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    * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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    * This code is free software; you can redistribute it and/or modify it
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    * published by the Free Software Foundation.  Oracle designates this
    * particular file as subject to the "Classpath" exception as provided
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   *
   * This code is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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  package sun.net.www.protocol.http;
  
  import java.net.URL;
  import java.io.IOException;
  import java.net.Authenticator.RequestorType;
  import java.util.HashMap;
  import sun.net.www.HeaderParser;
  import sun.misc.BASE64Decoder;
  import sun.misc.BASE64Encoder;
  import static sun.net.www.protocol.http.AuthScheme.NEGOTIATE;
  import static sun.net.www.protocol.http.AuthScheme.KERBEROS;
  
  /**
   * NegotiateAuthentication:
   *
   * @author weijun.wang@sun.com
   * @since 1.6
   */
  
  class NegotiateAuthentication extends AuthenticationInfo {
  
      private static final long serialVersionUID = 100L;
  
      final private HttpCallerInfo hci;
  
      // These maps are used to manage the GSS availability for diffrent
      // hosts. The key for both maps is the host name.
      // <code>supported</code> is set when isSupported is checked,
      // if it's true, a cached Negotiator is put into <code>cache</code>.
      // the cache can be used only once, so after the first use, it's cleaned.
      static HashMap <String, Boolean> supported = null;
      static HashMap <String, Negotiator> cache = null;
  
      // The HTTP Negotiate Helper
      private Negotiator negotiator = null;
  
     /**
      * Constructor used for both WWW and proxy entries.
      * @param hci a schemed object.
      */
      public NegotiateAuthentication(HttpCallerInfo hci) {
          super(RequestorType.PROXY==hci.authType ? PROXY_AUTHENTICATION : SERVER_AUTHENTICATION,
                hci.scheme.equalsIgnoreCase("Negotiate") ? NEGOTIATE : KERBEROS,
                hci.url,
                "");
          this.hci = hci;
      }
  
      /**
       * @return true if this authentication supports preemptive authorization
       */
      @Override
      public boolean supportsPreemptiveAuthorization() {
          return false;
      }
  
      /**
       * Find out if the HttpCallerInfo supports Negotiate protocol. In order to
       * find out yes or no, an initialization of a Negotiator object against it
       * is tried. The generated object will be cached under the name of ths
       * hostname at a success try.<br>
       *
       * If this method is called for the second time on an HttpCallerInfo with
       * the same hostname, the answer is retrieved from cache.
       *
       * @return true if supported
       */
      synchronized public static boolean isSupported(HttpCallerInfo hci) {
          if (supported == null) {
              supported = new HashMap <String, Boolean>();
              cache = new HashMap <String, Negotiator>();
          }
          String hostname = hci.host;
          hostname = hostname.toLowerCase();
         if (supported.containsKey(hostname)) {
             return supported.get(hostname);
         }
 
         Negotiator neg = Negotiator.getNegotiator(hci);
         if (neg != null) {
             supported.put(hostname, true);
             // the only place cache.put is called. here we can make sure
             // the object is valid and the oneToken inside is not null
             cache.put(hostname, neg);
             return true;
         } else {
             supported.put(hostname, false);
             return false;
         }
     }
 
     /**
      * Not supported. Must use the setHeaders() method
      */
     @Override
     public String getHeaderValue(URL url, String method) {
         throw new RuntimeException ("getHeaderValue not supported");
     }
 
     /**
      * Check if the header indicates that the current auth. parameters are stale.
      * If so, then replace the relevant field with the new value
      * and return true. Otherwise return false.
      * returning true means the request can be retried with the same userid/password
      * returning false means we have to go back to the user to ask for a new
      * username password.
      */
     @Override
     public boolean isAuthorizationStale (String header) {
         return false; /* should not be called for Negotiate */
     }
 
     /**
      * Set header(s) on the given connection.
      * @param conn The connection to apply the header(s) to
      * @param p A source of header values for this connection, not used because
      *          HeaderParser converts the fields to lower case, use raw instead
      * @param raw The raw header field.
      * @return true if all goes well, false if no headers were set.
      */
     @Override
     public synchronized boolean setHeaders(HttpURLConnection conn, HeaderParser p, String raw) {
 
         try {
             String response;
             byte[] incoming = null;
             String[] parts = raw.split("\\s+");
             if (parts.length > 1) {
                 incoming = new BASE64Decoder().decodeBuffer(parts[1]);
             }
             response = hci.scheme + " " + new B64Encoder().encode(
                         incoming==null?firstToken():nextToken(incoming));
 
             conn.setAuthenticationProperty(getHeaderName(), response);
             return true;
         } catch (IOException e) {
             return false;
         }
     }
 
     /**
      * return the first token.
      * @returns the token
      * @throws IOException if <code>Negotiator.getNegotiator()</code> or
      *                     <code>Negotiator.firstToken()</code> failed.
      */
     private byte[] firstToken() throws IOException {
         negotiator = null;
         if (cache != null) {
             synchronized(cache) {
                 negotiator = cache.get(getHost());
                 if (negotiator != null) {
                     cache.remove(getHost()); // so that it is only used once
                 }
             }
         }
         if (negotiator == null) {
             negotiator = Negotiator.getNegotiator(hci);
             if (negotiator == null) {
                 IOException ioe = new IOException("Cannot initialize Negotiator");
                 throw ioe;
             }
         }
 
         return negotiator.firstToken();
     }
 
     /**
      * return more tokens
      * @param token the token to be fed into <code>negotiator.nextToken()</code>
      * @returns the token
      * @throws IOException if <code>negotiator.nextToken()</code> throws Exception.
      *  May happen if the input token is invalid.
      */
     private byte[] nextToken(byte[] token) throws IOException {
         return negotiator.nextToken(token);
     }
 
     class B64Encoder extends BASE64Encoder {
         protected int bytesPerLine () {
             return 100000;  // as big as it can be, maybe INT_MAX
         }
     }
 
     // MS will send a final WWW-Authenticate even if the status is already
     // 200 OK. The token can be fed into initSecContext() again to determine
     // if the server can be trusted. This is not the same concept as Digest's
     // Authentication-Info header.
     //
     // Currently we ignore this header.
 
 }