Muly Oved wrote:
> Hi
>
> For design a non-trivial distributed database application,
> to be implemented in Application server.
>
> Here some guidelines and ideas I picked during my searching, I maybe wrong :)
>
> * Don�t expose entity beans to the clients:
> It is recommended that the client will talk with session beans and the
> session beans will talk with the entity beans.
Correct. Use stateful beans this way when they can encapsulate a process or agent like
functionality. Just wrapping entities in session beans arbitrarily is stupid. If you
need to
directly edit a specific entity bean -- that is not part of a larger unit-of-work --
access it
directly form the client.
> * Bean managed persistence is BAD:
> Also there is a clear and easy framework how to write the code for BMP.
> It is BAD to use it if performance is important.
> Using BMP will be VERY inefficient and will generate many small SQL operations.
>
Wrong. There is nothing that says BMP is less efficient then CMP at run time. It may
take more
time develop (unless using something like CocoBase) but there is no reason why it
would be less
peformant. Containers can do optimizations like caching but this is vendor specific.
> * Component managed persistence is problematic:
> Also theoretically the container can do some optimization to overcome
> the BMP problem, there still a problems There is no standard how to
> specify mapping to the component (Fields, and Find code)
> Most of the implementation are trivial and does not allow complex mapping
> between beans and database.
> Those limitations will be improved in the future, as technology
> mature, but it will certainly take time.
See above. And yes to the other stuff.
--
Richard Monson-Haefel
Author of Enterprise JavaBeans
Published by O'Reilly & Associates
( http://www.monson-haefel.com )
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