/*

 * 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

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

 *

 * 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.

 *

 */

package java.security;

import javax.security.auth.Subject;

import javax.security.auth.login.LoginException;

import javax.security.auth.callback.CallbackHandler;

/**

 * This class defines login and logout methods for a provider.

 *

 * <p> While callers may invoke <code>login</code> directly,

 * the provider may also invoke <code>login</code> on behalf of callers

 * if it determines that a login must be performed

 * prior to certain operations.

 *

 * @since 1.5

 */

public abstract class AuthProvider extends Provider {

    /**

     * Constructs a provider with the specified name, version number,

     * and information.

     *

     * @param name the provider name.

     * @param version the provider version number.

     * @param info a description of the provider and its services.

     */

    protected AuthProvider(String name, double version, String info) {

        super(name, version, info);

    }

    /**

     * Log in to this provider.

     *

     * <p> The provider relies on a <code>CallbackHandler</code>

     * to obtain authentication information from the caller

     * (a PIN, for example).  If the caller passes a <code>null</code>

     * handler to this method, the provider uses the handler set in the

     * <code>setCallbackHandler</code> method.

     * If no handler was set in that method, the provider queries the

     * <i>auth.login.defaultCallbackHandler</i> security property

     * for the fully qualified class name of a default handler implementation.

     * If the security property is not set,

     * the provider is assumed to have alternative means

     * for obtaining authentication information.

     *

     * @param subject the <code>Subject</code> which may contain

     *          principals/credentials used for authentication,

     *          or may be populated with additional principals/credentials

     *          after successful authentication has completed.

     *          This parameter may be <code>null</code>.

     * @param handler the <code>CallbackHandler</code> used by

     *          this provider to obtain authentication information

     *          from the caller, which may be <code>null</code>

     *

     * @exception LoginException if the login operation fails

     * @exception SecurityException if the caller does not pass a

     *  security check for

     *  <code>SecurityPermission("authProvider.<i>name</i>")</code>,

     *  where <i>name</i> is the value returned by

     *  this provider's <code>getName</code> method

     */

    public abstract void login(Subject subject, CallbackHandler handler)

        throws LoginException;

    /**

     * Log out from this provider.

     *

     * @exception LoginException if the logout operation fails

     * @exception SecurityException if the caller does not pass a

     *  security check for

     *  <code>SecurityPermission("authProvider.<i>name</i>")</code>,

     *  where <i>name</i> is the value returned by

     *  this provider's <code>getName</code> method

     */

    public abstract void logout() throws LoginException;

    /**

     * Set a <code>CallbackHandler</code>.

     *

     * <p> The provider uses this handler if one is not passed to the

     * <code>login</code> method.  The provider also uses this handler

     * if it invokes <code>login</code> on behalf of callers.

     * In either case if a handler is not set via this method,

     * the provider queries the

     * <i>auth.login.defaultCallbackHandler</i> security property

     * for the fully qualified class name of a default handler implementation.

     * If the security property is not set,

     * the provider is assumed to have alternative means

     * for obtaining authentication information.

     *

     * @param handler a <code>CallbackHandler</code> for obtaining

     *          authentication information, which may be <code>null</code>

     *

     * @exception SecurityException if the caller does not pass a

     *  security check for

     *  <code>SecurityPermission("authProvider.<i>name</i>")</code>,

     *  where <i>name</i> is the value returned by

     *  this provider's <code>getName</code> method

     */

    public abstract void setCallbackHandler(CallbackHandler handler);

}