001/* Authenticator.java -- Abstract class for obtaining authentication info
002   Copyright (C) 1998, 2000, 2003 Free Software Foundation, Inc.
003
004This file is part of GNU Classpath.
005
006GNU Classpath is free software; you can redistribute it and/or modify
007it under the terms of the GNU General Public License as published by
008the Free Software Foundation; either version 2, or (at your option)
009any later version.
010
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013MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014General Public License for more details.
015
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017along with GNU Classpath; see the file COPYING.  If not, write to the
018Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
01902110-1301 USA.
020
021Linking this library statically or dynamically with other modules is
022making a combined work based on this library.  Thus, the terms and
023conditions of the GNU General Public License cover the whole
024combination.
025
026As a special exception, the copyright holders of this library give you
027permission to link this library with independent modules to produce an
028executable, regardless of the license terms of these independent
029modules, and to copy and distribute the resulting executable under
030terms of your choice, provided that you also meet, for each linked
031independent module, the terms and conditions of the license of that
032module.  An independent module is a module which is not derived from
033or based on this library.  If you modify this library, you may extend
034this exception to your version of the library, but you are not
035obligated to do so.  If you do not wish to do so, delete this
036exception statement from your version. */
037
038package java.net;
039
040
041/**
042  * This abstract class provides a model for obtaining authentication
043  * information (in the form of a username and password) required by
044  * some network operations (such as hitting a password protected
045  * web site).
046  * <p>
047  * To make use of this feature, a programmer must create a subclass
048  * that knows how to obtain the necessary info.  An example
049  * would be a class that popped up a dialog box to prompt the user.
050  * After creating an instance of that subclass, the static
051  * <code>setDefault</code> method of this class is called to set up
052  * that instance as the object to use on subsequent calls to obtain
053  * authorization.
054  *
055  * @since 1.2
056  *
057  * @author Aaron M. Renn (arenn@urbanophile.com)
058  * @status Believed to be JDK 1.4 complete
059  */
060public abstract class Authenticator
061{
062  /*
063   * Class Variables
064   */
065
066  /**
067    * This is the default Authenticator object to use for password requests
068    */
069  private static Authenticator defaultAuthenticator;
070
071  /*
072   * Instance Variables
073   */
074
075  /**
076    * The hostname of the site requesting authentication
077    */
078  private String host;
079
080  /**
081    * InternetAddress of the site requesting authentication
082    */
083  private InetAddress addr;
084
085  /**
086    * The port number of the site requesting authentication
087    */
088  private int port;
089
090  /**
091    * The protocol name of the site requesting authentication
092    */
093  private String protocol;
094
095  /**
096    * The prompt to display to the user when requesting authentication info
097    */
098  private String prompt;
099
100  /**
101    * The authentication scheme in use
102    */
103  private String scheme;
104
105  /*
106   * Class Methods
107   */
108
109  /**
110    * This method sets the default <code>Authenticator</code> object (an
111    * instance of a subclass of <code>Authenticator</code>) to use when
112    * prompting the user for
113    * information.  Note that this method checks to see if the caller is
114    * allowed to set this value (the "setDefaultAuthenticator" permission)
115    * and throws a <code>SecurityException</code> if it is not.
116    *
117    * @param defAuth The new default <code>Authenticator</code> object to use
118    *
119    * @exception SecurityException If the caller does not have permission
120    * to perform this operation
121    */
122  public static void setDefault(Authenticator defAuth)
123  {
124    SecurityManager sm = System.getSecurityManager();
125    if (sm != null)
126      sm.checkPermission(new NetPermission("setDefaultAuthenticator"));
127
128    defaultAuthenticator = defAuth;
129  }
130
131  /**
132    * This method is called whenever a username and password for a given
133    * network operation is required.  First, a security check is made to see
134    * if the caller has the "requestPasswordAuthentication"
135    * permission.  If not, the method thows an exception.  If there is no
136    * default <code>Authenticator</code> object, the method then returns
137    * <code>null</code>.  Otherwise, the default authenticators's instance
138    * variables are initialized and it's <code>getPasswordAuthentication</code>
139    * method is called to get the actual authentication information to return.
140    *
141    * @param addr The address requesting authentication
142    * @param port The port requesting authentication
143    * @param protocol The protocol requesting authentication
144    * @param prompt The prompt to display to the user when requesting
145    *        authentication info
146    * @param scheme The authentication scheme in use
147    *
148    * @return A <code>PasswordAuthentication</code> object with the user's
149    *         authentication info.
150    *
151    * @exception SecurityException If the caller does not have permission to
152    *         perform this operation
153    */
154  public static PasswordAuthentication requestPasswordAuthentication(InetAddress addr,
155                                                                     int port,
156                                                                     String protocol,
157                                                                     String prompt,
158                                                                     String scheme)
159    throws SecurityException
160  {
161    return requestPasswordAuthentication(null, addr, port, protocol, prompt,
162                                         scheme);
163  }
164
165  /**
166    * This method is called whenever a username and password for a given
167    * network operation is required.  First, a security check is made to see
168    * if the caller has the "requestPasswordAuthentication"
169    * permission.  If not, the method thows an exception.  If there is no
170    * default <code>Authenticator</code> object, the method then returns
171    * <code>null</code>.  Otherwise, the default authenticators's instance
172    * variables are initialized and it's <code>getPasswordAuthentication</code>
173    * method is called to get the actual authentication information to return.
174    * This method is the preferred one as it can be used with hostname
175    * when addr is unknown.
176    *
177    * @param host The hostname requesting authentication
178    * @param addr The address requesting authentication
179    * @param port The port requesting authentication
180    * @param protocol The protocol requesting authentication
181    * @param prompt The prompt to display to the user when requesting
182    *        authentication info
183    * @param scheme The authentication scheme in use
184    *
185    * @return A <code>PasswordAuthentication</code> object with the user's
186    *         authentication info.
187    *
188    * @exception SecurityException If the caller does not have permission to
189    *         perform this operation
190    *
191    * @since 1.4
192    */
193  public static PasswordAuthentication requestPasswordAuthentication(String host,
194                                                                     InetAddress addr,
195                                                                     int port,
196                                                                     String protocol,
197                                                                     String prompt,
198                                                                     String scheme)
199    throws SecurityException
200  {
201    SecurityManager sm = System.getSecurityManager();
202    if (sm != null)
203      sm.checkPermission(new NetPermission("requestPasswordAuthentication"));
204
205    if (defaultAuthenticator == null)
206      return null;
207
208    defaultAuthenticator.host = host;
209    defaultAuthenticator.addr = addr;
210    defaultAuthenticator.port = port;
211    defaultAuthenticator.protocol = protocol;
212    defaultAuthenticator.prompt = prompt;
213    defaultAuthenticator.scheme = scheme;
214
215    return defaultAuthenticator.getPasswordAuthentication();
216  }
217
218  /*
219   * Constructors
220   */
221
222  /**
223    * Default, no-argument constructor for subclasses to call.
224    */
225  public Authenticator()
226  {
227  }
228
229  /*
230   * Instance Methods
231   */
232
233  /**
234    * This method returns the address of the site that is requesting
235    * authentication.
236    *
237    * @return The requesting site's address
238    */
239  protected final InetAddress getRequestingSite()
240  {
241    return addr;
242  }
243
244  /**
245   * Returns the hostname of the host or proxy requesting authorization,
246   * or <code>null</code> if not available.
247   *
248   * @return The name of the host requesting authentication, or
249   * <code>null</code> if it is not available.
250   *
251   * @since 1.4
252   */
253  protected final String getRequestingHost()
254  {
255    return host;
256  }
257
258  /**
259    * This method returns the port of the site that is requesting
260    * authentication.
261    *
262    * @return The requesting port
263    */
264  protected final int getRequestingPort()
265  {
266    return port;
267  }
268
269  /**
270    * This method returns the requesting protocol of the operation that is
271    * requesting authentication
272    *
273    * @return The requesting protocol
274    */
275  protected final String getRequestingProtocol()
276  {
277    return protocol;
278  }
279
280  /**
281    * Returns the prompt that should be used when requesting authentication
282    * information from the user
283    *
284    * @return The user prompt
285    */
286  protected final String getRequestingPrompt()
287  {
288    return prompt;
289  }
290
291  /**
292    * This method returns the authentication scheme in use
293    *
294    * @return The authentication scheme
295    */
296  protected final String getRequestingScheme()
297  {
298    return scheme;
299  }
300
301  /**
302    * This method is called whenever a request for authentication is made.  It
303    * can call the other getXXX methods to determine the information relevant
304    * to this request.  Subclasses should override this method, which returns
305    * <code>null</code> by default.
306    *
307    * @return The <code>PasswordAuthentication</code> information
308    */
309  protected PasswordAuthentication getPasswordAuthentication()
310  {
311    return null;
312  }
313} // class Authenticator