/*

 * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * 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.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

package javax.security.auth.callback;

/**

 * <p> Implementations of this interface are passed to a

 * {@code CallbackHandler}, allowing underlying security services

 * the ability to interact with a calling application to retrieve specific

 * authentication data such as usernames and passwords, or to display

 * certain information, such as error and warning messages.

 *

 * <p> {@code Callback} implementations do not retrieve or

 * display the information requested by underlying security services.

 * {@code Callback} implementations simply provide the means

 * to pass such requests to applications, and for applications,

 * if appropriate, to return requested information back to the

 * underlying security services.

 *

 * @since 1.4

 * @see javax.security.auth.callback.CallbackHandler

 * @see javax.security.auth.callback.ChoiceCallback

 * @see javax.security.auth.callback.ConfirmationCallback

 * @see javax.security.auth.callback.LanguageCallback

 * @see javax.security.auth.callback.NameCallback

 * @see javax.security.auth.callback.PasswordCallback

 * @see javax.security.auth.callback.TextInputCallback

 * @see javax.security.auth.callback.TextOutputCallback

 */

public interface Callback { }