@NotNull
  @Override
  public FileBasedIndex.InputFilter getInputFilter() {
    return new DefaultFileTypeSpecificInputFilter(XmlFileType.INSTANCE) {
      @Override
      public boolean acceptInput(@NotNull VirtualFile file) {
        return file.getName().endsWith(".xml");
      }
    };
  }
@NotNull
  @Override
  public FileBasedIndex.InputFilter getInputFilter()