well not necessarily just EJB... although i would put most of it there.
probably 99% of it would be in session EJB. I would use limited servlets for
business logic. mostly i would do....
JSP ------ Servlet ------- EJB
views controllers model/business logic
Al
----- Original Message -----
From: Phan Anh Tran <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Sunday, June 17, 2001 12:53 AM
Subject: Re: [JBoss-user] Obtaining a transaction from outside JBoss in
another VM Plan
> Basically, you are telling me to move all business logic from APP to an
EJB.
> I just don't believe it is always desirable to keep all business logic
> within EJBs. I don't think a business layer necessarily has to consist of
> EJBs alone.
>
> Anh
>
> ----- Original Message -----
> From: "David Jencks" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Saturday, June 16, 2001 8:52 PM
> Subject: Re: [JBoss-user] Obtaining a transaction from outside JBoss in
> another VM Plan
>
>
> > Hi,
> >
> > Ok, this is a slightly different question than the one I thought you
were
> > asking, and as you say, 2pc is not relevant. Here are my thoughts on
your
> > proposed design:
> >
> > 1. I assume that you do not want to hold transactions open while waiting
> > for human input. If you need to for some reason, you are apt to be in
> > trouble under high load as all those open transactions consume server
> > resources for unknown and long periods of time.
> >
> > 2. I like to think of the architecture of applications like this, in 5
> > layers.
> >
> > presentation layer (what do I see)----------- jsp
> >
> > presentation manager (workflow control, what do I see next) ------------
> > servlet
> >
> > service subsystem (business logic, data
manipulation) -------------session
> > ejb
> >
> > model subsystem (data model, system state) -------------------entity ejb
> >
> > persistence subsystem ---------(jdbc, db)
> >
> > I find this really clears up most of my questions about where to put
code,
> > and makes changes much simpler and more local. In this framework, I
> > haven't found a case where knowledge of transactions need to get above
the
> > business logic layer. I would be curious to know if you have an example
> > where this is appropriate.
> >
> > Thanks
> > david jencks
> >
> > On 2001.06.16 21:07:20 -0400 Phan Anh Tran wrote:
> > > Let's forget the 2PC stuff for now...Here is a scenaro:
> > >
> > > [APP/VM-1] <-> [EJB-1,EJB-2,...EJB-n/JBOSS/VM2] <-JDBC-> [DataStore-1]
> > >
> > > Each method of each of the EJBs forms a transaction by themselves if
> > > noone
> > > else issues explicit transaction control a la "begin,commit,abort".
> > >
> > > APP takes on this role. APP decides the set of EJBs' methods will
form
> 1
> > > transaction. Same problem, replace APP with say a servlet running in
a
> > > Servlet Container in a different VM and you still need the solution
> where
> > > it
> > > is possible to obtain a transaction from a separate VM.
> > >
> > > Sure, you could move the all the APP transaction control into one
single
> > > method of one single EJB...but that's not always desirable, I
believe...
> > >
> > > Anh
> > >
> > > ----- Original Message -----
> > > From: "David Jencks" <[EMAIL PROTECTED]>
> > > To: <[EMAIL PROTECTED]>
> > > Sent: Saturday, June 16, 2001 11:34 AM
> > > Subject: Re: [JBoss-user] Obtaining a transaction from outside JBoss
in
> > > another VM Plan
> > >
> > >
> > > > Hi,
> > > > I think the advice to stay away from distributed transactions is
> > > universal
> > > > design advice. Basically using distributed transactions just about
> > > > guarantees bad performance, as resources get tied up waiting for the
> > > 2pc
> > > to
> > > > make its way to all those other machines or vms not once but twice.
> If
> > > at
> > > > all possible, if you need things to happen on several machines, use
> > > > transactional messaging (jms, jbossmq) to break the work up into
> pieces
> > > > that can be all done on one machine + 1 resource manager + 1 message
> to
> > > the
> > > > next machine. I don't know what jboss/jbossmq actually does in this
> > > > scenario, however with a db and a message que as your transactional
> > > > resources the db (the slow part) could use 1pc:
> > > >
> > > > 1. prepare message commit
> > > > 2. 1pc on db
> > > > 3. commit message.
> > > >
> > > > This should be roughly as fast as 1pc to the db, since jbossmq is
> > > running
> > > > in the same vm as the rest of jboss.
> > > >
> > > > I learned the most about this subject from the (pre ejb) book "High
> > > > Performance Client Server" by Loosley and Douglas, isbn
0-471-16269-8
> > > >
> > > > david jencks
> > > >
> > > > On 2001.06.16 12:57:44 -0400 Phan Anh Tran wrote:
> > > > > We are at design time for a real system. Your suggestion "don't
use
> > > it"
> > > > > is
> > > > > that due to JBOSS specific implementation issues or is it a
> > > universal
> > > > > design advice?
> > > > >
> > > > > Do you have a copy of Vlada talk? Thanks.
> > > > >
> > > > > Anh
> > > > >
> > > > > ----- Original Message -----
> > > > > From: "marc fleury" <[EMAIL PROTECTED]>
> > > > > To: <[EMAIL PROTECTED]>
> > > > > Sent: Saturday, June 16, 2001 3:24 AM
> > > > > Subject: RE: [JBoss-user] Obtaining a transaction from outside
JBoss
> > > in
> > > > > another VM Plan
> > > > >
> > > > >
> > > > > > yes anatoly ackerman finished an integration of Tyrex (real DTM)
> in
> > > > > JBoss.
> > > > > >
> > > > > > We truly truly discourage the use of DTx (even Vlada matena had
a
> > > full
> > > > > talk
> > > > > > on that). So my question is "are you at design time" (in which
> case
> > > > > don't
> > > > > > use it) or is this "real life".
> > > > > >
> > > > > > marcf
> > > > > >
> > > > > > |-----Original Message-----
> > > > > > |From: [EMAIL PROTECTED]
> > > > > > |[mailto:[EMAIL PROTECTED]]On Behalf Of
Phan
> > > Anh
> > > > > > |Tran
> > > > > > |Sent: Saturday, June 16, 2001 3:11 AM
> > > > > > |To: [EMAIL PROTECTED]
> > > > > > |Subject: [JBoss-user] Obtaining a transaction from outside
JBoss
> > > in
> > > > > > |another VM Plan
> > > > > > |
> > > > > > |
> > > > > > |When does JBOSS plan to support the obtaining and using a
> > > transaction
> > > > > from
> > > > > > |another VM? 2.2.3? 2.3? Anytime in the near future?
> > > > > > |
> > > > > > |[App/VM1] <-> [EJB1,EJB2,.../JBOSS/VM2]
> > > > > > |
> > > > > > |App needs to setup and control the transactions, so in essence,
> my
> > > > > > |App needs
> > > > > > |to be able to obtain a UserTransaction via JNDI from a separate
> > > VM.
> > > I
> > > > > > |believe this feature is not supported right now, but I would
like
> > > to
> > > > > > |understand when the feature is planned to be incorporated into
> > > JBOSS?
> > > > > > |Thanks.
> > > > > > |
> > > > > > |Anh
> > > > > > |
> > > > > > |
> > > > > > |
> > > > > > |_________________________________________________________
> > > > > > |Do You Yahoo!?
> > > > > > |Get your free @yahoo.com address at http://mail.yahoo.com
> > > > > > |
> > > > > > |
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> > > > > >
> > > > > >
> > > > > >
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