Java Threads

[wdell]

Originally Posted by Aaron V

Basically my main problem is that I need to pulse solenoids. It's simple to set it open or closed based on other input, but I don't know how to use time as an input. I figure I need threads because I don't want to stop everything else in the code.

Finally I've both seen the wait() function in the object class and the delay() function in the Timer class - I'm not sure which is better to use and which thread it effects.

How often are you trying to pulse the solenoids?

package edu.wpi.first.wpilibj.templates;

import edu.wpi.first.wpilibj.Solenoid;

public class Pulser implements Runnable {

    Solenoid firstSolenoid = new Solenoid(1);

    public void run() {
        while (true) {
            try {
                firstSolenoid.set(true);
                Thread.sleep(1000); // sleep thread for 1 second
                firstSolenoid.set(false);
                Thread.sleep(1000); // sleep thread for another second
            } catch (InterruptedException ex) {
                ex.printStackTrace();
            }
        }
    }
}

That will pulse the solenoid on for a second, then off for a second. The sleep() function causes the thread to wait (time in milliseconds).

wait() causes the thread to sleep until another thread issues a notify() or notifyAll() command. It doesn't set a specific time to wait for.

You might try replacing the sleep() function with Timer.delay(), I think that would get rid of the try..catch statements.

package edu.wpi.first.wpilibj.templates;

import edu.wpi.first.wpilibj.Solenoid;
import edu.wpi.first.wpilibj.Timer;

public class Pulser implements Runnable {

    Solenoid firstSolenoid = new Solenoid(1);

    public void run() {
        while (true) {
            firstSolenoid.set(true);
            Timer.delay(1);
            firstSolenoid.set(false);
            Timer.delay(1);

        }
    }
}

To start the thread, you need to tell it to start() somewhere in your main program:

Pulser pulser = new Pulser();
new Thread(pulser).start();