attached to the extension line that names its extension point.
condition: shows the condition which the extending use case occurs

Question 10

If 1 use case specializes another what does that imply about its scenarios?

Answer 10

(326)
use cases can be classified using the standard generalization relationship. This means that the scenarios for the general use case are also scenarios of the specialized use case. Also, that the actors associated with the specialized use case can also participate in scenarios described by a general use case.

Question 11

How may use case participants and the subject be represented on an ibd?

Answer 11

(328)
enclosing frame: system context
parts: subject and participating actors
actors can appear on a bdd and a part on an ibd can be typed by the actor.
OR
Actors can be allocated to blocks using the allocate relationship and then the parts representing actors can be typed by the block.

Question 12

How are use case participants and the system under consideration (subject) represented in activities?

Answer 12

(329)
activity partitions: participants
activity/actions: elaborates a base use case, included use cases, and extending use cases.

Question 13

How are use case participants and the system under consideration (subject) represented in interactions?

Answer 13

(328)
1 or more interactions: elaborated use case described by sequence diagrams. different interactions may correspond to the base, included, and extended use cases.
The block that owns the interactions must have parts that correspond to the subject and participants, which can then be represented by lifelines in the interactions.