question: @ Override public void before ( PropertyInfoRestRep oldProps , PropertyInfoRestRep newProps ) { String newIntervalStr = newProps . getProperty ( BackupConstants . SCHEDULE_INTERVAL ) ; String newStartTimeStr = newProps . getProperty ( BackupConstants . SCHEDULE_TIME ) ; if ( ( newIntervalStr == null || newIntervalStr . isEmpty ( ) ) && ( newStartTimeStr == null || newStartTimeStr . isEmpty ( ) ) ) { _log . info ( "No changes in backup interval and start time" ) ; return ; } String intervalStr = ( newIntervalStr == null || newIntervalStr . isEmpty ( ) ) ? oldProps . getProperty ( BackupConstants . SCHEDULE_INTERVAL ) : newIntervalStr ; String startTimeStr = ( newStartTimeStr == null || newStartTimeStr . isEmpty ( ) ) ? oldProps . getProperty ( BackupConstants . SCHEDULE_TIME ) : newStartTimeStr ; _log . info ( "intervalStr={}, startTimeStr={}" , intervalStr , startTimeStr ) ; validateBackupIntervalAndStartTime ( intervalStr , startTimeStr ) ; }
target:  Check if backup related configurations conformed to rules, if not fail the property update.