Persistence and Scalable / Stateless Server Objects 
Author Message
 Persistence and Scalable / Stateless Server Objects

I'm trying to reconcile in my mind how object persistence (in any
form, relational db, xml file, oodb, etc.) goes along with server side
stateless objects.

I understand how Session and Entity beans work in a technical sense.
The way I think of this is basically the data and the methods that
work on the data are separated, as opposed to combined / encapsulated.
I'm currently working on a server-side system where I'm using a
"Business Object / Rules" layer, Data Access layer and Presentation
layer, and it works great. I just think there has to be a better way
in terms of the relationship between the Business and Data layers.

I guess I'm just wondering if "classical" OO persistence (like Scott
Amber describes in several white papers and articles,
http://www.*-*-*.com/ ) has a place in server side programming.

How do classical OO design concepts mesh with the world of stateless
server side programming?

I'm also looking for opinions and any pointers to writings on the
subject.

Thanks,
Bill.



Wed, 17 Dec 2003 01:52:13 GMT  
 Persistence and Scalable / Stateless Server Objects

Quote:

> I'm trying to reconcile in my mind how object persistence (in any
> form, relational db, xml file, oodb, etc.) goes along with server side
> stateless objects.

> I understand how Session and Entity beans work in a technical sense.
> The way I think of this is basically the data and the methods that
> work on the data are separated, as opposed to combined / encapsulated.
> I'm currently working on a server-side system where I'm using a
> "Business Object / Rules" layer, Data Access layer and Presentation
> layer, and it works great. I just think there has to be a better way
> in terms of the relationship between the Business and Data layers.

> I guess I'm just wondering if "classical" OO persistence (like Scott
> Amber describes in several white papers and articles,
> http://www.ambysoft.com/) has a place in server side programming.

> How do classical OO design concepts mesh with the world of stateless
> server side programming?

I like to view the stateless objects as Facades into the business
layer.  For each request the client makes, the session object uses the
business layer to respond, returns any required data and then lets go
of all resources.

Quote:
> I'm also looking for opinions and any pointers to writings on the
> subject.

I learned the most from a magazine called Distributed Computing, but
that got merged into another magazine.  Do know of any others right
now.

Regards,
John Urberg



Sat, 20 Dec 2003 00:52:05 GMT  
 Persistence and Scalable / Stateless Server Objects
You can find a additional info along the same line from Martin Fowler at his
site:

He call this beginning of a book or paper "Informations Systems
Architecture".

http://www.martinfowler.com/isa/index.html

I found especially interesting his discussion of 'Distributed Facade'
'Transactional Script'
and 'Domain Model'.

Hop this helps.
Jiri Lundak


Quote:

>> How do classical OO design concepts mesh with the world of stateless
>> server side programming?

>I like to view the stateless objects as Facades into the business
>layer.  For each request the client makes, the session object uses the
>business layer to respond, returns any required data and then lets go
>of all resources.

>> I'm also looking for opinions and any pointers to writings on the
>> subject.

>Regards,
>John Urberg



Sat, 20 Dec 2003 05:55:23 GMT  
 Persistence and Scalable / Stateless Server Objects


Quote:
>How do classical OO design concepts mesh with the world of stateless
>server side programming?

In much the same way that classical relational database design meshes
with denormalisation for performance reasons...

--
Nobody tells me anything either
but I like it that way. (Snoopy)
steve at otolith dot demon dot co dot uk
http://www.otolith.demon.co.uk/



Sun, 04 Jan 2004 04:08:32 GMT  
 Persistence and Scalable / Stateless Server Objects
The stateless server object is not the holder of the persistent data. This
resides in the database.

The server object is acting as a proxy for the stored data. Going stateless
is just saying that proxies may be invisibly swapped by the application
server as needed. This is normally done to share resources, such a memory or
database connections.)

So, to "reconcile" this (or "wrap your mind around" this), realize that the
state of the local object is being saved in the server. These are the key
issues. The so-called stateless server objects are just different paths
between the local object and the persistent data.

"Stateless object" is a misnomer. A group of objects (and possibly other
resources) are collaborating on the server to make this appear stateless,
providing transparent sharing of server resources. The state exists. It just
does not hamper resource sharing.

Yes, this is very OO. It can be considered a pattern for combining
transparent remote data with resource sharing.

--
Warren R. Zeigler Sr
http://www.UnderstandingObjects.com



Quote:
> I'm trying to reconcile in my mind how object persistence (in any
> form, relational db, xml file, oodb, etc.) goes along with server side
> stateless objects.

> I understand how Session and Entity beans work in a technical sense.
> The way I think of this is basically the data and the methods that
> work on the data are separated, as opposed to combined / encapsulated.
> I'm currently working on a server-side system where I'm using a
> "Business Object / Rules" layer, Data Access layer and Presentation
> layer, and it works great. I just think there has to be a better way
> in terms of the relationship between the Business and Data layers.

> I guess I'm just wondering if "classical" OO persistence (like Scott
> Amber describes in several white papers and articles,
> http://www.ambysoft.com/) has a place in server side programming.

> How do classical OO design concepts mesh with the world of stateless
> server side programming?

> I'm also looking for opinions and any pointers to writings on the
> subject.

> Thanks,
> Bill.



Fri, 09 Jan 2004 12:57:42 GMT  
 
 [ 5 post ] 

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