Dynamic Datasources/Daos

[davidcnoel]

An application I am starting to work on requires that I am able to connect to many different databases. I plan on using the standard Dao pattern but my problem is that I will not know which databases I am supposed to talk to until runtime. This will mean that I cannot configure my datasources in the usual fashion in a spring context. Is there any standard pattern to follow to solve this problem? I was thinking I would create a factory type of object that would manage multiple datasources. Basically you would request a datasource for a database with the name 'A' and it would create the datasource if it did not exist or return a reference to a datasource from the "pool" if it did exist. Even If I do this I still have a problem that the existing DaoSupport classes that spring provides only work with a single datasource. So I would think I would need some type of factory that would create a new instance of my Dao object for the particular datasource I want to talk to. I'm also going to want to take advantage of transactions through Spring AOP so I need to make sure I consider this as well.

I'm thinking this is a common issue so I hope there is an existing best practice or pattern to follow.

Any ideas?

Thanks

Dave

[Alarmnummer]

Check this topic:
http://forum.springframework.org/showthread.php?t=19806

If you create some kind of factory that returns your desired objects (or an environment with all desired objects) you have runtime access to your dependencies.

[rgeorgiev]

Do you have some standart criteria for connecting to different databases?
I so, look at <code>org.springframework.aop.target.HotSwappableTargetS ource</code>

[davidcnoel]

using a HotSwappableTargetSource with a proxy datasource worked. Thanks for the advice.

[barinek]

any chance you could post the java source?