On Wed, 22 Jan 2003, Charlie Toohey wrote:
> Date: Wed, 22 Jan 2003 10:31:23 -0800 > From: Charlie Toohey <[EMAIL PROTECTED]> > Reply-To: Struts Users Mailing List <[EMAIL PROTECTED]> > To: [EMAIL PROTECTED] > Subject: accessing DataSource, webapp design question > > This is more of a design question. I am using Struts and Tomcat, and have set > up a JNDI ref-resource to acquire a DataSource for my database, which works > fine. All of my value objects use the same database. > > The question is how to give each value object access to this DataSource. > > One option would be to lookup the JNDI contexts once, at application init, > and store the DataSource as an application scope attribute. Then whenever a > value object needs to do database work, they access this DataSource and do a > getConnection() / conn.close(). > > Another option would be to have each value object do the JNDI lookups (say, > in their constructors) and store the DataSource reference in a private field > --- then anytime they need to do database work, they use the private field > DataSource and do a getConnection() / conn.close() > > Is there any difference/advantage/disadvantage in having all value objects > using the same DataSource reference, stored at application scope, vs. all > value objects having their own reference to the DataSource ? > > Or another approach which is superior to these options ? > A third pattern is actually the recommended one -- do the lookup in your value object every time. It won't matter on Tomcat (which doesn't support these features), but it allows high-availabity servers to support transparent reconfiguration of existing connection pools, or even switching to a backup database, without making you shut down your application. Saving a reference to the connection pool you were given earlier makes all of that kind of support difficult to impossible. > Thanks, > Charlie Craig -- To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> For additional commands, e-mail: <mailto:[EMAIL PROTECTED]>
