[jbpm-dev] ContentMarshallerHelper.unmarshall()

[Alberto R. Galdo]

Hi,

   I'm posting in this list because I will post very low level details
which may not fit well in the user list. Please tell me if this is correct.

   We are trying to build a system using JBPM with human task, and we are
now using the recent LocalTaskService and LocalHTWorkItemHandler ... that
way:

humanTaskClient = new LocalTaskService(taskService);
....

LocalHTWorkItemHandler localHTWorkItemHandler = new
LocalHTWorkItemHandler(humanTaskClient, sesion);

....

   We are facing a NullpointerException when unmarshalling the result of a
completed human task. Here's the relevant stack trace:

11:11:21,734 ERROR [stderr] (http--0.0.0.0-8080-1)
java.lang.NullPointerException
11:11:21,734 ERROR [stderr] (http--0.0.0.0-8080-1)      at
org.jbpm.marshalling.impl.ProtobufProcessMarshaller.unmarshallVariableValue(ProtobufProcessMarshaller.java:270)
11:11:21,734 ERROR [stderr] (http--0.0.0.0-8080-1)      at
org.jbpm.task.utils.ContentMarshallerHelper.unmarshall(ContentMarshallerHelper.java:112)
11:11:21,750 ERROR [stderr] (http--0.0.0.0-8080-1)      at
org.jbpm.process.workitem.wsht.GenericHTWorkItemHandler$TaskCompletedHandler.handleCompletedTask(GenericHTWorkItemHandler.java:230)
11:11:21,750 ERROR [stderr] (http--0.0.0.0-8080-1)      at
org.jbpm.process.workitem.wsht.GenericHTWorkItemHandler$TaskCompletedHandler.execute(GenericHTWorkItemHandler.java:204)
11:11:21,750 ERROR [stderr] (http--0.0.0.0-8080-1)      at
org.jbpm.task.service.local.LocalTaskService$SimpleEventTransport.trigger(LocalTaskService.java:320)
11:11:21,750 ERROR [stderr] (http--0.0.0.0-8080-1)      at
org.jbpm.task.event.MessagingTaskEventListener.taskCompleted(MessagingTaskEventListener.java:80)
11:11:21,765 ERROR [stderr] (http--0.0.0.0-8080-1)      at
org.jbpm.task.event.TaskEventSupport.fireTaskCompleted(TaskEventSupport.java:46)
11:11:21,765 ERROR [stderr] (http--0.0.0.0-8080-1)      at
org.jbpm.task.service.TaskServiceSession.postTaskCompleteOperation(TaskServiceSession.java:563)
11:11:21,765 ERROR [stderr] (http--0.0.0.0-8080-1)      at
org.jbpm.task.service.TaskServiceSession.taskOperation(TaskServiceSession.java:495)
11:11:21,765 ERROR [stderr] (http--0.0.0.0-8080-1)      at
org.jbpm.task.service.local.LocalTaskService.complete(LocalTaskService.java:82)

   Some inspection lead us to locate this snippet that is


            ObjectMarshallingStrategyStore objectMarshallingStrategyStore =
marshallingConfigurationImpl.getObjectMarshallingStrategyStore();
            context = new MarshallerReaderContext(stream, null, null,
objectMarshallingStrategyStore, null, env);
            if(classloader != null){
                context.classLoader = classloader;
            }else{
                context.classLoader =
ContentMarshallerHelper.class.getClassLoader();
            }
            ExtensionRegistry registry = PersisterHelper.buildRegistry(
context, null );
            Header _header =
PersisterHelper.readFromStreamWithHeader(context, registry);
            Variable parseFrom =
JBPMMessages.Variable.parseFrom(_header.getPayload(), registry);
            Object value =
ProtobufProcessMarshaller.unmarshallVariableValue(context, parseFrom);


    which is radically different from the previous implementation (
protocol buffers appears ).

    The problem is that in this code  ( in ProtobufProcessMarshaller ) :

        ObjectMarshallingStrategy strategy = context.usedStrategies.get(
_variable.getStrategyIndex() );
        Object value = strategy.unmarshal( context.strategyContexts.get(
strategy ),
                                           context,

_variable.getValue().toByteArray(),
                                           (context.ruleBase ==
null)?null:context.ruleBase.getRootClassLoader() );
        return value;

     context.usedStrategies  and  context.strategyContexts are both Maps of
size 0. And so the NPE.

     Our process runs ok before creating the human task and it only fails
when completing a human task.

     Any insight on what can be happening here?

Greets,


Alberto R. Galdo
argaldo at gmail.com
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