/*
* $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 $
* $Revision: 480424 $
* $Date: 2006-11-29 06:56:49 +0100 (Wed, 29 Nov 2006) $
*
* ====================================================================
*
* 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.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
*/
package org.apache.commons.httpclient.auth;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* Authentication policy class. The Authentication policy provides corresponding
* authentication scheme interfrace for a given type of authorization challenge.
* <p>The following specifications are provided:
* <ul>
* <li><tt>Basic</tt>: Basic authentication scheme as defined in RFC2617
* (considered inherently insecure, but most widely supported)
* <li><tt>Digest</tt>: Digest authentication scheme as defined in RFC2617
* <li><tt>NTLM</tt>: The NTLM scheme is a proprietary Microsoft Windows
* Authentication protocol (considered to be the most secure among
* currently supported authentication schemes)
* </ul>
*
* @author <a href="mailto:oleg@ural.ru">Oleg Kalnichevski</a>
*
* @version $Revision: 480424 $
* @since 3.0
*/
public abstract class AuthPolicy {
private static final HashMap SCHEMES = new HashMap();
private static final ArrayList SCHEME_LIST = new ArrayList();
/**
* The key used to look up the list of IDs of supported {@link AuthScheme
* authentication schemes} in their order of preference. The scheme IDs are
* stored in a {@link java.util.Collection} as {@link java.lang.String}s.
*
* <p>
* If several schemes are returned in the <tt>WWW-Authenticate</tt>
* or <tt>Proxy-Authenticate</tt> header, this parameter defines which
* {@link AuthScheme authentication schemes} takes precedence over others.
* The first item in the collection represents the most preferred
* {@link AuthScheme authentication scheme}, the last item represents the ID
* of the least preferred one.
* </p>
*
* @see org.apache.commons.httpclient.params.DefaultHttpParams
*/
public static final String AUTH_SCHEME_PRIORITY = "http.auth.scheme-priority";
/**
* The NTLM scheme is a proprietary Microsoft Windows Authentication
* protocol (considered to be the most secure among currently supported
* authentication schemes).
*/
public static final String NTLM = "NTLM";
/**
* Digest authentication scheme as defined in RFC2617.
*/
public static final String DIGEST = "Digest";
/**
* Basic authentication scheme as defined in RFC2617 (considered inherently
* insecure, but most widely supported)
*/
public static final String BASIC = "Basic";
static {
AuthPolicy.registerAuthScheme(NTLM, NTLMScheme.class);
AuthPolicy.registerAuthScheme(DIGEST, DigestScheme.class);
AuthPolicy.registerAuthScheme(BASIC, BasicScheme.class);
}
/** Log object. */
protected static final Log LOG = LogFactory.getLog(AuthPolicy.class);
/**
* Registers a class implementing an {@link AuthScheme authentication scheme} with
* the given identifier. If a class with the given ID already exists it will be overridden.
* This ID is the same one used to retrieve the {@link AuthScheme authentication scheme}
* from {@link #getAuthScheme(String)}.
*
* <p>
* Please note that custom authentication preferences, if used, need to be updated accordingly
* for the new {@link AuthScheme authentication scheme} to take effect.
* </p>
*
* @param id the identifier for this scheme
* @param clazz the class to register
*
* @see #getAuthScheme(String)
* @see #AUTH_SCHEME_PRIORITY
*/
public static synchronized void registerAuthScheme(final String id, Class clazz) {
if (id == null) {
throw new IllegalArgumentException("Id may not be null");
}
if (clazz == null) {
throw new IllegalArgumentException("Authentication scheme class may not be null");
}
SCHEMES.put(id.toLowerCase(), clazz);
SCHEME_LIST.add(id.toLowerCase());
}
/**
* Unregisters the class implementing an {@link AuthScheme authentication scheme} with
* the given ID.
*
* @param id the ID of the class to unregister
*/
public static synchronized void unregisterAuthScheme(final String id) {
if (id == null) {
throw new IllegalArgumentException("Id may not be null");
}
SCHEMES.remove(id.toLowerCase());
SCHEME_LIST.remove(id.toLowerCase());
}
/**
* Gets the {@link AuthScheme authentication scheme} with the given ID.
*
* @param id the {@link AuthScheme authentication scheme} ID
*
* @return {@link AuthScheme authentication scheme}
*
* @throws IllegalStateException if a scheme with the ID cannot be found
*/
public static synchronized AuthScheme getAuthScheme(final String id)
throws IllegalStateException {
if (id == null) {
throw new IllegalArgumentException("Id may not be null");
}
Class clazz = (Class)SCHEMES.get(id.toLowerCase());
if (clazz != null) {
try {
return (AuthScheme)clazz.newInstance();
} catch (Exception e) {
LOG.error("Error initializing authentication scheme: " + id, e);
throw new IllegalStateException(id +
" authentication scheme implemented by " +
clazz.getName() + " could not be initialized");
}
} else {
throw new IllegalStateException("Unsupported authentication scheme " + id);
}
}
/**
* Returns a list containing all registered {@link AuthScheme authentication
* schemes} in their default order.
*
* @return {@link AuthScheme authentication scheme}
*/
public static synchronized List getDefaultAuthPrefs() {
return (List)SCHEME_LIST.clone();
}
}