Please Help!

package me.karatechimp29.bukkit;

import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.Material;
import org.bukkit.command.Command;
import org.bukkit.command.CommandSender;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.inventory.Inventory;
import org.bukkit.inventory.ItemStack;
import org.bukkit.inventory.meta.ItemMeta;
import org.bukkit.plugin.java.JavaPlugin;

public class Main extends JavaPlugin implements Listener{

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

	private void openGUI(Player player)
	{
		Inventory inv = Bukkit.createInventory(null, 9, ChatColor.GOLD + "Voting Menu");

		ItemStack Link1 = new ItemStack(Material.DIAMOND);
		ItemMeta Link1Meta = Link1.getItemMeta();
		ItemStack Link2 = new ItemStack(Material.DIAMOND);
		ItemMeta Link2Meta = Link1.getItemMeta();

		Link1Meta.setDisplayName(ChatColor.YELLOW + "Vote #1");
		Link1.setItemMeta(Link1Meta);
		Link2Meta.setDisplayName(ChatColor.YELLOW + "Vote #2");
		Link2.setItemMeta(Link2Meta);

		inv.setItem(1, Link1);
		inv.setItem(2, Link1);

		player.openInventory(inv);
	}

	public boolean onCommand(CommandSender sender, Command cmd, String label, String[] args)
	{
		if(cmd.getName().equalsIgnoreCase("vote")){
			if(sender instanceof Player)
			{
				this.openGUI(<player>);
				 //TODO: Fix Syntax Error, "openGUI(<player>);"
			}
		}

		return false;
	}

}