question: private void updateCommandCache ( String group , String command , boolean needNotify ) { String oldCommand = commandCache . get ( group ) ; if ( ! command . equals ( oldCommand ) ) { commandCache . put ( group , command ) ; if ( needNotify ) { notifyExecutor . execute ( new NotifyCommand ( group , command ) ) ; LoggerUtil . info ( String . format ( "command data change: group=%s, command=%s: " , group , command ) ) ; } } else { LoggerUtil . info ( String . format ( "command data not change: group=%s, command=%s: " , group , command ) ) ; } }
target:  update command cache of the group. update local cache when command changed, if need notify, notify command