Re: [JBoss-user] Optimise stateless session bean access from servlets

[Brian M. <bri...@au...>]

thanks very much StatsK,
very clear. I think the only thing I'm still unsure of is the lifecycle =
of stateless session beans.
If they can become bad at any stage, is it a good idea to cache it =
anyway do you reckon?
I really appreciate your help,
thanks,
Brian

  ----- Original Message -----=20
  From: Stas Krichevsky=20
  To: jbo...@li...=20
  Sent: Friday, March 07, 2003 3:44 PM
  Subject: RE: [JBoss-user] Optimise stateless session bean access from =
servlets


  Hi,

  Re. #1 - Probably you're right, but we're doing it in our product and =
till now everything worked. If the reference becomes bad, you can catch =
the exception and re-create the reference.

  Re. #2 - Sure, you can use try/catch blocks in jsp.

  Re. #3 - The difference between statefull and stateless beans is that =
in stateless bean you should pass the "state" to every bean method, i.e. =
container may give the same bean instance to different clients.



  Again, what I suggested was only performance optimization and if you =
didn't decide yet on the architecture of your product, it's better to =
look at some mvc framework and some design patterns first.

  ------------------------

  StasK



  -----Original Message-----
  From: Brian McSweeney [mailto:bri...@au...]=20
  Sent: Friday, March 07, 2003 4:37 PM
  To: jbo...@li...
  Subject: Re: [JBoss-user] Optimise stateless session bean access from =
servlets





  Thanks StasK,



  a few points though.=20



  1) I've heard you shouldn't hold references for ejbs in the session =
objects really.=20



  2) when you create the instance, I think you have to wrap it in a try =
catch block. I'm not sure if=20

  you can do this in scriptlets. But I don't know jsps well.



  3) If the session bean is stateless, does it make any sense to hold it =
in a HttpSessionObject?

  ( this leads me to ask the question - if a session bean is stateless, =
why is it called "session" at all?

  would love to know people's opinion about this. Am I being very =
stupid? )



  Brian

    ----- Original Message -----=20

    From: Stas Krichevsky=20

    To: jbo...@li...=20

    Sent: Friday, March 07, 2003 1:43 PM

    Subject: RE: [JBoss-user] Optimise stateless session bean access =
from servlets



    Hi,

    You could use http session to store instance of the session bean. =
Something like following:

    <%

                MyStatelessSession theBean =3D (MyStatelessSession) =
session.getAttribute("theBean");

                If (null =3D=3D theBean) {

                            // create the instance

                            session.setAttribute("theBean", theBean);

                }

                // use the bean.

    %>



    This way the instance of the bean will be created once per session.



    Of course you may look at some design patterns too, for example =
business delegate pattern (a good example can be found in "Programming =
Jakarta Struts" by Chuck Cavaness ).



    Hope this helps.



    ------------------------

    StasK



    -----Original Message-----
    From: Brian McSweeney [mailto:bri...@au...]=20
    Sent: Friday, March 07, 2003 2:03 PM
    To: jbo...@li...
    Subject: [JBoss-user] Optimise stateless session bean access from =
servlets



    Hi all,



    My business logic is controlled by stateless session beans.

    My front-end is probably going to be JSPs which use the session=20

    beans. I could create a reference to the session bean each time it's =


    used, but from my understanding of how it works, when the client=20

    calls MyStatelessSessionHome.create( ) we cannot tell if a new =
object=20

    is actually created on the server.=20



    My understanding is that the container can at any time decide which=20

    instance of the stateless session bean in the bean pool can be used =
for=20

    the client's reference. So, my question is - would it not be more =
optimal=20

    to actually create a reference to each of my stateless session beans =
on=20

    the main servlet startup (say in init) and let each of my jsps use =
the same=20

    reference. This would avoid the overhead of bean creation for each =
JSP.=20



    Thoughts,

    cheers,

    Brian