package MyHandler;
   sub handler($$) {
      my($class, $r) = @_;

      $class->do_this();
      $class->do_that();
   }

   sub do_this {
     # some default behavior
   }
   sub do_that {
     # some default behavior
   }

   package MyHandlerSubClass;
   use base qw(MyHandler);
   sub do_this {
      # do something else
   }
   sub do_that {
      ...
   }

##</code><code>##

   # I use Apache::DBI and also do something that resembles this in my code, but YMMV
   package My::DB;
   sub connect {
      my $r = Apache->request;
      my $dbh =$r->pnotes('MyDBIHandle');
      if(!$dbh) {
         $dbh = DBI->connect(...);
         $r->pnotes('MyDBIHandle' => $dbh);
      }
      return $dbh;
    }