If you add a map when starting a process, those values will be set as process variables. For example: [ a : "SomeString"; b : 3 ]. Simplest way to access these variables in a constraint is using a code constraint, something like: return "SomeOtherString".equals(a); or return b > 2; So you can just use process variables in your code constraints as if they were local variables. You just have to make sure you define them as process variables (click on the background of your flow and edit the variables property to do this). Kris ----- Original Message ----- From: "jeanjvr" <jeanjvr(a)live.co.za&gt; To: <rules-users(a)lists.jboss.org&gt; Sent: Monday, April 12, 2010 12:17 PM Subject: [rules-users] DROOLS FLOW: Accessing the Map parameter object in a Java constraint evaluation function Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm