[jboss-user] [jBPM] - jBPM Persistence: Object unmarshalling with Drools accumulate

[Jason J]

Jason J [https://community.jboss.org/people/jasonjho] created the discussion

"jBPM Persistence: Object unmarshalling with Drools accumulate"

To view the discussion, visit: https://community.jboss.org/message/773261#773261

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Environment: Drools 5.3.1 + jBPM5.2

I am using a custom ObjectMarshallingStrategy when using jBPM persistence b/c I am unable to serialize the Facts that are inserted into the working memory.

To do this, I am plugging in a custom strategy on the persistence environment as such:

env.set(EnvironmentName.OBJECT_MARSHALLING_STRATEGIES, new ObjectMarshallingStrategy[] {
                new MyResolverStrategy(...),
                new JPAPlaceholderResolverStrategy(persistenceEnv),
                new SerializablePlaceholderResolverStrategy(ClassObjectMarshallingStrategyAcceptor.DEFAULT)
        });




I also have a rule in the ksession that is used to trigger some events in the jBPM workflow.  This rule uses the "collect" feature of Drools and it accumulates Facts until a condition is met.

$currentApprovals: List(size >= 3) from collect(Approval() from $document.getCurrentApprovals())




I am getting the following exception

java.io.OptionalDataException: null
          at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1282) ~[na:1.6.0_31]
          at java.io.ObjectInputStream.readObject(ObjectInputStream.java:350) ~[na:1.6.0_31]
          at org.drools.marshalling.impl.InputMarshaller.readLeftTuple(InputMarshaller.java:714) ~[drools-core-5.3.1.Final-csi.jar:5.3.1.Final]
          at org.drools.marshalling.impl.InputMarshaller.readLeftTuple(InputMarshaller.java:619) ~[drools-core-5.3.1.Final-csi.jar:5.3.1.Final]
          at org.drools.marshalling.impl.InputMarshaller.readLeftTuples(InputMarshaller.java:584) ~[drools-core-5.3.1.Final-csi.jar:5.3.1.Final]
          at org.drools.marshalling.impl.InputMarshaller.readFactHandles(InputMarshaller.java:433) ~[drools-core-5.3.1.Final-csi.jar:5.3.1.Final]
          at org.drools.marshalling.impl.InputMarshaller.readSession(InputMarshaller.java:266) ~[drools-core-5.3.1.Final-csi.jar:5.3.1.Final]
          at org.drools.marshalling.impl.InputMarshaller.readSession(InputMarshaller.java:196) ~[drools-core-5.3.1.Final-csi.jar:5.3.1.Final]
          at org.drools.marshalling.impl.DefaultMarshaller.unmarshall(DefaultMarshaller.java:93) ~[drools-core-5.3.1.Final-csi.jar:5.3.1.Final]
          at org.drools.persistence.SessionMarshallingHelper.loadSnapshot(SessionMarshallingHelper.java:91) ~[drools-jbpm-persistence-jpa-5.3.1.Final-csi.jar:5.3.1.Final]
          ... 26 common frames omitted




Looking at this code, I see

case NodeTypeEnums.AccumulateNode: {
                // accumulate nodes generate new facts on-demand and need special procedures when de-serializing from persistent storage
                AccumulateMemory memory = (AccumulateMemory) context.wm.getNodeMemory( (BetaNode) sink );
                memory.betaMemory.getLeftTupleMemory().add( parentLeftTuple );

                readBehaviors( (BetaNode) sink,
                               memory.betaMemory,
                               context );

                AccumulateContext accctx = new AccumulateContext();
                parentLeftTuple.setObject( accctx );

                // first we de-serialize the generated fact handle
                InternalFactHandle handle = readFactHandle( context );
                accctx.result = new RightTuple( handle,
                                                (RightTupleSink) sink );

                // then we de-serialize the associated accumulation context
                accctx.context = (Serializable[]) stream.readObject();
... 
...



It looks like the last line above is doing some deserializing.  I am not familiar with this lower level code, but shouldn't this be using the ObjectMarshallingStrategy?  How will the objects be able to deserialize correctly if I am relying on my own strategy to resolve facts?

Any help would be appreciated!!
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