True-False Questions
1.
The words “actor” and “user” are synonyms as terms in a use case
diagram.
Answer: False Page Reference: 163 Difficulty: Moderate
2.
Use case modeling is one of the few non-iterative processes of OOSAD.
Answer: False Page Reference: 163, 180 Difficulty: Moderate
3.
In UML use case diagrams, actors exist outside the system that is being
modeled.
Answer: True Page Reference: 163 Difficulty: Easy
4.
It is possible for a single user to be represented by several actor
roles in a use case diagram.
Answer: True Page Reference: 163 Difficulty: Moderate
5.
Use-case diagrams depict user interaction with information systems.
Answer: True Page Reference: 164 Difficulty: Easy
6.
Adding new behaviors to a complete use case is represented through the
use of an <<extend>> relationship.
Answer: True Page Reference: 165 Difficulty: Moderate
7.
In UML use case diagrams, ellipses always appear inside the system
boundaries.
Answer: True Page Reference: 165 Difficulty: Easy
8.
In UML use case diagrams, lines that cross system boundaries are most
likely to be solid.
Answer: True Page Reference: 165 Difficulty: Moderate
9.
The relationship between a use case and a generic function commonly
used by many other use cases is labeled with <<include>>.
Answer: True Page Reference: 166 Difficulty: Moderate
10. In UML use case diagrams, arrows
on relationship lines indicate direction of data and process flow.
Answer: False Page Reference: 165-166 Difficulty: Moderate
11. In UML use case diagrams, lines
connecting use cases to each other for extension or inclusion are dotted.
Answer: True Page Reference: 165-166 Difficulty: Moderate
12. Abstract use cases have no direct
interactions with actors.
Answer: True Page Reference: 167 Difficulty: Moderate
13. Microsoft Visio puts use case
names below the use case ellipses.
Answer: False Page Reference: 167 Difficulty: Moderate
14. Generalization relationships
between actors are represented by solid lines with arrows.
Answer: True Page Reference: 169-170 Difficulty: Moderate
15. In UML diagrams, a use case with
an <<extend>> relationship pointing toward it is dependent on its
extension use case in order to function completely.
Answer: False Page Reference: 170 Difficulty: Hard
16. Use case descriptions focus
primarily on interactions with actors rather than internal processing steps.
Answer: True Page Reference: 170 Difficulty: Moderate
17. A use case diagram provides
detailed information about the user interaction steps that take place within a
use case.
Answer: False Page Reference: 170 Difficulty: Moderate
18. Cockburn’s “black” level
indicates a highly detailed use case description.
Answer: True Page Reference: 173 Difficulty: Moderate
19. In Cockburn’s use case template,
a precondition is the event that triggers the use case.
Answer: False Page Reference: 174 Difficulty: Moderate
20. In Cockburn’s use case template,
an extension describes steps that take place when something goes wrong during
the use case function.
Answer: True Page Reference: 174-175 Difficulty: Moderate
21. In Cockburn’s use case template,
an extension is equivalent to the <<extend>> relationship in a use
case diagram.
Answer: False Page Reference: 174-175 Difficulty: Moderate
Multiple-Choice Questions
22. Use case construction is a
technique used for:
a.
requirements determination.
b.
requirements structuring.
c.
user interface design.
d.
database design.
Answer: b Page
Reference: 162 Difficulty: Moderate
23. A use case represents:
a.
a class, its attributes and operations.
b.
a business case for using an information system.
c.
the system’s functionality under various conditions.
d.
the role a user plays when interacting with the system.
Answer: c Page
Reference: 163 Difficulty: Moderate
24. The name that identifies a use
case is most likely to be in the form of a(n):
a.
noun.
b.
verb.
c.
verb/noun combination.
d.
adjective.
Answer: c Page
Reference: 163 Difficulty: Moderate
25. An external entity that interacts
with a system is called a(n):
a.
use case.
b.
actor.
c.
stakeholder.
d.
association.
Answer: b Page
Reference: 163 Difficulty: Moderate
26. In UML notation, an ellipse
signifies a(n):
a.
actor.
b.
class.
c.
use case.
d.
system boundary.
Answer: c Page
Reference: 164-165 Difficulty: Easy
27. An abstract use case is one that
is:
a.
connected to an actor but not initiated by another use case.
b.
connected to an actor and initiated by another use case.
c.
not connected to an actor and not initiated by another use case.
d.
not connected to an actor but instead initiated by another use case.
Answer: d Page
Reference: 165, 167 Difficulty: Moderate
28. In a use case diagram, dotted
lines with arrows represent:
a.
data flows between actors and use cases.
b.
connections between use cases in a system.
c.
links between use cases and data stores.
d.
associations between classes and use cases.
Answer: b Page
Reference: 165-166 Difficulty: Moderate
29. In UML notation, the connection
between an actor and a use case is represented by:
a.
a dotted line with an arrow.
b.
a dotted line without an arrow.
c.
a solid line with an arrow.
d.
a solid line without an arrow.
Answer: d Page
Reference: 165 Difficulty: Moderate
30. Which use case label indicates
that one use case provides a variation of the behaviors and actions to the use
case it is connected to?
a.
<<extend>>
b.
<<include>>
c.
<<add>>
d.
<<expand>>
Answer: a Page
Reference: 165-166 Difficulty: Moderate
31. The <<extend>>
relationship between use cases would be used when behavior in the extending use
case is ____________ the extended use case.
a.
always needed by
b.
never needed by
c.
sometimes needed by
d.
unrelated to
Answer: c Page
Reference: 165-166 Difficulty: Hard
32. Which use case label indicates
that one use case is initiated and used by another use case?
a.
<<extend>>
b.
<<use>>
c.
<<initiate>>
d.
<<include>>
Answer: d Page
Reference: 166 Difficulty: Moderate
33. Which type of use case is most
likely to be pointed at by a dotted line labeled <<include>>?
a.
A use case that is initiated by an actor playing a role
b.
A use case that is specialized by another use case in the system
c.
A use case providing functionality that is used by several other use
cases
d.
A use case that exists outside the system boundary
Answer: c Page
Reference: 166 Difficulty: Hard
34. Which software product is a CASE
tool that includes user case diagramming capabilities?
a.
Rational Rose
b.
Microsoft Visio
c.
User Case Manager
d.
Unified Modeling Language
Answer: a Page
Reference: 167 Difficulty: Moderate
35. Under which circumstance will you
prefer an <<extend>> relationship instead of an
<<include>> relationship?
a.
Modeling a variation of a complete use case
b.
Factoring the common behavior among two or more use cases
c.
Connecting a use case to an actor
d.
Describing the detailed behavior of a use case
Answer: a Page
Reference: 170 Difficulty: Hard
36. What is the advantage of using a
template for writing a use case?
a.
Facilitates free form open-ended writing
b.
Encourages analyst to create complete use case
c.
Matches the UML format specifications
d.
Provides a diagrammatic representation of a use case
Answer: b Page
Reference: 172 Difficulty: Moderate
37. In Cockburn’s written use case
template, the level indicates:
a.
degree of importance.
b.
amount of detail.
c.
authority of stakeholders.
d.
degree of success.
Answer: b Page
Reference: 172-173 Difficulty: Moderate
38. In Cockburn’s written use case
template, a ____________ specifies what needs to be true in order for the use
case to execute.
a.
precondition
b.
minimal guarantee
c.
trigger
d.
requirement
Answer: a Page
Reference: 174 Difficulty: Moderate
39. In Cockburn’s written use case
template, the event initiating a use case is called a(n):
a.
precondition.
b.
stakeholder.
c.
extension.
d.
trigger.
Answer: d Page
Reference: 174 Difficulty: Moderate
40. In Cockburn’s written use case
template, the behaviors that will occur in the case of system exceptions or
some other failure takes place in the:
a.
failure scenario.
b.
extensions.
c.
preconditions.
d.
exception description.
Answer: b Page Reference: 174-175 Difficulty: Moderate
41. All of the following help achieve
the goal of use case completeness
EXCEPT:
a.
Obtain all functional requirements before use case development begins.
b.
Include rapid prototyping as part of the requirements structuring
process.
c.
Write a user manual as the requirements structure process takes place.
d.
Iteratively review use cases and generate new ones based on user
evaluations.
Answer: a Page
Reference: 179 Difficulty: Hard
Essay and Problem-Solving
Questions
42. What is the purpose of use case
modeling? At what stage in the systems development process will use case
modeling take place? What are the inputs to use case modeling and what are its
outputs?
Answer:
The
purpose of use case modeling is to analyze the functional requirements of a
system. It takes place in the early stages of systems development, during the
analysis phase. Primarily, it is taking place during requirements structuring,
and inputs to this process are the requirements that had been obtained from
interviews, questionnaires, JAD sessions, observations, and document analyses
of the requirements determination process. The outputs from use case modeling
are use case diagrams and written use cases.
Page
Reference: 163 Difficulty: Easy
43. What is a use case? What is the
most appropriate verbal form in which to identify a use case? In a use case model, what does a use case
generally interact with? How does use-case modeling promote forward and backward
traceability in object-oriented development? Finally, what questions can the
systems analyst ask herself in order to generate use cases for the system
model?
Answer:
A
use case is a depiction of a system’s behavior or functionality under various
conditions as the system responds to requests from the user. They are generally
identified using verb phrases including a verb indicating the action to take
and a noun indicating the object that is acted upon. Use cases interact either with actors or with
other use cases. Use case-driven design supports forward traceability in that
requirements specified in a use case will guide the construction and
modification of elements in other analysis and design models. Similarly, a design change in other analysis
models can be traced backward to see its effects on use case requirements. In
developing a use case model, the identification of use cases can benefit from
the following questions. First, what are the main tasks performed by each
actor? Second, will an actor read or update any information in a system? Third,
does the actor inform the system of events occurring outside the system? And
fourth, is the actor to be informed of any unexpected changes that occur within
the system?
Page
Reference: 163 Difficulty: Moderate
44. List each of the elements of a
UML use case diagram, and describe what they look like and what they represent.
Answer:
A
use case diagram consists of four elements. A stick figure represents actors,
which are roles played by external entities of a system, usually system users.
An oval shape describes a use case, which represent elements of system behavior
in response to user interaction. Solid lines between actors and use cases
represent connections indicating the actor’s involvement with the system
function of the use case. Connections can also exist between use cases. These
are usually represented as dashed lines with arrows. There are two major types
of connections between use cases; one is an include relationship and the other
is an extend relationship. Extend refers to adding new behaviors or actions to
a default use case. Include refers to a relationship in which one use case uses
another use case. The final symbol of a use case diagram is a system boundary,
which is a box surrounding the use case symbols and separating them from the
external actors.
Page
Reference: 164-166 Difficulty: Moderate
45. Compare and contrast the
different types of connections that are represented in a use case diagram. Give
the meanings of each of these connections, describe the circumstances under
which each type of connection is appropriate, and give a verbal description of
what the connection looks like. Relate this discussion to the concepts of
include, extend, and generalize. Also, discuss how this relates to the
distinction between abstract and non-abstract use cases.
Answer:
The
different connections include associations between actors and use cases,
associations between actors themselves, and associations between use cases. A
typical association between an actor and a use case is a solid line containing
no arrowheads, and does not imply any direction of data flow; it merely shows
that an actor is involved in a use case. The connections between use cases
imply either an extension or inclusion relationship. In an extend relationship,
the extending use case points to the base use case with a dotted line that has
an arrowhead at the base use case; that dotted line is labeled as
<<extend>>. This type of relationship is appropriate when you wish
to model a variation of a complete use case as an alternative to the original
use case. Another type of relationship is an include relationship, in which one
use case uses the functionality of another. In this case, a dotted arrow points
from one use case to the use case that it relies on for the additional
functionality, and the dotted line is labeled with <<include>>.
This type of relationship is appropriate when the intent is to factor a common
among multiple use cases into a shared generalized use case. Another type of
association can exist between different actors; in this case one actor role is
a generalization of a more specific actor role, and the representation is with
a solid arrow that leads from the specific actor role to the more general actor
role. The distinction between an abstract and a non-abstract use case is
determined based on whether the use case is initiated by an actor or another
use case; those use cases that are initiated by other use cases instead of
actors are called abstract use cases.
Page
Reference: 164-167, 170 Difficulty: Moderate
46. Draw a use case diagram for an
ATM machine with the following functionality. A customer’s interaction with the
system involves logging in, making withdrawal requests, deposit requests, and
balance inquiry requests. If the customer logs in, there is a possibility
(although rare) that the system will confiscate the card (for example, if the
login is incorrect or if the bank determines that the customer’s balance is
significantly under zero). Card confiscation involves triggering an alert,
which will be received by the branch manager of the bank. If the customer does
a balance inquiry, this of course causes the system to check the balance.
Checking the balance is also done when the customer requests a withdrawal,
since the system must verify that enough money is in his account. In principle,
checking the balance is a function that may be performed to support many use
cases throughout the system.
Answer: (See next page.)
Page
Reference: entire chapter Difficulty: Hard
47. Draw a use case diagram for a
hospital admissions system. This system serves six types of users: patients,
admissions receptionists, floor nurses, medical technologists, physicians, and
release receptionists. When a patient comes to the hospital, the patient and
admissions technologist use the system to perform a check-in procedure.
Check-in procedures all involve the same steps, such as getting patient
information, insurance, information, etc. Some check-ins are for inpatients;
for these there are additional check-in steps for assigning the patient to a
room and bed. The floor nurse uses the system to perform two tasks. First is
the task of obtaining a list of all patients on the floor. Second is a task of
entering patient notes. The medical technologist also performs two tasks on the
system. One is to retrieve the patient record, and the second is to enter lab
service notes. The physician performs two tasks as well, one of which is to
obtain her rounds schedule and the other is to enter patient notes (which is
the same system process used by the floor nurse). Finally, the patient and
release receptionist go through the check-out procedure.
As
can be expected, there are some tasks that are shared by several processes.
Specifically, check-in, check-out, entering patient notes and entering lab
services all require updating the patient record in the database. Also,
retrieving the patient record is a task required to support processes such as
listing floor patients, receiving rounds schedules, and updating the patient
record.
Answer:
Page
Reference: entire chapter Difficulty: Hard
48. List and describe the sections of
Cockburn’s written use case template, discussing the sorts of information
contained in each section.
Answer:
Cockburn’s
use case template consists of the following sections: a title, the primary
actor, an indicator of the level, a list of stakeholders, a precondition, a
minimal guarantee, a success guarantee, a trigger, a main success scenario, and
a list of extensions. The title is the name of the use case, similar to the
name that will appear in the oval of a use case diagram. The primary actor is
the role that is directly associated with the use case. Level has to do with
the level of detail at which the use case is described. Cockburn suggested five
levels, from most abstract to most detailed: white, kite, blue, fish, and
black. The stakeholders are the people in whose interest the system is being
developed. Preconditions are criteria which must be satisfied in order for the
use case to start. The minimal guarantee is the very least promised about the
result of the use case; this would correspond to a failure condition in the use
case. At the very least, a failure condition should not result in any
detrimental effects to the system as a whole. The success guarantee identifies
what the stakeholders can expect as a result when the use case successfully
accomplishes its tasks. The trigger is an event that initiates a use case. The
main success scenario outlines the user interaction steps that take place in
order to meet the success guarantee. Extensions are a list of behaviors or
functions in the use case that take place if steps in the main success scenario
fail for some reason.
Page
Reference: 172-175 Difficulty: Moderate
49. Using the template suggested by
Cockburn, create a written use case for the following scenario:
An
employee must record his or her time and expenses in order to assist the
payroll department to process correct payments to the employee. The activities
that the employee should perform will begin by viewing the screen for entering
time reporting information. The employee will enter time reporting information
for each task performed during the pay period and then submit this information
to the system. When the system receives this submitted information, it will
look up salary and benefits data for the employee and use this to calculate
payment, then respond with an acknowledgement that details all time reporting
information as well as the total pay amount that will accrue to the employee.
Similarly,
the employee should be able to view a form containing all expense-related
information, and then enter expense data and submit this to the system. When
the system receives this submittal, it will look up expense categories to
verify that the employee is qualified to claim reimbursement, and then presents
an acknowledgement detailing all expenses and the total reimbursement.
In
the case that a failure occurs in time reporting, the system should present the
detailed error message about the cause of failure, and instruct the user which
inputs need to be corrected. The employee may then decide to retry, or simply
cancel the operation. Similar activities should occur for dealing with expense
reporting errors.
The
main beneficiaries of this use case will be the employee, of course, as well as
the payroll department. The use case
will be triggered when the user selects time and expense reporting from a menu
of options, but ONLY if the employee as
already logged into the system with a valid employeeID and password, and ONLY
if the employee has not already submitted time or expense information for the
given pay period.
The
best-case scenario in this use case is for the time and expense information to
have been successfully entered into the system and positive acknowledgements
sent back to the user, but at the very least, the system should be able to
rolls back any uncompleted transaction and log an error message so that the
system administrator can be alerted.
Answer:
|
Title: Record Time and
Expenses
|
|
Primary Actor: Employee
|
|
Level: Kite
|
|
Stakeholders: Employee,
Payroll Department
|
|
Precondition: Employee has
logged in with a valid Employee ID and password, and the employee has not
already entered time and expenses for the current pay period.
|
|
Trigger: Employee selects
Time and Expenses from the menu of options.
|
|
Minimum Guarantee: System
rolls back any uncompleted transaction and an error log is recorded for the
system administrator.
|
|
Success Guarantee:
Employee’s time and expense information is loaded into the database and an
acknowledgment message detailing the time and expenses are displayed to the
employee with option for printing.
|
|
Main success scenario:
1)
the employee is presented with a screen for entering time reporting
information
2)
employee enters time reporting information for each task performed
during the pay period
3)
employee submits time reporting information to the system
4)
the system looks up salary and benefits information for the employee
in order to calculate payment
5)
the system presents an acknowledgment to the employee detailing all
time reporting information, and a total pay amount that will accrue to the
employee
6)
the employee is presented with a screen for entering expense
reporting information
7)
employee enters expense reporting information for all expenses
accrued during the pay period
8)
employee submits expense reporting information
9)
the system looks up expense categories and employee information to
verify that employee is qualified to claim all expenses submitted
10) the system presents an
acknowledgment to the employee detailing all expenses and totaling the amount
of money that will be refunded to the employee
|
|
Extensions
1)
Time reporting submission fails
a.
Message created to tell employee about specific errors, identifying the
inputs that need correction, and allowing employee to retry the time report
submission
b.
Employee either retries entering the time reporting information or
cancels time reporting
2)
Expense reporting submission fails
a.
Message created to tell employee about specific errors, identifying
the inputs that need correction, and allowing employee to retry the expense
report submission
b.
Employee either retries entering the expense reporting information or
cancels expense reporting
|
Page
Reference: 172-180 Difficulty: Hard
50. Discuss the goal of completeness
as it relates to use case modeling. Why is it important for systems
development? Describe some ways in which the goal of completeness can be
achieved during the requirements structuring process.
Answer:
When
developing a use case model, it is important to represent as much of the system
functionality as possible. The more complete the model, the more likely the
completed system will, in fact, meet all the customer needs. There are a
variety of approaches the systems analyst can use to ensure completeness. One
is to work continuously with the customer to revise and refine requirements as
the use cases are being written. In this sense, requirements structuring and
requirements determination are taking place in parallel. Making use of rapid
prototyping in conjunction with use case modeling also helps ensure
completeness, as use cases can be refined based on user feedback regarding
prototype functionality, and the modified use cases can in turn lead to
improvements in the prototype. Yet another way of facilitating completeness is
to develop the user manual early in the requirements structuring process. The
user manual can provide lists of functionality that can be used to generate new
use cases or fill in details of existing use cases in the model.
Page
Reference: 179-180 Difficulty: Moderate
Nice compilation of questions but..
ReplyDeletewhy can't i see the images for the use case diagrams? :/