Override ProgressiveMediaSource to update file before play

Hello,

I have a question abuot a good path to acquire this functionality.
I am dynamically downloading MP4 file to local directory which is then used as a ExoPlayer MediaSource. This MediaSource is then played by ExoPlayer in continous loop.

This file is being updated every hour by a different thread and new copy is download and then stored near the current playing one with a .tmp extension.

What functionality i want to achieve is when current MP4 play ends, i want to have a chance to rename file.mp4.tmp to file.mp4 so the new downloaded copy can get playing.

Scenario:
1. file.mp4 plays (length 10 minutes) in a loop
2. New copy of file.mp4 is downloaded and stored as file.mp4.tmp
3. When file.mp4 reaches EOF, rename file.mp4.tmp to file.mp4
4. Play file.mp4 in a loop again
5. Goto :1

I checked that MediaSource is Final so i cannot override it.

Qeustion is - how is the best minimalistic way to glue into code to get a chance to hit the moment when ExoPlayer closes current file and tries to reopen it so i can make a simple f.renameTo().

I already have ConcatenatingMediaSource which i am using, but this path needs to reorder whole playlist which i don't want to do.