/*
 * Copyright (c) 1998-2003 Caucho Technology -- all rights reserved
 *
 * This file is part of Resin(R) Open Source
 *
 * Each copy or derived work must preserve the copyright notice and this
 * notice unmodified.
 *
 * Resin Open Source is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Resin Open Source 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, or any warranty
 * of NON-INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Resin Open Source; if not, write to the
 *   Free SoftwareFoundation, Inc.
 *   59 Temple Place, Suite 330
 *   Boston, MA 02111-1307  USA
 *
 * @author Scott Ferguson
 *
 * $Id: Filter.java,v 1.2 2004/09/29 00:12:46 cvs Exp $
 */

package javax.servlet;

import java.io.IOException;

/**
 * Filters the request or response to a servlet.  Filters will
 * typically call the next filter in the chain, eventually reaching
 * the servlet at the bottom.
 *
 * @since Servlet 2.3
 */
public interface Filter {
  /**
   * Initialize the filter.
   */
  public void init(FilterConfig filterConfig)
    throws ServletException;

  /**
   * doFilter performs the actual work of a filter, either modifying
   * the request or the response.  It will typically call the
   * chain.doFilter() to invoke the next filter in the chain.
   *
   * @param request the servlet request
   * @param response the servlet response
   * @param chain the next filter in the chain
   */
  public void doFilter(ServletRequest request,
                       ServletResponse response,
                       FilterChain chain)
    throws ServletException, IOException;

  /**
   * Cleanup the filter.
   */
  public void destroy();
}
