public List<Theme> completeThemeContains(String query) {
    List<Theme> allThemes = service.getThemes();
    List<Theme> filteredThemes = new ArrayList<Theme>();

    for (int i = 0; i < allThemes.size(); i++) {
      Theme skin = allThemes.get(i);
      if (skin.getName().toLowerCase().contains(query)) {
        filteredThemes.add(skin);
      }
    }

    return filteredThemes;
  }
 public char getThemeGroup(Theme theme) {
   return theme.getDisplayName().charAt(0);
 }