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From Rahul Akolkar <>
Subject Re: [scxml-eclipse] User Feedback
Date Mon, 02 Aug 2010 18:12:47 GMT
On Mon, Aug 2, 2010 at 1:17 PM, Christopher Dragert
<> wrote:
> Hi, thank you for your response.  I have replied inline:
>>> I've gone through some of the basic functionality of the plug-in and
>>> generally found it to be good.  I have several points of feedback:
>>> 1) A small feature request:  Can you display the event name on the diagam
>>> like you do for a condition?
>> Yes,  we can display event name one the diagram, but i do not want to do it
>>like this, too many characters on the diagram will make the canvas more
> Harel [1] states that "The general syntax of an expression labelling a transition in
a state chart is “m[c]/a” where m is the message that triggers the transition, c is a
condition that guards the transition from being taken unless it is true when m occurs, and
a is an action that is carried out if and when the transition is taken. All of these parts
are optional."
> I think that the reduction of clutter is not a strong argument to go against general
syntax, as the graphical representation loses a lot of meaning when "m" is not shown.  If
no conditions are used, then the graphical representation shows only unlabelled transitions,
which does not explain the behaviour of the state-chart.  While Harel says these parts are
optional, it doesn't make a lot of sense to omit information that is meaningful.
> That being said, showing "/a" will be hard in scxml, since this refers to a block of
executable content.  Preferrably, the block of executable content would be shown in the format
"m[c]/executable content window", however, this could become very cluttered and perhaps something
alternate could be done to show the link between the transition and its executable content.

I agree with the three paragraphs above. Transitions must minimally
display m[c] graphically.

With respect to the /a part, some of the sophisticated tools (such as
the Rational Software Architect) do this by having an icon which when
double clicked opens an activity diagram where the entire executable
content sequence can be modeled.

>>> 3) There seems to be no way to have executable content on a transition.  Is
>>> this under development?
>>I do not find any executable content on a transition in W3C's SCXML
>>specification recommendtaion, so i am not clear what you mean.
> As Jacob mentioned, the SCXML standard allows executable content as children for transitions
(section 3.3.2)
>>> 4)  Seems to crash frequently and give out of memory errors, even while
>>> using -Xmx1024m.  I have to save and restart every minute or two.
>>In my development experience, i have not came across crash situation, so i
>>think there may be something wrong in your environment. Or, if it crash when
>>you are debug/running source code, you can export plug-in jars, and install
>>them in Eclipse environmet, i do not think it will crash more
> I am using the eclipse environment that was indicated and followed the instructions to
get the code.  This should mean the environment is identical to yours?  Anyway, I'll produce
some detailed bug reports to give you more information.

Yup, ways to reproduce this will be very useful to know where to begin
in terms of addressing it.


> Regards,
> Chris Dragert
> [1] Harel, D., Kugler, H.: The RHAPSODY Semantics of Statecharts or, On the Executable
Core of the UML). In: Integration of Software Specification Techniques for Application in
Engineering, Lecture Notes in Computer Science, vol. 3147, pp.325–354. Springer, Berlin
Heidelberg New York (2004).

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