@Override
  public String toString() {
    int nscnt = xnamespaces.size();
    int vcnt = 0;
    for (Map<String, Object> cmap : xvariables.values()) {
      vcnt += cmap.size();
    }
    return String.format(
      "[XPathExpression: %d namespaces and %d variables for query %s]",
      nscnt, vcnt, getExpression());
  }
@Override
  public String toString()