/*

  * 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.apache.shiro.web.env;

 import javax.servlet.ServletContextEvent;

 import javax.servlet.ServletContextListener;

 /**

  * Bootstrap listener to startup and shutdown the web application's Shiro

  * {@link WebEnvironment} at ServletContext startup and shutdown respectively.  This class exists only to

  * implement the {@link ServletContextListener} interface. All 'real' logic is done in the parent

  * {@link EnvironmentLoader} class.

  * <h2>Usage</h2>

  * Define the following in {@code web.xml}:

  * <pre>

  * <listener>

  *     &lt;listener-class&gt;<code>org.apache.shiro.web.env.EnvironmentLoaderListener</code>&lt;/listener-class&gt;

  * </listener>

  * </pre>

  * Configuration options, such as the {@code WebEnvironment} class to instantiate as well as Shiro configuration

  * resource locations are specified as {@code ServletContext} {@code context-param}s and are documented in the

  * {@link EnvironmentLoader} JavaDoc.

  * <h2>Shiro Filter</h2>

  * This listener is almost always defined in conjunction with the

  * {@link org.apache.shiro.web.servlet.ShiroFilter ShiroFilter} to ensure security operations for web requests.  Please

  * see the {@link org.apache.shiro.web.servlet.ShiroFilter ShiroFilter} JavaDoc for more.

  *

  *

  * @see EnvironmentLoader

  * @see org.apache.shiro.web.servlet.ShiroFilter ShiroFilter

  * @since 1.2

  */

 public class EnvironmentLoaderListener extends EnvironmentLoader implements ServletContextListener {

     /**

      * Initializes the Shiro {@code WebEnvironment} and binds it to the {@code ServletContext} at application

      * startup for future reference.

      *

      * @param sce the ServletContextEvent triggered upon application startup

      */

     public void contextInitialized(ServletContextEvent sce) {

         initEnvironment(sce.getServletContext());

     }

     /**

      * Destroys any previously created/bound {@code WebEnvironment} instance created by

      * the {@link #contextInitialized(javax.servlet.ServletContextEvent)} method.

      *

      * @param sce the ServletContextEvent triggered upon application shutdown

      */

     public void contextDestroyed(ServletContextEvent sce) {

         destroyEnvironment(sce.getServletContext());

     }

 }