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.env;
020
021import javax.servlet.ServletContextEvent;
022import javax.servlet.ServletContextListener;
023
024/**
025 * Bootstrap listener to startup and shutdown the web application's Shiro
026 * {@link WebEnvironment} at ServletContext startup and shutdown respectively.  This class exists only to
027 * implement the {@link ServletContextListener} interface. All 'real' logic is done in the parent
028 * {@link EnvironmentLoader} class.
029 * <h2>Usage</h2>
030 * Define the following in {@code web.xml}:
031 * <pre>
032 * &lt;listener&gt;
033 *     &lt;listener-class&gt;<code>org.apache.shiro.web.env.EnvironmentLoaderListener</code>&lt;/listener-class&gt;
034 * &lt;/listener&gt;
035 * </pre>
036 * Configuration options, such as the {@code WebEnvironment} class to instantiate as well as Shiro configuration
037 * resource locations are specified as {@code ServletContext} {@code context-param}s and are documented in the
038 * {@link EnvironmentLoader} JavaDoc.
039 * <h2>Shiro Filter</h2>
040 * This listener is almost always defined in conjunction with the
041 * {@link org.apache.shiro.web.servlet.ShiroFilter ShiroFilter} to ensure security operations for web requests.  Please
042 * see the {@link org.apache.shiro.web.servlet.ShiroFilter ShiroFilter} JavaDoc for more.
043 *
044 *
045 * @see EnvironmentLoader
046 * @see org.apache.shiro.web.servlet.ShiroFilter ShiroFilter
047 * @since 1.2
048 */
049public class EnvironmentLoaderListener extends EnvironmentLoader implements ServletContextListener {
050
051    /**
052     * Initializes the Shiro {@code WebEnvironment} and binds it to the {@code ServletContext} at application
053     * startup for future reference.
054     *
055     * @param sce the ServletContextEvent triggered upon application startup
056     */
057    public void contextInitialized(ServletContextEvent sce) {
058        initEnvironment(sce.getServletContext());
059    }
060
061    /**
062     * Destroys any previously created/bound {@code WebEnvironment} instance created by
063     * the {@link #contextInitialized(javax.servlet.ServletContextEvent)} method.
064     *
065     * @param sce the ServletContextEvent triggered upon application shutdown
066     */
067    public void contextDestroyed(ServletContextEvent sce) {
068        destroyEnvironment(sce.getServletContext());
069    }
070}