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From "Rafael R. Aschoff" <roque.raf...@gmail.com>
Subject Re: Changing Workflow at runtime
Date Thu, 13 Oct 2011 21:42:56 GMT
Hi Tammo,
It may sound hard indeed, but for what you said, it does look feasible as
I will see what I can do with this and in some point in the future, give you
guys a feedback.
Who knows if it will turn out to be and extension like Adaptive ODE :)


On Thu, Oct 13, 2011 at 6:33 PM, Tammo van Lessen <tvanlessen@gmail.com>wrote:

> Hi Rafael,
> this sounds like a typical research project ;) ODE is not designed to
> properly support this, since, as you know, allowing adhoc changes to
> already running process instances opens a can of worms.
> However, here is how it could go:
> In ODE, BPEL processes are compiled into a serializable OModel, which is
> basically an optimized representation of the process model, each
> activity got an id. During runtime, the process model is loaded and when
> the process model is started, runtime classes (in most cases the
> activity name in uppercase) will be instantiated. These classes
> implement the execution semantics of the activities. Eg sequence
> compiles to OSequence, which is during runtime evaluated by SEQUENCE.
> This basically looks for child activities, gets the first one, creates
> an UPPERCASE instance of that and delegates the execution to the virtual
> process machine. Once it is completed, the control is given back to
> SEQUENCE, which looks for the next activity, creates an UPPERCASE
> instance and so on. The object graph of these UPPERCASE classes is
> serialized and persisted to make the engine robust. So much for the
> theory. If you want to change the process model, it should be possible
> to change the OModel in parts that have not yet been processed by the
> UPPERCLASS instances. Changing those is probably much more difficult,
> since you then may need to change the state of such classes as well.
> Basically it depends on your use case, but it could worth a try. No
> warranties, however :)
> I hope that helps a bit,
>  Tammo
> On 13.10.2011 15:46, Rafael R. Aschoff wrote:
> > Hello all,
> >
> > I am not very familiar with the ODE source code and was looking for a way
> to
> > change the workflow during runtime.
> >
> > I would like to know if someone has an advice on that, where should I
> look?
> >
> > More precisely, I want to change the internal logic of a BPEL process
> based
> > on some monitored events.
> >
> > On a second phase, I would like to change the logic just for a particular
> > user instance, which means that future calls to the BPEL process will not
> > perceive the changes.
> >
> >
> > For what I have seen so far, to change future logic I could try to
> > manipulate the output of the ODE BPEL Compiler. I do not know if I could
> do
> > the per user instance, but it seems possible for future executions.
> >
> > In order to control the logic per user, I guess I would have to use the
> > Process Management API, but I could not find any information of the
> > possibility to change the execution instance itself.
> >
> >
> >
> >
> > Best regards,
> --
> Tammo van Lessen - http://www.taval.de

Rafael Roque Aschoff

Ph.D. Candidate

School of Informatics

City University London

Phone: +44 (0)20 7040 3252


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