package ru.nestway.mysql;

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

public abstract class Database
{
  protected Connection connection;

  protected Database()
  {
    this.connection = null;
  }

  public abstract Connection openConnection()
    throws SQLException, ClassNotFoundException;

  public boolean checkConnection()
    throws SQLException
  {
    return (this.connection != null) && (!this.connection.isClosed());
  }

  public Connection getConnection()
  {
    return this.connection;
  }

  public boolean closeConnection()
    throws SQLException
  {
    if (this.connection == null) {
      return false;
    }
    this.connection.close();
    return true;
  }

  public ResultSet querySQL(String query)
    throws SQLException, ClassNotFoundException
  {
    if (!checkConnection()) {
      openConnection();
    }
    Statement statement = this.connection.createStatement();

    ResultSet result = statement.executeQuery(query);

    return result;
  }

  public int updateSQL(String query)
    throws SQLException, ClassNotFoundException
  {
    if (!checkConnection()) {
      openConnection();
    }
    Statement statement = this.connection.createStatement();

    int result = statement.executeUpdate(query);

    return result;
  }
}