Re: [Concern-users] Article or whitepaper to describe ideas behind con:cern

[Holger E. <he...@me...>]

Quoting Andy Depue <an...@ma...>:

> I'm curious if anyone here is aware of an article or whitepaper that mi=
ght=20
> describe some of the ideas behind con:cern?  At the moment, I'm attempt=
ing to
>=20
> absorb as much as possible via google translations (german to english),=
=20
> source code, and the examples.  This is a little challenging.  I unders=
tand
>=20
> basic ideas, but feel like I'm missing the "big picture", so to speak.
>=20
> As an example, I keep running into something that clues me in to the fa=
ct
> that=20
> I'm probably not understanding pre/postconditions.  I'm looking at some=
=20
> example models and often see this kind of thing (as a postcondition in =
this
>=20
> case):
>=20
>   ((genehmigt || !genehmigt) && entschieden)
>      For the help of english speakers, here is the google translation:
>   ((approved || !approved) && decided)
>=20
> 'genehmigt' (approved) is a boolean, no?  Then the test (genehmigt=20
> || !genehmigt) will always be true, so why include it at all?  What am =
I=20
> missing here?

These are boolean, right and the expression is allways true. This is only=
 the
graphical arrangement. Of yourse, if you ommit all postconditions, the pr=
ocess
will still work. In some cases, postconditions are important in order to
validate the execution result. In other cases, like this one, it's only a=
bout
the graphical arrangement.

> Also, one thing I'm beginning to infer is that because con:cern is subj=
ect=20
> based, it has no need for process instances.  For example, in OSWorkflo=
w I=20
> would specifically instantiate an approval process.  There may be many=20
> "instances" of that one process in play at any given moment, all in var=
ious
>=20
> states.  Am I correct that con:cern is centered around subject instance=
s, not
>=20
> process instances?  So, instead of instantiating a new approval process=
, I=20
> instead introduce a new subject instance (in an unapproved state) into=20
> con:cern, and it automatically begins the approval process for that new=
=20
> instance?

right. the state is basically a function of the subject's properties. In =
os
workflow, the process state can be incosistent with the process instance =
data.
in con:cern, you can manipulate the subject arbitrarily (undo, manual
intervention, ..) and the process will always continue correctly accordin=
g to
the subject's state.

> Thanks for any aid as I continue to wrap my mind around con:cern despit=
e the
>=20
> language barrier. :)

I have translated the slides of a presentation, I held lately on the gse =
meeting
at ibm .. attachment.

Regards,


Holger Engels
(Dipl Inf Med)

--
Consultant, Architect, Developer
Mobile: +49 176 20119752


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