[Esml-users] Re: RE Esml-users Event ports with null event refs

[Sandeep Neema]

Jesse,
The specific events to publish are often instance-specific decision i.e.
a Component user can customize the specific event-types published by a
component when instantiating a component in the system. This is the
reason why these event references are 'null'. In fact this information
(i.e. null event-types) is coming from the PRISM interface of Rational
Rose, where some publish/subscribe ports of components are typed with
'ANY Event'. 

Hope that clarifies it. Please feel free to send an email if you have
further questions.

Thanks
Sandeep


--
Sandeep Neema
Research Scientist,
Institute of Software Integrated Systems, Vanderbilt University
Phone: 615-343-9996
Email: sandeep.k.neema at vanderbilt.edu

-----Original Message-----
From: Jesse Greenwald [mailto:jesse at cis.ksu.edu] 
Sent: Tuesday, May 11, 2004 4:02 PM
To: esml-users
Subject: [Esml-users] Re: RE Esml-users Event ports with null event refs

Hi Feng,

Thanks for the quick response!

I now understand that the null event reference means the port can
publish or subscribe any type of event.  But, I don't understand what
the purpose of this is.  ESML is intended to be used on Prism based
component system.  Isn't it possible to determine the specific event
types of all event ports on Prism components?  I think this would be
desirable since it would allow the tool to more accurately determine if
event connections between components are valid.

Thanks,
Jesse

On Mon, 2004-05-10 at 13:19, Feng Shi wrote:
> Jesse,
> 
> In ESML model, the ComponentType models contained in ComponentTypes
> folder are defined as the archetype model, while the ComponentType
> models in Interaction diagram are the instances of these archetype
> models.
> 
> If the EventTypeRef refers to null object, it means that the event
port
> attached with it can subscribe or publish any type of event. If the
> EventTypeRef refers to a specific type of event, then the event port
can
> only subscribe or publish the same type of event.
> 
> ESML allows user to set the EventTypeRef refer to specific event type
> for instance model, like TACTICAL_STEERING. Meanwhile, such reference
> can also be set in archetype level, like BM__ModalComponentImpl, and
it
> will propagate to its all instance model.
> 
> Hope this helps,
> 
> Feng
> 
> -----Original Message-----
> From: Jesse Greenwald [mailto:jesse at cis.ksu.edu] 
> Sent: Monday, May 10, 2004 1:08 PM
> To: esml-users
> Subject: [Esml-users] Event ports with null event refs
> 
> Hi,
> 
> I've been taking a look at some of the example models that are
included
> with ESML.  While looking at them, I've noticed that some event ports
on
> some components have null event type refs.  That is, when I double
click
> on EventTypeRef box attached to the port, the following error message
is
> displayed: "Unable to show referred object of null reference".  Is
this
> an error in the model, or does this have a special meaning?
> 
> One example of this can be found in the MC__ModalSP model.  The
ANY_pub
> port of the BM__ModalComponentImpl has a null event type reference. 
> But, when I double click TACTICAL_STEERING (from Interaction
ModalSP_3)
> and open up the component, it has a non-null event type ref.
> 
> Thanks,
> Jesse
> 
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