content: /* jcifs smb client library in Java
   * Copyright (C) 2002  "Michael B. Allen" <jcifs at samba dot org>
   * 
   * This library is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   * 
   * This library 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
   * Lesser General Public License for more details.
   * 
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   */
  
  package jcifs.smb;
  
  
  /**
   * This class can be extended by applications that wish to trap authentication related exceptions and automatically
   * retry the exceptional operation with different credentials. Read <a href="../../../authhandler.html">jCIFS Exceptions
   * and NtlmAuthenticator</a> for complete details.
   */
  
  public abstract class NtlmAuthenticator {
  
      private static NtlmAuthenticator auth;
  
      private String url;
      private SmbAuthException sae;
  
  
      /**
       * Set the default <tt>NtlmAuthenticator</tt>. Once the default authenticator is set it cannot be changed. Calling
       * this metho again will have no effect.
       * 
       * @param a
       */
  
      public synchronized static void setDefault ( NtlmAuthenticator a ) {
          if ( auth != null ) {
              return;
          }
          auth = a;
      }
  
  
      /**
       * 
       * @return the default authentiucation credentials
       */
      public static NtlmAuthenticator getDefault () {
          return auth;
      }
  
  
      protected final String getRequestingURL () {
          return this.url;
      }
  
  
      protected final SmbAuthException getRequestingException () {
          return this.sae;
      }
  
  
      /**
       * Used internally by jCIFS when an <tt>SmbAuthException</tt> is trapped to retrieve new user credentials.
       * 
       * @param url
       * @param sae
       * @return credentials returned by prompt
       */
      public static NtlmPasswordAuthenticator requestNtlmPasswordAuthentication ( String url, SmbAuthException sae ) {
          return requestNtlmPasswordAuthentication(auth, url, sae);
      }
  
  
      /**
       * @param a
       * @param url
       * @param sae
       * @return credentials returned by prompt
       */
      public static NtlmPasswordAuthenticator requestNtlmPasswordAuthentication ( NtlmAuthenticator a, String url, SmbAuthException sae ) {
          if ( a == null ) {
              return null;
          }
          synchronized ( a ) {
              a.url = url;
              a.sae = sae;
              return a.getNtlmPasswordAuthentication();
          }
      }
  
  
      /**
       * An application extending this class must provide an implementation for this method that returns new user
       * credentials try try when accessing SMB resources described by the <tt>getRequestingURL</tt> and
       * <tt>getRequestingException</tt> methods.
       * If this method returns <tt>null</tt> the <tt>SmbAuthException</tt> that triggered the authenticator check will
       * simply be rethrown. The default implementation returns <tt>null</tt>.
       */
      protected NtlmPasswordAuthenticator getNtlmPasswordAuthentication () {
          return null;
      }
  }
  