You seem to have lost the plot too. Actors can be classed as primary or
secondary actors to a given use-case.
Primary actors initiate the use case.
Secondary actors are "used" in some way by the use case in order for it to
complete its basic or alternate path. Secondary actors are normally other
systems or components within a system, although sometimes (I can't think
when) they could be humans.
The diagram does not show the flow of information as you say, but show the
interactions/involvement between use cases and actors.
Haydn
"Baynes, Steve"
<stephen.baynes@eds To: [EMAIL PROTECTED]
.com> cc:
Sent by: Subject: RE: (ROSE) Use case to
actor Yes or
owner-rose_forum@ra No
tional.com
09/10/2001 14:48
Please respond to
"Baynes, Steve"
This discussion is quite interesting but many people seem to be missing the
point. The use case diagram shows involvement. All actors are involved in
the use case and therefore point to the use case. The diagram is not
showing the flow of information. This is modelled using other artefacts
(activity diagram, collaboration diagram etc).
Actors are involved in use cases, use cases are not involved in actors, any
actors.
Hope this helps.
Steve
-----Original Message-----
From: Kelly, Stephen [mailto:[EMAIL PROTECTED]]
Sent: 09 October 2001 14:04
To: [EMAIL PROTECTED]
Subject: RE: (ROSE) Use case to actor Yes or No
In this example you will clearly end up with an artificial representation
of
what you really want to say.
A real person such as a customer service clerk cannot have something done
to
them by the system. In real life, what would happen is the system would
generate an email (action by the system), and at some arbitray
(undefinable)
point the customer service clerk would read emails (action by the person
actor). The fact that the system generates an email doesn't guarantee that
the email will be read (the whole customer service department might quit!).
Also, setting up a username and password doesn't happen as a result of the
email being generated. It happens as a result of the customer service clerk
doing something to the system.
The fact that the customer service clerk might decide to do something as a
result of reading the email is nothing to do with the system - i.e. the
actions of a person actor cannot be predicted by a use case within a
system.
The situation would be far better documented as a 'request new user
registration' use case, intiated by the broker, which interacts with the
email system. And then a separate and independent use case like 'create new
user' initiated by a customer servive 'actor'.
The other important thing to remember is that use cases don't really say
anything about the 'flow of control'. They are supposed to represent the
functions / actions of a system. So, don't make the mistake of thinking in
terms of 'this use case happen, then the next use case happens, etc.'.
Stephen.
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
> Sent: 09 October 2001 13:12
> To: Kelly, Stephen; 'Jo�o Paulo Marto Pereira';
> [EMAIL PROTECTED]
> Subject: RE: (ROSE) Use case to actor Yes or No
>
>
> Hi,
>
> Stephen mentioned that a use case should never point to a
> person actor.
> From my point of view, this is not true. The actor who
> initiates the use
> case points to the use case. The use case points to actors
> (persons or systems)
> who participate in that use case later on.
>
> Example: A broker registers himself online in a financial
> trading system.
> Customer Service reveives an email to check the registration
> and provide
> username and password for the broker.
> Here the broker initiates the use case wheras customer
> service enters the
> game due to the initial request of the broker.
>
> I hope that helps.
>
> Regards
> J�rg
>
> ___________________________________________________________
> Joerg Dirbach mailto:[EMAIL PROTECTED]
> Software Architect / Software Engineering Trainer
> Object Technology Center
> Zuehlke Engineering AG Wiesenstrasse 10a CH-8952 Schlieren
> Phone: +41 (0) 1 733 65 71 Fax: +41 (0) 1 733 69 02
> http://www.zuehlke.com/
>
>
> -- Original-Nachricht --
>
> >
> >The example you gave is a clear case where it is a very bad
> idea to relate
> >a
> >use case to an actor.
> >
> >It makes no sense at all that a 'system' should do something
> to a 'person'.
> >Even if you imagine the system flashing a message on that
> 'person's' screen,
> >the system is not really doing something to the person - it
> is simply doing
> >something to a system device.
> >
> >You should never have a causal relationship _from_ a use
> case _to_ a person
> >'actor'.
> >
> >On the other hand, many analysts treat external systems as
> 'actor's. In
> this
> >case you might have a relationship from one of your use cases to the
> >'actor'.
> >
> >For example, one of your requirements might be that your
> system send data
> >to
> >an external accounting system for the company's book-keeping.
> >In this case you could represent the accounting system as an
> 'actor' and
> >may
> >have a use case like 'post accounting item' which is related
> to this actor.
> >
> >When doing this it is a good idea to ensure that in your diagrams the
> >stereotype display of 'actor's that are really external
> systems is different
> >to the stereotype display of people 'actor's - use the icon
> (a stick man)
> >for people and the label (a box with the <<actor>> label)
> for external
> >systems.
> >
> >Stephen.
> >
> >> -----Original Message-----
> >> From: Jo�o Paulo Marto Pereira [mailto:[EMAIL PROTECTED]]
> >> Sent: 09 October 2001 11:42
> >> To: [EMAIL PROTECTED]
> >> Subject: (ROSE) Use case to actor Yes or No
> >>
> >>
> >>
> >> Hi, again
> >>
> >> I've had answers saying I could point a use case to an actor,
> >> an others that
> >> said, no way! Is it possible and desireble or not?
> >>
> >> Thanks
> >>
> >> P.S. Please reply to [EMAIL PROTECTED], there are more
> >> people out that
> >> with the same problem
> >>
> >>
> >> _________________________________________________________________
> >> Get your FREE download of MSN Explorer at
> >> http://explorer.msn.com/intl.asp
> >>
> >> **************************************************************
> >> **********
> >> * Rose Forum is a public venue for ideas and discussions.
> >> * For technical support, visit http://www.rational.com/support
> >> *
> >> * Admin.Subscription Requests: [EMAIL PROTECTED]
> >> * Archive of messages:
> >> http://www.rational.com/support/usergroups/rose/rose_forum.jsp
> >> * Other Requests: [EMAIL PROTECTED]
> >> *
> >> * To unsubscribe from the list, please send email
> >> *
> >> * To: [EMAIL PROTECTED]
> >> * Subject:<BLANK>
> >> * Body: unsubscribe rose_forum
> >> *
> >> **************************************************************
> >> ***********
> >>
> >*************************************************************
> ***********
> >* Rose Forum is a public venue for ideas and discussions.
> >* For technical support, visit http://www.rational.com/support
> >*
> >* Admin.Subscription Requests: [EMAIL PROTECTED]
> >* Archive of messages:
> http://www.rational.com/support/usergroups/rose/rose_forum.jsp
> >* Other Requests: [EMAIL PROTECTED]
> >*
> >* To unsubscribe from the list, please send email
> >*
> >* To: [EMAIL PROTECTED]
> >* Subject:<BLANK>
> >* Body: unsubscribe rose_forum
> >*
> >*************************************************************
> ************
> >
> >
>
>
>
> ________________________________________
> E-Mail for everyone! http://www.bluemail.ch/ powered by Bluewin!
>
>
************************************************************************
* Rose Forum is a public venue for ideas and discussions.
* For technical support, visit http://www.rational.com/support
*
* Admin.Subscription Requests: [EMAIL PROTECTED]
* Archive of messages:
http://www.rational.com/support/usergroups/rose/rose_forum.jsp
* Other Requests: [EMAIL PROTECTED]
*
* To unsubscribe from the list, please send email
*
* To: [EMAIL PROTECTED]
* Subject:<BLANK>
* Body: unsubscribe rose_forum
*
*************************************************************************
************************************************************************
* Rose Forum is a public venue for ideas and discussions.
* For technical support, visit http://www.rational.com/support
*
* Admin.Subscription Requests: [EMAIL PROTECTED]
* Archive of messages:
http://www.rational.com/support/usergroups/rose/rose_forum.jsp
* Other Requests: [EMAIL PROTECTED]
*
* To unsubscribe from the list, please send email
*
* To: [EMAIL PROTECTED]
* Subject:<BLANK>
* Body: unsubscribe rose_forum
*
*************************************************************************
--
Haydn Robinson, Software Engineer Sophos Anti-Virus
email: [EMAIL PROTECTED] http://www.sophos.com
US Support: +1 888 SOPHOS 9 UK Support: +44 1235 559933
************************************************************************
* Rose Forum is a public venue for ideas and discussions.
* For technical support, visit http://www.rational.com/support
*
* Admin.Subscription Requests: [EMAIL PROTECTED]
* Archive of messages: http://www.rational.com/support/usergroups/rose/rose_forum.jsp
* Other Requests: [EMAIL PROTECTED]
*
* To unsubscribe from the list, please send email
*
* To: [EMAIL PROTECTED]
* Subject:<BLANK>
* Body: unsubscribe rose_forum
*
*************************************************************************
