Run scheduled task everyday at midnight

How would I go about doing this?

I considered setting an hourly task and checking if the current hour is 0 using Calendar.HOUR_OF_DAY, but that seems a bit hacky.

 

You could schedule a repeating task with the initial delay the time until midnight then the second delay being one day

 

I do this exact thing with one of my loggers.

 

Code:java

Calendar midnight = Calendar.getInstance();
midnight.set(Calendar.HOUR_OF_DAY, 0);
midnight.set(Calendar.MINUTE, 0);
midnight.set(Calendar.SECOND, 0);
midnight.set(Calendar.MILLISECOND, 1);
midnight.set(Calendar.DAY_OF_YEAR, midnight.get(Calendar.DAY_OF_YEAR) + 1);
long tillMidnight = midnight.getTimeInMillis() - System.currentTimeMillis() - 1;
long ticksTillMidnight = tillMidnight / 50;

 

CorrieKay Well at least I'm not the only one XD

So that as the initial delay, then 20*60*60*24 as the repeating time?

Pretty clever.

 

Yes

Ty :3

 

Clever, yes, but i dont see it working. It works by ticks, which can be affected by lag. The more lag you get, the farther an farther it gets off course.

 

That's a good point. Hrm. If the server ran for too long it would be pretty far off after a while.

 

You could also schedule a repeating task that takes a portion of the 24 hours, and will recalculate the remaining time when called. Or recalculate the time at each midnight

 

You'd still have to account for the 24 hours between each firing of the event.

Lets say you took 1.1 seconds to fire 20 ticks, instead of 1 second to fire 20 ticks. After an hour, youre suddenly six minutes late. After 24 hours, when it should fire, youre suddnly (if my math is correct) almost two and a half hours late.

You would reach this discrepancy with just .1 second of lag. Thats 20 ticks in the time it would take 22 ticks. Its a little extreme, but its not unrealistic, and creates such a huge discrepancy of time. Two and a half hours is a HUGE amount of time to miss :\

 

In that case you should store the starting time somewhere (I assume you start at midnight to keep things a bit easy) and use a repeating task to check each x amount of seconds (x depends on how precise you want it). Pseudo

Code:

main: // ignored
  x = System.currentTimeMillis()
  goto wait
execute:
  // do stuff
  dif = System.currentTimeMillis() - x - millis in day
  x = System.currentTimeMillis() - dif
wait:
  time = System.currentTimeMillis()
  if time - x > millis in day
    goto execute
  else
    goto wait

 

Why are you making the last sentence (tillMidnight / 50), mustn't it be tillMidnight * 0.02 (20/1000)?

 

1 / 50 = 0.02

So it's the same.

 

O.O xD ok, I accept your answer... [facepalm]