Reload or Renew Periodically

[surfmore]

Hi,

I am creating a resource that has URLs loaded from a file.

I would like to use the URL one time until using all URLs and after that restart to use from the beginning. Also would like to get random each time.

http://prntscr.com/rdq81q

Should I use reload or renew periodically and what is the difference. And how to make it grab randomly? and what is greedy algorithm?

thanks a lot

[surfmore]

Can anyone help please.