[rules-users] Problem with DSL in Drools 4.0.3

[tansey]

I have included a reference to "expander" in my DRL.  The files look as
follows:

(src/main/rules/mylang.dsl)
[consequence][]Log "{msg}"=System.out.println("{msg}");

(src/main/rules/Sample.drl)
package com.sample

expander mylang.dsl

import com.sample.DroolsTest.Message;
 
rule "Hello World"
	when
		m : Message( status == Message.HELLO, message : message )
	then
		System.out.println( message ); 
		m.setMessage( "Goodbye cruel world" );
		m.setStatus( Message.GOODBYE );
		update( m );
end

rule "GoodBye"
	no-loop true
	when
		m : Message( status == Message.GOODBYE, message : message )
	then
		System.out.println( message ); 
		m.setMessage( message );
		
end

(src/main/java/DroolsTest.java)
package com.sample;

import java.io.InputStreamReader;
import java.io.Reader;

import org.drools.RuleBase;
import org.drools.RuleBaseFactory;
import org.drools.WorkingMemory;
import org.drools.compiler.PackageBuilder;
import org.drools.rule.Package;

/**
 * This is a sample file to launch a rule package from a rule source file.
 */
public class DroolsTest {

    public static final void main(String[] args) {
        try {
        	
        	//load up the rulebase
        	RuleBase ruleBase = readRule();
            WorkingMemory workingMemory = ruleBase.newStatefulSession();
            
            //go !
            Message message = new Message();
            message.setMessage(  "Hello World" );
            message.setStatus( Message.HELLO );
            workingMemory.insert( message );
            workingMemory.fireAllRules();   
            
            
        } catch (Throwable t) {
            t.printStackTrace();
        }
    }

    /**
     * Please note that this is the "low level" rule assembly API.
     */
	private static RuleBase readRule() throws Exception {
		//read in the source
		Reader source = new InputStreamReader(
DroolsTest.class.getResourceAsStream( "/Sample.drl" ) );
		
		//optionally read in the DSL (if you are using it).
		Reader dsl = new InputStreamReader( DroolsTest.class.getResourceAsStream(
"/mylang.dsl" ) );
		
		//Use package builder to build up a rule package.
		//An alternative lower level class called "DrlParser" can also be used...
		
		PackageBuilder builder = new PackageBuilder();
		
		//this wil parse and compile in one step
		//NOTE: There are 2 methods here, the one argument one is for normal DRL.
		//builder.addPackageFromDrl( source );

		//Use the following instead of above if you are using a DSL:
		builder.addPackageFromDrl( source, dsl );
		
		//get the compiled package (which is serializable)
		Package pkg = builder.getPackage();
		//add the package to a rulebase (deploy the rule package).
		RuleBase ruleBase = RuleBaseFactory.newRuleBase();
		ruleBase.addPackage( pkg );
		return ruleBase;
	}
	
	public static class Message {
		public static final int HELLO = 0;
		public static final int GOODBYE = 1;
		
		private String message;
		
		private int status;
		
		public String getMessage() {
			return this.message;
		}
		
		public void setMessage(String message) {
			this.message = message;
		}
		
		public int getStatus() {
			return this.status;
		}
		
		public void setStatus( int status ) {
			this.status = status;
		}
	}
    
}




Anstis, Michael (M.) wrote:
> 
> Can you provide your DRL and DSL?
> 
> Have you included a reference to "expander" in your DRL?
> 
> -----Original Message-----
> From: rules-users-bounces at lists.jboss.org
> [mailto:rules-users-bounces at lists.jboss.org] On Behalf Of tansey
> Sent: 31 October 2007 07:55
> To: rules-users at lists.jboss.org
> Subject: [rules-users] Problem with DSL in Drools 4.0.3
> 
> 
> I'm new to Drools, and I've setup the latest version of it in Eclipse 3.2.
> I'm having trouble whenever I try to use a DSL though.  I took the
> standard
> Hello World example and added the 'mylang.dsl' file, and changed the lines
> in DroolsTest.readRule() as follows:
> 
> private static RuleBase readRule() throws Exception {
> 		//read in the source
> 		Reader source = new InputStreamReader(
> DroolsTest.class.getResourceAsStream( "/Sample.drl" ) );
> 		
> 		//optionally read in the DSL (if you are using it).
> 		Reader dsl = new InputStreamReader(
> DroolsTest.class.getResourceAsStream(
> "/mylang.dsl" ) );
> 
> 		//Use package builder to build up a rule package.
> 		//An alternative lower level class called "DrlParser" can
> also be used...
> 		
> 		PackageBuilder builder = new PackageBuilder();
> 
> 		//this wil parse and compile in one step
> 		//NOTE: There are 2 methods here, the one argument one is
> for normal DRL.
> 		//builder.addPackageFromDrl( source );
> 
> 		//Use the following instead of above if you are using a DSL:
> 		builder.addPackageFromDrl( source, dsl );
> 		
> 		//get the compiled package (which is serializable)
> 		Package pkg = builder.getPackage();
> 		
> 		//add the package to a rulebase (deploy the rule package).
> 		RuleBase ruleBase = RuleBaseFactory.newRuleBase();
> 		ruleBase.addPackage( pkg );
> 		return ruleBase;
> 	}
> 
> 
> Even if I remove all rules from the dsl file, it still gives me the same
> error:
> org.drools.rule.InvalidRulePackage: 
> [4] Unable to expand: m : Message( status == Message.HELLO, message :
> message )
> [6] Unable to expand: 		System.out.println( message ); 
> [7] Unable to expand: 		m.setMessage( "Goodbye cruel world" );
> [8] Unable to expand: 		m.setStatus( Message.GOODBYE );
> [9] Unable to expand: 		update( m );
> [5] Unable to expand: m : Message( status == Message.GOODBYE, message :
> message )
> [7] Unable to expand: 		System.out.println( message );
> [8] Unable to expand: 		m.setMessage( message );
> 	at org.drools.rule.Package.checkValidity(Package.java:424)
> 	at
> org.drools.common.AbstractRuleBase.addPackage(AbstractRuleBase.java:361)
> 	at com.sample.DroolsTest.readRule(DroolsTest.java:64)
> 	at com.sample.DroolsTest.main(DroolsTest.java:21)
> 
> 
> 
> Anyone have an idea of what's wrong?
> -- 
> View this message in context:
> http://www.nabble.com/Problem-with-DSL-in-Drools-4.0.3-tf4722439.html#a13501
> 597
> Sent from the drools - user mailing list archive at Nabble.com.
> 
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> 
>  
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> 

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