/*
* Copyright 2002-2016 the original author or authors.
*
* Licensed 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.springframework.web.context;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;
/**
* Bootstrap listener to start up and shut down Spring's root {@link WebApplicationContext}.
* Simply delegates to {@link ContextLoader} as well as to {@link ContextCleanupListener}.
*
* <p>As of Spring 3.1, {@code ContextLoaderListener} supports injecting the root web
* application context via the {@link #ContextLoaderListener(WebApplicationContext)}
* constructor, allowing for programmatic configuration in Servlet 3.0+ environments.
* See {@link org.springframework.web.WebApplicationInitializer} for usage examples.
*
* @author Juergen Hoeller
* @author Chris Beams
* @since 17.02.2003
* @see #setContextInitializers
* @see org.springframework.web.WebApplicationInitializer
*/
public class ContextLoaderListener extends ContextLoader implements ServletContextListener {
/**
* Create a new {@code ContextLoaderListener} that will create a web application
* context based on the "contextClass" and "contextConfigLocation" servlet
* context-params. See {@link ContextLoader} superclass documentation for details on
* default values for each.
* <p>This constructor is typically used when declaring {@code ContextLoaderListener}
* as a {@code <listener>} within {@code web.xml}, where a no-arg constructor is
* required.
* <p>The created application context will be registered into the ServletContext under
* the attribute name {@link WebApplicationContext#ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE}
* and the Spring application context will be closed when the {@link #contextDestroyed}
* lifecycle method is invoked on this listener.
* @see ContextLoader
* @see #ContextLoaderListener(WebApplicationContext)
* @see #contextInitialized(ServletContextEvent)
* @see #contextDestroyed(ServletContextEvent)
*/
public ContextLoaderListener() {
}
/**
* Create a new {@code ContextLoaderListener} with the given application context. This
* constructor is useful in Servlet 3.0+ environments where instance-based
* registration of listeners is possible through the {@link javax.servlet.ServletContext#addListener}
* API.
* <p>The context may or may not yet be {@linkplain
* org.springframework.context.ConfigurableApplicationContext#refresh() refreshed}. If it
* (a) is an implementation of {@link ConfigurableWebApplicationContext} and
* (b) has <strong>not</strong> already been refreshed (the recommended approach),
* then the following will occur:
* <ul>
* <li>If the given context has not already been assigned an {@linkplain
* org.springframework.context.ConfigurableApplicationContext#setId id}, one will be assigned to it</li>
* <li>{@code ServletContext} and {@code ServletConfig} objects will be delegated to
* the application context</li>
* <li>{@link #customizeContext} will be called</li>
* <li>Any {@link org.springframework.context.ApplicationContextInitializer ApplicationContextInitializer}s
* specified through the "contextInitializerClasses" init-param will be applied.</li>
* <li>{@link org.springframework.context.ConfigurableApplicationContext#refresh refresh()} will be called</li>
* </ul>
* If the context has already been refreshed or does not implement
* {@code ConfigurableWebApplicationContext}, none of the above will occur under the
* assumption that the user has performed these actions (or not) per his or her
* specific needs.
* <p>See {@link org.springframework.web.WebApplicationInitializer} for usage examples.
* <p>In any case, the given application context will be registered into the
* ServletContext under the attribute name {@link
* WebApplicationContext#ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE} and the Spring
* application context will be closed when the {@link #contextDestroyed} lifecycle
* method is invoked on this listener.
* @param context the application context to manage
* @see #contextInitialized(ServletContextEvent)
* @see #contextDestroyed(ServletContextEvent)
*/
public ContextLoaderListener(WebApplicationContext context) {
super(context);
}
/**
* Initialize the root web application context.
*/
@Override
public void contextInitialized(ServletContextEvent event) {
initWebApplicationContext(event.getServletContext());
}
/**
* Close the root web application context.
*/
@Override
public void contextDestroyed(ServletContextEvent event) {
closeWebApplicationContext(event.getServletContext());
ContextCleanupListener.cleanupAttributes(event.getServletContext());
}
}