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[protege-discussion] pprj not saving meta-class

Tania Tudorache tudorache at
Thu Jun 5 18:09:01 PDT 2008


I understand from your email that you are using the XML Backend. Is this 

The undefined class message means that there is an instance of a class, 
for which you don't have any definition in the xml file. Could it be 
that the class was included from another project and the class is not 
found anymore (e.g. you removed the included project, or the included 
project is not found)? In any case, Protege will create the class for 
you and add it under a :UNDEFINED class.

Second issue with the metaclass. From your description, it seems that 
the metaclass is abstract. The metaclass should not be abstract if you 
have classes that are instances of it. Is the message that you get 
similar to the one attached to this email? If the metaclass is abstract, 
the solution is to make it concrete, and you won't get that message anymore.


Len Yabloko wrote:
> Dear Protege developers, 
> I noticed a strange behavior in saving project as .pprj with meta-classes: for some reason some meta-classes are not properly saved resulting in messages like that when opening .pprj file
> Undefined class: OPERAND_TYPE found while loading instances
> The strange thing to me is that using .xml file instead of .pprj seem solves the problem. This happens the same way in both Protege 3.3.1 and 3.4 beta (500). I did not have this problem before, so it is something about my meta-classes that changed. But what? May be the large number of instance classes can cause it? Because every time when opening meta-class I get a message about large number of  instances asking me if I really want to make the class "concrete" (why??)
> Thank you in advance for your help.
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