Date: Mon, 7 Jun 2010 17:28:12 +0800 From: "wenjinchao" <wenjinchao0418(a)gmail.com&gt; Subject: [rules-users] how to fire a subset of rules in KB? To: "rules-users" <rules-users(a)lists.jboss.org&gt; Message-ID: <201006071728086572085(a)gmail.com&gt; Content-Type: text/plain; charset="us-ascii" Hi all, I'm a newbie for drools. And i want to know how to fire a subset of rules in KB, suppose there are three rules named A,B,C, and I want to fire rule A only. by the way, suppose there is a drl file containing rule, and i have set up KB, and call fireAllRules through statefulKnowledgeSession. After that, the rule file is changed, how to load rules dynamicly? Is there any solution? Thanks in advance! best regards. 2010-06-07 Wenjinchao Hi, I'll take a crack at you first question.... Check out Agenda Filters: http://legacy.drools.codehaus.org/Agenda The example listed is using Rule Names, but you can use the following to look at Meta Attribute values instead: AgendaFilter filter = new AgendaFilter() { @Override public boolean accept(Activation activation) { // Filter out rule Hello World from Sample.drl for execution if (activation.getRule().getMetaAttribute("Purpose").equals("Print Hello World")) { return true; } return false; } }; On your rules, you'll want to add a meta attribute for groups A, B, and C. Here's an example: rule "Hello World" @Purpose(Print Hello World) <--- THIS IS YOUR META-ATTRIBUTE when m : Message( status == Message.HELLO, myMessage : message ) then System.out.println( myMessage ); m.setMessage( "Goodbye cruel world" ); m.setStatus( Message.GOODBYE ); update( m ); end