/* Copyright 2004, 2005, 2006 Acegi Technology Pty Limited

  *

  * 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.acegisecurity.providers;

 import org.acegisecurity.Authentication;

 import org.acegisecurity.AuthenticationException;

 /**

  * Indicates a class can process a specific  {@link

  * org.acegisecurity.Authentication} implementation.

  *

  * @author Ben Alex

  * @version $Id: AuthenticationProvider.java 1784 2007-02-24 21:00:24Z luke_t $

  */

 public interface AuthenticationProvider {

     //~ Methods ========================================================================================================

     /**

      * Performs authentication with the same contract as {@link

      * org.acegisecurity.AuthenticationManager#authenticate(Authentication)}.

      *

      * @param authentication the authentication request object.

      *

      * @return a fully authenticated object including credentials. May return <code>null</code> if the

      *         <code>AuthenticationProvider</code> is unable to support authentication of the passed

      *         <code>Authentication</code> object. In such a case, the next <code>AuthenticationProvider</code> that

      *         supports the presented <code>Authentication</code> class will be tried.

      *

      * @throws AuthenticationException if authentication fails.

      */

     Authentication authenticate(Authentication authentication)

         throws AuthenticationException;

     /**

      * Returns <code>true</code> if this <Code>AuthenticationProvider</code> supports the indicated

      * <Code>Authentication</code> object.

      * <p>

      * Returning <code>true</code> does not guarantee an <code>AuthenticationProvider</code> will be able to

      * authenticate the presented instance of the <code>Authentication</code> class. It simply indicates it can support

      * closer evaluation of it. An <code>AuthenticationProvider</code> can still return <code>null</code> from the

      * {@link #authenticate(Authentication)} method to indicate another <code>AuthenticationProvider</code> should be

      * tried.

      * </p>

      * <p>Selection of an <code>AuthenticationProvider</code> capable of performing authentication is

      * conducted at runtime the <code>ProviderManager</code>.</p>

      *

      * @param authentication DOCUMENT ME!

      *

      * @return <code>true</code> if the implementation can more closely evaluate the <code>Authentication</code> class

      *         presented

      */

     boolean supports(Class authentication);

 }