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 {
    static <mainclass> plugin;
    public TPS(<mainclass> plugin) {
        TPS.plugin = plugin;
    }

    public int tps = 0;
    public long second = 0;

    public float getServerTPS() {
        return tps;
    }

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

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