Reading shibboleth IdP configuration from database

[Rod Widdowson]

> 1.  I define three different DBResources one each for relying party,
attribute
> resolver and attribute filter implementing the
>      org.springframework.core.io.Resource interface and possibly the
> net.shibboleth.utilities.java.support.resource.Resource interface.

Or one resource and use configuration to make the three different values.

 
> 2.  These three resources will be beans defined in services.xml file with
three
> unique ids.

Yup.

> 3.  The p:serviceConfigurations-ref attribute of the beans(services)
> shibboleth.AttributeResolverService, shibboleth.AttributeFilterService and
>      shibboleth.RelyingPartyResolverService ( in the file
services-system.xml) will
> point to the three DBResources respectively.

You shouldn't have to edit any of the system files.  You want to edit the
definitions of these beans in service.xml to add your resources.  Instead 

<value>whatever</value> 

Do 

<ref>whatever</ref>