/***
 * Copyright (c) 2009 Caelum - www.caelum.com.br/opensource
 * All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); 
 * you may not use this file except in compliance with the License. 
 * You may obtain a copy of the License at 
 * 
 * 	http://www.apache.org/licenses/LICENSE-2.0 
 * 
 * Unless required by applicable law or agreed to in writing, software 
 * distributed under the License is distributed on an "AS IS" BASIS, 
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 
 * See the License for the specific language governing permissions and 
 * limitations under the License. 
 */
package br.com.caelum.vraptor.musicjungle.dao;

import java.util.List;

import org.hibernate.HibernateException;

import br.com.caelum.vraptor.musicjungle.model.User;

/**
 * Data Access Object of User entity.
 * 
 * @author Lucas Cavalcanti
 * @author Rodrigo Turini
 */
public interface UserDao {

	/**
	 * Finds an user by login and password.
	 *
	 * @return found user if it is unique
	 * @throws HibernateException, if there are more than one user
	 */
	User find(String login, String password);

	/**
	 * Finds an user by login
	 *
	 * @return found user if it is unique
	 * @throws HibernateException, if there are more than one user
	 */
	User find(String login);

	/**
	 * Adds the user on database
	 */
	void add(User user);

	/**
	 * Synchronize the user data with the database. 
	 * Any not saved modification on user will be overwritten.
	 * @return 
	 */
	void refresh(User user);

	/**
	 * Update the user on database.
	 */
	void update(User user);

	/**
	 * Retrieves all users from database.
	 */
	List<User> listAll();

	/**
	 * Checks if there is already an user with given login.
	 *
	 * @return true if there exists a user
	 */
	boolean containsUserWithLogin(String login);

}