private final static void submitArtistTasks() 
			 throws MasterException {

		try {
			
			//submit tasks to do.
			//Waiting until all tasks are done
			MasterMetadata.artistES.invokeAll(MasterMetadata.artistTasks); 
			
			//Clean the queue
			MasterMetadata.artistTasks.clear(); 
		
		} catch (Exception e) {
			throw new MasterException("Exception "+e.getMessage(), e);
		}
	}