[rules-users] Errors in running the HelloWorldExample

[Edson Tirelli]

   Sudipta,

    I believe the problem is that you can't import classes from the default
package into your rules file, but I'm not sure.

    Try making Message a top level class (not an inner class) and put it in
a package (not the default one). Import it in the DRL and you shall be fine.

    We need a closer look at this before releasing next major final version.

    []s
    Edson


2007/4/5, Sudipta deb <sudipta_hitk at yahoo.co.in>:
>
> Sir,
>
> I want to run a simple drools example i.e. HelloWorldExample from command
> line
>
> My HelloWorldExample.java--->
>
>
> 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;
> import org.drools.compiler.PackageBuilderConfiguration;
> import org.drools.compiler.*;
> import java.lang.String;
> import java.io.*;
>
> /**
>  * This is a sample file to launch a rule package from a rule source file.
>  */
>
>
> public class HelloWorldExample
> {
>
>     public static final void main(final String[] args)
>     {
>         try
>         {
>
>             //load up the rulebase
>             final RuleBase ruleBase = loadRules();
>             final WorkingMemory workingMemory = ruleBase.newWorkingMemory
> ();
>
>             //go !
>             final Message message = new Message();
>             message.setMessage( "Hello World " );
>             message.setStatus( Message.HELLO );
>             workingMemory.assertObject( message );
>             workingMemory.fireAllRules();
>
>         }
>         catch ( final Throwable t )
>         {
>             t.printStackTrace();
>         }
>     }
>
>     public static RuleBase loadRules()
>     {
>           RuleBase ruleBase=null;
>           try
>           {
>
>                String [] ruleFiles = new String [1];
>                ruleFiles[0]  = "HelloWorld.drl";
>
>
>
>                PackageBuilderConfiguration pkgBuilderCfg = new
> PackageBuilderConfiguration();
>                pkgBuilderCfg.setCompiler(
> PackageBuilderConfiguration.JANINO);
>                PackageBuilder builder = new PackageBuilder(pkgBuilderCfg);
>                for( int i = 0, j = ruleFiles.length; i<j; i++ )
>                {
>                 builder.addPackageFromDrl(new InputStreamReader(
> HelloWorldExample.class.getResourceAsStream( ruleFiles[i] )) );
> //HelloWorldExample.class.getResourceAsStream( "HelloWorld.drl" )
>                 //new InputStreamReader(getClass().getResourceAsStream(
> ruleFiles[i] ) )
>                }
>
>                final Package pkg = builder.getPackage();
>                ruleBase = RuleBaseFactory.newRuleBase();
>                ruleBase.addPackage(pkg);
>
>
>           }
>           catch (Exception fe)
>           {
>                fe.printStackTrace();
>           }
>           return ruleBase;
>      }
>
>     /**
>      * Please note that this is the "low level" rule assembly API.
>      */
>     private static RuleBase readRule() throws Exception
>     {
>         //read in the source
>         final Reader source = new InputStreamReader(
> HelloWorldExample.class.getResourceAsStream( "HelloWorld.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...
>
>         final 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)
>         final Package pkg = builder.getPackage();
>
>         //add the package to a rulebase (deploy the rule package).
>         final 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(final String message)
>         {
>             this.message = message;
>         }
>
>         public int getStatus()
>         {
>             return this.status;
>         }
>
>         public void setStatus(final int status)
>         {
>             this.status = status;
>         }
>     }
>
>
> }
>
> My HelloWorld.drl-->
> package drools_test;
>
> import HelloWorldExample.*;
>
>
> 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 );
>         modify( m );
> end
>
> rule "GoodBye"
>     no-loop true
>     when
>         m : Message( status == Message.GOODBYE, message : message )
>     then
>         System.out.println( message );
>         m.setMessage( message );
> end
>
> Now compilation works absolutely fine but when i am trying to run it some
> errors are coming
>
> Warning: An error occurred compiling a semantic invoker. Errors should
> have been reported elsewhere.
> Warning: An error occurred compiling a semantic invoker. Errors should
> have been reported elsewhere.
> org.drools.rule.InvalidRulePackage: Rule Compilation error Class "
> HelloWorldExample.Message" not found Class "HelloWorldExample.Message" not
> found Class "java.lang.Object" has no method named "setMessage"
> Exception:0
> Rule Compilation error Class "HelloWorldExample.Message" not found Class "
> HelloWorldExample.Message" not found Class "java.lang.Object" has no
> method named "setMessage" Exception:0
>
>     at org.drools.rule.Package.checkValidity(Unknown Source)
>     at org.drools.common.AbstractRuleBase.addPackage(Unknown Source)
>     at HelloWorldExample.loadRules(HelloWorldExample.java:68)
>     at HelloWorldExample.main(HelloWorldExample.java:29)
>
> I put all the jar files in the classpath. Please help me.
>
> With regards,
>
> Sudipta Deb.  (+919831606520)
> Kolkata,India
>
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>


-- 
  Edson Tirelli
  Software Engineer - JBoss Rules Core Developer
  Office: +55 11 3124-6000
  Mobile: +55 11 9218-4151
  JBoss, a division of Red Hat @ www.jboss.com
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