Please gentleman
Don't compare EJB with Metro ... that would be like comparing the old Soviet Union with the USA ... "you HAVE to do it this way(EJB/old SU)" against "tell what are your intensions and what do you want to achieve, then you are very welcome" ... at leat it was at the begining of the universe ... : O)
in the first case you have to put layers on top of others so things work out at hoc (the history of J2EE)
in the second case you not even set up the rules (of course the basic ones, the ones that unically define Metro), you set up the protocol for the rules (and I wander if is possible to put scripts on the context map, so the needs of the component can be defined at a syntax level supported by an ortogonal small set of semantics --it means actual entry values) ... actually you could, by putting a BeanShell interpreter on that map ...
//maquina
From: Niclas Hedhman <[EMAIL PROTECTED]> Reply-To: "Avalon framework users" <[EMAIL PROTECTED]> To: "Avalon framework users" <[EMAIL PROTECTED]> Subject: Re: Avalon vs EJB [was; Avalon and EJB] Date: Thu, 25 Nov 2004 02:55:08 +0800
On Thursday 25 November 2004 02:20, El Quijote wrote:
> Can I not achieve exchangeability simply by encapsulating Java-Objects > and using well defined interfaces?
If you manufacture both the bolt and the nut at the same time, this is of
course no problem.
But if true component oriented programming is going to emerge (no matter what
people say; It doesn't exist today.) that is not feasible. Tools and runtime
platforms must be able to juggle the component as an entity, and make it fit
into a large picture without any modifications.
Avalon tried to start that journey.
> How does Avalon compare to the EJB-concept? Is it comparable at all?
EJB is also based on the notion of component oriented programming, but fails
fairly miserable, as it sacrifices both proper OO as well as COP principles,
with its persistent Bean-centric view of applications.
Avalon has been accused of tight integration of components to the framework...
Apparently not from EJB developers, since not only are you very stuck to the
EJB model once you do extends EJBHome. If you try to develop an application
that is not transaction driven (Request/Response) with J2EE you will soon see
how miserable the states are in that platform.
It is funny to see J2EE developers be amazed over the elegance of Metro/Magic
applications. :o)
Cheers Niclas -- +------//-------------------+ / http://www.dpml.net / / http://niclas.hedhman.org / +------//-------------------+
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