/*
 *  eXist Open Source Native XML Database
 *  Copyright (C) 2001-04 Wolfgang M. Meier
 *  wolfgang@exist-db.org
 *  http://exist-db.org
 *
 *  This program 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
 *  of the License, or (at your option) any later version.
 *
 *  This program 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 program; if not, write to the Free Software
 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 * 
 *  $Id$
 */
package org.exist.http.servlets;
import java.io.IOException;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.exist.security.User;

/**
 * Interface for HTTP authentication methods.
 * 
 * @author wolf
 */
public interface Authenticator {
	
    /**
     * Try to authenticate the user specified in the HTTP request.
     * 
     * @param request
     * @param response
     * @return The authenticated user or null if the user isn't autenticated
     * @throws IOException
     */
	public User authenticate(HttpServletRequest request, HttpServletResponse response)
	throws IOException;
	
	/**
	 * Send an WWW-Authenticate header back to client.
	 * 
	 * @param request
	 * @param response
	 * @throws IOException
	 */
	public void sendChallenge(HttpServletRequest request,
			HttpServletResponse response) throws IOException;
}