code: public void onStoreUpdate( @Observes final ArtifactStorePreUpdateEvent event )
      {
          logger.trace( "Got store-update event: {}", event );
  
          if ( ArtifactStoreUpdateType.UPDATE == event.getType() )
          {
              for ( ArtifactStore store : event )
              {
                  removeMetadataCacheContent( store, event.getChangeMap() );
              }
          }
      }
docs: Listen to an #{@link ArtifactStorePreUpdateEvent} and clear the metadata cache due to changed memeber in that event
  
  @param event