I agree with you Jim .. similar to COM and DCOM ......
-----Original Message-----
From: Jim Preston [mailto:[EMAIL PROTECTED]]
Sent: Friday, June 16, 2000 2:22 PM
To: [EMAIL PROTECTED]
Subject: Re: EJB and JavaBeans
I don't want to start an argument, but I don't see how you can call ordinary
beans a client-side technology. When a JSP uses a bean for data access or
storage, that's all strictly server-side. You may be storing client-related
data in the bean, but the bean exists and is used only on the server. I'd
call that a server-side usage myself. And the examples you give of the
purposes of EJBs can all be done with ordinary beans, if your server side is
not distributed. Indeed, even if your database is on a different machine
than your web server, there's no reason that you can't use ordinary beans
with JDBC to allow your JSP/servlet to talk to the database.
I don't see that it's the purpose that distinguishes EJBs from ordinary
beans, it's the environment in which they're used. JavaBeans are a component
model. EJBs are a distributed component model. The basic purpose of both is
to encapsulate business logic, to keep it separate from presentation. If
you're working in a simple environment, with one web server and a database
server (and your database interactions are simple queries and updates), you
have no real need for EJBs; ordinary beans can do the job just fine. You can
have ordinary beans that encapsulate business entities and business
processes. If your environment is distributed, with servers all over the
place (or you do big database transactions), then EJBs are needed.
GUI widgets are just one use of JavaBeans, certainly not the only use.
--Jim Preston
-----Original Message-----
From: A mailing list about Java Server Pages specification and reference
[mailto:[EMAIL PROTECTED]]On Behalf Of Eddie Sheffield
Sent: Friday, June 16, 2000 10:36 AM
To: [EMAIL PROTECTED]
Subject: Re: EJB and JavaBeans
Other than having "JavaBean" in the name, they are totally different things
with different purposes. Ordinary JavaBeans are more client-side technology,
either visual (like some kind of GUI widget) or non-visual (a timer bean
e.g.) Even beans used in JSPs and Servlets are in most respect client-type
beans (clients to a database server or an EJB, perhaps).
Enterprise JavaBeans (EJBs) on the other hand are STRICTLY server side beans
(there is some client side code associated with each EJB - stubs used to
communicate across the wire to the actual EJBs). EJBs do not exist outside
of an EJB server such as the J2EE Reference Implementation, WebSphere,
WebLogic, etc. They cannot act as client side GUI widgets like an ordinary
bean. They represent either business entities (called entity beans - things
like customers, accounts, orders, etc.) or business processes (called
session beans - actions like logging in to a system, placing an order, etc.)
So EJBs will not (and cannot) replace regular JavaBeans. Likewise regular
JavaBeans will not (and cannot) replace EJBs. They are separate (although
occasionally complementary as in a non-visual JavaBean in a servlet or JSP
that fronts/communicates with an EJB) technologies that happen to share a
similar name and some high level abstract concepts.
Eddie Sheffield
----- Original Message -----
From: "Apollo Mcowiti" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, June 05, 2000 7:43 PM
Subject: Re: EJB and JavaBeans
> True, but
> I still tend to think that with the neat way EJB envisions(spelling?) to
> solve the distributed computing problem, it is here to stay for a long
time.
> And when there have been well defined core EJBs for most enterprises(don't
> they all use similar business logic?)we should achieve OO's dream of (a
high
> percentage ) code reuse,and then ordinary beans should really die.
>
> apollo
>
> -----Original Message-----
> From: Jim Preston [mailto:[EMAIL PROTECTED]]
> Sent: Monday, June 05, 2000 5:54 PM
> To: [EMAIL PROTECTED]
> Subject: Re: EJB and JavaBeans
>
>
> I don't think it's a question of replacing. EJBs are essentially a
super-set
> of ordinary beans, and the latter will certainly have their place in the
> scheme of things for a while to come. Besides, ordinary beans aren't
really
> a "thing", it's more a set of conventions that enable a Java class to be
> used in certain ways, like being called from the get/setProperty tag of a
> jsp. Finally, EJBs require an EJB-enabled server, so their use is more
> restricted. Look at it this way: electric screwdrivers have many
advantages
> over the old manual kind, but you can still buy both in the stores, and
> sometimes a manual one is better suited to the job at hand (no pun
> intended).
>
> --Jim Preston
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