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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Actually, it looks like style 2 below
screws up the code generated by the BONExtender, not just the UDM framework. Why
isn’t it disallowed by constraint in MetaGME?<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>--Matt<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> <st1:PersonName
w:st="on">Matthew J. Emerson</st1:PersonName> <br>
<b><span style='font-weight:bold'>Sent:</span></b> Wednesday, April 20, 2005
10:24 AM<br>
<b><span style='font-weight:bold'>To:</span></b> <st1:PersonName w:st="on">udm-users</st1:PersonName>;
<st1:PersonName w:st="on">gme-users</st1:PersonName><br>
<b><span style='font-weight:bold'>Subject:</span></b> [<st1:PersonName w:st="on">udm-users</st1:PersonName>]
MetaGME / UDM UML Connection issue</span></font><o:p></o:p></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I’m having an issue with connections in these two
metamodeling languages.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>In MetaGME, if you need multiple classes to be associated
through the same kind of connection, there are two ways to specify it. The
first is to use inheritance to group together those types which play the src
role and those types which play the dst role (<b><span style='font-weight:bold'>style
1</span></b>):<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><img width=319 height=256 id="_x0000_i1025"
src="cid:image001.jpg@01C54596.32293720"><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>The other way to do it is to reuse the association class (<b><span
style='font-weight:bold'>style 2</span></b>):<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><img width=434 height=188 id="_x0000_i1027"
src="cid:image002.jpg@01C54596.32293720"><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Both of these are perfectly legal in MetaGME and result in the
same GME paradigm. However, the second style is not legal in UDM-style UML.
Here’s the UML generated with MetaGME2UML:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><img width=505 height=206 id="_x0000_i1029"
src="cid:image003.jpg@01C54596.32293720"> <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Notice the duplicated role names. The UDM code generator
apparently counts on the role names being unique to avoid namespace collisions.
It’s possible to change the role names by hand to be unique, but I would
probably run into another problem because MetaGME2UML writes changes into the
‘General Preferences’ field of each Connection:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><img width=445 height=361 id="_x0000_i1031"
src="cid:image004.jpg@01C54596.32293720"><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I suspect that the role names in the MetaGME metamodel must
correspond to the role names in the UML metamodel in order to use the MGA
backend with UDM. I haven’t looked at the UDM source code, but I
doubt it’s set up to search for multiple sName / dName pairs for each
Connection in the GME registry.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Not knowing this, I’ve built a large, complicated
metamodel which uses style 2 about 15 times. I thought everything was peachy
until I decided I wanted to do something with UDM…and I ran into this
gotcha. Somehow this discrepancy between the MetaGME and UDM UML needs to be
addressed, but it’s not obvious which language should change: MetaGME or
UDM UML. Should we limit the expressiveness of MetaGME using a constraint so
people don’t run into trouble with UDM, or should UDM step up and support
everything which can be expressed in MetaGME?<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Maybe it would be best to change the MetaGME2UML interpreter
to be more intelligent about how it handles connections so that neither UDM nor
MetaGME has to change. Somehow that interpreter should recognize the use of
style 2 and converts it automatically to style 1. This would be really easy if
MetaGME2UML were a GReAT transformation.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Matt Emerson</span></font><o:p></o:p></p>
<p class=MsoNormal><st1:place w:st="on"><st1:PlaceName w:st="on"><font size=2
face=Arial><span style='font-size:10.0pt;font-family:Arial'>ISIS-Vanderbilt</span></font></st1:PlaceName><font
size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'> <st1:PlaceType
w:st="on">University</st1:PlaceType></span></font></st1:place><o:p></o:p></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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