Get TPS Rate of Bukkit Server

package ;

import org.bukkit.Bukkit;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.server.PluginEnableEvent;

/*
 *
 * @author KeybordPiano459
 */
public class TPS implements Listener {
    public TPS(Plugin plugin) {
        this.plugin = plugin;
    }

    public int tps = 0;
    public long sec = 0;

    public float getServerTPS() {
        return tps;
    }

    @EventHandler
    public void onPluginEnable(PluginEnableEvent event) {
        if (event.getPlugin() == plugin) {
            Bukkit.getServer().getScheduler().scheduleSyncRepeatingTask(plugin, new Runnable() {
                long seconds;
                int ticks;

                @Override
                public void run() {
                    seconds = System.currentTimeMillis() / 1000;
                    if (sec == seconds) ticks++;
                    else {
                        sec = seconds;
                        tps = tps == 0 ? ticks : (tps + ticks) / 2;
                        ticks = 0;
                    }
                }
            }, 20, 1);
        }
    }
}