void doRemove(Map<String, T> toRemove) {
      if (toRemove != null) {
        synchronized (myMappings) {
          for (String url : toRemove.keySet()) {
            VirtualFile file = VirtualFileManager.getInstance().findFileByUrl(url);
            if (file == null) continue;
            myMappings.remove(file);
          }
        }
      }
    }
void doRemove(Map<String, T> toRemove)