public class EclipseLinkMetadataSource extends XMLMetadataSource
{
    public EclipseLinkMetadataSource()
    {
        super();
    }

    @Override
    public XMLEntityMappings getEntityMappings(Map<String, Object> properties, ClassLoader classLoader, SessionLog log)
    {
        Reader reader = getEntityMappingsReader();

        try
        {
            return XMLEntityMappingsReader.read(getRepositoryName(), reader, classLoader, properties);
        }
        finally
        {
            if (reader!=null)
            {
                try
                {
                    reader.close();
                }
                catch (IOException e)
                {
                    // ignore
                }
            }
        }
    }

    private static Reader getEntityMappingsReader()
    {
        StringBuffer xml = new StringBuffer();

        xml.append("<?xml version=\"1.0\"?>\n");
        xml.append("<entity-mappings " +
            "xmlns=\"http://www.eclipse.org/eclipselink/xsds/persistence/orm\" " +
            "xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" " +
            "version=\"2.1\">\n");

        xml.append("  <persistence-unit-metadata>\n");
        xml.append("    <xml-mapping-metadata-complete/>\n");
        xml.append("    <exclude-default-mappings/>\n");
        xml.append("  </persistence-unit-metadata>\n");

        xml.append("  <entity class=\"" + User.class.getName() + "\" access=\"PROPERTY\" name=\"User\">\n");
        xml.append("    <table name=\"APPLICATION_USER\"/>\n");
        xml.append("    <attributes>\n");
        xml.append("      <id name=\"id\">\n");
        xml.append("        <column name=\"AU_ID\"/>\n");
        xml.append("      </id>\n");
        xml.append("      <basic name=\"displayName\" access=\"VIRTUAL\" attribute-type=\"java.lang.String\" fetch=\"EAGER\">\n");
        xml.append("        <column name=\"DISPLAY_NAME\"/>\n");
        xml.append("      </basic>\n");
        xml.append("      <one-to-many name=\"groups\" access=\"VIRTUAL\" attribute-type=\"" + Set.class.getName() +
            "\" fetch=\"LAZY\" target-entity=\"" + UserGroup.class.getName() + "\">\n");
        xml.append("        <join-column name=\"AU_ID\" referenced-column-name=\"AU_ID\"/>\n");
        xml.append("      </one-to-many>\n");
        xml.append("    </attributes>\n");
        xml.append("  </entity>\n");

        xml.append("  <entity class=\"" + UserGroup.class.getName() + "\" access=\"PROPERTY\" name=\"UserGroup\">\n");
        xml.append("    <table name=\"APPLICATION_USER_GROUP\"/>\n");
        xml.append("    <attributes>\n");
        xml.append("      <id name=\"groupRef\">\n");
        xml.append("        <column name=\"GROUP_REF\"/>\n");
        xml.append("      </id>\n");
        xml.append("      <many-to-one name=\"createdBy\" target-entity=\"" + User.class.getName() + "\" fetch=\"LAZY\">\n");
        xml.append("        <join-column name=\"CREATED_BY\" referenced-column-name=\"AU_ID\"/>\n");
        xml.append("      </many-to-one>\n");
        xml.append("    </attributes>\n");
        xml.append("  </entity>\n");

        xml.append("</entity-mappings>\n");

        System.out.println(xml.toString());

        return new StringReader(xml.toString());
    }
}