private String getHost(Resource resource, String clusterName, String componentName) throws SystemException {
    return hostNamePropertyId == null ?
      hostProvider.getHostName(clusterName, componentName) :
      hostProvider.getHostName((String) resource.getPropertyValue(hostNamePropertyId));
  }
SQL based property/metrics provider required for ambari-scom.
contrib/ambari-scom/ambari-scom-server/src/main/java/org/apache/ambari/scom/SQLPropertyProvider.java