DAO 's factory is right or not! URGENT 2004-07-15 - By Jaise George
Back
Hi,
I am not fully convinced by Manish's approach. I would say the Map he is
implementing is neither a cache nor a pool. Because both pool and cache
will have more than one instances. Manish's implementation can more
precisely be called as a Sigleton Pool. And I feel that whatever
advantage he gets by not instantiating a DAO everytime, is lost due to
the synchronization that he has to take care in his DAO. I doubt you
will end up in tackling synchronisation later.
Regards
Jaise
-- --Original Message-- --
From: A mailing list for Java(tm) 2 Platform, Enterprise Edition
[mailto:J2EE-INTEREST@(protected)] On Behalf Of Manish Malhotra
Sent: Thursday, July 15, 2004 3:17 PM
To: J2EE-INTEREST@(protected)
Subject: Re: DAO's factory is right or not! URGENT
Thanks Ben,
Means I can implement something like connection / thread pool for DAO's.
And yes you are right that there is no performance by DAO caching. But
just the Factory pattern I intorduced. So that there wod be less
dependency between Beans & DAO's.
And Im not able to identify the methods of DAO which needs to be
synchropnized. Ir there any property which I need to look in to the
methods to identify.
Im calling som private methods also in DAO and passing the connection
object from one methods to another. Is there any issue in this?
Manish
-- --Original Message-- --
From: A mailing list for Java(tm) 2 Platform, Enterprise Edition
[mailto:J2EE-INTEREST@(protected)]On Behalf Of Ben Hill
Sent: Thursday, July 15, 2004 3:00 PM
To: J2EE-INTEREST@(protected)
Subject: Re: DAO's factory is right or not! URGENT
> -- --Original Message-- --
> From: Manish Malhotra [mailto:manish.mmalhotra@(protected)]
> Sent: 15 July 2004 10:16
> To: HILL, Ben -Syntegra UK
> Subject: RE: DAO's factory is right or not! URGENT
>
>
> Ben,
>
> We have implemented the Data Access Object pattern to access the
> interact with data base. And to get the different DAO objects we used
> DAO factory.
>
> So, my issue is that we are maintaining cache of DAO objects in the
> factory. And using the same object for multiple request.
You're storing the DAO in a map, but there will only be one instance of
the DAO in there - therefore you're not really adding any performance
improvement over a regular singleton. If you make a call to
getBankOverrideDAO() and the map does not have a DAO in there, one will
be instantiated and put into the map. Each consecutive call on
getBankOverrideDAO() will then return this instance as it will be able
to find it in the map. You *may* have some threading issues with the DAO
but just make sure any methods that need to be are synchronized.
If you really wished to maintain a pool of DAOs, you'd more likely have
a list of many DAOs that you could serve out in (an example of one of
may
strategies) a round-robin method. In this method, you'd create a pool of
DAOs by instantiating them all and adding them to a list. When a request
comes in, you would give them the "next" DAO. When you have served the
next DAO, you'd increment the pointer to point at the DAO behind that
one in the list. Again, this is just a round-robin example. You could
get much more clever and implement load-balancing algorithms etc.
You may also wish to think about how the pool of DAOs grows and shrinks
to deal with load. You could have an initial pool size, then if that
pool is fully used, increase the pool by adding more instances in. Then,
if load decreases; shrink the DAOs again to free DB connections... There
is lots to work with...
HTH
Ben
>
> So, Is this implementation is ok with point of view PERFORMANCE.
>
> Or what I found on net for this pattern is they are creating new
> Object of DAO every time in the Factory where, Im creating only once
> and then using the same.
>
> I hope this will clear my question
>
> Thanks & Regards,
> Manish Malhotra
>
> -- --Original Message-- --
> From: ben.hill@(protected) [mailto:ben.hill@(protected)]
> Sent: Thursday, July 15, 2004 2:29 PM
> To: manish.mmalhotra@(protected)
> Subject: RE: DAO's factory is right or not! URGENT
>
>
>
>
> > -- --Original Message-- --
> > From: Manish Malhotra [mailto:manish.mmalhotra@(protected)]
> > Sent: 15 July 2004 09:55
> > To: J2EE-INTEREST@(protected)
> > Subject: DAO's factory is right or not! URGENT
> >
> >
> > Im again sending this query because no body has replied yet. I need
> > some help as early as possible.
>
>
> What exactly are you asking?
>
> Cheers,
>
> Ben
>
>
> ********************************************************************
>
> This email may contain information which is privileged or
> confidential. If you are not the intended recipient of this email,
> please notify the sender immediately and delete it without reading,
> copying, storing, forwarding or disclosing its contents to any other
> person Thank you
>
> Check us out at http://www.btsyntegra.com
>
> ********************************************************************
>
********************************************************************
This email may contain information which is privileged or confidential.
If you are not the intended recipient of this email, please notify the
sender immediately and delete it without reading, copying, storing,
forwarding or disclosing its contents to any other person Thank you
Check us out at http://www.btsyntegra.com
********************************************************************
========================================================================
===
To unsubscribe, send email to listserv@(protected) and include in the
body of the message "signoff J2EE-INTEREST". For general help, send
email to listserv@(protected) and include in the body of the message
"help".
========================================================================
===
To unsubscribe, send email to listserv@(protected) and include in the
body of the message "signoff J2EE-INTEREST". For general help, send
email to listserv@(protected) and include in the body of the message
"help".
===========================================================================
To unsubscribe, send email to listserv@(protected) and include in the body
of the message "signoff J2EE-INTEREST". For general help, send email to
listserv@(protected) and include in the body of the message "help".
|
|
