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 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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
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package org.apache.catalina;

import java.util.Iterator;

Abstract representation of a database of Users and Groups that can be maintained by an application, along with definitions of corresponding Roles, and referenced by a Realm for authentication and access control. 
Author:
Craig R. McClanahan
Since:
4.1/**
 * 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.
 *
 * @author Craig R. McClanahan
 * @since 4.1
 */
public interface UserDatabase {

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

    
Returns:
the set of Groups defined in this user database./**
     * @return the set of {@link Group}s defined in this user database.
     */
    public Iterator<Group> getGroups();


    
Returns:
the unique global identifier of this user database./**
     * @return the unique global identifier of this user database.
     */
    public String getId();


    
Returns:
the set of Roles defined in this user database./**
     * @return the set of {@link Role}s defined in this user database.
     */
    public Iterator<Role> getRoles();


    
Returns:
the set of Users defined in this user database./**
     * @return the set of {@link User}s defined in this user database.
     */
    public Iterator<User> getUsers();


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

    
Finalize access to this user database.
Throws:
Exception – if any exception is thrown during closing/**
     * 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 Group defined in this user database. 
Params:
groupname – The group name of the new group (must be unique)
description – The description of this group
Returns:
The new group/**
     * 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
     * @return The new group
     */
    public Group createGroup(String groupname, String description);


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


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


    
Params:
groupname – Name of the group to return
Returns:
the Group with the specified group name, if any; otherwise return null./**
     * @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);


    
Params:
rolename – Name of the role to return
Returns:
the Role with the specified role name, if any; otherwise return null./**
     * @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);


    
Params:
username – Name of the user to return
Returns:
the User with the specified user name, if any; otherwise return null./**
     * @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.
Throws:
Exception – if any exception is thrown during opening/**
     * Initialize access to this user database.
     *
     * @exception Exception if any exception is thrown during opening
     */
    public void open() throws Exception;


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


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


    
Remove the specified User from this user database. 
Params:
user – The user to be removed/**
     * 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.
Throws:
Exception – if any exception is thrown during saving/**
     * 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;


    
Perform any background processing (e.g. checking for changes in persisted
storage) required for the user database.
/**
     * Perform any background processing (e.g. checking for changes in persisted
     * storage) required for the user database.
     */
    public default void backgroundProcess() {
        // NO-OP by default
    }
}