It sounds to me like it probably is not worth it for you to move to EJBs
considering how much you have invested in your current technology.
But some reasons we use EJBs where I work:
a) portability. Stored procedures, mentioned in another post, are not
portable at all. Whereas EJBs will run on a mainframe (Websphere),
midrange (AS/400) or Unix to PCs (weblogic, orion, websphere, etc) with
pretty much any database backend.
b) Sure, you have lookups, but then if you want remote access ...
c) NO SQL in our code (that could become a weird chant...). Fits the KISS
principle and eliminates one learning curve (SQL is steeper than learning
EJB and XML descriptors that's for sure). Plus, any change to the data
model is not that big a deal to us with EJBs because it is easier to
restructure an object and it's XML descriptors rather than chase down
every SQL call to update/modify it. Especially in the maintenance phase
where the original programmers are no longer around and no-one knows just
where that insert/update/delete is happening...
d) Learning EJB is not that big a deal. We put together a large website
all EJB based (with servlets and JSPs to round out MVC) in less than 3
months. No one on the project had seen EJBs before. Even lightweight
java programmers (less than a years experience) picked up on the concepts
and were productive. Performance is on par with any other java
environment I've seen, even under heavy load (given that you have the
appropriate hardware behind it).
I think what we have is a case of fear, uncertainty and doubt. My
experience with EJBs has been so good I'm going back to rewrite some of my
personal-hobby-related sites into EJBs. That is how impressed I am with
EJB.
-Alexandre
On Mon, 9 Oct 2000 12:00:34 -0700
"Duffey, Kevin" <[EMAIL PROTECTED]> wrote:
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
- - -
Actually, I know all about it. I have read up on it in those books and
others. Infact, we have already separated our code into those tiers but it
all runs in the servlet engine. This is what I am talking about. I am
using
the Struts framework to allow all forms submitted to a single controller
servlet, which then calls upong action classes. Those action classes then
figure out what "session" class to call upon. These "session" classes are
our logic (ejb) code, but its not in the EJB container..it runs in our
servlet engine. It is separated, just not from the servlet engine itself.
However, by compexity of building EJBs, I think I mean what goes into it.
Instead of a single class, we would have 2 (or is it 3) interfaces and an
implementation class. To access it, its not as simple as a class/reference
variable to an object in the servlet engine, you have to do a lookup,
etc..its a bit more code. Sure..its not terribly complex, but compared to
doing it the way we are now, there is quite a bit more work involved than
what we are doing now. Also, actually testing and learning how exactly it
works is a process that will take a little time. All of these things add
up.
What I am wondering is..is it really worth it if supposedly EJB doesn't
offer much in the way of performance..it just separates the logic into a
separate "tier" of servers. Our code is already separated long those tiers
now..and it will probably be easier for us to move to EJB than those that
have logic in their servlets.
> -----Original Message-----
> From: Russ White [mailto:[EMAIL PROTECTED]]
> Sent: Monday, October 09, 2000 11:32 AM
> To: Orion-Interest
> Subject: RE: EJB vs Servlets
>
>
> You should read up on J2EE so you can understand what separation of
> data/logic/presentation is all about. I would recommend any
> of the O'Reilly
> books on the subject(s). Also Development of EJBs is very
> simple. Especially
> with a good IDE like VA, Forte, or JBuilder. Orion even comes
> with a simple tool
> for creating very useful EntityBeans from a GUI.
>
> > -----Original Message-----
> > From: [EMAIL PROTECTED]
> > [mailto:[EMAIL PROTECTED]]On Behalf Of
> Duffey, Kevin
> > Sent: Monday, October 09, 2000 1:22 PM
> > To: Orion-Interest
> > Subject: EJB vs Servlets
> >
> >
> > Hey all,
> >
> > I know this is a little off-topic, but seeing as how Orion
> is about the only
> > fully compliant EJB server, I figured this would be a
> better place to ask.
> >
> > Lately I have talked to a number of people that have been
> moving towards EJB
> > and pulled back because they have found it to be more
> tedious to develop, as
> > well as the end result was slower than just using Servlets.
> >
> > I ask this because it appears to me that the servlet engine
> (at least with
> > 2.2) being able to be failed over, load-balanced, etc,
> seems to be quite as
> > capable for scalability and fault-tolerance as the ejb
> engine used to be. I
> > do realize that the EJB container offers transaction management, but
> > connection pooling is available in the servlet engine at
> the server level as
> > well. So, if you lose speed in development time and
> performance, what is the
> > real benefits of moving to EJB? I should say this with
> caution..I am sure
> > the EJB engine/container offers some things the servlet
> container doesn't,
> > but I would think its possible to actually put those
> abilities in the
> > servlet container.
> >
> > Anyways..I'll be interested in hearing any feedback on this.
> >
> > Thanks.
> >
> >
>
---
Sent via the OfficeServant.com web-mail server
Come to the free anytime, anywhere web-based office applications server
Received: from druid.evermind.net [195.84.237.200] by officeservant.com
with ESMTP
(SMTPD32-5.01) id A8FE2D5A0288; Mon, 09 Oct 2000 15:22:22 CST
Received: from druid.evermind.net (IDENT:[EMAIL PROTECTED]
[127.0.0.1])
by druid.evermind.net (8.9.3/8.9.3) with SMTP id VAA15292;
Mon, 9 Oct 2000 21:05:53 -0100
Received: from Exchange1.buymedia.com ([206.216.192.6])
by paladin.evermind.net (8.9.3/8.9.3) with ESMTP id WAA08670
for <[EMAIL PROTECTED]>; Mon, 9 Oct 2000 22:02:29 -0400
Received: by Exchange1.buymedia.com with Internet Mail Service
(5.5.2650.21)
id <4BKH1V4Z>; Mon, 9 Oct 2000 12:01:45 -0700
Message-ID: <[EMAIL PROTECTED]>
From: Duffey, Kevin <[EMAIL PROTECTED]>
To: Orion-Interest <[EMAIL PROTECTED]>
Subject: RE: EJB vs Servlets
Date: Mon, 9 Oct 2000 12:00:34 -0700
MIME-Version: 1.0
X-Mailer: Orion ListServer
Content-Type: text/plain;
charset= iso-8859-1
Reply-To: Orion-Interest <[EMAIL PROTECTED]>
Sender: [EMAIL PROTECTED]
Content-Transfer-Encoding: 7bit
X-RCPT-TO: <[EMAIL PROTECTED]>
X-UIDL: 2842
Status: U
