001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.apache.shiro.web.servlet;
020
021import org.slf4j.Logger;
022import org.slf4j.LoggerFactory;
023
024import javax.servlet.*;
025import java.io.IOException;
026import java.util.List;
027
028/**
029 * A proxied filter chain is a {@link FilterChain} instance that proxies an original {@link FilterChain} as well
030 * as a {@link List List} of other {@link Filter Filter}s that might need to execute prior to the final wrapped
031 * original chain.  It allows a list of filters to execute before continuing the original (proxied)
032 * {@code FilterChain} instance.
033 *
034 * @since 0.9
035 */
036public class ProxiedFilterChain implements FilterChain {
037
038    //TODO - complete JavaDoc
039
040    private static final Logger log = LoggerFactory.getLogger(ProxiedFilterChain.class);
041
042    private FilterChain orig;
043    private List<Filter> filters;
044    private int index = 0;
045
046    public ProxiedFilterChain(FilterChain orig, List<Filter> filters) {
047        if (orig == null) {
048            throw new NullPointerException("original FilterChain cannot be null.");
049        }
050        this.orig = orig;
051        this.filters = filters;
052        this.index = 0;
053    }
054
055    public void doFilter(ServletRequest request, ServletResponse response) throws IOException, ServletException {
056        if (this.filters == null || this.filters.size() == this.index) {
057            //we've reached the end of the wrapped chain, so invoke the original one:
058            if (log.isTraceEnabled()) {
059                log.trace("Invoking original filter chain.");
060            }
061            this.orig.doFilter(request, response);
062        } else {
063            if (log.isTraceEnabled()) {
064                log.trace("Invoking wrapped filter at index [" + this.index + "]");
065            }
066            this.filters.get(this.index++).doFilter(request, response, this);
067        }
068    }
069}