java/org/apache/tomcat/websocket/server/WsContextListener.java

/*
 *  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.tomcat.websocket.server;

import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;

/**
 * In normal usage, this {@link ServletContextListener} does not need to be
 * explicitly configured as the {@link WsSci} performs all the necessary
 * bootstrap and installs this listener in the {@link ServletContext}. If the
 * {@link WsSci} is disabled, this listener must be added manually to every
 * {@link ServletContext} that uses WebSocket to bootstrap the
 * {@link WsServerContainer} correctly.
 */
public class WsContextListener implements ServletContextListener {

    @Override
    public void contextInitialized(ServletContextEvent sce) {
        ServletContext sc = sce.getServletContext();
        // Don't trigger WebSocket initialization if a WebSocket Server
        // Container is already present
        if (sc.getAttribute(Constants.SERVER_CONTAINER_SERVLET_CONTEXT_ATTRIBUTE) == null) {
            WsSci.init(sce.getServletContext(), false);
        }
    }

    @Override
    public void contextDestroyed(ServletContextEvent sce) {
        ServletContext sc = sce.getServletContext();
        Object obj = sc.getAttribute(Constants.SERVER_CONTAINER_SERVLET_CONTEXT_ATTRIBUTE);
        if (obj instanceof WsServerContainer) {
            ((WsServerContainer) obj).destroy();
        }
    }
}