[gme-users] Ordering of sets in Bon

[Zoltan Molnar]

Hi,

Unfortunately VC6.0 doesn't support the specialization "getB<Bcomparison>"
in
std::set<B, BComparison>    bSet    =    b->getB<BComparison>();

But a version like this is accepted by vc6, (it doesn't require the
specialization)
std::set<B, BComparison>    bSet    =    b->getB( bSet);

Would it be OK?

Zoli

> -----Original Message-----
> From: gme-users-bounces at list.isis.vanderbilt.edu 
> [mailto:gme-users-bounces at list.isis.vanderbilt.edu] On Behalf 
> Of Jacques Kerner
> Sent: Tuesday, April 20, 2004 8:26 AM
> To: A list for GME users to share thoughts and discuss bugs and fixes.
> Subject: Re: [gme-users] Ordering of sets in Bon
> 
> 
> Hi, it's me again, on ordering (sorry).
> 
> I would still like to suggest an additional generated 
> function to allow 
> the user to specify how a returned set should be ordered. 
> Note that my 
> suggestion does not break the current API.
> 
> For instance, let's suppose we have Model "A" that can 
> aggregate Atoms 
> "B". What the BONExtender generates is :
> 
> class AImpl :
>   virtual public BON::ModelImpl
> {
> public:
>     std::set<B> getB();
> };
> 
> and
> 
> std::set<B> AImpl::getB()
> {
>     std::set<B> res;
>     std::set<BON::FCO> roles = getChildFCOsAs("B");
>     for( std::set<BON::FCO>::iterator i = roles.begin(); i != 
> roles.end(); ++i)
>     {
>         TypeReference elem(*i);
>         ASSERT(elem);
>         res.insert(elem);
>     }
>     return res;
> }
> 
> ordering is done in the insert function, and uses the operator< that 
> relies on the reference counter to compare two fcos. I suggest the 
> addition of the following template function to the AImpl 
> class declaration:
> 
> template <class T>
> std::set<B, T> AImpl::getB()
> {
>     std::set<B, T> res;
>     std::set<BON::FCO> roles = getChildFCOsAs("B");
>     for( std::set<BON::FCO>::iterator i = roles.begin(); i != 
> roles.end(); ++i)
>     {
>         TypeReference elem(*i);
>         ASSERT(elem);
>         res.insert(elem);
>     }
>     return res;
> }
> 
> Adding this function allows the user to use his own comparison Trait :
> 
> std::set<B, BComparison>    bSet    =    b->getB<BComparison>();
> 
> with, for instance, a Comparison class based on the x coordinate in 
> "MyAspect" aspect.
> 
>     class BComparison
>     {
>     public:
>         //! This method orders two Bs with respect to their x 
> coordinate 
> in the diagram
>         /** (thanks to Peter Volgyesi for the trick... :)
>         */
>         bool operator()(
>             const B& _Left,
>             const B& _Right
>         ) const
>         {
>             return 
> (_Left->getRegistry()->getLocation("MyAspect").first 
> < _Right->getRegistry()->getLocation("MyAspect").first);
>         }
>     };
> 
> or whatever Trait the user defines for his own needs.
> 
> Again, please note that my suggestion does not break the current API, 
> since the user can still call the regular untemplated getB() method. 
> Furthermore, this does not imply any additional performance 
> cost other 
> than implied by the user comparison function. Using this 
> avoids the need 
> to reorder the sets after they have been recovered. If the 
> user wants to 
> get the set as fast as possible, she uses the untemplated 
> getB() method, 
> but if she wants to order it in her own way, this is still 
> faster that 
> getting the set and THEN reordering it.
> 
> I have succesfully tested this method with GME 4.3.17, with 
> Visual 7.1. 
> Hoping there are no issues with this that I am anaware of ...
> 
> Best Regards,
> 
> Jacques Kerner.
> 
> Peter Volgyesi a écrit :
> 
> >Hi,
> >
> >Collections coming from the model database are never 
> ordered. (This is 
> >a property of our modeling engine and not BON specific, and it is 
> >because of internal caching mechanisms.) One can argue, why don't we 
> >order these lists, however it seems a better (general) 
> approach to me 
> >to provide data as fast as possible that can be sorted by the upper 
> >layers on demand.
> >
> >Anyway, the MONTraverser interpreter (Paradigms/MetaGME folder) does 
> >implement some kind of sorting (MONDialog.cpp). Feel free to 
> use that 
> >code.
> >
> >For retrieving graphical position of an object in a given 
> aspect, use 
> >this:
> >fco->getRegistry()->getLocation("AspectName");
> >
> >fco must be a BON FCO object (eg.: BON::Atom)
> >
> >Regards,
> >
> >--
> >peter
> >
> >
> >  
> >
> >>-----Original Message-----
> >>From: gme-users-bounces at list.isis.vanderbilt.edu
> >>[mailto:gme-users-bounces at list.isis.vanderbilt.edu] On Behalf 
> >>Of Jacques Kerner
> >>Sent: Tuesday, April 06, 2004 9:45 AM
> >>To: A list for GME users to share thoughts and discuss bugs 
> and fixes.
> >>Subject: [gme-users] Ordering of sets in Bon
> >>
> >>Hi,
> >>
> >>I would like to know how the std::set<...> returned by
> >>BONExtender generated functions are ordered. For instance, I 
> >>have a model named "Container" that aggregates "Contained" 
> >>Atoms "contained1", "contained2" 
> >>and "contained3" and I was uable to figure out how the 
> >>ordering was made. Sometimes the order is by creation of the 
> >>contained elements, sometimes not, ...
> >>
> >>Is there a way to impose the ordering on the returned sets ?
> >>Do I have to define a specific operator < for this ? Could 
> >>BonExtender generate one from a rule in the meta model ?
> >>
> >>I also wondered if one can retrieve the position of elements
> >>in diagrams in BON .
> >>
> >>Thank you in advance.
> >>
> >>Jacques Kerner. _______________________________________________
> >>gme-users mailing list
> >>gme-users at list.isis.vanderbilt.edu
> >>http://list.isis.vanderbilt.edu/mailman/listinfo/gme-users
> >>    
> >>
> >
> >_______________________________________________
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> >gme-users at list.isis.vanderbilt.edu
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> >
> >  
> >
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