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From Rodney Waldhoff <rwaldh...@apache.org>
Subject Re: [Pool] Newbie question on pools (modified subject)
Date Wed, 19 Mar 2003 16:38:15 GMT
In addition to all the things Craig lists, if you're using the
commons-pool API directly, you can use pool.invalidateObject() to have the
pool dispose of a previously active object. (E.g., if you know that some
object you've borrowed has gone bad.)

On Wed, 19 Mar 2003, Craig R. McClanahan wrote:

>
>
> On Wed, 19 Mar 2003, Donie Kelly wrote:
>
> > Date: Wed, 19 Mar 2003 11:07:46 -0000
> > From: Donie Kelly <donie.kelly@tecnomen.ie>
> > Reply-To: Jakarta Commons Users List <commons-user@jakarta.apache.org>
> > To: 'Jakarta Commons Users List' <commons-user@jakarta.apache.org>
> > Subject: [Pool] Newbie question on pools (modified subject)
> >
> > Hi
> > Sorry about posting without proper subject. I'm resending in case a lot of
> > you are using filtering.
> >
> > Donie
> >
> > -----Original Message-----
> > From: Donie Kelly [mailto:donie.kelly@tecnomen.ie]
> > Sent: 19 March 2003 11:03
> > To: Jakarta Commons (E-mail)
> > Subject: Newbie question on pools
> >
> > Hi all
> >
> > I've looked through the source and all the javadocs and I cannot find a way
> > to do the following with the pool library. Note I have marked that I can
> > achieve parts of the intended functions:
> >
> > 1)      Get a connection from the pool (I can do this)
> > 2)      Use the connection (I can do this)
> > 3)      Return the connection to the pool (I can do this)
> > 4)      When I get a connection and I have detected it has failed how can I
> > mark it for removal as it may have been dropped by the server at the other
> > end of the connection (HOW TO??)
> >
> >
>
> If you are using the [pool] APIs directly, you can set the testOnBorrow
> and/or testOnReturn properties to validate objects as they are being
> borrowed, or as they are being returned.  See the [pool] API docs on
> GenericObjectPool for more info.
>
> If you are using something like BasicDataSource from [dbcp] for database
> connection pools, these APIs let you define a 'validationQuery' parameter
> that represents an SQL SELECT statement.  The pool will ensure that this
> statement executes with no failures before letting you borrow it, throwing
> the connection away if not.  There are other tweaks for things like
> periodically testing the idle connections in the pool as well.
>
> > I understand that I can use the pool ObjectPoolFactory to test connections
> > on retrieval and submission to the pool but this is an overhead I don't
> > want. I want the pool to drop the connection when the application has
> > decided it is bad. I know the other way is desirable and I will probably
> > implement this by using the evictor thread but surely it's important for the
> > application to be able to decide that the connection is useless??
> >
>
> If you don't want the overhead of testOnBorrow (it's a price I feel
> willing to pay, because the app should not even have to worry about things
> like this), then you probably want to explore the testOnReturn thing
> instead.
>
> > The connection I'm pooling is a Corba connection object.
> > Thanks for any insights or help.
> >
> > Donie
> >
> >
>
> Craig
>
>
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