Events

All events live in io.github.robie.projectone.api.event and are fired on the thread that owns the affected region.

Event	Cancellable	Fired when
ProjectOnePreCountEvent	Yes	Before a player's count changes
ProjectOneCountEvent	No	After the count has changed
ProjectOneReloadEvent	No	After configuration reloads

The Pre / past-tense split is worth copying: a cancellable event before the change and an informational one after it removes the ambiguity of "can I still stop this?".

Listening

import org.bukkit.event.EventHandler;
import org.bukkit.event.EventPriority;
import org.bukkit.event.Listener;

public final class CountListener implements Listener {

    @EventHandler(priority = EventPriority.NORMAL, ignoreCancelled = true)
    public void onPreCount(ProjectOnePreCountEvent event) {
        if (event.getNewCount() > 100) {
            event.setCancelled(true);
        }
    }
}

Register it in onEnable:

getServer().getPluginManager().registerEvents(new CountListener(), this);

Priorities

Use MONITOR only to observe, never to change anything — by then other plugins have decided the outcome. Set ignoreCancelled = true unless you specifically want to see cancelled events.

Threading

Listeners run on the region thread that owns the event's location. Do not block: no database queries, no HTTP calls, no Thread.sleep. Hand work off with the async scheduler and come back to the region thread to apply results.

Do not assume the main thread

Bukkit.isPrimaryThread() is not a useful check on Folia. If your listener needs to touch a different region than the event's, schedule to that region explicitly.