EclipseLink/Examples/JPA/MetadataSource/PropertyOverrides

MetadataSource was extended to support properties overrides. To simply access properties file in persistence unit, specify in persistence.xml xml meta data source:

<property name="eclipselink.metadata-source" value="XML"/>

this of course could be combined with overriding mappings, too:

<property name="eclipselink.metadata-source" value="XML"/>
<property name="eclipselink.metadata-source.xml.url" value="foo://bar"/>

Specify properties file name in the Java application:

Map properties = new HashMap();
properties.put("eclipselink.metadata-source.properties.file", "extension.properties");
JpaHelper.getEntityManagerFactory(em).refreshMetadata(properties);

extensions.properties file contains the new properties' values, for instance:

javax.persistence.jtaDataSource=MyJtaDataSource
javax.persistence.nonJtaDataSource=MyNonJtaDataSource

After that the new EntityManagers created from this factory will use the properties specified in extension.properties file.

Alternatively to implement their own MetadataSource

<property name="eclipselink.metadata-source" value="mypackage.MyMetadataSource"/>

user need now to implement the new method getPropertyOverrides, too:

public class MyMetadataSource implement MetadataSource {
 
    @Override
    public XMLEntityMappings getEntityMappings(Map<String, Object> properties, ClassLoader classLoader, SessionLog log) {
      ...
    }
    @Override
    public Map<String, Object> getPropertyOverrides(Map<String, Object> properties, ClassLoader classLoader, SessionLog log) {
      ...
    }
}