JDBCSingleton.java

package com.wildcodeschool.wildmail;

import java.sql.*;

public class JDBCSingleton {

    public static final String DATABASE_URL = "jdbc:mysql://localhost:3306/wild_mail?serverTimezone=Europe/Paris";
    public static final String MYSQL_USER = "wildadmin";
    public static final String MYSQL_PASSWORD = "w1ld$fun";

    private JDBCSingleton() {}

    private static JDBCSingleton instance = null;
    private Connection connection = null;

    public static JDBCSingleton getInstance() {

        if (instance == null) {
            instance = new JDBCSingleton();
        }
        return instance;
    }

    public Connection getConnection() throws SQLException {

        if (connection == null || connection.isClosed()) {
            connection = DriverManager.getConnection(DATABASE_URL, MYSQL_USER, MYSQL_PASSWORD);
        }

        return connection;
    }

    public ResultSet executeQuery(String request) throws SQLException {

        PreparedStatement statement = connection.prepareStatement(request);
        ResultSet resultSet = statement.executeQuery();

        return resultSet;
    }
}