How to fire events using Bukkit API?

Question

I was looking at how to create and fire events using Bukkit API.

public class PlayerDisconnect implements Listener {
    @EventHandler
    public void onQuit(PlayerQuitEvent event){
        //code
    }
}

I mean, doesn't matter the name of the method (in this case onQuit, I can use onDisconnect, onLeave, etc. and it will still be called by PlayerQuitEvent), it calls every method using PlayerQuitEvent as a parameter. I want to be able to replicate that behaviour.

Answer 1

You can create and call your own custom events using the Bukkit Event API. Spigot has a good starting tutorial on the Event API.

A simple example of a Cancellable event that takes a Player:

...
import org.bukkit.entity.Player;
import org.bukkit.event.Cancellable;
import org.bukkit.event.Event;
import org.bukkit.event.HandlerList;

public class MyCustomEvent extends Event implements Cancellable
{
    private static final HandlerList handlers = new HandlerList();

    private final Player player;
    private boolean cancelled;

    public MyCustomEvent(Player player)
    {
        this.player = player;
    }

    public static HandlerList getHandlerList()
    {
        return handlers;
    }

    public Player getPlayer()
    {
        return this.player;
    }

    public HandlerList getHandlers()
    {
        return handlers;
    }

    @Override
    public boolean isCancelled() 
    {
        return cancelled;
    }

    @Override
    public void setCancelled(boolean cancelled) 
    {
        this.cancelled = cancelled;
    }

}

Which you can then call elsewhere in your custom event like so

...
MyCustomEvent event = new MyCustomEvent(player);
Bukkit.getPluginManager().callEvent(event);
if (event.isCancelled())
    return;
...

Finally, you would listen for the event like you would any other event:

...
@EventHandler
public void onMyCustomEvent(MyCustomEvent event){
    Player player = event.getPlayer();
    ...
}