import javax.swing.*;
import java.sql.*;
 
public class Database {
 
    private Connection connection;
    private static String databaseName = "";
    private static String databaseUsername = "";
    private static String databasePassword = "";
    private static String driver = "com.mysql.jdbc.Driver";
 
    public Connection getConnection() {
        createConnection();
        return connection;
    }
 
    public void createConnection() {
        if (connection == null) {
            try {
                Class.forName(driver);
                String url = "jdbc:mysql://localhost/" + databaseName;
 
                connection = DriverManager.getConnection(
                        url, databaseUsername, databasePassword);
 
            } catch (Exception e) {
                JOptionPane.showMessageDialog(new JFrame(),
                        "Database connection could not be established." +
                        "Please check your network connection and restart.",
                        "Error Message", JOptionPane.ERROR_MESSAGE);
                e.printStackTrace();
                connection = null;
            }
        }
    }
}