I am working on a command called /home for players to teleport home after 30 seconds of not moving, if player moves, intermission is canceled. How do I check if player moved to cancel the teleportation?

 

My code so far.

 

package mod.cbultimate.stranded.command;//Created by CBU on 23/1/2017.

import net.minecraft.command.CommandBase;
import net.minecraft.command.CommandException;
import net.minecraft.command.ICommandSender;
import net.minecraft.server.MinecraftServer;

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

public class CommandHome extends CommandBase {
    private Timer timer = new Timer();
    private TimerTask cooldown;
    private TimerTask intermission;

    @Override
    public String getCommandName() {
        return "home";
    }

    @Override
    public String getCommandUsage(ICommandSender sender) {
        return "Return to your spawn location after 30 seconds. Moving may interupt the teleportation.";
    }

    @Override
    public void execute(MinecraftServer server, ICommandSender sender, String[] args) throws CommandException {
        intermission = new transmission();
        timer.schedule(intermission, 5000);
    }

    private class transmission extends TimerTask{
        @Override
        public void run() {
            System.out.println("Teleported.");
        }
    }
}

At the end of a player tick (

TickEvent.PlayerTickEvent

with

TickEvent.Phase.END

), the

Entity#prevPosX

/

Y

/

Z

fields will have different values to the

Entity#posX

/

y

/

z

fields if the player moved that tick. If

Entity#setPositionAndRotation

was used to directly set the player's position, the fields will have the same value as each other.

 

You should be using tick events rather than threads to schedule tasks. Minecraft is mostly single-threaded, so it's not safe to interact with normal classes from outside of the main client/server thread. Real time may not correspond directly to game ticks, especially if the server is lagging or paused. If a player schedules a teleport and then pauses the game, they wouldn't expect to be teleported while the game is paused.

 

You may want to use the Capabiltiy System to store the timer for each player.