RE: Hibernate

Its true that you may share a session b/t multiple client requests, 
however, a session is *not* thread safe.  Thus, you will need to ensure 
that during updates only one client has access to it at a time.

Actually, I like your idea of keeping a Session in the RequestCycle.  Any 
component that needs a session could grab it from the RC.  One way to do 
this would be to create a base component that has a getSession() 
method.  Calling getSession() would retrieve an existing Session from the 
RC, or if none is found, create a Session and store it in the RC.  This 
component could also automatically add itself as a pageDetach listener for 
the page it is rendered on - when the page detaches, the component could 
grab the Session and flush / commit any transactions.

Sessions are supposed to be lightweight, so creating and disposing one for 
each request for which one is required shouldn't be a problem.

My earlier strategy of keeping one session for each client and detaching it 
when not in use would be more applicable to a situation where a users 
action spanned multiple requests before it was committed to the db (for 
instance a multi-page form that only get stored if it is complete).

More ideas welcome. . .

ee

At 11/13/2002, you wrote:
>I had figured that I would just use a singleton to store the
>SessionFactory. That seems to be working so far.
>
>The very end of the hibernate docs say: "When using a servlet only, you
>may reuse the same session for multiple client requests. Just remember
>to disconnect the session before returning control to the client."
>
>That leaves me to believe there is some reason not to hold open a
>session for an entire Visit... What do you think of just placing it in
>the request cycle? Then somewhere putting something to close it before
>completing the render of the entire page.. not sure how to accomplish
>this.. just an idea.
>
>Has anyone else had success?
>
>Luke Galea
>Software Development
>BlueCat Networks
>905-762-5225
>
>
>-----Original Message-----
>From: Eric Everman [mailto:[email protected]]
>Sent: November 12, 2002 7:01 PM
>To: Luke Galea; Tapestry Developer
>Subject: Re: [Tapestry-developer] Hibernate
>
>Hi Luke-
>
>I'm new to Tapestry, but have been using Hibernate for a while, so your
>questions struck a chord with me.  I am planning a Hibernate / Tapestry
>demo project, just so I can try combining the two.
>
>My current thinking for accessing the SessionFactory is to place it in
>the
>servlet application context at startup via a custom Tapestry
>Servlet.  Hibernate sessions would be created as needed for each client
>and
>stored in their Visit object.  Sessions are light weight, serializable,
>and
>'detachable' from the database, so I'm planning on allowing a client to
>keep the same session until their Visit is GC'ed.
>
>Each action on the part of the client involving Hibernate would then
>access
>the new or existing session, re-attach it to the db, *do stuff*, flush
>to
>db, then detach.
>
>Out of all of this, the part that seems most cumbersome is the need to
>access the servlet context for a global variable - it really seems like
>Tapestry should provide easier access to application level variables.
>
>Cheers,
>
>Eric Everman
>
>
>At 11/12/2002, Luke Galea wrote:
>
> >Hello..
> >
> >We are using Hibernate for our project.. and I am looking at using the
> >contrib Table component with Hibernate. As I know I am not the first to
>
> >use Tapestry with Hibernate I have a few questions.
> >
> >
> >    * Has anyone implemented a Hibernate-centric version of the Table
> > Model? Is there interest in such a thing being developed and added to
>the
> > contrib?
> >    * Where is the best place to store the Hibernate session so it can
>be
> > used through the request.. should it be place in the request cycle?
>How
> > should I ensure that it is closed before the cycle completes?
>
>
>
>-------------------------------------------------------
>This sf.net email is sponsored by: Are you worried about
>your web server security? Click here for a FREE Thawte
>Apache SSL Guide and answer your Apache SSL security
>needs: http://www.gothawte.com/rd523.html
>_______________________________________________
>Tapestry-developer mailing list
>[email protected]
>https://lists.sourceforge.net/lists/listinfo/tapestry-developer



-------------------------------------------------------
This sf.net email is sponsored by: Are you worried about 
your web server security? Click here for a FREE Thawte 
Apache SSL Guide and answer your Apache SSL security 
needs: http://www.gothawte.com/rd523.html