> -----Oprindelig meddelelse-----
> Fra: Francois Staes [SMTP:[EMAIL PROTECTED]]
> Sendt: 21. februar 1999 20:20
> Til: [EMAIL PROTECTED]
> Emne: Question regarding Session and Entity Beans
>
>
> Hello,
>
> I'm rather new to EJB technology, so I might be asking stupid
> questions....
>
> I'm having a number of conceptual questions regarding the relationship
> between Entity Beans and Sessions
> Beans.
>
> To facilitate the discussion, I'll try to focus on one example
> throughout the message: suppose one has to implement
> a customer care system where client applications will be used to
> manipulate customer information (e.g. name, address,
> phone number, etc.).
>
> Obviously, we would like to implement the Customer class as an entity
> bean (preferably using some kind of container
> managed persistency). This Customer bean than would have a number of
> accessor methods to get/set the various customer
> attributes.
>
> It's clear that it is not feasible to expose these methods to client
> applications as this would require many calls to be made from the
> client application to the EJB server to retrieve a customer's name,
> address, etc..
>
> Hence, it is proposed quite often to use a session bean to hide the
> entity bean to the client application. The client application then talks
>
> to the session bean, and the session bean talks to the entity bean.
>
> Although I understand the advantages of this approach quite clearly
> (especially when having clients that only need to access some of
> the attributes of the entity bean, and as a logical place for
> implementing business logic rules), I don't see very well how it solves
> the
> communication problem mentioned above. One could allow the client
> application to retrieve customer information from the session bean
> in two ways:
>
> - Implement a large number of methods in the session bean to retrieve a
> specified customer's name, address, etc.
> (and having the same excessive communication problem as explained
> before);
>
> - Implement one (or a few) methods in the session bean, and have these
> methods work in a CustomerData object (something that
> holds information on a customer and that can be sent to the client
> application and back using serialization).
>
> When implementing the second solution there obviously is a strong
> relationship between this CustomerData object and the original
> entity bean.
>
> So, I'm wondering whether I'm the only one with these thoughts, and
> whether any tools have been defined to generate this kind of
> CustomerData objects from a given entity bean.
>
> Anyone willing to share some thoughts on this ?
>
> Thanks,
>
> Francois Staes
> <<Fil: Card for Francois Staes>>
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