Re: [mdr-users] Re: XML Namespaces and Custom Metamodels

Hi Pieter,
your problem has nothing to do with namespaces. If "tracing" would be a 
namespace, you would see "tracing:Node" instead of "tracing.Node" in the 
XMI. According to XMI spec., fully qualified names of elements are used 
in the XML nodes, so it seems that there is a class "Node" in a package 
called "tracing" in your metamodel. If this is the case, then the XMI is 
correct. The problem seems to be in the reading phase - XMI reader is 
trying to find package "tracing" to find class "Node" in it to create an 
instance of it. However it is not able to. This usually happens if you 
pass a wrong extent to the XMI reader - make sure you pass an instance 
of your tracing metamodel to the XMI reader. If you are passing instance 
of some other metamodel that does not contain tracing package, then this 
is the error you will get.
Martin

Pieter Van Gorp wrote:

>Looking at the XMI and the Java code over and over again, I can't find
>why the Node element cannot be found.  Removing the "tracing." prefix
>didn't solve the problem.  I wonder how it's possible that MDR was
>able to write XMI that it cannot read again without throwing
>exceptions...
>
>Any ideas?
>
>Kind regards,
>-- Pieter.
>
>On 8/4/05, Pieter Van Gorp <[email protected]> wrote:
>  
>
>>I may have been too fast by assuming that the exception was caused by
>>an XML namespace problem.  In fact, I now believe that the XMI reader
>>(XML parser) is looking for elements in the default (nameless)
>>namespace and cannot find elements like "tracing.Node".  I'm not sure
>>why the parser complains about an unknown "package" instead of an
>>unknown "element" though...
>>
>>Keep in touch,
>>Pieter.
>>
>>On 8/4/05, Pieter Van Gorp <[email protected]> wrote:
>>    
>>
>>>Hi all,
>>>how can I set the XML namespace to be used in the XMI for models
>>>conforming to my own metamodel?
>>>
>>>I've created a metamodel for creating traceability links across UML
>>>models.  Therefore, my metamodel clusters the UML metamodel (more info
>>>on http://www.fots.ua.ac.be/motmot/docs/traceability-p3.php).  The
>>>problem is that when I serialize a traceability model to XMI, only
>>>"UML" is defined as an XML namespace and "tracing" (which should be
>>>the namespace for elements in the clustering model) is undefined.
>>>
>>>This leads to exceptions when the XMI is read in again.  For example:
>>>org.netbeans.lib.jmi.util.DebugException: Element name cannot be
>>>resolved, unknown package: tracing.Node
>>>        at org.netbeans.lib.jmi.xmi.XmiContext.resolveElementName(XmiContext.java:527)
>>>        at org.netbeans.lib.jmi.xmi.XmiElement$Content.startSubElement(XmiElement.java:354)
>>>        at org.netbeans.lib.jmi.xmi.XmiSAXReader.startElement(XmiSAXReader.java:223)
>>>
>>>XMI of the erraneous traceability model:
>>><?xml version = '1.0' encoding = 'ISO-8859-1' ?>
>>><XMI xmi.version = '1.2' xmlns:UML = 'org.omg.xmi.namespace.UML'
>>>timestamp = 'Thu Aug 04 15:51:23 CEST 2005'>
>>>  <XMI.header>
>>>    <XMI.documentation>
>>>      <XMI.exporter>Netbeans XMI Writer</XMI.exporter>
>>>      <XMI.exporterVersion>1.0</XMI.exporterVersion>
>>>    </XMI.documentation>
>>>  </XMI.header>
>>>  <XMI.content>
>>>    <tracing.Node xmi.id = 'a1' role = 'reference to a1'>
>>>      <tracing.Node.trace>
>>>        <tracing.Trace xmi.idref = 'a2'/>
>>>      </tracing.Node.trace>
>>>      <tracing.Node.content>
>>>        <UML:Attribute xmi.idref = 'a3'/>
>>>      </tracing.Node.content>
>>>    </tracing.Node>
>>>    <tracing.Node xmi.id = 'a4' role = 'reference to a2'>
>>>      <tracing.Node.trace>
>>>        <tracing.Trace xmi.idref = 'a2'/>
>>>      </tracing.Node.trace>
>>>      <tracing.Node.content>
>>>        <UML:Attribute xmi.idref = 'a5'/>
>>>      </tracing.Node.content>
>>>    </tracing.Node>
>>>    <tracing.Trace xmi.id = 'a2'>
>>>      <tracing.Trace.node>
>>>        <tracing.Node xmi.idref = 'a1'/>
>>>        <tracing.Node xmi.idref = 'a4'/>
>>>      </tracing.Trace.node>
>>>    </tracing.Trace>
>>>  </XMI.content>
>>></XMI>
>>>I thought it may be due to a missing tag in the specification of my
>>>metamodel but couldn't find a solution on the website for the UML
>>>profile for MOF...
>>>
>>>Thanks in advance for your help,
>>>--
>>>Pieter Van Gorp
>>>       Teaching and Research Assistant
>>>       FOrmal Techniques in Software engineering (FOTS)
>>>       University of Antwerp
>>>       Middelheimlaan 1
>>>       2020 Antwerpen - Belgium
>>>       Office: G.304
>>>       Phone: +32 3 265 38 71
>>>       Fax: +32 3 265 37 77
>>>       http://www.fots.ua.ac.be/~pvgorp/research/
>>>       http://motmot.sourceforge.net/
>>>
>>>      
>>>