@Override
  public Object setVariable(String qname, Object value) {
    if (qname == null) {
      throw new NullPointerException(
        "Cannot get variable value for null qname");
    }
    final int pos = qname.indexOf(':');
    if (pos >= 0) {
      return setVariable(qname.substring(pos + 1),
                         getNamespace(qname.substring(0, pos)), value);
    }
    return setVariable(qname, Namespace.NO_NAMESPACE, value);
  }
@Override
  public Object setVariable(String qname, Object value)