question: public void storeDevice ( Device d ) { if ( ! isMaster ) return ; if ( d == null ) return ; long now = System . nanoTime ( ) ; writeUpdatedDeviceToStorage ( d ) ; lastWriteTimes . put ( d . getDeviceKey ( ) , now ) ; }
target:  Write the given device to storage if we are MASTER. Use this method if the device has significantly changed (e.g., new AP, new IP, entities removed).