What is a use case scenario?
2 posts in topic
Flat View  Flat View
TOPIC ACTIONS:
 

Posted By:   Bala_S
Posted On:   Tuesday, May 28, 2002 11:25 PM

There are two questions, 1. In many of the UML books, while describing the sequence diagrams, it has been said that 'sequence diagrams are meant for realising a use case scenario'. A use case scenario is a realized path/instance of a use case. Please explain what is a use case scenario ?. Why do we call it as an instance of use case ? And, Sequence diagrams deal with objects rather than calsses. Why ? 2. In the same way, association is called as set of links. And link is a one connection between two instances. Could you please differentiate association and links ? Thanks a lot, Bala.    More>>

There are two questions,



1. In many of the UML books, while describing the sequence diagrams, it has been said that 'sequence diagrams are meant for realising a use case scenario'.

A use case scenario is a realized path/instance of a use case.

Please explain what is a use case scenario ?. Why do we call it as an instance of use case ?

And, Sequence diagrams deal with objects rather than calsses. Why ?



2. In the same way, association is called as set of links. And link is a one connection between two instances. Could you please differentiate association and links ?



Thanks a lot,

Bala.

   <<Less

Re: What is a use case scenario?

Posted By:   irfan_mansha  
Posted On:   Monday, June 24, 2002 10:46 PM

1. A use case consists of different situation/scenarios. Each scenario is called instnace of use case.


Sequence diagrams deal with objects which r also basically represent classes.


Re: What is a use case scenario?

Posted By:   Sebastien_Meric  
Posted On:   Wednesday, May 29, 2002 10:50 PM

Hello,


The use case diagram shows the way your system will be use, who will use it (who could be other computers, ...). It also shows inputs and outputs from your system.

Lets talk about the classical login use case diagram... (make yours)


The sequence diagram will show one (an instance thought) use from the general use case ... lets say for exemple a login sequence that will run ok ; or a sequence that will, on the other hand, not run ok. Those are two instances of the same use case (login) but will present different results to the user.


And now you understand that has use case talk about generality, it deals with classes but sequence diagram cannot deal with classes because it's like a real application of your use case. And thus has you show this real application you must deal with instanciated classes (that is : objects)


In the same order of idea, the association shows that to classes are connected or could be, while the link is the computed and instanciated association. One is general way of use, the other one is the use of it.

association : to go from there to there by train, you need a tiket

link : I'm gooing from Berlin to Paris by train tomorow morning and I have got my tiket


Regards

About | Sitemap | Contact