1 /*
   2  * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 
  27 package javax.security.auth.callback;
  28 
  29 /**
  30  * <p> Implementations of this interface are passed to a
  31  * {@code CallbackHandler}, allowing underlying security services
  32  * the ability to interact with a calling application to retrieve specific
  33  * authentication data such as usernames and passwords, or to display
  34  * certain information, such as error and warning messages.
  35  *
  36  * <p> {@code Callback} implementations do not retrieve or
  37  * display the information requested by underlying security services.
  38  * {@code Callback} implementations simply provide the means
  39  * to pass such requests to applications, and for applications,
  40  * if appropriate, to return requested information back to the
  41  * underlying security services.
  42  *
  43  * @see javax.security.auth.callback.CallbackHandler
  44  * @see javax.security.auth.callback.ChoiceCallback
  45  * @see javax.security.auth.callback.ConfirmationCallback
  46  * @see javax.security.auth.callback.LanguageCallback
  47  * @see javax.security.auth.callback.NameCallback
  48  * @see javax.security.auth.callback.PasswordCallback
  49  * @see javax.security.auth.callback.TextInputCallback
  50  * @see javax.security.auth.callback.TextOutputCallback
  51  */
  52 public interface Callback { }