Getting the Duration from ExoPlayer

In my case while using ExoPlayer, I needed to grab the duration of a audio file being stream from the web. ExoPlayer has a simple way to do this once the file is loaded. Here is the snipped.

mExoPlayer.addListener(new ExoPlayerEventListener() {
  @Override
  public void onPlayerStateChanged(boolean playWhenReady, int playbackState) {
    if (playbackState == ExoPlayer.STATE_READY) {
      long duration = audioPlayer.getDuration();
    }
  }

  @Override
  public void onPlayWhenReadyCommitted() {
  }

  @Override
  public void onPlayerError(ExoPlaybackException error) {
  }
 });