</servlet-mapping>

    <servlet>

        <servlet-name>wsChat</servlet-name>

        <servlet-class>websocket.chat.ChatWebSocketServlet</servlet-class>

    </servlet>

    <servlet-mapping>

        <servlet-name>wsChat</servlet-name>

        <url-pattern>/websocket/chat</url-pattern>

        handleCollisions(snakes);

    }

    private void handleCollisions(Collection<Snake> snakes) {

    }

    public synchronized Location getHead() {

        return head;

/*

 * 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 websocket.chat;

import org.apache.catalina.websocket.MessageInbound;

import org.apache.catalina.websocket.StreamInbound;

import org.apache.catalina.websocket.WebSocketServlet;

import org.apache.catalina.websocket.WsOutbound;

import util.HTMLFilter;

import java.io.IOException;

import java.nio.ByteBuffer;

import java.nio.CharBuffer;

import java.util.Set;

import java.util.concurrent.CopyOnWriteArraySet;

import java.util.concurrent.atomic.AtomicInteger;

/**

 * Example web socket servlet for chat.

 */

public class ChatWebSocketServlet extends WebSocketServlet {

    private static final long serialVersionUID = 1L;

    private static final String GUEST_PREFIX = "Guest";

    private final AtomicInteger connectionIds = new AtomicInteger(0);

    private final Set<ChatMessageInbound> connections =

            new CopyOnWriteArraySet<ChatMessageInbound>();

    @Override

    protected StreamInbound createWebSocketInbound(String subProtocol) {

        return new ChatMessageInbound(connectionIds.incrementAndGet());

    }

    private final class ChatMessageInbound extends MessageInbound {

        private final String nickname;

        private ChatMessageInbound(int id) {

            this.nickname = GUEST_PREFIX + id;

        }

        @Override

        protected void onOpen(WsOutbound outbound) {

            connections.add(this);

            String message = String.format("* %s %s",

                    nickname, "has joined.");

            broadcast(message);

        }

        @Override

        protected void onClose(int status) {

            connections.remove(this);

            String message = String.format("* %s %s",

                    nickname, "has disconnected.");

            broadcast(message);

        }

        @Override

        protected void onBinaryMessage(ByteBuffer message) throws IOException {

            throw new UnsupportedOperationException(

                    "Binary message not supported.");

        }

        @Override

        protected void onTextMessage(CharBuffer message) throws IOException {

            // Never trust the client

            String filteredMessage = String.format("%s: %s",

                    nickname, HTMLFilter.filter(message.toString()));

            broadcast(filteredMessage);

        }

        private void broadcast(String message) {

            for (ChatMessageInbound connection : connections) {

                try {

                    CharBuffer buffer = CharBuffer.wrap(message);

                    connection.getWsOutbound().writeTextMessage(buffer);

                } catch (IOException ignore) {

                    // Ignore

                }

            }

        }

    }

}

<!--

  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.

-->

<!DOCTYPE html>

<html>

<head>

    <title>Apache Tomcat WebSocket Examples: Chat</title>

    <style type="text/css">

        input#chat {

            width: 410px

        }

        #console-container {

            width: 400px;

        }

        #console {

            border: 1px solid #CCCCCC;

            border-right-color: #999999;

            border-bottom-color: #999999;

            height: 170px;

            overflow-y: scroll;

            padding: 5px;

            width: 100%;

        }

        #console p {

            padding: 0;

            margin: 0;

        }

    </style>

    <script type="text/javascript">

        var Chat = {};

        Chat.socket = null;

        Chat.connect = (function(host) {

            if ('WebSocket' in window) {

                Chat.socket = new WebSocket(host);

            } else if ('MozWebSocket' in window) {

                Chat.socket = new MozWebSocket(host);

            } else {

                Console.log('Error: WebSocket is not supported by this browser.');

                return;

            }

            Chat.socket.onopen = function () {

                Console.log('Info: WebSocket connection opened.');

                document.getElementById('chat').onkeydown = function(event) {

                    if (event.keyCode == 13) {

                        Chat.sendMessage();

                    }

                };

            };

            Chat.socket.onclose = function () {

                document.getElementById('chat').onkeydown = null;

                Console.log('Info: WebSocket closed.');

            };

            Chat.socket.onmessage = function (message) {

                Console.log(message.data);

            };

        });

        Chat.initialize = function() {

            Chat.connect('ws://' + window.location.host + '/examples/websocket/chat');

        };

        Chat.sendMessage = (function() {

            var message = document.getElementById('chat').value;

            if (message != '') {

                Chat.socket.send(message);

                document.getElementById('chat').value = '';

            }

        });

        var Console = {};

        Console.log = (function(message) {

            var console = document.getElementById('console');

            var p = document.createElement('p');

            p.style.wordWrap = 'break-word';

            p.innerHTML = message;

            console.appendChild(p);

            while (console.childNodes.length > 25) {

                console.removeChild(console.firstChild);

            }

            console.scrollTop = console.scrollHeight;

        });

        Chat.initialize();

    </script>

</head>

<body>

<noscript><h2 style="color: #ff0000">Seems your browser doesn't support Javascript! Websockets rely on Javascript being enabled. Please enable

    Javascript and reload this page!</h2></noscript>

<div>

    <p>

        <input type="text" placeholder="type and press enter to chat" id="chat">

    </p>

    <div id="console-container">

        <div id="console"></div>

    </div>

</div>

</body>

</html>