question: private static final void rescheduleMissedAlarms ( ContentResolver cr , Context context , AlarmManagerInterface manager ) { long now = System . currentTimeMillis ( ) ; long ancient = now - DateUtils . DAY_IN_MILLIS ; String [ ] projection = new String [ ] { CalendarContract . CalendarAlerts . ALARM_TIME } ; if ( Build . VERSION . SDK_INT >= 23 && ContextCompat . checkSelfPermission ( context , Manifest . permission . READ_CALENDAR ) != PackageManager . PERMISSION_GRANTED ) { Log . d ( TAG , "Manifest.permission.READ_CALENDAR is not granted" ) ; return ; } Cursor cursor = cr . query ( CalendarAlerts . CONTENT_URI , projection , WHERE_RESCHEDULE_MISSED_ALARMS , ( new String [ ] { Long . toString ( now ) , Long . toString ( ancient ) , Long . toString ( now ) } ) , SORT_ORDER_ALARMTIME_ASC ) ; if ( cursor == null ) { return ; } if ( DEBUG ) { Log . d ( TAG , "missed alarms found: " + cursor . getCount ( ) ) ; } try { long alarmTime = - 1 ; while ( cursor . moveToNext ( ) ) { long newAlarmTime = cursor . getLong ( 0 ) ; if ( alarmTime != newAlarmTime ) { if ( DEBUG ) { Log . w ( TAG , "rescheduling missed alarm. alarmTime: " + newAlarmTime ) ; } AlertUtils . scheduleAlarm ( context , manager , newAlarmTime ) ; alarmTime = newAlarmTime ; } } } finally { cursor . close ( ) ; } }
target:  Searches the CalendarAlerts table for alarms that should have fired but have not and then reschedules them. This method can be called at boot time to restore alarms that may have been lost due to a phone reboot.