code: void disableAllFileFieldsExcept(Set<String> fieldNames) {
  
          for (InputElement field : getAllFields()) {
              if (isFileField(field)) {
                  boolean shouldDisable = !fieldNames.contains(field.getName());
                  field.setDisabled(shouldDisable);
              }
          }
      }
docs: Disables all file input fields except the one with the given name.<p>
  
  @param fieldNames the set of names of fields that should not be disabled