/**
   * Returns the status of a given cache file on hdfs.
   *
   * @param conf configuration
   * @param cache cache file
   * @return FileStatus object of the file
   * @throws IOException
   */
  public static FileStatus getFileStatus(Configuration conf, URI cache) throws IOException {
    FileSystem fileSystem = FileSystem.get(cache, conf);
    Path filePath = new Path(cache.getPath());

    return fileSystem.getFileStatus(filePath);
  }
  /**
   * Returns mtime of a given cache file on hdfs.
   *
   * @param conf configuration
   * @param cache cache file
   * @return mtime of a given cache file on hdfs
   * @throws IOException
   */
  public static long getTimestamp(Configuration conf, URI cache) throws IOException {
    FileSystem fileSystem = FileSystem.get(cache, conf);
    Path filePath = new Path(cache.getPath());

    return fileSystem.getFileStatus(filePath).getModificationTime();
  }