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