Sequence Diagram

I am doing a project on Online reservation System of an Airline. I completed the use case modelling of the system and conceptual model too. My question for sequence diagram is that all actor are involved for that particular course of action, can we include interface as part of that diagram. In some cases if Log In use case is not invoked by the customer then we can do nothing becasue it provides interface. for the flight confirmations in my case may include interface as an object or instance or not
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Farrukh,
Could be more specific on your requirements.I am not sure on what you mean by including interfaces in Sequence Diagrams.
Sequence Diagrams show how groups of objects collaborate in some behaviour.Also it helps to understand the overall flow of control for your system.
- Sandeep

i have following use cases
Log In USe cases
Flight Confirmation Use Case
reservation USe case
Fair calculation use case
and so on
in case of reservation use case the log in use case must be invoked by the customer that provides the interface which includes other options. So if customer invoke reservation use case then for the sequence diagram of reservation use case can we include some part of login use case becasue without the that use case you cannot call reservation use case. At top of this we should include other message passing. i hope so some idea is clear.
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Hi,
I would suggest you identify the concepts in the use case and then consider drawing Sequence Diagrams.Instead of describing in terms of use cases, it is better to use concepts/classes/objects for your requirement.Also, Sequence Diagrams are drawn to show interaction between objects for each and every use case.
If you wish to consider interaction between different use cases, perhaps Use Case Diagram is a better artifact.It allows you to show an include relationship between Login use case and Reservation use case.
The UML specification defines an << include >> relationship, for representing such a behaviour across more than one use case.This avoids the need to copy the description of that behaviour.
So your Use Case Diagram could be something like this:

Hope this helps,
Sandeep
[This message has been edited by Desai Sandeep (edited May 29, 2001).]

Farrukh,
I would suggest that you specify the successful completion of the Login use case as a pre-condition to the reservation use case. This way you can make the reservation use case more cohesive by focusing it on the main things that happen when a reservation is made. The example below uses the convention of underlining other use cases referred to (see "Writing Effective Use Cases" by Alistair Cockburn)
Example:
Use case name: Make a Reservation
Pre-condition: Login User use case successfully completed
...
Main Scenario:
1. ....
Alternative Scenarios:
...

HTH,
Junilu

[This message has been edited by JUNILU LACAR (edited May 29, 2001).]

Reservation Use Case
Primary Actor Customer
Secondary Actor Airline System
Purpose:To provide Reservation facility on customer demand.
DescriptionCustomer has to provide the attributes values and system communicates with Airline System accordingly.
Pre-ConditionLog In must have been started.
Post-ConditionsDisplay the customer�s query and ready for the next operation
TriggerCustomer invokes Reservation Use-Case from the main menu.

Typical Course of Actions

1:Customer chooses Reservation and provide the system with departure city, due date, destination city and number of seats required.
2:System sends customer query to Airline system for confirmation.
3:Airline System accepts the customer query.
4:Query is searched in the Airline System and possible results is being sent back to the System6:Communication between Airline System and the given system is terminated.
5:System display the results to the customer.

Alternate course of Actions:
1.a: Customer doesn�t choose any options.1.b: Customer provides invalid departure and destination city name.
1a: System does not respond till any option selected
1.b:Informs the customer and abort confirmation
2.a: Communication between system and Airline is Broken.
2.a: Error message is displayed and operation is aborted.
3.a: Failure in the Airline System
3.a: Error screen is displayed and operation is aborted.

well in this case can we include log In use case as part of reservation use case.as the sequence diagram includes the implementation details of the scenearios
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Hi farrukh,
As you have specified the pre-condition that Login Use case is required, I hope this should take care of your requirement.
However, if you want to say that Reservation use case uses Login use case, you can mention this by using a keyword initiate.
For example :

Reservation Use case
Typical Course of Events

This use case begins with Customer arriving at the reservation terminal.

The Customer chooses Reservation Type

For Reservation Type 1, initiate Login use case

.....

.....

Related Use cases

Login Use case

...

The Login Use case would be a use case written seperately.
Ofcourse, the initiate keyword is useful if you have different kinds of logins for different kind of reservations.
Does this help?
Sandeep
[This message has been edited by Desai Sandeep (edited June 01, 2001).]

thanks for the help
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