/*
 * Copyright (C) 2005-2010 Alfresco Software Limited.
 *
 * This file is part of Alfresco
 *
 * Alfresco 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 3 of the License, or
 * (at your option) any later version.
 *
 * Alfresco 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 Alfresco. If not, see <http://www.gnu.org/licenses/>.
 */
package org.alfresco.web.app.servlet;

import javax.servlet.http.HttpServletRequest;

/**
 * An interface for objects capable of extracting an externally authenticated user ID from an HTTP request.
 * 
 * @author dward
 */
public interface RemoteUserMapper
{
   /**
    * Gets an externally authenticated user ID from an HTTP request.
    * 
    * @param request
    *           the request
    * @return the user ID or <code>null</code> if the user is unauthenticated
    */
   public String getRemoteUser(HttpServletRequest request);
}