In theory if a user has always had Lore attached to their Haystack it should never be necessary to regenerate the OEM graph. However, in the case where the data either becomes corrupt, or the Lore database is added to Haystack at some later time, a service is provided to regenerate the OEM graph from scratch. HsOEMGenerator is a simple utility service that is invoked with the generateOEM() procedure. This procedure checks to see which location is specified for the OEM file in the HsConfigService. It then creates the necessary header information and iteratively retrieves all Straws in the HsPersistentObjectService. For each of these Straws, the HsOEMGenerator invokes the generateOEM() method and saves the resulting OEM structure to disk.
A user may then use the OEM loading facility in Lore to reload the new data into the Haystack Lore database.