/*
 * Copyright 2002,2004 The Apache Software Foundation.
 * 
 * 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 org.apache.catalina;


import java.util.Iterator;


/**
 * <p>Abstract representation of a database of {@link User}s and
 * {@link Group}s that can be maintained by an application,
 * along with definitions of corresponding {@link Role}s, and
 * referenced by a {@link Realm} for authentication and access control.</p>
 *
 * @author Craig R. McClanahan
 * @version $Revision$ $Date$
 * @since 4.1
 */

public interface UserDatabase {


    // ------------------------------------------------------------- Properties


    /**
     * Return the set of {@link Group}s defined in this user database.
     */
    public Iterator getGroups();


    /**
     * Return the unique global identifier of this user database.
     */
    public String getId();


    /**
     * Return the set of {@link Role}s defined in this user database.
     */
    public Iterator getRoles();


    /**
     * Return the set of {@link User}s defined in this user database.
     */
    public Iterator getUsers();


    // --------------------------------------------------------- Public Methods


    /**
     * Finalize access to this user database.
     *
     * @exception Exception if any exception is thrown during closing
     */
    public void close() throws Exception;


    /**
     * Create and return a new {@link Group} defined in this user database.
     *
     * @param groupname The group name of the new group (must be unique)
     * @param description The description of this group
     */
    public Group createGroup(String groupname, String description);


    /**
     * Create and return a new {@link Role} defined in this user database.
     *
     * @param rolename The role name of the new role (must be unique)
     * @param description The description of this role
     */
    public Role createRole(String rolename, String description);


    /**
     * Create and return a new {@link User} defined in this user database.
     *
     * @param username The logon username of the new user (must be unique)
     * @param password The logon password of the new user
     * @param fullName The full name of the new user
     */
    public User createUser(String username, String password,
                           String fullName);


    /**
     * Return the {@link Group} with the specified group name, if any;
     * otherwise return <code>null</code>.
     *
     * @param groupname Name of the group to return
     */
    public Group findGroup(String groupname);


    /**
     * Return the {@link Role} with the specified role name, if any;
     * otherwise return <code>null</code>.
     *
     * @param rolename Name of the role to return
     */
    public Role findRole(String rolename);


    /**
     * Return the {@link User} with the specified user name, if any;
     * otherwise return <code>null</code>.
     *
     * @param username Name of the user to return
     */
    public User findUser(String username);


    /**
     * Initialize access to this user database.
     *
     * @exception Exception if any exception is thrown during opening
     */
    public void open() throws Exception;


    /**
     * Remove the specified {@link Group} from this user database.
     *
     * @param group The group to be removed
     */
    public void removeGroup(Group group);


    /**
     * Remove the specified {@link Role} from this user database.
     *
     * @param role The role to be removed
     */
    public void removeRole(Role role);


    /**
     * Remove the specified {@link User} from this user database.
     *
     * @param user The user to be removed
     */
    public void removeUser(User user);


    /**
     * Save any updated information to the persistent storage location for
     * this user database.
     *
     * @exception Exception if any exception is thrown during saving
     */
    public void save() throws Exception;


}