Advanced Use Case
Modeling
ECE 621
Association Relationship
•Association relationships only show which actors
interact with the system to perform a given use case
•Association relationship DO NOT model the flow of
data between the actor and the system
•A directed association relationship only shows if the
system or the actor initiates the connection
Association Relation Example
Abstract Use Case
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Abstract use cases cannot be performed
Abstract use cases only provide partial behavior
and thus they need to be implemented
Generalization Relationship
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Child use case provides a specialized version of
the behavior in the parent use case.
The generalization relationship are used to
implement an abstract
Generalization Relationship 2
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The “Buy Tickets” use case is concrete
because it can be performed all by itself
Include Relationship
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Include relationship are used to model
behavior repetition or reuse
Extend Relationship
Extension use cases usually contain
behavior that it optional or exceptional
 Extension use cases are usually
performed upon a condition being satisfied
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Extension Points
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Extension points state where the behavior
in the extension use case is inserted into
the base use case.
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 Template
Use 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
Buy Tickets – Basic Flow
The 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 the
tickets 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 reject
the 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.
Buy Tickets - Alternative Flows
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If the System cannot find the required seats,
then Customer is notified and the use case ends
If the Customer rejects the offered tickets, the
use case ends
If the Customer’s payment information cannot be
verified, the Customer is notified to contact
customer service and then the use case ends
Buy Ticket - Subflows
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After the Customer enters the information
regarding the requested seats; the system
the systems first checks to see if there are
any tickets in the given section; then the
system checks if there are any
consecutive seats as there is the required
number of tickets.
Buy Team Merchandise –
Extension Points
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Extension Points:
Whenever team merchandise is purchased
and a ticket is entered for a chance to win