private static String getPrefix(XmlFile file, String nsPrefix, String namespace, List<XmlSchemaProvider> providers) {
    String prefix = nsPrefix;
    if (prefix == null) {
      for (XmlSchemaProvider provider : providers) {
        prefix = provider.getDefaultPrefix(namespace, file);
        if (prefix != null) {
          break;
        }
      }
    }
    if (prefix == null) {
      prefix = "";
    }
    return prefix;
  }
private static String getPrefix(XmlFile file, String nsPrefix, String namespace, List<XmlSchemaProvider> providers)