Hi Aravind,
Please see below ....
Aravind Naidu wrote:
>
> Now, with the resultset method, I have the following points.
> - If I was getting data from non-db sources, then I have to map it to a
> resultset interface anyway, I might as well put it into a simple object
> graph.
The first time I used this technique was on a CORBA project that obtained data
from IMS as well as JDBC. The implementation of ResultSet provided accessor
methods that allowed us to merge data from these disparate sources into one
ResultSet. The ResultSet interface hid the set methods making the object
immutable to the client.
Placing this same data into an object graph would not have made things simpler
since the client developers needed to place the data into tables. The ResultSet
interface was much better because the data was delivered in the same schema
(tabular) that it was presented in. In addition, generic builders were made
that could take any result set and map it into a table. Builders were made that
generated HMTL tables as well as populating Swing tables. This allowed the
CORBA service interfaces to be reused for different client presentations (HTML
for printing and GUI for perusing). This would not be possible with an object
graph because the builders could not be generic; each builder would have to know
the structure of the graph in advance.
>
> - The signature of the business method then becomes largely meaningless.
>
The method name, its arguments, and its interface are very expressive. The
method PayRoll.getEmployeeSalaries(int DepartmentID) is more then expressive
enough.
The one downfall of the the ResultSet is that a developer can not examine its
interface to determine the type of data it contains. The developer must look at
the documentation (we placed this information in the method comments ). Of
source, the same is true of the detail objects since the developer must examine
the JavaDoc or source code which is just another form of documentation.
Richard
--
Richard Monson-Haefel
Author of Enterprise JavaBeans, 2nd Edition
Published by O'Reilly & Associates
http://www.EjbNow.com
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