import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class CoreMySQL {

	private static final String host = "localhost";
	private static final int port = 3306;
	private static final String database = "database";
	private static final String username = "root";
	private static final String password = "root";
	private Connection connection;

	public void openConnection() throws SQLException, ClassNotFoundException {
		if (connection != null && !connection.isClosed()) {
			return;
		}

		synchronized (this) {
			if (connection != null && !connection.isClosed()) {
				return;
			}
			Class.forName("com.mysql.jdbc.Driver");
			connection = DriverManager.getConnection("jdbc:mysql://" + host + ":" + port + "/" + database + "?autoReconnect=true", username, password);

		}
	}

	public ResultSet execute(String s) {
		if (connection == null) {
			try {
				openConnection();
			} catch (ClassNotFoundException | SQLException e) {
				e.printStackTrace();
			}
		}
		try {
			Statement statement = connection.createStatement();
			return statement.executeQuery(s);
		} catch (SQLException e) {
			e.printStackTrace();
			try {
				connection.close();
			} catch (SQLException e1) {
				e1.printStackTrace();
			}
			connection = null;
			try {
				openConnection();
			} catch (ClassNotFoundException | SQLException e1) {
				e1.printStackTrace();
			}
			try {
				Statement statement = connection.createStatement();
				return statement.executeQuery(s);
			} catch (SQLException e1) {
				e1.printStackTrace();
			}
		}
		return null;
	}

	public int executeUpdate(String string) {
		if (connection == null) {
			try {
				openConnection();
			} catch (ClassNotFoundException | SQLException e) {
				e.printStackTrace();
			}
		}
		try {
			return connection.createStatement().executeUpdate(string);
		} catch (SQLException e) {
			e.printStackTrace();
			try {
				connection.close();
			} catch (SQLException e1) {
				e1.printStackTrace();
			}
			connection = null;
			try {
				openConnection();
			} catch (ClassNotFoundException | SQLException e1) {
				e1.printStackTrace();
			}
			try {
				return connection.createStatement().executeUpdate(string);
			} catch (SQLException e1) {
				e1.printStackTrace();
			}
		}
		return -1;
	}

}