So you want the rule to fire if there exists a String from subset which is not in superset? From: rules-users-bounces(a)lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org] On Behalf Of Kumar Pandey Sent: 11 October 2010 13:19 To: rules-users(a)lists.jboss.org Subject: [rules-users] Check if fact is subset of items in the rule Posting a new thread for this specific problem that has been a head scratcher for me for days now. Here is the problem space. I have a rule that can have a superset of elements such as say "String1", "String2", "String3" , "String4". These are known in rule creation time. Fact can have subset say "String1", "String4" How can I form a drl to check to verify that fact is a subset of elements in the rule? I need to not fire the rule if fact is a subset but I should be able to add a not if I can first figure out if it is a sub set. Any help would be greatly appreciated. Thanks Kumar ________________________________ ************************************************************************************** This message is confidential and intended only for the addressee. If you have received this message in error, please immediately notify the postmaster(a)nds.com and delete it from your system as well as any copies. The content of e-mails as well as traffic data may be monitored by NDS for employment and security purposes. To protect the environment please do not print this e-mail unless necessary. NDS Limited. Registered Office: One London Road, Staines, Middlesex, TW18 4EX, United Kingdom. A company registered in England and Wales. Registered no. 3080780. VAT no. GB 603 8808 40-00 **************************************************************************************

I think I have pointed you to my implementation of a custom operator doing set operations. What keeps you from adopting this technique? -W 2010/10/11 Kumar Pandey <kumar.pandey(a)gmail.com&gt;

I got it to work using eval like so when ... eval($mycontext.isNotSubset("STRING1", "STRING2","STRING3", "STRING4")) I have the logic in isNotSubset method in context class to check if the set the context is subset of array passed in the call to the method. This works but I believe this can't make use of the rete optimization ? Thanks Kumar -- View this message in context: http://drools-java-rules-engine.46999.n3.nabble.com/Check-if-fact-is-subs... Sent from the Drools - User mailing list archive at Nabble.com.

Wolfgang gave a great solution. On 12 October 2010 02:23, kpandey <kumar.pandey(a)gmail.com&gt; wrote: