topic Re: How do we handle outcomes and transitions in Activiti in Alfresco Archive

How do we handle outcomes and transitions in Activiti

rmoskal — Thu, 24 Feb 2011 22:23:38 GMT

I am porting an app from jbpm 4. In jpdl we had the notion of different transitions for tasks. It would be super helpful to me if I could understand how this notion translates to Activiti and BPMN. In jpdl each task had a notion of different outcomes or transitions. You could control flow by comp

Re: How do we handle outcomes and transitions in Activiti

frederikherema1 — Fri, 25 Feb 2011 06:58:41 GMT

Hi Robert,

We ran into this when integrating Activiti in Alfresco. Alfresco has created a layer of abstraction on top op JBPM 3, the WorkflowService. This workflow-api took over the outcome/transitions behavior.

The way we implemented this with Activiti is the folowing:

Forms are defined within alfresco, using taskform-config. We map it in the process-definition using the formKey.

On the taskform-definition in ALF we define a property (eg: wf_approvalOutcome) which has a list-constraint on it, containing the transitions, eg. Approve and Reject. Also a property (hidden) with fixed name (bpm_outcomePropertyName) points to the name of the property that will determine the outcome (in this case, wf_approvalOutcome)

The ALF-share UI renders this as 2 buttons (Approve and Reject) instead of a combo-box and only one button (Next) as usually with this kind of form-property on workflow-forms.

A gateway right after the task uses the wf_approvalOutcome to determine further path.

A tasklistener is added (transparently using parselistener) to each task. In the endTaskListener we copy the value of the wf_approvalOutcome to the property specified by Alfresco API, bpm_outcome, so the existing UI's show the outcome of all tasks just the way that it's done with JBPM.

So your idea with the outcomes variable sounds good. You can for example always use task-variables with the same name to keep the outcome in.

Re: How do we handle outcomes and transitions in Activiti

ronald_van_kuij — Fri, 25 Feb 2011 09:11:58 GMT

I'm trying to hande it in a kind of similar way. It works, but I'm not happy with it (not Activiti's fault) and personally I think that Activiti has a strong point proposing a 'composite' user task for BPMN2.1. Why? There already is a 'composite' gateway since one can be created by using others (and I do not know by heart which ones :-))

I even think a it would make a very welcome custom extension for the time being. Not sure about all the consequences though.

Re: How do we handle outcomes and transitions in Activiti

jbarrez — Fri, 25 Feb 2011 11:11:03 GMT

Basically you should store the value of the chosen button and use it later in an exclusive gateway.

Re: How do we handle outcomes and transitions in Activiti

rmoskal — Fri, 25 Feb 2011 15:00:26 GMT

Thanks. This has all been very helpful. My preference is to let the work flow engine bear the weight of this (the form variables). But others on the team may have other ideas and we may wind up doing something like the alfresco folks did.

Thanks again!

Robert