I guess one of the ways you can handle it
via
a) Create a CustomHttpServletRequestWrapper (serializable class) that
implements HttpServletRequest.
b) Before you insert this wrapper class in drools session through your
POJO, pass the values you need from your actual request object like – parameter
map , attribute map (make sure attributes are serializable) through constructor
to the wrapper class– and provide the implementation of only those methods that
you will need in service or the ones that are related to parameter map
/attributes such as
i.
getAttribute(java.lang.String name)
ii.
getAttributeNames()
iii.
getParameter(java.lang.String name)
iv.
getParameterMap()
v.
getParameterNames()
vi.
getParameterValues(java.lang.String name)
vii.
removeAttribute(java.lang.String name)
viii.
setAttribute(java.lang.String name,
java.lang.Object o)
c) Either leave all other methods as
empty or throw java.lang.UnsupportedOperationException
I hope there is not too much of dependency
on request object in your service class.
From:
Pardeep.Ruhil@lntinfotech.com [mailto:Pardeep.Ruhil@lntinfotech.com]
Sent: Thursday, November 19, 2009
1:35 AM
To: Vijay K Pandey
Cc: kris.verlaenen@cs.kuleuven.be;
rules-users@lists.jboss.org
Subject: RE: [rules-users] Drools
Flow :Persistence Problem : Restore StatefulKnowledgeSession from database
Hi, Vijay,
I am not doing this to store request object.
loadSession.insert(request);
What I am doing is I created a pojo class having setter and
getter method of HttpServletRequest and some other class objects and
declare this(request) as transient.
So because of that this will not get store into the database
and rest of the variables of pojo class gets way into the database.
What you are telling to take the request map and insert that ,
I have done that part.
But I have a service written in my project which takes request
object as a parameter , which I have called in the ActionWorkItemHandler (custom Action Work Item made to execute
my service).
Now inside the exceute(WorkITem
workItem, WorkItemManager manager) method of ActionWorkItemHandler when I am trying to
retrieve the request object after loading session from the
database.
I am getting it as null, which
is obvious as it was not stored in the database.
So I just want to know if I have a non serilizable object , how
can I pass that into the process and use this in a custom
ActionWorkItemHandler.
Please let me know if you understand what I am saying.
Thanks & Regards
Pardeep Ruhil
L&T Infotech Ltd
Mumbai
Ph: +919820283884
Larsen & Toubro Infotech Ltd.
www.Lntinfotech.com
This Document is classified as:
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L&T Infotech Confidential
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This Email may contain confidential or privileged information for the intended
recipient (s) If you are not the intended recipient, please do not use or
disseminate the information, notify the sender and delete it from your system.
|
Vijay K
Pandey <VPandey@mdes.ms.gov>
11/19/2009 10:44 AM |
|
I don’t understand what you meant by storing the
HttpServletRequest object? With the default marshalling strategy for JPA in
place I don’t think you can insert a non serializable object? How come
this piece of code is working fine at your end?
loadSession.insert(request);
Which set of objects are you looking from the request? May be
you want to get hold of the request parameter map -- or create a list of
attribute map and insert those instead of HttpServletRequest object
Am I missing something of what you meant in your email?
From:
Pardeep.Ruhil@lntinfotech.com [mailto:Pardeep.Ruhil@lntinfotech.com]
Sent: Wednesday, November 18, 2009 10:15 PM
To: Vijay K Pandey; rules-users@lists.jboss.org
Cc: kris.verlaenen@cs.kuleuven.be
Subject: RE: [rules-users] Drools Flow :Persistence Problem :
Restore StatefulKnowledgeSession from database
Hi Vijay,
Thanks for your reply.
The problem is that object that I am inserting it into the session object is
NOT serializable, as you know HttpServletRequest object is not serializable.
So because of this I am not able to store this object into the database.
So that's why I am asking how can i do this if my object is not serilizable.
Thanks & Regards
Pardeep Ruhil
nt (s) If you are not the intended recipient, please do not use or disseminate
the information, notify the sender and delete it from your system.
|
Vijay K
Pandey <VPandey@mdes.ms.gov>
11/18/2009 10:56 PM |
|
You have to load the same ‘StatefulKnowledgeSession’
in which you have inserted your objects. The inserted objects are serialized and stored in the column “rules_byte_array” of the session_info table.
So you have to load the same session – to get to your inserted objects.
There is a difference the way process map objects are handled – such as
Map<String, Object> parameters = new
HashMap<String, Object>();
parameters.put("x", "hello");
parameters.put("y", "hey I am y");
ksession.startProcess( "myprocess", parameters );
In the above case the parameters are not stored as part of the “session info”
table. These are stored separately like in “process instance info” table +
(some/other tables if you use variable persistence strategy)– so if you don’t
have the rules which are based on the objects you are inserting – you can get
the same done through process parameters in which case you can get hold of the
process instance through any new session or the same session and then its
parameters.
Vijay
From: Pardeep.Ruhil@lntinfotech.com
[mailto:Pardeep.Ruhil@lntinfotech.com]
Sent: Wednesday, November 18, 2009 12:38 AM
To: rules-users@lists.jboss.org
Cc: kris.verlaenen@cs.kuleuven.be; Vijay K Pandey
Subject: Re: [rules-users] Drools Flow :Persistence Problem :
Restore StatefulKnowledgeSession from database
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@cs.kuleuven.be>
11/17/2009 04:17 PM |
|
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@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@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@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@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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