code: public int getNode(Source source)
    {
  
  //    if (source instanceof DOMSource)
  //      return ((DOMSource) source).getNode();
  
      // TODO: Not sure if the BaseID is really the same thing as the ID.
      String url = source.getSystemId();
  
      if (null == url)
        return DTM.NULL;
  
      int n = m_sourceTree.size();
  
      // System.out.println("getNode: "+n);
      for (int i = 0; i < n; i++)
      {
        SourceTree sTree = (SourceTree) m_sourceTree.elementAt(i);
  
        // System.out.println("getNode -         url: "+url);
        // System.out.println("getNode - sTree.m_url: "+sTree.m_url);
        if (url.equals(sTree.m_url))
          return sTree.m_root;
      }
  
      // System.out.println("getNode - returning: "+node);
      return DTM.NULL;
    }
docs: Given a Source object, find the node associated with it.
  
  @param source The Source object to act as the key.
  
  @return The node that is associated with the Source, or null if not found.