plugin.yml

name: PrivateBrewingStand
version: 1.0
main: com.bringholm.privatebrewingstand.PrivateBrewingStand
author: AlvinB

PrivateBrewingStand.java

package com.bringholm.privatebrewingstand;

import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.inventory.InventoryOpenEvent;
import org.bukkit.inventory.BrewerInventory;
import org.bukkit.plugin.java.JavaPlugin;

public class PrivateBrewingStand extends JavaPlugin implements Listener {

    @Override
    public void onEnable() {
        this.getServer().getPluginManager().registerEvents(this, this);
    }

    @EventHandler
    public void onInventoryOpen(InventoryOpenEvent e) {
        if (e.getInventory() instanceof BrewerInventory) {
            // By the time this event is fired the player
            // has already been added as a viewer, so we
            // check if there are more than 1 player
            // in the list.
            if (e.getViewers().size() > 1) {
                e.setCancelled(true);
            }
        }
    }
}