docs: public Iterator getAllExtentClasses()
      {
          ArrayList subTypes = new ArrayList();
  
          subTypes.addAll(_extents);
  
          for (int idx = 0; idx < subTypes.size(); idx++)
          {
              ClassDescriptorDef curClassDef = (ClassDescriptorDef)subTypes.get(idx);
  
              for (Iterator it = curClassDef.getExtentClasses(); it.hasNext();)
              {
                  ClassDescriptorDef curSubTypeDef = (ClassDescriptorDef)it.next();
  
                  if (!subTypes.contains(curSubTypeDef))
                  {
                      subTypes.add(curSubTypeDef);
                  }
              }
          }
          return subTypes.iterator();
      }