How do you keep the machine awake?

Question

I have a piece of server-ish software written in Java to run on Windows and OS X. (It is not running on a server, but just a normal user's PC - something like a torrent client.) I would like the software to signal to the OS to keep the machine awake (prevent it from going into sleep mode) while it is active.

Of course I don't expect there to be a cross platform solution, but I would love to have some very minimal C programs/scripts that my app can spawn to inform the OS to stay awake.

Any ideas?

Solution 1

I use this code to keep my workstation from locking. It's currently only set to move the mouse once every minute, you could easily adjust it though.

It's a hack, not an elegant solution.

import java.awt.*;
import java.util.*;
public class Hal{

    public static void main(String[] args) throws Exception{
        Robot hal = new Robot();
        Random random = new Random();
        while(true){
            hal.delay(1000 * 60);
            int x = random.nextInt() % 640;
            int y = random.nextInt() % 480;
            hal.mouseMove(x,y);
        }
    }
}

Solution 2

On Windows, use the SystemParametersInfo function. It's a Swiss army-style function that lets you get/set all sorts of system settings.

To disable the screen shutting off, for instance:

SystemParametersInfo( SPI_SETPOWEROFFACTIVE, 0, NULL, 0 );

Just be sure to set it back when you're done...

Solution 3

Adding to scarcher2's code snippet above and moving mouse by only 1 pixel. I have moved the mouse twice so that some change occurs even if pointer is on extremes:

while(true){
            hal.delay(1000 * 30);       
            Point pObj = MouseInfo.getPointerInfo().getLocation();
            System.out.println(pObj.toString() + "x>>" + pObj.x + "  y>>" + pObj.y);
            hal.mouseMove(pObj.x + 1, pObj.y + 1);  
            hal.mouseMove(pObj.x - 1, pObj.y - 1);
            pObj = MouseInfo.getPointerInfo().getLocation();
            System.out.println(pObj.toString() + "x>>" + pObj.x + "  y>>" + pObj.y);
        }

Solution 4

I have a very brute-force technique of moving the mouse 1 point in the x direction and then back every 3 minutes.

There may me a more elegant solution but it's a quick fix.

Solution 5

Wouldn't all the suggestions moving the mouse back and forth drive the user crazy? I know I'd remove any app that would do that as soon as I can isolate it.

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