/*

  * 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 limitations

  * under the License.

  */

 package org.apache.shiro.realm;

 import java.util.Collection;

 /**

  * Enables Shiro end-users to configure and initialize one or more {@link Realm Realm} instances

  * in any manner desired.

  * <p/>

  * This interface exists to support environments where end-users may not wish to use Shiro's default

  * text-based configuration to create and configure realms, and instead wish to retrieve a realm configured in a

  * proprietary manner.  An implementation of this interface can access that proprietary mechanism to retrieve the

  * already-created <tt>Realm</tt>s.

  *

  * <p>The <code>Realm</code> instances returned will used to construct the application's

  * {@link org.apache.shiro.mgt.SecurityManager SecurityManager} instance.

  *

  * @since 0.9

  */

 public interface RealmFactory {

     /**

      * Returns a collection of {@link Realm Realm} instances that will be used to construct

      * the application's SecurityManager instance.

      *

      * <p>The order of the collection is important.  The {@link org.apache.shiro.mgt.SecurityManager SecurityManager}

      * implementation will consult the Realms during authentication (log-in) and authorization (access control)

      * operations in the collection's <b>iteration order</b>.  That is, the resulting collection's

      * {@link java.util.Iterator Iterator} determines the order in which Realms are used.

      *

      * @return the <code>Collection</code> of Realms that the application's <code>SecurityManager</code> will use

      *         for security data access.

      */

     Collection<Realm> getRealms();

 }