xref: /unit/src/java/nginx/unit/websocket/server/WsContextListener.java (revision 1157:7ae152bda303)
1 /*
2  *  Licensed to the Apache Software Foundation (ASF) under one or more
3  *  contributor license agreements.  See the NOTICE file distributed with
4  *  this work for additional information regarding copyright ownership.
5  *  The ASF licenses this file to You under the Apache License, Version 2.0
6  *  (the "License"); you may not use this file except in compliance with
7  *  the License.  You may obtain a copy of the License at
8  *
9  *      http://www.apache.org/licenses/LICENSE-2.0
10  *
11  *  Unless required by applicable law or agreed to in writing, software
12  *  distributed under the License is distributed on an "AS IS" BASIS,
13  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  *  See the License for the specific language governing permissions and
15  *  limitations under the License.
16  */
17 package nginx.unit.websocket.server;
18 
19 import javax.servlet.ServletContext;
20 import javax.servlet.ServletContextEvent;
21 import javax.servlet.ServletContextListener;
22 
23 /**
24  * In normal usage, this {@link ServletContextListener} does not need to be
25  * explicitly configured as the {@link WsSci} performs all the necessary
26  * bootstrap and installs this listener in the {@link ServletContext}. If the
27  * {@link WsSci} is disabled, this listener must be added manually to every
28  * {@link ServletContext} that uses WebSocket to bootstrap the
29  * {@link WsServerContainer} correctly.
30  */
31 public class WsContextListener implements ServletContextListener {
32 
33     @Override
contextInitialized(ServletContextEvent sce)34     public void contextInitialized(ServletContextEvent sce) {
35         ServletContext sc = sce.getServletContext();
36         // Don't trigger WebSocket initialization if a WebSocket Server
37         // Container is already present
38         if (sc.getAttribute(Constants.SERVER_CONTAINER_SERVLET_CONTEXT_ATTRIBUTE) == null) {
39             WsSci.init(sce.getServletContext(), false);
40         }
41     }
42 
43     @Override
contextDestroyed(ServletContextEvent sce)44     public void contextDestroyed(ServletContextEvent sce) {
45         ServletContext sc = sce.getServletContext();
46         Object obj = sc.getAttribute(Constants.SERVER_CONTAINER_SERVLET_CONTEXT_ATTRIBUTE);
47         if (obj instanceof WsServerContainer) {
48             ((WsServerContainer) obj).destroy();
49         }
50     }
51 }
52