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From Oscar Carrillo <tom...@daydream.stanford.edu>
Subject RE: OT: db pool problems - jdbc connection count?
Date Thu, 30 Oct 2003 19:41:38 GMT
Thanks for a more complete solution Yoav!

I'm still using a homebrew connection pool, so I'm lacking in some
features. I'm planning on moving to one of the standard connection pools
since they exist now and look quite good.

Can I put your example up on my site when I finally get to doing a HOWTO
on how to do connection pools?

Regards,
Oscar

On Thu, 30 Oct 2003, Shapira, Yoav wrote:

> 
> Howdy,
> It's very similar to how you get a connection.  Let's say your
> datasource is defined in server.xml with name "jdbc/myDataSource".
> Then:
> 
> InitialContext ic = new InitialContext();
> DataSource ds = (DataSource)
> ic.lookup("java:comp/env/jdbc/myDataSource");
> 
> If you wanted a connection, you'd call ds.getConnection().  But you want
> to find the number of active connections, which is not part of the
> DataSource interface.  So you need to cast ds to the specific type,
> which is the type your specified in server.xml.
> 
> Assuming that type is org.apache.commons.dbcp.BasicDataSource, you'd do:
> BasicDataSourcs bds = (BasicDataSource) ds;
> int numActive = bds.getNumActive();
> int numIdle = bds.getNumIdle();
> System.out.println("There are " + numActive + 
> " active connections and " + numIdle + 
> " idle connections in the pool.");
> 
> I'm assuming you're using DBCP.  If you're using another connection
> pool, the above code must be modified accordingly.
> 
> Yoav Shapira
> Millennium ChemInformatics
> 
> 
> >-----Original Message-----
> >From: john-paul delaney [mailto:jp@justatest.com]
> >Sent: Thursday, October 30, 2003 6:30 PM
> >To: Tomcat Users List
> >Subject: RE: OT: db pool problems - jdbc connection count?
> >
> >Thanks Yoav... sorry it's a wee bit above my immediate understanding
> (e.g
> >lookup my connection pool by JNDI name - I could do with an example of
> what
> >this means) plese be patient and point me to a resource that will give
> me
> >some lead to catch up with you.
> >
> >
> >regards
> >/j-p.
> >
> >
> >On Thu, 30 Oct 2003, Shapira, Yoav wrote:
> >>
> >> Howdy,
> >> You can write a bit of code to do this:
> >>
> >> - Create an InitialContext
> >> - Get the java:comp/env context
> >> - Lookup your connection pool by JNDI name
> >> - Cast your connection pool to the appropriate type as specified in
> your
> >> server.xml
> >>
> >> Then you can call the implementation-specific method, e.g.
> >> getNumActive() / getNumIdle() for
> >> org.apache.commons.dbcp.BasicDataSource, to look at values.
> >>
> >> Yoav Shapira
> >> Millennium ChemInformatics
> >
> >
> >
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