| Class | Description | 
|---|---|
| AbstractODFObserver | Abstract  Observerfor observing events on a Program or Course. | 
| ClearLevelCacheObserver | This observer clears the cache of enumerated  OrgUnitvalues orContents which arepart of reference tablewhen anOrgUnitor reference table content is added, modified, moved or deleted. | 
| ClearODFPageCacheObserver | Clear ODF caches when page ODF root page has changed | 
| InvalidateCacheOnContentValidationOrUnpublishingObserver | Observerfor observing content validation or tagging in order to 
 invalidate cache on front-office. | 
| InvalidateCacheOnOrgunitChangedObserver | Observerfor observing OrgUnit validation, unpublishing, deletion or moving 
 (with eventObservationConstants.EVENT_CONTENT_MODIFIED, which will lead to sometimes invalidating cache whereas it is not necessary)
  in order to invalidate cache on front-office. | 
| SynchronizedContentTranslatedObserver | Observerfor observing content translation in order to synchronize live workspace. |