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    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 06:56:49 +0100 (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;
    34  import java.util.HashMap;
    35  import java.util.List;
    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   SCHEMES     = new HashMap();
    61      private static final ArrayList SCHEME_LIST = new ArrayList();
    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 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 NTLM = "NTLM";
    87
    88      /**
    89       * Digest authentication scheme as defined in RFC2617.
    90       */
    91      public static final String 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 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 id, Class clazz) {
    126          if (id == null) {
    127              throw new IllegalArgumentException("Id may not be null");
    128          }
    129         if (clazz == null) {
    130             throw new IllegalArgumentException("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 id) {
    143          if (id == null) {
    144              throw new IllegalArgumentException("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 id)
    160         throws IllegalStateException {
    161
    162         if (id == null) {
    163             throw new IllegalArgumentException("Id may not be null");
    164         }
    165         Class clazz = (Class)SCHEMES.get(id.toLowerCase());
    166         if (clazz != null) {
    167             try {
    168                 return (AuthScheme)clazz.newInstance();
    169             } catch (Exception e) {
    170                 LOG.error("Error initializing authentication scheme: " + id, e);
    171                 throw new IllegalStateException(id +
    172                     " authentication scheme implemented by " +
    173                     clazz.getName() + " could not be initialized");
    174             }
    175         } else {
    176             throw new IllegalStateException("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 getDefaultAuthPrefs() {
    187         return (List)SCHEME_LIST.clone();
    188     }
    189 }