Minecraft Bukkit Plugin, runTask(Plugin plugin)

Question

i try to make a minecraft plugin with bukkit and i will try to change the time every 500ms but when i start that in the main thread, the server crashes. So i tried the runTask(); function but i do not know where i can find the parameter Plugin, because it says it needs runTask(Plugin plugin);. Here is my code:

dayNight file:

import org.bukkit.Bukkit;
import org.bukkit.World;
import org.bukkit.command.Command;
import org.bukkit.command.CommandExecutor;
import org.bukkit.command.CommandSender;
import org.bukkit.plugin.Plugin;
import org.bukkit.scheduler.BukkitTask;
import org.bukkit.plugin.java.JavaPlugin;

public class dayNight implements CommandExecutor
{

    public void sleep(int time)
    {
        try
        {
            Thread.sleep(time);
        }
        catch (InterruptedException e)
        {
            throw new RuntimeException(e);
        }
    }

    public static void changeTimeEvent(CommandSender sender, int time)
    {
        sender.getServer().getWorld("world").setTime(time);
    }

    @Override
    public boolean onCommand(CommandSender sender, Command command, String label, String[] args)
    {
        Plugin plugin;
        new dayNightTask().runTask(plugin);

and the dayNightTask file:

import org.bukkit.Bukkit;
import org.bukkit.World;
import org.bukkit.scheduler.BukkitRunnable;

public class dayNightTask extends BukkitRunnable
{

    public void sleep(int time)
    {
        try
        {
            Thread.sleep(time);
        }
        catch (InterruptedException e)
        {
            throw new RuntimeException(e);
        }
    }

    @Override
    public void run()
    {
        World world = Bukkit.getWorld("world");
        for (int i = 0; i < 500000; i++)
        {
            world.setTime(0);
            sleep(500);
            world.setTime(16000);
            sleep(500);
        }
    }
}

I do not know how i can find the plugin parameter for the runTask(); function, please help :) best regards

Answer 1

Spigot include own timer task. You should NEVER use Thread.sleep() on spigot, and less in main thread. Here you are just totally blocking the main thread.

You should use Bukkit.getScheduler().

1. Use Runnable instead of BukkitRunnable

2. Use method showed in documentation. In your case, runTaskLater should answer

3. Finally, this is what you will have in your dayNightTask class:

public class dayNightTask implements Runnable {

    @Override
    public void run() {
        World world = Bukkit.getWorld("world");
        for (int i = 0; i < 500000; i++) {
            world.setTime(0);
            Bukkit.getScheduler().runTaskLater(MyPlugin.getInstance(), () ->  world.setTime(16000), 10);
        }
    }
}

10 is in tick. 20 ticks = 1 second, if you want each 0.5 second, you want each 10 ticks.

Now, in your command, you should use :

Bukkit.getScheduler().runTaskTimer(plugin, new dayNightTask(), delay);

PS: The plugin instance should the object of the class that extends JavaPlugin. Such as said in documentation (Eclipse, Intellij Idea ...) you should have a class that extendds JavaPlugin.

You should save the instance of this, you can do this in 2 ways:

1. Pass object into constructor, for example: new dayNight(this) then in the constructor, do :

private JavaPlugin plugin;

public dayNight(JavaPlugin pl) {
   this.plugin = pl;
}

2. Create a static class :

// declare object and method
private static JavaPlugin instance;
public static JavaPlugin getInstance() {
   return instance;
}

@Override
public void onEnable() { // this class should already exist
   instance = this; // set instance as current object
}

Answer 2

You can try using Executors in java. They're asynchron and easy to use.

https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/Executors.html