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Java > Open Source Codes > org > apache > commons > httpclient > auth > AuthPolicy


1 /*
2  * $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//httpclient/src/java/org/apache/commons/httpclient/auth/AuthPolicy.java,v 1.6 2004/05/13 04:02:00 mbecke Exp $
3  * $Revision: 480424 $
4  * $Date: 2006-11-29 05:56:49 +0000 (Wed, 29 Nov 2006) $
5  *
6  * ====================================================================
7  *
8  * Licensed to the Apache Software Foundation (ASF) under one or more
9  * contributor license agreements. See the NOTICE file distributed with
10  * this work for additional information regarding copyright ownership.
11  * The ASF licenses this file to You under the Apache License, Version 2.0
12  * (the "License"); you may not use this file except in compliance with
13  * the License. You may obtain a copy of the License at
14  *
15  * http://www.apache.org/licenses/LICENSE-2.0
16  *
17  * Unless required by applicable law or agreed to in writing, software
18  * distributed under the License is distributed on an "AS IS" BASIS,
19  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
20  * See the License for the specific language governing permissions and
21  * limitations under the License.
22  * ====================================================================
23  *
24  * This software consists of voluntary contributions made by many
25  * individuals on behalf of the Apache Software Foundation. For more
26  * information on the Apache Software Foundation, please see
27  * <http://www.apache.org/>.
28  *
29  */
30
31 package org.apache.commons.httpclient.auth;
32
33 import java.util.ArrayList JavaDoc;
34 import java.util.HashMap JavaDoc;
35 import java.util.List JavaDoc;
36
37 import org.apache.commons.logging.Log;
38 import org.apache.commons.logging.LogFactory;
39
40 /**
41  * Authentication policy class. The Authentication policy provides corresponding
42  * authentication scheme interfrace for a given type of authorization challenge.
43  * <p>The following specifications are provided:
44  * <ul>
45  * <li><tt>Basic</tt>: Basic authentication scheme as defined in RFC2617
46  * (considered inherently insecure, but most widely supported)
47  * <li><tt>Digest</tt>: Digest authentication scheme as defined in RFC2617
48  * <li><tt>NTLM</tt>: The NTLM scheme is a proprietary Microsoft Windows
49  * Authentication protocol (considered to be the most secure among
50  * currently supported authentication schemes)
51  * </ul>
52  *
53  * @author <a HREF="mailto:oleg@ural.ru">Oleg Kalnichevski</a>
54  *
55  * @version $Revision: 480424 $
56  * @since 3.0
57  */
58 public abstract class AuthPolicy {
59
60     private static final HashMap JavaDoc SCHEMES = new HashMap JavaDoc();
61     private static final ArrayList JavaDoc SCHEME_LIST = new ArrayList JavaDoc();
62     
63     /**
64      * The key used to look up the list of IDs of supported {@link AuthScheme
65      * authentication schemes} in their order of preference. The scheme IDs are
66      * stored in a {@link java.util.Collection} as {@link java.lang.String}s.
67      *
68      * <p>
69      * If several schemes are returned in the <tt>WWW-Authenticate</tt>
70      * or <tt>Proxy-Authenticate</tt> header, this parameter defines which
71      * {@link AuthScheme authentication schemes} takes precedence over others.
72      * The first item in the collection represents the most preferred
73      * {@link AuthScheme authentication scheme}, the last item represents the ID
74      * of the least preferred one.
75      * </p>
76      *
77      * @see org.apache.commons.httpclient.params.DefaultHttpParams
78      */
79     public static final String JavaDoc AUTH_SCHEME_PRIORITY = "http.auth.scheme-priority";
80
81     /**
82      * The NTLM scheme is a proprietary Microsoft Windows Authentication
83      * protocol (considered to be the most secure among currently supported
84      * authentication schemes).
85      */
86     public static final String JavaDoc NTLM = "NTLM";
87     
88     /**
89      * Digest authentication scheme as defined in RFC2617.
90      */
91     public static final String JavaDoc DIGEST = "Digest";
92
93     /**
94      * Basic authentication scheme as defined in RFC2617 (considered inherently
95      * insecure, but most widely supported)
96      */
97     public static final String JavaDoc BASIC = "Basic";
98     
99     static {
100         AuthPolicy.registerAuthScheme(NTLM, NTLMScheme.class);
101         AuthPolicy.registerAuthScheme(DIGEST, DigestScheme.class);
102         AuthPolicy.registerAuthScheme(BASIC, BasicScheme.class);
103     }
104     
105     /** Log object. */
106     protected static final Log LOG = LogFactory.getLog(AuthPolicy.class);
107
108     /**
109      * Registers a class implementing an {@link AuthScheme authentication scheme} with
110      * the given identifier. If a class with the given ID already exists it will be overridden.
111      * This ID is the same one used to retrieve the {@link AuthScheme authentication scheme}
112      * from {@link #getAuthScheme(String)}.
113      *
114      * <p>
115      * Please note that custom authentication preferences, if used, need to be updated accordingly
116      * for the new {@link AuthScheme authentication scheme} to take effect.
117      * </p>
118      *
119      * @param id the identifier for this scheme
120      * @param clazz the class to register
121      *
122      * @see #getAuthScheme(String)
123      * @see #AUTH_SCHEME_PRIORITY
124      */
125     public static synchronized void registerAuthScheme(final String JavaDoc id, Class JavaDoc clazz) {
126          if (id == null) {
127              throw new IllegalArgumentException JavaDoc("Id may not be null");
128          }
129         if (clazz == null) {
130             throw new IllegalArgumentException JavaDoc("Authentication scheme class may not be null");
131         }
132         SCHEMES.put(id.toLowerCase(), clazz);
133         SCHEME_LIST.add(id.toLowerCase());
134     }
135
136     /**
137      * Unregisters the class implementing an {@link AuthScheme authentication scheme} with
138      * the given ID.
139      *
140      * @param id the ID of the class to unregister
141      */
142     public static synchronized void unregisterAuthScheme(final String JavaDoc id) {
143          if (id == null) {
144              throw new IllegalArgumentException JavaDoc("Id may not be null");
145          }
146         SCHEMES.remove(id.toLowerCase());
147         SCHEME_LIST.remove(id.toLowerCase());
148     }
149
150     /**
151      * Gets the {@link AuthScheme authentication scheme} with the given ID.
152      *
153      * @param id the {@link AuthScheme authentication scheme} ID
154      *
155      * @return {@link AuthScheme authentication scheme}
156      *
157      * @throws IllegalStateException if a scheme with the ID cannot be found
158      */
159     public static synchronized AuthScheme getAuthScheme(final String JavaDoc id)
160         throws IllegalStateException JavaDoc {
161
162         if (id == null) {
163             throw new IllegalArgumentException JavaDoc("Id may not be null");
164         }
165         Class JavaDoc clazz = (Class JavaDoc)SCHEMES.get(id.toLowerCase());
166         if (clazz != null) {
167             try {
168                 return (AuthScheme)clazz.newInstance();
169             } catch (Exception JavaDoc e) {
170                 LOG.error("Error initializing authentication scheme: " + id, e);
171                 throw new IllegalStateException JavaDoc(id +
172                     " authentication scheme implemented by " +
173                     clazz.getName() + " could not be initialized");
174             }
175         } else {
176             throw new IllegalStateException JavaDoc("Unsupported authentication scheme " + id);
177         }
178     }
179
180     /**
181      * Returns a list containing all registered {@link AuthScheme authentication
182      * schemes} in their default order.
183      *
184      * @return {@link AuthScheme authentication scheme}
185      */
186     public static synchronized List JavaDoc getDefaultAuthPrefs() {
187         return (List JavaDoc)SCHEME_LIST.clone();
188     }
189 }
190
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