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1   /* Copyright 2004 Acegi Technology Pty Limited
2    *
3    * Licensed under the Apache License, Version 2.0 (the "License");
4    * you may not use this file except in compliance with the License.
5    * You may obtain a copy of the License at
6    *
7    *     http://www.apache.org/licenses/LICENSE-2.0
8    *
9    * Unless required by applicable law or agreed to in writing, software
10   * distributed under the License is distributed on an "AS IS" BASIS,
11   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12   * See the License for the specific language governing permissions and
13   * limitations under the License.
14   */
15  
16  package org.acegisecurity.providers;
17  
18  import org.acegisecurity.Authentication;
19  import org.acegisecurity.AuthenticationException;
20  
21  
22  /***
23   * Indicates a class can process a specific  {@link
24   * org.acegisecurity.Authentication} implementation.
25   *
26   * @author Ben Alex
27   * @version $Id: AuthenticationProvider.java,v 1.5 2005/11/17 00:55:49 benalex Exp $
28   */
29  public interface AuthenticationProvider {
30      //~ Methods ================================================================
31  
32      /***
33       * Performs authentication with the same contract as {@link
34       * org.acegisecurity.AuthenticationManager#authenticate(Authentication)}.
35       *
36       * @param authentication the authentication request object.
37       *
38       * @return a fully authenticated object including credentials. May return
39       *         <code>null</code> if the <code>AuthenticationProvider</code> is
40       *         unable to support authentication of the passed
41       *         <code>Authentication</code> object. In such a case, the next
42       *         <code>AuthenticationProvider</code> that supports the presented
43       *         <code>Authentication</code> class will be tried.
44       *
45       * @throws AuthenticationException if authentication fails.
46       */
47      public Authentication authenticate(Authentication authentication)
48          throws AuthenticationException;
49  
50      /***
51       * Returns <code>true</code> if this <Code>AuthenticationProvider</code>
52       * supports the indicated <Code>Authentication</code> object.
53       * 
54       * <p>
55       * Returning <code>true</code> does not guarantee an
56       * <code>AuthenticationProvider</code> will be able to authenticate the
57       * presented instance of the <code>Authentication</code> class. It simply
58       * indicates it can support closer evaluation of it. An
59       * <code>AuthenticationProvider</code> can still return <code>null</code>
60       * from the {@link #authenticate(Authentication)} method to indicate
61       * another <code>AuthenticationProvider</code> should be tried.
62       * </p>
63       * 
64       * <P>
65       * Selection of an <code>AuthenticationProvider</code> capable of
66       * performing authentication is conducted at runtime the
67       * <code>ProviderManager</code>.
68       * </p>
69       *
70       * @return <code>true</code> if the implementation can more closely
71       *         evaluate the <code>Authentication</code> class presented
72       */
73      public boolean supports(Class authentication);
74  }