Sorry - I wrote this reply before realizing that you were asking about an "editor", not just incorporating Drools into an RCP.  I am posting this in case other are having the more mundane problem of making a RCP execute Drools rules.

- Mike

I have been trying to do this for a while, and have managed to create an RCP that does work.  I know at least one other person has responded on this list as having accomplished it.  His response indicated that he created a separate plugin for all the Drools components, and referred to it from his main plugin.  He also indicated that the objects needed for the DRL file had to be in the same plugin as the Drools engine components.

This has not been my experience.  I created a plugin that contains the Drools components and the dependent jars in the /lib folder of the Drools distribution.  That plugin's file must be edited to add the line:

Eclipse-BuddyPolicy: registered

to the end because this will allow the plugin to access any other plugins that want to be accessed by the Drools plugin.  So suppose you name your plugin MinimalDrools;  the last line of the shows that it is registered as a Eclipse buddy.

Now export the plugin in a deployable format, and then drag the new plugin into the Eclipse plugin folder and restart Eclipse.

Now your project plugin needs to depend on this newly added plugin.  In addition, in your project plugin, you must add the reciprocal part of the buddy registration:

Eclipse-RegisterBuddy: MinimalDrools

With this structure, I added a rules directory in the root of the plugin, and in my application code:

private void fireDroolsRulesEngine() throws Exception {
GlucoseDecisionState decisionState = new GlucoseDecisionState();
Reader source;
final PackageBuilder builder = new PackageBuilder();
source = new InputStreamReader(FileLocator.toFileURL(
if (builder.hasErrors()) {

Package pkg = builder.getPackage();
RuleBase ruleBase = RuleBaseFactory.newRuleBase();
StatefulSession session = ruleBase.newStatefulSession();

// setup the debug listeners
session.addEventListener( new DebugAgendaEventListener() );
session.addEventListener( new DebugWorkingMemoryEventListener() );


// setup the audit logging
final WorkingMemoryFileLogger glucoseLogger = new WorkingMemoryFileLogger( session );
glucoseLogger.setFileName( "glucoseLogFile" ); 


This works.  It is necessary to add the dependency of MinimalDrools to you feature, etc. if you are exporting a complete application.

This being said, I cannot successfully run JUnit tests on the Drools part of my RCP.  I can unit test everything else, including things like Hibernate, my database connections, etc.  But the MinimalDrools plugin does not satisfy some aspect of the Eclipse JUnit setup.  The Drools compiler does initialize, but something prevents the package from instantiating (several previous posts on this that remain unresolved).

Good luck.

Date: Sat, 08 Dec 2007 19:04:52 +0100
From: Michael Sizaki <>
Subject: [rules-users] Drools and eclipse RCP
Message-ID: <>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed


is it possible to use the drools editor etc in an eclipse RCP
application? At the moment, org.drools.eclipse plugin
depends on debug and jdt and other eclipse IDE related

I would want a simple way for users to enter rules into
my RCP application.