[Puppet Users] can I pass a class or type to be executed into another class?

Hello, I have a module "mywebapp" which calls the tomcat::war module with
specific parameters, to upgrade the war file and restart tomcat. This works
great. What I would like to do is modify the code so that if, and only if
tomcat needs to be restarted, BEFORE it is restarted, I want to perform a
file operation. I want to do this because the operation will tell our load
balancer the server is about to go offline, and not to direct any traffic
to the server. I don't want to do this unless the war file is actually
going to be upgraded, which only the tomcat::war type knows.

The tomcat::war module which looks roughly like this (I'm simplifying for
brevity):

define tomcat7::war (
     ... params
) {

   ... variable definitions ...

   file { "${tomcat7::sites_dir}/${destFile}":
     notify => Exec["clean_${tomcat7::sites_dir}/${contextPath}"],
   }

   exec { "clean_${tomcat7::sites_dir}/${contextPath}":
     command => "rm -rf ${contextPath} ; mkdir ${contextPath} ; unzip
${contextPath}.war -d ${contextPath}/",
     cwd => "${tomcat7::sites_dir}",
     notify => Class['tomcat7::service'],
   }
}

what I would like to do is pass a parameter into tomcat::war so that if
that the parameter is set, the class (or type) referenced in the parameter
is Notified instead of Exec["clean_${tomcat7::sites_dir}/${contextPath}"],
and then Exec["clean_${tomcat7::sites_dir}/${contextPath}"] would be
notified AFTER my code.

This would allow my code a chance to notify the load balancer and pause
before cleaning and restarting tomcat. I don't want the special
load-balancer code in tomcat::war, because it is unique to 'mywebapp'.

Is there a way to do this at all?