Sleep until a certian time of day

[dcnorman07]

I have a script that I want to run constantly, except between the hours of 11:00 pm and 6 a.m. During those times, I want the script to sleep...

The way it is now, it checks the Hour at the beginning of each iteration and if it is not between 23 and 6, then it runs as normal, but if the Hour is between 23 and 6, it sleeps for one hour and checks again every hour until the time is not between 23 and 6, then resumes...

I can't have it check too often because there are only so many iterations it runs through until it will stop, and then I re-start it manually (basically so I can see the progress).

I am wanting this to be more precise...

Is there a way instead of saying:

sleep(3600);

to somehow tell it to sleep until 6 am, and then resume? :confused:


A condensed version of what I have looks like this:

public void testMain(Object[] args) 

            {
                        Object[] objdataToPass = new Object[1];
                        objdataToPass[0] = new Integer(1);
                        int error_tally = 0;
                        for (int i = 0; i < 1000; i++)
                        {
                           Date date = new Date();
      SimpleDateFormat formatter = new SimpleDateFormat("k"); // hour 1-24
                    String time = formatter.format(date);
                    int hour = Integer.parseInt(time);
                                    if (
                                           // Current time is after 6 AM
                                           hour >= 6
                                           &&
                                           // Current time is before 11 PM
                                           hour <= 23
                                    )
                                           {
                                                ***Run Script Here***
                                           }            
             
                                      else
                                           {
                                              sleep(3600);
                                            }

Any help on getting this thing to sleep between 11 pm and 6 am would be greatly appreciated.

Thank you!

[masijade]

Take a look at Java.util.Timer and TimerTask. Design a TimerTask that does nothing but send a notify(). Place that in a Timer for a specific time then sync on the object that should get the notify and wait() on it.

[dcnorman07]

Could you give me an example.?

I'm not sure I quite understand how to do that.... :eek:

[Norm]

Can you compute the number of millisecs from the current time to the time you want to wakeup and sleep for that duration.
Create some kind of date object for when you want to wakeup and get out its time as long.

[Supamagier]

System.currentTimeMillis() to get the ms.

[Norm]

That's the current time. How do you get the ms for 6AM tomorrow morning?

[dcnorman07]

That's the current time. How do you get the ms for 6AM tomorrow morning?

Norm is on to something there, if I could get the number ms until 6AM from the time it enters the sleep, that would be PERFECT!

The reason being, is that it's not always going to be exactly 11PM when the script reaches the sleep, it could be anywhere up to 11:25PM...I just don't want it to begin the loop again after 11PM, so if I could somehow calculate the number of ms until 6AM from the time it reaches the sleep, then viola! :D

[Norm]

So start looking at the various classes that will create some kind of date object, like Calendar. There'll be a method you can call to get its time in ms. Then subtract off the current time in ms.

[masijade]

import java.util.Date;
import java.util.Timer;
import java.util.TimerTask;

...

    public void waitUntil(Date date) {
        final Object o = new Object();
        TimerTask tt = new TimerTask() {
            public void run() {
                synchronized (o) {
                    o.notify();
                }
            }
        };
        Timer t = new Timer();
        t.schedule(tt, date);
        synchronized(o) {
            try {
                o.wait();
            } catch (InterruptedException ie) {}
        }
        t.cancel();
        t.purge();
    }

...

[Norm]

masijade:
How do you get the Date object for the wakeup time?

[masijade]

Make one. It is simply a method to call with the date that he wants to wake as a parameter. I would assume that he would be calling it programmatically. Truth be told, I would put the time in a properties file and create the date using the current date (+1 if the time is before the current time) and the time in the properties file. I would also put an "earliest time to be called" in the same properties file, and after each "processing round" check to see if the time is equal to or after that time and then call the method using the other. In that way it is completely flexible as to the "stop" and "start" times.

[masijade]

Here is a complete implemetation (untested):

// Properties File
stopHour=11
startHour=6

package bogustest;

import java.io.IOException;
import java.io.InputStream;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.Properties;
import java.util.Timer;
import java.util.TimerTask;

public class NewClass {

    private int stopHour;
    private int startHour;
    private Timer timer = new Timer(true);  // Create just one and make it a daemon thread.

    public void readProperties() {
        Properties props = new Properties();
        InputStream is = null;

        try {
            is = getClass().getResourceAsStream("propertiesFileName");
            props.load(is);
        } catch (IOException ioe) {
            ioe.printStackTrace();
        } finally {
            if (is != null) try { is.close(); } catch (IOException ioe) {}
        }

        if (props.entrySet().size() != 2) {
            System.err.println("Not all Properties Defined.");
            System.exit(1);
        } else {
            stopHour = Integer.valueOf(props.getProperty("stopHour"));
            startHour = Integer.valueOf(props.getProperty("startHour"));
        }
    }

    public void checkTime() {
        GregorianCalendar gc = new GregorianCalendar();
        int currentHour = gc.get(Calendar.HOUR_OF_DAY);

        if (currentHour >= stopHour) {
            if (currentHour >= startHour) {
                gc.add(Calendar.DAY_OF_MONTH, 1);
            }
            gc.set(Calendar.HOUR_OF_DAY, startHour);
            gc.set(Calendar.MINUTE, 0);
            gc.set(Calendar.SECOND, 0);
            gc.set(Calendar.MILLISECOND, 0);
            waitUntil(gc.getTime());
        }
    }

    public void process() {
        while (true) {
            // run script here
            checkTime();
        }
    }

    public static void main(String[] args) {
        (new NewClass()).process();
    }

    public void waitUntil(Date date) {
        final Object o = new Object();
        TimerTask tt = new TimerTask() {
            public void run() {
                synchronized (o) {
                    o.notify();
                }
            }
        };
        timer.schedule(tt, date);
        synchronized(o) {
            try {
                o.wait();
            } catch (InterruptedException ie) {}
        }
        timer.cancel();
        timer.purge();
        readProperties();
    }
}

Edit Again!: Oops, it should be currentTime >= startTime not <= (already corrected).

Also, because waitUntil calls readProperties again, at the end of it, you can change the start and stop times while the program is in wait mode, and the next time it needs to wait it will use those new times.

[joostdiet]

This is the most simple solution i could think of...
set hours minutes secs on gregorian calendartime.

        int hours = 21;
        int minutes = 0;
        int seconds = 0;

        Calendar calendar = new GregorianCalendar();
        long curTime = calendar.getTimeInMillis();

        Calendar calendarTime = new GregorianCalendar();
        calendarTime.set(calendar.get(calendar.YEAR), calendar.get(calendar.MONTH), calendar.get(calendar.DATE), hours, minutes, seconds);
        if (calendar.get(calendar.HOUR_OF_DAY) > hours-1){
            calendarTime.add(calendar.get(calendar.DAY_OF_MONTH), +1);
        }
        calendarTime.getTimeInMillis();
        long nextRunTime = calendarTime.getTimeInMillis();
        
        long waitTime = nextRunTime - curTime;