[CentOS] Swatch monitor for inactivity?

[Sean Carolan]

>>Does anyone know if this is possible with the swatch program?
>
> I don't see how as swatch is looking for things that happen, not
> those that don't.

I figured as much.  Before I go and write my own, are there any
general purpose utilities that can simply monitor a log file for
inactivity?  In other words once logs stop being written I would like
my monitoring script to let me know about it or perform some action.