Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ package org.jsecurity.web.servlet; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import javax.servlet.*; import java.io.IOException; import java.util.List; /** * @author Les Hazlewood * @since 0.9 */ public class FilterChainWrapper implements FilterChain { private static final Log log = LogFactory.getLog(FilterChainWrapper.class); private FilterChain orig; private List<Filter> filters; private int index = 0; public FilterChainWrapper(FilterChain orig, List<Filter> filters) { this.orig = orig; this.filters = filters; this.index = 0; } public void doFilter(ServletRequest request, ServletResponse response) throws IOException, ServletException { if (this.filters == null || this.filters.size() == this.index) { //we've reached the end of the wrapped chain, so invoke the original one: if (log.isTraceEnabled()) { log.trace("Invoking original filter chain."); } this.orig.doFilter(request, response); } else { if (log.isTraceEnabled()) { log.trace("Invoking wrapped filter at index [" + this.index + "]"); } this.filters.get(this.index++).doFilter(request, response, this); } } }