[jboss-jira] [JBoss JIRA] Commented: (JBRULES-1554) "not in" used with "or" is not thread safe

[Edson Tirelli (JIRA)]

    [ http://jira.jboss.com/jira/browse/JBRULES-1554?page=comments#action_12411594 ] 
            
Edson Tirelli commented on JBRULES-1554:
----------------------------------------

Hi Jan,

Thanks for reporting and providing test case. The problem is that your example is sharing the Package objects among multiple threads. Package was never designed to be shared, since it contains objects whose attributes change when added to a rulebase.

In your specific example, the "or" in the rule is forcing the RulebaseBuilder to clone the $str declaration for each logical branch and recalculating its offset. That will obviously cause problems when the package object is shared among multiple rulebases.

Changing your test to share the already compiled rulebase (the way it was always designed to be) or share nothing between threads, makes it work.

So, the question is: is there a valid use case for sharing the packages instead of the compiled rulebase? 

One option is to clone the packages for each thread you want to use. A simple way of doing that is cloning by in-memory serialization (in case you don't store the packages already serialized):

    protected static Object serializeIn(final byte[] bytes) throws IOException,
                                                    ClassNotFoundException {
        final ObjectInput in = new ObjectInputStream( new ByteArrayInputStream( bytes ) );
        final Object obj = in.readObject();
        in.close();
        return obj;
    }

    protected static byte[] serializeOut(final Object obj) throws IOException {
        // Serialize to a byte array
        final ByteArrayOutputStream bos = new ByteArrayOutputStream();
        final ObjectOutput out = new ObjectOutputStream( bos );
        out.writeObject( obj );
        out.close();

        // Get the bytes of the serialized object
        final byte[] bytes = bos.toByteArray();
        return bytes;
    }


======
            Package pkg = precompilePackages();
            byte[] serializedPkg = serializeOut( pkg );

			int threadCount=30;
			int iterations = 300;
			TestThread[] threads= new TestThread[threadCount];
			for(int i =0;i<threadCount;i++)
			{
				threads[i]= new TestThread();
				threads[i].setPkg( (Package) serializeIn( serializedPkg ));
=======

What do you think?

Edson

> "not in" used with "or" is not thread safe
> ------------------------------------------
>
>                 Key: JBRULES-1554
>                 URL: http://jira.jboss.com/jira/browse/JBRULES-1554
>             Project: JBoss Drools
>          Issue Type: Bug
>      Security Level: Public(Everyone can see) 
>          Components: Reteoo
>    Affects Versions: 4.0.5
>            Reporter: Jan Boboli
>         Assigned To: Edson Tirelli
>             Fix For: 5.0.0-M1, 4.0.7
>
>         Attachments: ll.zip, project2.zip
>
>
> "not in" used with "or" is not thread safe.
> following construct causes ClassCastExeption when executed in parallel by different threads :
> when:
> 		$validateOrderIn : ValidateOrderIn(
> 		)
> 		Sim(
> 			$sim : sim
> 		)
> 		(
> 			__sims( 
> 				sim == $sim,
> 				$status : status not in ( "n", "o", "p")
> 			)
> 		)
> 		or
> 		(
> 			__sims( 
> 				sim == $sim,
> 				$status : status not in ("r", "l", "m" )
> 			)	
> 		)
> 	then ...

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