4:07 a.m.
Thought I'd update my post for anyone Googling this. I am not sure if
my solution is correct (or if I am addressing the wrong problem)
though it has been satisfactory so far in our testing environment.
What I did was create an event listener implementing
ProcessEventListener and RuleFlowEventListenerExtension that would
grab the ProcessInstance fact handle from working memory and update it
on the following events:
@Override
public void beforeProcessStarted(ProcessStartedEvent processStartedEvent) {
maintainPorcessInstance(processStartedEvent.getKnowledgeRuntime(),
processStartedEvent.getProcessInstance());
}
@Override
public void beforeNodeLeft(ProcessNodeLeftEvent processNodeLeftEvent) {
if(processNodeLeftEvent.getNodeInstance() instanceof SubProcessNodeInstance) {
maintainPorcessInstance(processNodeLeftEvent.getKnowledgeRuntime(),
processNodeLeftEvent.getProcessInstance());
}
}
@Override
public void afterVariableChange(RuleFlowVariableChangeEvent
ruleFlowVariableChangeEvent, WorkingMemory workingMemory) {
maintainProcessInstance(ruleFlowVariableChangeEvent, workingMemory);
}
This means that I do not need to manually update the ProcessInstance
when entering a subflow or after changing a rule flow variable.
Cheers,
Gareth
On 1 March 2011 09:04, Gareth Evans <evans.g.p(a)gmail.com> wrote:
I'll try to make my questions less verbose:
1) When you change a flow variable what is the best way to update the
WorkflowProcessInstance object in working memory if you are using
subflows and hence have multiple WorkflowProcessInstances?
2) If I insert the WorkflowProcessInstance for both a parent flow and
child subflow and reference it in the LHS of a rule using
"processInstance : WorkflowProcessInstance()" I get activations for
both instances of the object. The documentation says that this should
only match the current process instance. Am I doing something wrong?
Cheers!
Gareth
On 25 February 2011 08:48, Gareth Evans <evans.g.p(a)gmail.com> wrote:
> Hello,
>
> I am having some problems using WorkflowProcessInstance in rules. I
> have searched and not been able to find an answer to my question.
>
> I am attempting to use rule flows to define business processes and
> rules both in ruleflow groups to be executed on demand of the process
> and outside of a ruleflow group for "global" rules and to potentially
> direct the ruleflow(/process) is to run. Many of these processes are
> comprised of subprocesses which I have been using sub flows to model.
>
> I have used flow variables to store some minimal information about the
> process such as what the process ID corresponds to in the existing
> data model I am working with. My intent was so that I could use a
> single rule flow group in many rule flows to extract information from
> the database for the corresponding process ID in the working memory
> (this extraction would also depend on other facts in the working
> memory).
>
> I've inserted the WorkflowProcessInstance by using an action node in
> the "parent" process and it seems to work fine. My problem arises when
> I am then in a "child" process/subflow and try to invoke this single
> rule flow group with a different process ID in the flow variable,
> there are no activations. I think this happens because the
> WorkflowProcessInstance has not been updated in working memory so it
> will not know that there might be a new process ID stored in the flow
> variable (it has the same name in both flows as it is meant to
> represent the same thing).
>
> If I insert the WorkflowProcessInstance again in the sub flow I get
> activations in the rule flow group for facts in the working memory
> associated with both the parent and child sub flow which almost makes
> sense except for this:
>
> "We have added special logic to make sure that a variable
> processInstance of type WorkflowProcessInstance will only match to the
> current process instance and not to other process instances in the
> Working Memory."
>
> It seems that it is matching both instances of
> WorkflowProcessInstance. I use the convention of starting variable
> names from the LHS of a rule with a $ but I have tested it without and
> I get the same result. Is this expected behaviour?
>
> An alternative I've been trying to figure out is how to update the
> WorkflowProcessInstance in working memory in the child process. Since
> it is actually a different object I'm unsure how to do this. Should I
> retract all instances and then insert the current? Is there a way to
> do this more cleanly than looking through all working memory objects
> and checking their type in an action node?
>
> Finally (or perhaps firstly...), am I going about this correctly?
>
> Cheers,
> Gareth
>