how to determine if tomcat is running

[Thomas Fischer]

i'm writing a script (on a unix-system) which should do different tasks 
wether tomcat is running or not. to do so the script has to figure out 
the status of tomcat. most daemons use .pid-files or anything similar. 
but i found nothing for tomcat.

i've looked all through the documentation but found nothing about the 
runtime status of tomcat. how can i find out if tomcat is already 
running?

thanks for any responses,

thomas.