I have been working with the standalone version
of MDR for a little
while now and with the help of this mailing list
(thanks to all) I
managed to overcome most problems encountered so
far. But now I'm out
of ideas so I'd like to ask here about this problem:
Sometimes the default XMIWriter seems to ignore
entire classes when serializing a collection of
objects into XMI

Here's an example metamodel which shows that
problem described further below (beware the curse
of ASCII-art ;):

+-----------------+       +-----------------+
| NewPack1.ClassA |@------| NewPack2.ClassC |
+-----------------+       +-----------------+
   |       ^                       @
   |       |                       |
   @       |                       |
+-----------------+       +-----------------+
| NewPack1.ClassB |       | NewPack2.ClassD |
+-----------------+       +-----------------+

where '@---' means an association, in particular a
composition at the
end where the '@' is,
and '<---' indicates an inheritance relation
(between ClassA and
ClassB). The prefix in front of the class name
shows the package the
class is related to. The NewPack1 and NewPack2
prefixes should indicate
their package.

(Source + XMI as an Eclipse project can be
obtained from
http://members.yline.com/~tom_at_work/mdrprob.zip
, doesn't include
mdr-standalone jars)

In my main class (MakeExample.java) in the main
method run() after the
usual stuff (initializing MDR, loading metamodel,
...) I simply create a
few instances of classes of my MOF-Model and try
to save them:

protected void run() throws Exception {
    // also try createEx1(): gives a null pointer
exception
    // while writing the XML
    Collection col = createEx2();           
       
    // dump contents of model
    MdrTools.dumpModelPackage(getModelPackage());
    
    // write data
       
XMIWriterFactory.getDefault().createXMIWriter().write(new
FileOutputStream("test.xml"), col, "2.0" ); // 2.0
or 1.2 doesn't matter
}

Here's the method creating instances:

private Collection createEx2() {
    LinkedList result = new LinkedList();

    ClassA a_1 =
getNewPack1().getClassA().createClassA("aClass1");
    ClassA a_2 =
getNewPack1().getClassA().createClassA("aClass2");
       
    ClassB b_1 =
getNewPack1().getClassB().createClassB("bClass1");
    
    ClassC c_1 =
getNewPack2().getClassC().createClassC("cClass1");
    ClassC c_2 =
getNewPack2().getClassC().createClassC("cClass2");
       
    ClassD d_1 =
getNewPack2().getClassD().createClassD();
                   
    getNewPack1().getAssoAtoC().add(a_1, c_1);
    getNewPack1().getAssoAtoC().add(a_1, c_2);
       
    getNewPack1().getAssoBtoA().add(b_1, a_1); //!

    getNewPack2().getAssoDtoC().add(d_1, c_1);
       
    result.add(a_1); result.add(a_2);
    result.add(b_1);       
    result.add(c_1); result.add(c_2);
    result.add(d_1);
       
    return result;
}   

As you can see, it just creates a few instances of
metamodel classes,
including some associations...
The problem are the contents of the generated XMI
file:

<?xml version = '1.0' encoding = 'ISO-8859-1' ?>
<XMI version = '2.0' xmlns = 'http://www.omg.org/XMI'>
  <NewPack1.ClassA id = 'a1' name = 'aClass2'/>
  <NewPack1.ClassB id = 'a2' name = 'bClass1'/>
  <NewPack2.AssoDtoC>
    <NewPack2.ClassD idref = 'a3'/>
    <NewPack2.ClassC idref = 'a4'/>
  </NewPack2.AssoDtoC>
  <NewPack1.AssoBtoA>
    <NewPack1.ClassB idref = 'a2'/>
    <NewPack1.ClassA idref = 'a5'/>
  </NewPack1.AssoBtoA>
  <NewPack1.AssoAtoC>
    <NewPack1.ClassA idref = 'a5'/>
    <NewPack2.ClassC idref = 'a6'/>
    <NewPack1.ClassA idref = 'a5'/>
    <NewPack2.ClassC idref = 'a4'/>
  </NewPack1.AssoAtoC>
</XMI>

Parts of the input collection are missing, in
particular
 - ClassA with "aClass1". But if you comment out
the line marked with
"//!" at least all the objects from NewPack1 are
serialized.
 - all class instances from the NewPack2 package

[These two issues seem to be separate]