Java tutorial
/* * $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 com.microsoft.tfs.core.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 com.microsoft.tfs.core.httpclient.params.DefaultHttpParams */ public static final String AUTH_SCHEME_PRIORITY = "http.auth.scheme-priority"; /** * The SPNEGO ("negotiate") scheme as defined in RFC4559. */ public static final String NEGOTIATE = "Negotiate"; /** * 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 { /* * Negotiate and NTLM are handled by com.microsoft.tfs.jni, and may or * may not actually be available. */ if (NegotiateScheme.isSupported()) { AuthPolicy.registerAuthScheme(NEGOTIATE, NegotiateScheme.class); } if (NTLMScheme.isSupported()) { 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, final 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"); } final Class clazz = (Class) SCHEMES.get(id.toLowerCase()); if (clazz != null) { try { return (AuthScheme) clazz.newInstance(); } catch (final 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(); } }