6ed Solutions Chap05

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Systems Analysis and Design in a Changing World, sixth edition 5-1

Chapter 5 Extending the Requirements Models

Solutions to End-of-Chapter Problems

Review Questions

1. What are the models that describe use cases in more detail?

Fully developed use case description, activity diagrams, and system sequence diagrams.

2. What two U! dia"rams are used to model domain classes?

Prolem domain class diagram and state machine diagram.

#. Which part of a use case description can also be modeled b$ usin" an acti%it$ dia"ram?

!he "#lo$ o# activities% section.

&. E'plain the difference between a use case and a scenario. (i%e a specific e'ample of a use case

with a few possible scenarios.

& use case is the entire #unction or user goal or event. & scenario is one speci#ic version or

instance o# that use case.

From RM' $e have Create customer accountas a use case. (ut $e might have Create online

Customer accountand Create instore customer accountand even Create phone customeraccountas di##erent scenarios.

5. !ist the parts or compartments of a full$ de%eloped use case description.

)se case name *cenario

!riggering event

(rie# description

&ctors

Related use cases

*ta+eholders

Preconditions

Postconditions

Flo$ o# activities

Exception conditions

). Compare*contrast precondition and postcondition.

& precondition descries the "states% o# data and the system that must exist e#ore the use case

can egin. For example to add an item to a shopping cart, the item must exist in the dataase.

& postcondition descries the states o# data and the system that must exist a#ter the use casecompletes. For example a#ter Create a customer accountuse case, a customer account oect

-record must exist.


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+. Compare*contrast postcondition and e'ception condition.

& post condition, as explained aout descries states o# the data and the system. &n exception

condition descries some non/normal situation in the processing, i.e. in the #lo$ o# activities,

that must e handled in some $ay..

,. Compare*contrast business process and flow of acti%ities for a use case. E'plain how an

acti%it$ dia"ram can be used to model both.

& usiness process is larger than a use case. & usiness process might include various manual

usiness procedures oth e#ore and a#ter the "usiness event% that causes the use case to occur.

0o$ever, an activity diagram is a po$er#ul model to descrie all types o# sequences o# tas+sand activities. !he various s$imlanes can represent various users or user groups as $ell as

system activities.

. What is the purpose of an SS? What s$mbols are used in an SS?

&n **1 -system sequence diagram is used to descrie the messages that #lo$ into and out o# asystem, i.e. et$een the system and the use case user. !he symols include2

*tic+ #igure #or the actor

(ox $ith oect name #or the system oect

3ertical dashed lines #or oect li#elines

0ori4ontal arro$s #or messages

0ori4ontal dashed arro$s #or return data

Comment ox #or comments

1/. What are the steps re0uired to de%elop an SS?

. 6denti#y the input messages -#rom the activity diagram

7. 1escrie the input message using the **1 message syntax

8. &dd message conditions such as looping or true9#alse conditions

:. &dd all output message data

11. Write a complete SS messa"e from the actor to the s$stem with the actor asin" the s$stem

to be"in the process for updatin" information about a specific product.

updateProduct6n#ormation -product61, update6n#ormation

12. What is the name of the se0uence dia"ram s$mbol used to represent the e'tension of an ob3ect

throu"hout the duration of a use case?

;i#eline or oect li#eline

1#. What are the two wa$s to show a returned %alue on a se0uence dia"ram?

Either $ith a return value on the le#t hand side o# the equal -2


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Systems Analysis and Design in a Changing World, sixth edition 5-#

sho$n y a dashed line and laeled $ith the return data.

1&. What are two wa$s to show repetition on a se0uence dia"ram?

Either $ith an asteris+ on the message lael or a loop #rame around the message-s.

15. What are the three t$pes of frames used on a se0uence dia"ram?

;oop #ramerepeat or loop the contents o# the #rame

'pt #ramesend or do not send the message ased on true9#alse condition&lt #ramei#/else alternative #lo$s ased on condition

1). What is the s$mbol for a true*false condition on a se0uence dia"ram?

& true9#alse condition is sho$n in rac+ets = >

1+. What are the parameters of a messa"e?

!he parameters represent the input data, i.e. the data that is eing passed to the destination

oect.

1,. !ist the primar$ steps for de%elopin" a SS.

'oops, duplicate question. *ee question ?.

1. What is an ob3ect state?

&n oect state is the state o# eing o# an oect, and is usually measured y a set o# values. 6t is

comparale to a status condition.

2/. What is a state transition?

& state transition is the movement o# an oect #rom one state to another state.

21. When considerin" re0uirements states and state transitions are important for understandin"

which other dia"ram?

*tates and !ransitions are part o# the state machine diagram #or an oect class. !here#ore, they

help to understand the oects in the class diagram.

22. What U! dia"ram is used to show the states and transitions for an ob3ect?

*tates and !ransitions are part o# the state machine diagram, $hich descries the activity o# theoects in an oect class.

2#. !ist the elements that mae up a transition description. Which elements are optional?


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Systems Analysis and Design in a Changing World, sixth edition 5-&

Transition-name (parameters, ... ) [guard-condition] / action-expression

&ny o# the three elements may e empty, i.e. are optional.

2&. What is a composite state? What is it used for?

& composite state is a high/level state in that it may have other states and transitions inside o# it.6t is used to represent concurrent states. For example, a printer may e in the "on% state, $hich

is a composite state, and it may e "idle% $hich is an internal state $ithin "on.%

25. What is meant b$ the termpath?

& path is a sequence o# states and transitions. 6t may e a complete path to descrie an entire

origin to destination path, or it may e a "snippet% o# a path and only contain a #e$ states andtransitions.

2). What is the purpose of a "uard-condition?

& guard/condition determines $hether or not a transition can #ire. )sually #irst the trigger #ires

to noti#y the transition that it should execute, ut e#ore it egins execution, it tests to see i# theguard/condition is true.

2+. 4dentif$ the models e'plained in this chapter and their relationship to one another.

!he t$o main models #or requirements are the )se case model,$hich identi#ies the use cases or

the "processes,% and the 1omain model class diagram, $hich identi#ies the in#ormation or data

#or the system.

!he )se case diagram is supported y )se Case 1escriptions, &ctivity diagrams, and *ystem

*equence diagrams. !he 1omain model class diagram is supported y *tate machine diagrams.


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Problems and Exerises

1. fter readin" the followin" narrati%e do the followin"6

i. e%elop an acti%it$ dia"ram for each scenario.

ii. Complete a full$ de%eloped use case description for each scenario.

Contractor Sale acti%it$ dia"ram6


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Systems Analysis and Design in a Changing World, sixth edition 5-)

Contractor Sale full$ de%eloped use case description6

)se Case @ame2 Create a ne$ sale*cenario2 Create ne$ sale to a contractor -on account sale

!riggering Event2 Contractor $ants to purchase items.

(rie# 1escription2 & contractor $ants to purchase items. !he cler+ rings up the items and then

adds them to the contractorAs account.

&ctors2 *ales cler+

*ta+eholders2 *ales cler+

&ccounting department*ales department

Preconditions2 Customer account must exist.6nventory items must exist.

Postconditions2 @e$ sale is created.*ales line items are created and connected to the sale.

Customer-contractor account is updated.

Flo$ o# &ctivities2 &ctor *ystem

. Cler+ enters contractor 61.

7. Cler+ enters each item.

8. Cler+ indicates the end o# the sale.

:. 6# contractor $ants receipt, requests

receipt.

. *ystem validates contractor

account.7. *ystem #inds item in

inventory, #inds price, adds to

total.8. *ystem calculates total and

adds to contractor account.

:. *ystem prints receipt.

ExceptionConditions2

. 6# contractor account is out o# alance, treat this sale as a cash sale, orstop process and send contractor to accounting cler+.

7. 6# system has in#ormation missing, sales cler+ calls manager and

manually enters in#ormation.

8. 6# contractor account alance is over the limit, treat as cash sale, cancel,or send contractor to accounting cler+.


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Systems Analysis and Design in a Changing World, sixth edition 5-+

Sale to public acti%it$ dia"ram6


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Systems Analysis and Design in a Changing World, sixth edition 5-,

Sale to public full$ de%eloped use case description6

)se Case @ame2 Create a ne$ sale

*cenario2 & ne$ cash sale!riggering Event2 Cash customer $ants to purchase items.

(rie# 1escription2 & cash customer $ants to purchase items. !he cler+ enters the item 61, andthe system creates a sales tic+et. Customer pays $ith cash, chec+ or credit

card.

&ctors2 *ales cler+

*ta+eholders2 *ales cler+

&ccounting department*ales department

Preconditions2 6nventory items must exist.

Postconditions2 @e$ sale is created.

*ales line items are created and connected to the sale.Payment transaction is created.


. Cler+ starts ne$ cash sale.

7. Cler+ enters each item.

8. Cler+ indicates the end o# the sale.

:. Cler+ indicates type o# payment and

enters in#ormation.

7. *ystem #inds item ininventory, #inds price, displays

in#ormation, adds to total.

8. *ystem calculates total.

:. *ystem processes payment and

creates payment transaction.


7. 6# system has in#ormation missing, sales cler+ calls manager andmanually enters in#ormation.

:. 6# customer credit card #ails approval, require cash or cancel sale.


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Systems Analysis and Design in a Changing World, sixth edition 5-

2. 7ased on the followin" narrati%e de%elop either an acti%it$ dia"ram or a full$ de%eloped

description for the use case ofAdd a new vehile to an existing poliyin a car insurance s$stem.

Customer Clerk System

H

Provide Policy #

Enter Policy #

Find policy/display details

Verify status

Provide car details

Enter car informationValidate car information

against standards

Include coverage type/select amount

for each coverage type

Enter coverageinformation

Validate against standards/add to policy

end for each

Validate comination

coverages!e" driver

for each additional driver

Provide name and percent

Enter name and percent

$dd driver to car

end for each

%pdate policy/calculater premium/

print statement

Invoke $dd ne"driver use case

yes

H


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Systems Analysis and Design in a Changing World, sixth edition 5-1/

)se Case @ame2 &dd a ne$ vehicle to an existing policy

*cenario2 !elephone instance $ith customer and cler+

!riggering Event2 Customer uys a ne$ vehicle.(rie# 1escription2 Customer provides car in#ormation, requests coverage $ith amounts,

identi#ies drivers o# the ne$ car. *ystem updates the policy.

&ctors2 Customer service cler+

*ta+eholders2 Customer Customer service department

Preconditions2 Customer policy must exist and e up to date.*tandard3ehicle control tales #or this vehicle type and year must exist.

*tandardCoverage tales exist.

Postconditions2 @e$ vehicle oect created and connected to policy.&lso connected to *tandard3ehicle.

@e$ coverage oects created and connected to vehicle.&lso connected to *tandardCoverage.@e$ driver -6nsuredPerson -i# necessary created and added to policy.

Existing drivers and percentages updated.

Policy updated $ith ne$ premiums.


. Cler+ enters customer in#ormation.

7. Cler+ veri#ies policy is current.

8. Cler+ enters car identi#ication

in#ormation.:. Cler+ enters each type o# coverage

customer requests, includingdeductiles and coverage amount.5. Cler+ indicates all coverages have

een entered.

B. Cler+ invo+esAdd new personusecase i# necessary.

. Cler+ changes driver percentages on

this car and other cars.D. Cler+ indicates everything is

complete.

. *ystem #inds policy and

displays details.

8. *ystem validates that car has

+no$n standard.:. *ystem validates coverage

requests.

5. *ystem does comination

validation on policy.

. *ystem updates driver

in#ormation.D. *ystem updates policy,

calculates ne$ premium, prints

ne$ statement.


7. 6# policy is not current, cler+ requests payment or collects necessaryin#ormation.

8. 6# car type is not in system, cler+ re#ers customer to under$riting tohandle this situation.

:. 6# coverage requests are out o# range, cler+ as+s customer #or changed

amount.5. 6# some comination is invalid, return to step :.


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#. (i%en the followin" list of classes and associations for the pre%ious car insurance s$stem list

the preconditions and postconditions for the use caseAdd a new vehileto an e'istin" polic$.

Preconditions2 Customer policy must exist and e up to date.

*tandard3ehicle control tales #or this vehicle type and year must exist.*tandardCoverage tales exist.

Postconditions2 @e$ vehicle oect created and connected to policy.

&lso connected to *tandard3ehicle.@e$ coverage oects created and connected to vehicle.

&lso connected to *tandardCoverage.

@e$ driver -6nsuredPerson -i# necessary created and added to policy.Existing drivers and percentages updated.

Policy updated $ith ne$ premiums.


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&. e%elop an SS based on the narrati%e and $our acti%it$ dia"ram for problem 1.

Contractor Sale6


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Systems Analysis and Design in a Changing World, sixth edition 5-1#

Public sale6

5. e%elop a n SS based on the narrati%e or $our acti%it$ dia"ram for problem 2.


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). 8e%iew the cellular telephone state machine dia"ram shown in 9i"ure 5-21 and then answer

the followin" 0uestions. :;ote that this telephone has characteristics not found in ordinar$

telephones. 7ase $our answers onl$ on the state machine dia"ram.

6ed Solutions Chap05

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