You'll have to write it in to the Action part of your decision table. Here's one way to do it with a decision table. What suites best for your needs requires a bit more info on the details.
Condition | Action
a : Message |
$param | a.setPrio( a.getTemplate( $param) ); update(a);
--------------------------
count == 45 | "123"
If you need, you can add the System.out.prinln
calls in the Action block as well. If you have a lot of operations to execute, it might be better to create a helper function for that.