[eclipselink-dev] enhancement 344837 - Extensibility Metadata Repository

[Christopher Delahunt <christopher.delahunt@xxxxxxxxxx>]

https://bugs.eclipse.org/bugs/show_bug.cgi?id=344837

This feature adds:
org.eclipse.persistence.jpa.MetadataRepositoryReader.java  - interface 
used by EclipseLink to pull metadata from the repository
org.eclipse.persistence.jpa.MetadataRepositoryAdapter - trivial class 
implementing the interface
org.eclipse.persistence.jpa.XMLMetadataRepository - implementation that 
can read from a specified xml file or URL

The Repository class is specified to a persistence unit using property 
"eclipselink.metadata-repository".  It also adds
"eclipselink.metadata-repository.xml.file" and 
"eclipselink.metadata-repository.xml.url" for use with the XML 
implementation.

Tests to be added in a later checkin. 

Checked into main
Reviewed by Tom Ware