[mdr-users] XML Namespaces and Custom Metamodels

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/