How to time an action in teleop without delaying teleop.

[SamCarlberg]

You can use java.util.Timer and java.util.TimerTask to schedule something to happen in the future while your program still runs.

// local or class variables
final int solenoidDelay = 65; // milliseconds
final Timer myTimer = new Timer();
final TimerTask closeSolenoidTask = new TimerTask() {

    @Override
    public void run() {
        closeSolenoid();
    }
};

...

mySolenoid.open();
myTimer.schedule(closeSolenoidTask, solenoidDelay);

[Ben Wolsieffer]

Originally Posted by SamCarlberg

You can use java.util.Timer and java.util.TimerTask to schedule something to happen in the future while your program still runs.

This method would work in this case (assuming the Solenoid methods are thread-safe), but I would be worried about possible race conditions if more complicated logic were to later be added in the TimerTask.

Also: Hi Sam!

[SamCarlberg]

Originally Posted by lopsided98

This method would work in this case (assuming the Solenoid methods are thread-safe), but I would be worried about possible race conditions if more complicated logic were to later be added in the TimerTask.

Also: Hi Sam!

Hey Ben!

Solenoid methods are thread-safe. I'd be more worried about scheduling a close, doing some stuff, then opening the solenoid (and expecting it to stay open) before the scheduled close happens. In this case, the methods for opening/closing the solenoid should have checks to see if it's been claimed by a different call.

private boolean claimed = false;

public void openSolenoid() {
    if (!claimed) {
        claimed = true;
        // open it
    }
}

public void closeSolenoid() {
    if (claimed) {
        claimed = false;
        // close it
    }
}

But I don't think it's a problem for something this simple.

[origamitaco]

Definitely need to switch to command-based robot and don't forget to use requires(); with your commands and subsystems, otherwise your whole robot will still pause. WPIlib documentation should be able to take it from there.

[JesseK]

Originally Posted by SamCarlberg

Hey Ben!

Solenoid methods are thread-safe. I'd be more worried about scheduling a close, doing some stuff, then opening the solenoid (and expecting it to stay open) before the scheduled close happens. In this case, the methods for opening/closing the solenoid should have checks to see if it's been claimed by a different call.


But I don't think it's a problem for something this simple.

It can be solved by limiting the exposure of the solenoid to a class that governs the entire mechanism, then by calling TimerTask.cancel() to eliminate the auto-close when the mechanism is told to do something different.