zkoss/zk

/* Filter.java

    Purpose:
        
    Description:
        
    History:
        Mon Sep 22 18:18:53     2008, Created by tomyeh

Copyright (C) 2008 Potix Corporation. All Rights Reserved.

{{IS_RIGHT
    This program is distributed under LGPL Version 2.1 in the hope that
    it will be useful, but WITHOUT ANY WARRANTY.
}}IS_RIGHT
*/
package org.zkoss.web.util.resource;

import java.io.IOException;

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

/**
 * A filter is an object that performs filtering task on a request to
 * {@link Extendlet}.
 *
 * @author tomyeh
 * @since 3.5.1
 */
public interface Filter {
    /** Initializes the resource processor.
     */
    public void init(FilterConfig config);

    /** Causes the next filter in the chain to be invoked, or
     * if the calling filter is the last filter in the chain, causes the resource at the end of the chain to be invoked.
     *
     * @param request the request (never null).
     * @param response the response (never null).
     * @param pi the path info that the request is targeting.
     */
    public void doFilter(HttpServletRequest request, HttpServletResponse response, String pi, FilterChain chain)
            throws ServletException, IOException;
}