Need to externalize the JBossEntityResolver configuration and support namespace to schema resolution

With the increased use of JBossXB and its leveraging of the JBossEntityResolver as a means for locating element schemas, we need support for externalizing the configuration of the JBossEntityResolver. We also need to have the notion of resolving a namespace to a schema URI since in general there is no publicID for an element, and a generally unsable systemID since it can be a function of the deployment and server run dir.

Implementing the javax.xml.transform.URIResolver resolve method:

public javax.xml.transform.Source resolve(String href, String base)
throws javax.xml.transform.TransformerException

might be a better api for resolving namespaces.

I have tried integrating the apache commons xml catalog resolver but have not been happy with its semantics and configuration support as yet. We certainly could at least use the catalog.xml schema for representing the externalized mappings.