KDRPlugin

package me.Mrjoecool234.kdr;

import java.text.DecimalFormat;
import java.text.NumberFormat;

import org.bukkit.ChatColor;
import org.bukkit.entity.EntityType;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.EventPriority;
import org.bukkit.event.Listener;
import org.bukkit.event.entity.PlayerDeathEvent;
import org.bukkit.event.player.AsyncPlayerChatEvent;
import org.bukkit.event.player.PlayerJoinEvent;

public class KDR implements Listener {
    KDRMain plugin;

    public KDR(KDRMain instance) {
    plugin = instance;
    }


    @EventHandler
    public void Kills(PlayerDeathEvent event){
        if (event.getEntityType() == EntityType.PLAYER) {
        Player player = event.getEntity();
        Player killer = event.getEntity().getKiller();
        String playername = player.getName();
        if(killer instanceof Player){
            plugin.getConfig().set(killer.getName() + ".kills", plugin.getConfig().getDouble(killer.getName() + ".kills") + 1);
        }
        if(player instanceof Player){
            plugin.getConfig().set(playername + ".deaths", plugin.getConfig().getDouble(playername + ".deaths") + 1);
            }
        }
     }
     @EventHandler(priority = EventPriority.HIGHEST)
     public void Chat(AsyncPlayerChatEvent event){
        double kdr = plugin.getConfig().getDouble(event.getPlayer().getName() + ".kills") / plugin.getConfig().getDouble(event.getPlayer().getName() + ".deaths");
        DecimalFormat df = new DecimalFormat("#.##");
        event.setFormat(ChatColor.GREEN + "[" + ChatColor.DARK_GRAY + df.format(kdr) + ChatColor.GREEN + "] " + "%s : %s");
     }

}