/*

  * 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.mgt;

 import org.apache.shiro.authc.AuthenticationException;

 import org.apache.shiro.authc.AuthenticationInfo;

 import org.apache.shiro.authc.AuthenticationToken;

 import org.apache.shiro.authc.Authenticator;

 import org.apache.shiro.authc.pam.ModularRealmAuthenticator;

 import org.apache.shiro.util.LifecycleUtils;

 /**

  * Shiro support of a {@link SecurityManager} class hierarchy that delegates all

  * authentication operations to a wrapped {@link Authenticator Authenticator} instance.  That is, this class

  * implements all the <tt>Authenticator</tt> methods in the {@link SecurityManager SecurityManager}

  * interface, but in reality, those methods are merely passthrough calls to the underlying 'real'

  * <tt>Authenticator</tt> instance.

  *

  * <p>All other <tt>SecurityManager</tt> (authorization, session, etc) methods are left to be implemented by subclasses.

  *

  * <p>In keeping with the other classes in this hierarchy and Shiro's desire to minimize configuration whenever

  * possible, suitable default instances for all dependencies are created upon instantiation.

  *

  * @since 0.9

  */

 public abstract class AuthenticatingSecurityManager extends RealmSecurityManager {

     /**

      * The internal <code>Authenticator</code> delegate instance that this SecurityManager instance will use

      * to perform all authentication operations.

      */

     private Authenticator authenticator;

     /**

      * Default no-arg constructor that initializes its internal

      * <code>authenticator</code> instance to a

      * {@link org.apache.shiro.authc.pam.ModularRealmAuthenticator ModularRealmAuthenticator}.

      */

     public AuthenticatingSecurityManager() {

         super();

         this.authenticator = new ModularRealmAuthenticator();

     }

     /**

      * Returns the delegate <code>Authenticator</code> instance that this SecurityManager uses to perform all

      * authentication operations.  Unless overridden by the

      * {@link #setAuthenticator(org.apache.shiro.authc.Authenticator) setAuthenticator}, the default instance is a

      * {@link org.apache.shiro.authc.pam.ModularRealmAuthenticator ModularRealmAuthenticator}.

      *

      * @return the delegate <code>Authenticator</code> instance that this SecurityManager uses to perform all

      *         authentication operations.

      */

     public Authenticator getAuthenticator() {

         return authenticator;

     }

     /**

      * Sets the delegate <code>Authenticator</code> instance that this SecurityManager uses to perform all

      * authentication operations.  Unless overridden by this method, the default instance is a

      * {@link org.apache.shiro.authc.pam.ModularRealmAuthenticator ModularRealmAuthenticator}.

      *

      * @param authenticator the delegate <code>Authenticator</code> instance that this SecurityManager will use to

      *                      perform all authentication operations.

      * @throws IllegalArgumentException if the argument is <code>null</code>.

      */

     public void setAuthenticator(Authenticator authenticator) throws IllegalArgumentException {

         if (authenticator == null) {

             String msg = "Authenticator argument cannot be null.";

             throw new IllegalArgumentException(msg);

         }

         this.authenticator = authenticator;

     }

     /**

      * Passes on the {@link #getRealms() realms} to the internal delegate <code>Authenticator</code> instance so

      * that it may use them during authentication attempts.

      */

     protected void afterRealmsSet() {

         super.afterRealmsSet();

         if (this.authenticator instanceof ModularRealmAuthenticator) {

             ((ModularRealmAuthenticator) this.authenticator).setRealms(getRealms());

         }

     }

     /**

      * Delegates to the wrapped {@link org.apache.shiro.authc.Authenticator Authenticator} for authentication.

      */

     public AuthenticationInfo authenticate(AuthenticationToken token) throws AuthenticationException {

         return this.authenticator.authenticate(token);

     }

     public void destroy() {

         LifecycleUtils.destroy(getAuthenticator());

         this.authenticator = null;

         super.destroy();

     }

 }