lecture 2 - Advanced Use Case Modeling(1).ppt

7/27/2019 lecture 2 - Advanced Use Case Modeling(1).ppt

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Advanced Use Case

Modeling

ECE 621


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Association RelationshipAssociation relationships only show which actorsinteract with the system to perform a given use case

Association relationship DO NOT model the flow ofdata between the actor and the system

A directed association relationship only shows if the

system or the actor initiates the connection


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Association Relation Example


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Abstract Use Case

Abstract use cases cannot be performed

Abstract use cases only provide partial behavior

and thus they need to be implemented


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Generalization Relationship

Child use case provides a specialized version ofthe behavior in the parent use case.

The generalization relationship are used to

implement an abstract


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Generalization Relationship 2

The Buy Tickets use case is concrete

because it can be performed all by itself


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Include Relationship

Include relationship are used to modelbehavior repetition or reuse


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Extend Relationship

Extension use cases usually containbehavior that it optional or exceptional

Extension use cases are usuallyperformed upon a condition being satisfied


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Extension Points

Extension points state where the behaviorin the extension use case is inserted into

the base use case.


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Use Case Descriptions

Usually is used in a template

There must be one use case description

for every use case shown in the diagram

There must be one actor description for

every actor shown in the diagram


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Sample TemplateUse Case Name

Preconditions: Things that must be satisfied first

Basic Flow: normal scenario

Alternative Flows: slight deviations

Sub Flows: repetitive behavior

Exception Points: where will the extension

behavior be inserted

Postconditions: things that must be satisfied

before leaving

Special Requirements


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Buy Tickets Basic FlowThe system displays to the customer a calendar for all

season games. The Customer then chooses the game

he/she would like to attend. The Customer then

specifies the section in which he/she would like thetickets to be located. The System checks whether the

requested tickets are available or not. If they are

available, the System offers these tickets to the

Customer. The Customer chooses to accept or rejectthe tickets. If the Customer accepts the tickets, the

Customer is offered the option to pay either by a credit

card or using the hockey team card. Upon, verification

of payment information, the tickets are issued.


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Buy Tickets - Alternative Flows

If the System cannot find the required seats,

then Customer is notified and the use case ends

If the Customer rejects the offered tickets, theuse case ends

If the Customers payment information cannot be

verified, the Customer is notified to contact

customer service and then the use case ends


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Buy Ticket - Subflows

After the Customer enters the information

regarding the requested seats; the system

the systems first checks to see if there areany tickets in the given section; then the

system checks if there are any

consecutive seats as there is the requirednumber of tickets.


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Buy Team Merchandise

Extension Points Extension Points:

Whenever team merchandise is purchased

and a ticket is entered for a chance to win

lecture 2 - Advanced Use Case Modeling(1).ppt

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