question: public TrackerOperation createTrackerOperation ( String source , String description ) { Preconditions . checkArgument ( ! Strings . isNullOrEmpty ( source ) , SOURCE_IS_EMPTY_MSG ) ; Preconditions . checkNotNull ( ! Strings . isNullOrEmpty ( description ) , "Description is null or empty" ) ; TrackerOperationImpl po = new TrackerOperationImpl ( source . toUpperCase ( ) , description , this ) ; if ( saveTrackerOperation ( source , po ) ) { return po ; } return null ; }
target:  Creates tracker operation and save it to DB