On Sat, 12 Aug 2000 15:46:43 GMT, Tom Jordan <[EMAIL PROTECTED]>
wrote:
>I would like to know what approaches people are taking to design entity
>beans so that they behave in a read only manner and are sharable across
>users. I am really interested in a portable design not BEAs read only
>beans.
>
>For example, if you have a catalog of products, ideally I would like to
>populate a bean with a product once and all subsequent users of the bean
>would access that instance and not have to repopulate or go to the database
>each time. In my use so far, I notice that every call to the beans methods
>results in the ejbload and ejbstore methods being called, making the
>operation very expensive in terms of database calls.
>
>any thoughts?
If you go with a server that has a read-only flag for CMP, that should
work for you.
The safest bet, however, is to use BMP and simply don't implement
ejbSave. So, it wont matter how many times the server invokes ejbSave;
you won't go to the DB anyway.
Then there's the issue of ejbLoad. If you choose a server that allows
you to use any EJB-spec commit option, simply choose option A (state is
valid on tx commit). If you don't have that possibility, well, there's
not alot you can do :-(
So:
* Don't implement ejbSave
* Choose a server that allows you to use commit option A (most servers
*should* allow this)
I could do a jBoss plug here, saying that we support read-only CMP
beans, and blah blah this feature that feature, but you already guessed
that, right? ;-)
Oh, and the discussion some week ago on synched clustered caching of
EntityBeans: the kind of usage you have here would work very well with
that, but it would not only work very well for read-only, but also
read-mostly (if you have occasional changes).
/Rickard
--
Rickard Öberg
Email: [EMAIL PROTECTED]
http://www.telkel.com
http://www.jboss.org
http://www.dreambean.com
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