12:38 a.m.
Hi Kris,
Thanks for you valuable input and Vijay of course clearing some of my
doubts by asking question on this.
Much of my doubt are clear except one.
When we are reloading the StatefulKnowledgeSession from the database using
the below line
StatefulKnowledgeSession loadSession= JPAKnowledgeService.
loadStatefulKnowledgeSession(id, kbase, null, env);
This session object is different from the one that is created when we
first created
StatefulknowledgeSession object using
StatefulKnowledgeSession initialSession= JPAKnowledgeService.
newStatefulKnowledgeSession(kbase, null, env);
Am I right ?
Now In my case I have a HumanWorkItemHandler class for handling the
humantask and there is ActionWorkITemHandler for my customAction workItem,
which both are initailsed with the initialSession object.
Now when I load the session from the database to complete the
HumanWorkItemHandler task I got a different session object i.e.
loadSession.
Now when I insert something in the loadsession using
loadSession.insert(request); So that I can use the same in
ActionWorkItemHandler to exceute the action for the request.
I am not able to retrieve the same request object i.e.
(HttpServletRequest) from the session in ActionWorkItemHandler
as when i do
Collection obj = loadSession.getObject();
I get request as null. Because this loadSession is different from the
one I have inserted.
Kindly help in this, or I have misunderstood the concept.
Thanks & Regards
Pardeep Ruhil
Kris Verlaenen <kris.verlaenen(a)cs.kuleuven.be>
11/17/2009 04:17 PM
To
Rules Users List <rules-users(a)lists.jboss.org>, Vijay K Pandey
<VPandey(a)mdes.ms.gov>
cc
"Pardeep.Ruhil(a)lntinfotech.com" <Pardeep.Ruhil(a)lntinfotech.com>
Subject
Re: [rules-users] Drools Flow :Persistence Problem : Restore
StatefulKnowledgeSession from database
Preferably you should cache the session itself as well (so you don't
have to recreate it all the time) and reuse that across you application.
Or you could have multiple independent sessions as well. If you store
the key of the session somewhere, you can easily restore this session
(or sessions) after failure.
Kris
Quoting Vijay K Pandey <VPandey(a)mdes.ms.gov>:
Let's say where we don't need timers - in those cases one can
create
(create only if its not there) a global session (create the
sessioninfo at the drools startup - store the session primary key
somewhere) - reuse this session across everywhere?
Vijay
-----Original Message-----
From: rules-users-bounces(a)lists.jboss.org
[mailto:rules-users-bounces@lists.jboss.org] On Behalf Of Kris
Verlaenen
Sent: Monday, November 16, 2009 5:12 PM
To: Rules Users List; Pardeep.Ruhil(a)lntinfotech.com
Subject: Re: [rules-users] Drools Flow :Persistence Problem : Restore
StatefulKnowledgeSession from database
Pardeep,
The behavior you are describing is indeed correct. The session in
this
case is a global session, meaning that it will be used for all
process
instances. Note however that, unless you are using timers, all
other
state (process instance state, work items, etc.) is persisted
separately
and the session state will basically be empty.
It is also possible to have one session per process instance (or
whatever partitioning you like). A session has a unique id (which
you
can specify when reloading the session). You'll then have to load
the
right session before continuing the execution of your process
instance.
Kris
Quoting Pardeep.Ruhil(a)lntinfotech.com:
> Hi Salaboy,
> Thanks for you replying.
> Yes, of course it is storing multiple process instance Id in the
> database.
> But, what I feel is that it will fail when I am trying to run two
> workflow
> at the same time simultaneously, using the same code by
dynamically
> providing the workflow name and the parameters for each of them.
> Ideally there should be two entries for the
StatfulKnowledgeSession
> object
> because when I try to load the StatefulKnowledgeSession object
from
> the
> database it will give me the session object of the workflow which
is
> last
> executed.
>
> For example lets suppose I have two workflow 1 and 2 having two
> humantask
> in each of them . So when I finish the first Human Task of both
> workflow
> one by one. SessionInfo present in the database is of workflow 2
> (if 2
> is executed last). Because there is no field in the sessioninfo
> entity of
> the database regarding to which workflow it belongs to. Am I right
?
> So when I try to finish the 1st workflow by executing the 2nd
> humantask
> left in it , I need to reload the StatfulKnowledgeSession object
from
> the
> database. As there is no way of distinguishing that the session
> object
> store in the database is of which workflow , there might be a
problem
> as I
> may get the ksession object of 2nd workflow.
>
> In case of Process Instance it is fine , because there is a field
> 'processId' which will distinguish which processInstanceId belongs
to
>
> which worklowId or processId.
> But in case of Session , there is noting as such.
> I don't what I am saying is handled in drools persistence. Please
let
> me
> know if it there or not.
>
> Thanks & Regards
>
> Pardeep Ruhil
>
>
>
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