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From "Antony Paul" <antonypau...@hotmail.com>
Subject Re: Design advice needed.
Date Mon, 03 Nov 2003 11:13:56 GMT
It is not a scenario of threading at all. I found a document related to this
at
http://theserverside.com/patterns/thread.jsp?thread_id=6894
----- Original Message -----
From: <achana@saysit.com>
To: "Tomcat Users List" <tomcat-user@jakarta.apache.org>
Sent: Monday, November 03, 2003 1:18 PM
Subject: Re: Design advice needed.


> Ummm, didn't want to butt in, but why r u multi-threading a read, then
> write to Oracle?
> Without using roll locking, wouldn't it be the right thing to do using
> synchronized thread e.g. like this
> import java.io.*;
> public class ModifyAccountBalance
> {
>   DespositThread Deposit1, Deposit2;
>   Deposit1 = new DepositThread(account, 1234);
>   Deposit2 = new DepositThread(account, 4321);
>   // strut yourstuff here
> }
> synchronized void Deposit (int depositAmt, String accountName)
> {
>   // codes for updating the account balance
> }
> class DepositThread extends Thread
> {
>   // more codes
>    DepositThread
> (...)
>    { // you might like to set the amounts etc here
>    }
>    public void run()
>    {
>      account.Deposit(depositAmt, accountName);
>    }
> }
>
> John Zukowski's books explain that in detail.
> Using synchronization, the first deposit will write and update Oracle
> before the second deposit kicks in.
> What I would like to know is if I have multile JVMs, would this model
> hold true ?????? It should since TC starts up one instance and
> multi-thread it, but we have programmatically forced it to be singled
> threaded.
> Like to hear back n this one.
>
> Johan Kok wrote:
> >
> > Wish I could, it's been eight years since I was did any DBA/DB
development
> > work. Either go to the manual, or contact a oracle list.
> >
> > > -----Original Message-----
> > > From: Antony Paul [mailto:antonypaul24@hotmail.com]
> > > Sent: 03 November 2003 09:10
> > > To: Tomcat Users List; jkok@messianic.dyndns.org
> > > Subject: Re: Design advice needed.
> > >
> > >
> > > Can u pls mention what is that Oracle feature ?. Reading the
> > > data again is
> > > time consuming.
> > > ----- Original Message -----
> > > From: "Johan Kok" <jkok@messianic.dyndns.org>
> > > To: "'Tomcat Users List'" <tomcat-user@jakarta.apache.org>
> > > Sent: Monday, November 03, 2003 12:17 PM
> > > Subject: RE: Design advice needed.
> > >
> > >
> > > > Anthony,
> > > >
> > > > Did you consider reading the record without locks, and when
> > > an updated are
> > > > made, to take a write-lock, check that the original record
> > > are still the
> > > > same and then apply, otherwise fail.
> > > >
> > > > Your intentions might not work unless all writes are passed
> > > through the
> > > > container, as Oracle will not have any control, until a
> > > write occurs, i.e.
> > > > you will have to open with read only, and only take out a
> > > lock when you
> > > are
> > > > going to write, as described above. for safety sake your
> > > container will
> > > have
> > > > to re-read the data in any case, before commiting,
> > > otherwise it may update
> > > > changed data, e.g. updates that are made through other
> > > processes or even
> > > > triggers.
> > > >
> > > > If my memory serves me right, that is something you can do
> > > easily with
> > > > Oracle (i.e. there's a standard feature implemented), even
> > > with Oracle
> > > 6/7.
> > > >
> > > >
> > > >
> > > >
> > > > > -----Original Message-----
> > > > > From: Antony Paul [mailto:antonypaul24@hotmail.com]
> > > > > Sent: 03 November 2003 08:36
> > > > > To: Tomcat Users List
> > > > > Subject: Design advice needed.
> > > > >
> > > > >
> > > > > Hi all,
> > > > >     I need a replacement for row level locking in database.
> > > > > The requirement
> > > > > is if two users are updating the same row of a table only
> > > the user who
> > > > > updates first will be made to database second user must
> > > get a failed
> > > > > message. This can be done using row level locking. But it
> > > > > allows only one
> > > > > user to open page for editing at same time. If another user
> > > > > has locked the
> > > > > row then second user cannot lock the same row or update it.
> > > > > So I want to
> > > > > implement locking in Container. Is there any design patterns
> > > > > available for
> > > > > this. Or have anyone implemented this. I am using Tomcat
> > > > > 4.1,Servlets JSP
> > > > > and Oracle 8i. The application is using  MVC pattern but do
> > > > > not use Struts.
> > > > >
> > > > > Antony Paul
> > > > >
> > > > >
> > > ---------------------------------------------------------------------
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> > > > > For additional commands, e-mail:
> > > tomcat-user-help@jakarta.apache.org
> > > > >
> > > > >
> > > >
> > > >
> > > >
> > > ---------------------------------------------------------------------
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> > > >
> > > >
> > >
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> > >
> > >
> >
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>


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