On Mar 25, 2010, at 3:52 AM, Jean-Louis MONTEIRO wrote:
Hi,
Some month ago, i used a Spring feature called
DynamicRoutingDatasource in
order to split data on database servers.
Here is a short description
http://blog.springsource.com/2007/01/23/dynamic-datasource-routing/
http://blog.springsource.com/2007/01/23/dynamic-datasource-routing/ .
I will need to implement such a feature in OpenEJB for my company.
So, i wonder if we could make that feature available in the Apache
OpenEJB
distribution.
That all seems really trivial. I don't see the harm in implementing it.
Seems like it would take all of one hour to create a DataSource
wrapper that looked up "openejb:Resource/<ID>" and delegated to it
where ID could be supplied via some class that the user supplied --
that way they take responsibility for the thread local and how/where
it is set in their application code (a ThreadLocal<String> is all
they'd need). Say some Router interface used by the RoutingDataSource
implementation. RoutingDataSource can be defined in the service-
jar.xml and have a "Router" property which can be set by the user to
the class name of their impl. (doesn't have to be "Router" and
"RoutingDataSource", could be any name. I kind of like just plain
"DynamicDataSource").
I'd prefer to put off any creation of a larger application context
kind of thing for the fact that "what datasource do you really want"
can get really simple, so let's start there. Spring has a context
concept, OSGi has one as well, and guess what JDCI has one too (a
bunch actually). Anyway, I'd prefer not to create our own just yet as
we have a lot of standards-based work to do real soon in this area.
Seems like whatever we do would be obsoleted almost immediately.
The basic idea of DataSources being a tad more dynamic is good
though. We can do simple now and potentially tie it into other
context-providing APIs later -- could support them all eventually if
we keep the DataSource simple enough.
-David
