Re: design question, how to handle this project

    Hi Ashish,

    While we don't have the complete context and requirements, in general I
agree with Paul Holm's analysis.  While the agent option decouples and
makes things very generic, the data would have to be handled twice and you
have software to maintain on the client.  I'm a big fan of messaging and use
XML when appropriate, but in a homogeneous environment ( which can here
be expanded to any system with a DBMS and JDBC driver ) that just wants to
grab the data for processing, these layers introduce complexity and impact
performance.  Remember that SQL provides a standard for formats too and
you can just talk directly to the DBMS engine over the network.

    The main thing I would add is a class ( possibly with subclasses per
version ) that knows how to access and format the data into a standard
ResultSet according to the "query operations" table Paul mentioned.  Then I
would take advantage of the network latency mentioned by Sergio ( and the
fact that the remote system is doing most of the work ) by having a method
in the class that runs as a thread to access the data.  Your reporting
process can create an instance for each machine you want to access and
start them up.  You could also implement a callback to inform the main
process when the operation is finished and the data is ready.  You could
subset operations any way you like to conserve connections and memory, or
maximize performance.

    It's probably a different story if the data needs to be massaged,
summarized or interaction between the values from different tables on the
same system needs to happen before getting to your reporting process.  Most
of the concepts would be the same, but most activity should
occur on the remote systems - essentially Sergio's agents.

    Again, we don't have the info to make the proper judgement, so that'll
have to be left up to you.


                                                         Joe Sam

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----- Original Message -----
From: "Ashish Kulkarni" <kulkarni_ash1312@xxxxxxxxx>
To: <java400-l@xxxxxxxxxxxx>
Sent: Tuesday, July 20, 2004 11:48 AM
Subject: design question, how to handle this project


> Hi
> We have about 30 AS400 system in USA and around the
> world running one home developed software, we need to
> develop a project which will get data from all AS400
> and display them on a website or some report.
> Here are some more details.
> 1. Each AS400 may be running different version of this
> software, so the file and tables may be different, so
> this project has to handle this.
> 2. Each AS400 may or may not want to participate in
> this project, so have to some how give funtion like to
> register
> 3. The data extraction has to happen in real time, and
> not create a pool of data in batch some where and then
> display it.
>
> I was thinking of following design options
> 1. A common database where the system ip address and
> the version it is running registered, so a java
> program will go to each system and extract data when
> required
> 2. Webservice, each AS400 system running tomcat or
> websphere and webservices, then register these
> webservices to UDDI server, and then call these to
> extract data.
> (some machines may not have sufficient hardware to run
> tomcat or websphere)
>
> What may be different approcahes for this kind of
> system, and what may be the best approach. and what
> you will do if you have to desing this kind of sytem.
>
> Ashish
>