code: public String getNamespaceURI(String prefix) throws NamespaceException, RepositoryException
     {
        String uri = null;
        // look in session first
        if (namespaces.size() > 0)
        {
           uri = namespaces.get(prefix);
           if (uri != null)
           {
              return uri;
           }
        }
  
        return workspace.getNamespaceRegistry().getURI(prefix);
     }
docs: {@inheritDoc}