package com.alexnevsky.hotel.dao;
import static com.alexnevsky.hotel.dao.DAOUtil.close;
import static com.alexnevsky.hotel.dao.DAOUtil.prepareStatement;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import com.alexnevsky.hotel.dao.exception.DAOException;
import com.alexnevsky.hotel.model.Admin;
/**
* This class represents a SQL Database Access Object for the {@link Admin} DTO.
* This DAO should be used as a central point for the mapping between the Admin
* DTO and a SQL database.
*
* @version 1.0 15.05.2011
* @author Alex Nevsky
*/
public final class AdminDAO {
// Constants ---------------------------------------------------------------
private static final String SQL_FIND_BY_ID = "SELECT `id`, `login`, `password` FROM `Admin` WHERE `id` = ?";
private static final String SQL_FIND_BY_LOGIN_AND_PASSWORD = "SELECT `id`, `login`, `password` FROM `Admin` WHERE `login` = ? AND `password` = ?";
private static final String SQL_LIST_ORDER_BY_ID = "SELECT `id`, `login`, `password` FROM `Admin` ORDER BY `id`";
private static final String SQL_INSERT = "INSERT INTO `Admin` (`login`, `password`) VALUES (?, ?)";
private static final String SQL_UPDATE = "UPDATE `Admin` SET `login` = ?, `password` = ? WHERE `id` = ?";
private static final String SQL_DELETE = "DELETE FROM `Admin` WHERE `id` = ?";
private static final String SQL_EXIST_LOGIN = "SELECT `id` FROM `Admin` WHERE `login` = ?";
private static final String SQL_EXIST_LOGIN_AND_PASSWORD = "SELECT `id` FROM `Admin` WHERE `login` = ? AND `password` = ?";
// Vars --------------------------------------------------------------------
private AbstractDAOFactory daoFactory;
// Constructors ------------------------------------------------------------
/**
* Construct an Admin DAO for the given AbstractDAOFactory. Package private
* so that it can be constructed inside the DAO package only.
*
* @param daoFactory
* The AbstractDAOFactory to construct this Admin DAO for.
*/
AdminDAO(AbstractDAOFactory daoFactory) {
this.daoFactory = daoFactory;
}
// Actions -----------------------------------------------------------------
/**
* Returns the Admin from the database matching the given ID, otherwise null.
*
* @param id
* The ID of the Admin to be returned.
* @return The Admin from the database matching the given ID, otherwise null.
* @throws DAOException
* If something fails at database level.
*/
public Admin find(Long id) throws DAOException {
return this.find(SQL_FIND_BY_ID, id);
}
/**
* Returns the Admin from the database matching the given login and
* password, otherwise null.
*
* @param login
* The login of the Admin to be returned.
* @param password
* The password of the Admin to be returned.
* @return The Admin from the database matching the given login and
* password, otherwise null.
* @throws DAOException
* If something fails at database level.
*/
public Admin find(String login, String password) throws DAOException {
return this.find(SQL_FIND_BY_LOGIN_AND_PASSWORD, login, hashCodeIfNecessary(password));
}
/**
* Returns the Admin from the database matching the given SQL query with the
* given values.
*
* @param sql
* The SQL query to be executed in the database.
* @param values
* The PreparedStatement values to be set.
* @return The Admin from the database matching the given SQL query with the
* given values.
* @throws DAOException
* If something fails at database level.
*/
private Admin find(String sql, Object... values) throws DAOException {
Connection connection = null;
PreparedStatement preparedStatement = null;
ResultSet resultSet = null;
Admin admin = null;
try {
connection = this.daoFactory.getConnection();
preparedStatement = prepareStatement(connection, sql, false, values);
resultSet = preparedStatement.executeQuery();
if (resultSet.next()) {
admin = mapAdmin(resultSet);
}
} catch (SQLException e) {
throw new DAOException(e);
} finally {
close(connection, preparedStatement, resultSet);
}
return admin;
}
/**
* Returns a list of all users from the database ordered by Admin ID. The
* list is never null and is empty when the database does not contain any Admin.
*
* @return A list of all users from the database ordered by Admin ID.
* @throws DAOException
* If something fails at database level.
*/
public List<Admin> list() throws DAOException {
Connection connection = null;
PreparedStatement preparedStatement = null;
ResultSet resultSet = null;
List<Admin> users = new ArrayList<Admin>();
try {
connection = this.daoFactory.getConnection();
preparedStatement = connection.prepareStatement(SQL_LIST_ORDER_BY_ID);
resultSet = preparedStatement.executeQuery();
while (resultSet.next()) {
users.add(mapAdmin(resultSet));
}
} catch (SQLException e) {
throw new DAOException(e);
} finally {
close(connection, preparedStatement, resultSet);
}
return users;
}
/**
* Create the given Admin in the database. The Admin ID must be null,
* otherwise it will throw IllegalArgumentException. If the Admin ID value is
* unknown, rather use {@link #save(Admin)}.
* After creating, the DAO will set the obtained ID in the given Admin.
*
* @param admin
* The Admin to be created in the database.
* @throws IllegalArgumentException
* If the Admin ID is not null.
* @throws DAOException
* If something fails at database level.
*/
public void create(Admin admin) throws IllegalArgumentException, DAOException {
if (admin.getId() != null) {
throw new IllegalArgumentException("Admin is already created, the Admin ID is not null.");
}
Object[] values = { admin.getLogin(), hashCodeIfNecessary(admin.getPassword()) };
Connection connection = null;
PreparedStatement preparedStatement = null;
ResultSet generatedKeys = null;
try {
connection = this.daoFactory.getConnection();
preparedStatement = prepareStatement(connection, SQL_INSERT, true, values);
int affectedRows = preparedStatement.executeUpdate();
if (affectedRows == 0) {
throw new DAOException("Creating Admin failed, no rows affected.");
}
generatedKeys = preparedStatement.getGeneratedKeys();
if (generatedKeys.next()) {
admin.setId(generatedKeys.getLong(1));
} else {
throw new DAOException("Creating Admin failed, no generated key obtained.");
}
} catch (SQLException e) {
throw new DAOException(e);
} finally {
close(connection, preparedStatement, generatedKeys);
}
}
/**
* Update the given Admin in the database. The Admin ID must not be null,
* otherwise it will throw IllegalArgumentException. If the Admin ID value is
* unknown, rather use {@link #save(Admin)}.
*
* @param admin
* The Admin to be updated in the database.
* @throws IllegalArgumentException
* If the Admin ID is null.
* @throws DAOException
* If something fails at database level.
*/
public void update(Admin admin) throws DAOException {
if (admin.getId() == null) {
throw new IllegalArgumentException("Admin is not created yet, the Admin ID is null.");
}
Object[] values = { admin.getLogin(), hashCodeIfNecessary(admin.getPassword()), admin.getId() };
Connection connection = null;
PreparedStatement preparedStatement = null;
try {
connection = this.daoFactory.getConnection();
preparedStatement = prepareStatement(connection, SQL_UPDATE, false, values);
int affectedRows = preparedStatement.executeUpdate();
if (affectedRows == 0) {
throw new DAOException("Updating Admin failed, no rows affected.");
}
} catch (SQLException e) {
throw new DAOException(e);
} finally {
close(connection, preparedStatement);
}
}
/**
* Save the given Admin in the database. If the Admin ID is null, then it will
* invoke {@link #create(Admin)}, else it will invoke {@link #update(Admin)}.
*
* @param admin
* The Admin to be saved in the database.
* @throws DAOException
* If something fails at database level.
*/
public void save(Admin admin) throws DAOException {
if (admin.getId() == null) {
this.create(admin);
} else {
this.update(admin);
}
}
/**
* Delete the given Admin from the database. After deleting, the DAO will set
* the ID of the given Admin to null.
*
* @param admin
* The Admin to be deleted from the database.
* @throws DAOException
* If something fails at database level.
*/
public void delete(Admin admin) throws DAOException {
Object[] values = { admin.getId() };
Connection connection = null;
PreparedStatement preparedStatement = null;
try {
connection = this.daoFactory.getConnection();
preparedStatement = prepareStatement(connection, SQL_DELETE, false, values);
int affectedRows = preparedStatement.executeUpdate();
if (affectedRows == 0) {
throw new DAOException("Deleting admin failed, no rows affected.");
} else {
admin.setId(null);
}
} catch (SQLException e) {
throw new DAOException(e);
} finally {
close(connection, preparedStatement);
}
}
/**
* Returns true if the given login exist in the database.
*
* @param login
* The login which is to be checked in the database.
* @return True if the given login exist in the database.
* @throws DAOException
* If something fails at database level.
*/
public boolean existAdminLogin(String login) throws DAOException {
return this.exist(SQL_EXIST_LOGIN, login);
}
/**
* Returns true if the given login and password exist in the database.
*
* @param login
* The login which is to be checked in the database.
* @param password
* The password which is to be checked in the database.
* @return True if the given login exist in the database.
* @throws DAOException
* If something fails at database level.
*/
public boolean existAdmin(String login, String password) throws DAOException {
return this.exist(SQL_EXIST_LOGIN_AND_PASSWORD, login, hashCodeIfNecessary(password));
}
/**
* Returns true if the given SQL query with the given values returns at
* least one row.
*
* @param sql
* The SQL query to be executed in the database.
* @param values
* The PreparedStatement values to be set.
* @return True if the given SQL query with the given values returns at
* least one row.
* @throws DAOException
* If something fails at database level.
*/
private boolean exist(String sql, Object... values) throws DAOException {
Connection connection = null;
PreparedStatement preparedStatement = null;
ResultSet resultSet = null;
boolean exist = false;
try {
connection = this.daoFactory.getConnection();
preparedStatement = prepareStatement(connection, sql, false, values);
resultSet = preparedStatement.executeQuery();
exist = resultSet.next();
} catch (SQLException e) {
throw new DAOException(e);
} finally {
close(connection, preparedStatement, resultSet);
}
return exist;
}
// Helpers -----------------------------------------------------------------
/**
* Generate hash code for the given password if necessary. That is, if it is
* not already hashed.
*
* @param password
* The password to generate a hash for if necessary.
* @return The hash of the given password or the same value if it is already
* hashed.
*/
private static Long hashCodeIfNecessary(String password) {
return !"^((-)?[0-9]*)".matches(password) ? password.hashCode() : new Long(password);
}
/**
* Map the current row of the given ResultSet to an Admin.
*
* @param resultSet
* The ResultSet of which the current row is to be mapped
* to an Admin.
* @return The mapped Admin from the current row of the given ResultSet.
* @throws SQLException
* If something fails at database level.
*/
private static Admin mapAdmin(ResultSet resultSet) throws SQLException {
return new Admin(resultSet.getLong("id"), resultSet.getString("login"), resultSet.getString("password"));
}
}