/**
  * Scan directories to cleanup removed files and playlists.
  *
  * @param dirsToRefresh list of the directory to refresh, null if all of them
  * @return whether some items have been removed
  */
 public boolean cleanRemovedFiles(List<Directory> dirsToRefresh) {
   long l = System.currentTimeMillis();
   // directories cleanup
   boolean bChanges = cleanDirectories(dirsToRefresh);
   // files cleanup
   bChanges = bChanges | cleanFiles(dirsToRefresh);
   // Playlist cleanup
   bChanges = bChanges | cleanPlaylist(dirsToRefresh);
   // clear history to remove old files referenced in it
   if (Conf.getString(Const.CONF_HISTORY) != null) {
     History.getInstance().clear(Integer.parseInt(Conf.getString(Const.CONF_HISTORY)));
   }
   // delete old history items
   l = System.currentTimeMillis() - l;
   Log.debug(
       "{{"
           + getName()
           + "}} Old file references cleaned in: "
           + ((l < 1000) ? l + " ms" : l / 1000 + " s, changes: " + bChanges));
   return bChanges;
 }
 /** @return currently selected ambience or null if "all" ambience selected */
 public Ambience getSelectedAmbience() {
   String sDefault = Conf.getString(Const.CONF_DEFAULT_AMBIENCE);
   return getAmbience(sDefault);
 }