001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.apache.shiro.realm;
020
021import java.util.Collection;
022
023/**
024 * Enables Shiro end-users to configure and initialize one or more {@link Realm Realm} instances
025 * in any manner desired.
026 * <p/>
027 * This interface exists to support environments where end-users may not wish to use Shiro's default
028 * text-based configuration to create and configure realms, and instead wish to retrieve a realm configured in a
029 * proprietary manner.  An implementation of this interface can access that proprietary mechanism to retrieve the
030 * already-created <tt>Realm</tt>s.
031 *
032 * <p>The <code>Realm</code> instances returned will used to construct the application's
033 * {@link org.apache.shiro.mgt.SecurityManager SecurityManager} instance.
034 *
035 * @since 0.9
036 */
037public interface RealmFactory {
038
039    /**
040     * Returns a collection of {@link Realm Realm} instances that will be used to construct
041     * the application's SecurityManager instance.
042     *
043     * <p>The order of the collection is important.  The {@link org.apache.shiro.mgt.SecurityManager SecurityManager}
044     * implementation will consult the Realms during authentication (log-in) and authorization (access control)
045     * operations in the collection's <b>iteration order</b>.  That is, the resulting collection's
046     * {@link java.util.Iterator Iterator} determines the order in which Realms are used.
047     *
048     * @return the <code>Collection</code> of Realms that the application's <code>SecurityManager</code> will use
049     *         for security data access.
050     */
051    Collection<Realm> getRealms();
052
053}