MapleInventoryIdentifier.java

package client.inventory;

import database.DatabaseConnection;
import java.io.Serializable;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.concurrent.atomic.AtomicInteger;

public class MapleInventoryIdentifier implements Serializable {

    private static final long serialVersionUID = 21830921831301L;
    private final AtomicInteger runningUID = new AtomicInteger(0);
    private static final MapleInventoryIdentifier instance = new MapleInventoryIdentifier();

    public static int getInstance() {
        return instance.getNextUniqueId();
    }

    public int getNextUniqueId() {
        if (this.runningUID.get() <= 0) {
            this.runningUID.set(initUID());
        } else {
            this.runningUID.set(this.runningUID.get() + 1);
        }
        return this.runningUID.get();
    }

    public int initUID() {
        int ret = 0;
        try {
            int[] ids = new int[5];
            Connection con = DatabaseConnection.getConnection();
            PreparedStatement ps = con.prepareStatement("SELECT MAX(uniqueid) FROM inventoryitems WHERE uniqueid > 0");
            ResultSet rs = ps.executeQuery();
            if (rs.next()) {
                ids[0] = (rs.getInt(1) + 1);
            }
            rs.close();
            ps.close();

            ps = con.prepareStatement("SELECT MAX(petid) FROM pets");
            rs = ps.executeQuery();
            if (rs.next()) {
                ids[1] = (rs.getInt(1) + 1);
            }
            rs.close();
            ps.close();

            ps = con.prepareStatement("SELECT MAX(ringid) FROM rings");
            rs = ps.executeQuery();
            if (rs.next()) {
                ids[2] = (rs.getInt(1) + 1);
            }
            rs.close();
            ps.close();

            ps = con.prepareStatement("SELECT MAX(partnerringid) FROM rings");
            rs = ps.executeQuery();
            if (rs.next()) {
                ids[3] = (rs.getInt(1) + 1);
            }
            rs.close();
            ps.close();

            for (int i = 0; i < ids.length; i++) {
                if (ids[i] > ret) {
                    ret = ids[i];
                }
            }
        } catch (SQLException e) {
             e.printStackTrace();
        }
         return ret;
    }
}