import com.sun.org.apache.xml.internal.utils.StringComparable; //导入依赖的package包/类
/**
   * Get the string or numeric value of a specific level key for this sort
   * element. The value is extracted from the DOM if it is not already in
   * our sort key vector.
   */
  private final Comparable stringValue(int level) {
      // Get value from our array if possible
      if (_scanned <= level) {
          AbstractTranslet translet = _settings.getTranslet();
          Locale[] locales = _settings.getLocales();
          String[] caseOrder = _settings.getCaseOrders();

          // Get value from DOM if accessed for the first time
          final String str = extractValueFromDOM(_dom, _node, level,
                                                 translet, _last);
          final Comparable key =
              StringComparable.getComparator(str, locales[level],
                                             _collators[level],
                                             caseOrder[level]);
          _values[_scanned++] = key;
          return(key);
      }
      return((Comparable)_values[level]);
}