//
   //  ========================================================================
   //  Copyright (c) 1995-2016 Mort Bay Consulting Pty. Ltd.
   //  ------------------------------------------------------------------------
   //  All rights reserved. This program and the accompanying materials
   //  are made available under the terms of the Eclipse Public License v1.0
   //  and Apache License v2.0 which accompanies this distribution.
   //
   //      The Eclipse Public License is available at
  //      http://www.eclipse.org/legal/epl-v10.html
  //
  //      The Apache License v2.0 is available at
  //      http://www.opensource.org/licenses/apache2.0.php
  //
  //  You may elect to redistribute this code under either of these licenses.
  //  ========================================================================
  //
  
  package com.acme;
  
  import java.io.IOException;
  import java.util.List;
  import java.util.ListIterator;
  import java.util.concurrent.CopyOnWriteArrayList;
  
  import javax.servlet.ServletException;
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  
  import org.eclipse.jetty.websocket.api.RemoteEndpoint;
  import org.eclipse.jetty.websocket.api.Session;
  import org.eclipse.jetty.websocket.api.annotations.OnWebSocketClose;
  import org.eclipse.jetty.websocket.api.annotations.OnWebSocketConnect;
  import org.eclipse.jetty.websocket.api.annotations.OnWebSocketMessage;
  import org.eclipse.jetty.websocket.api.annotations.WebSocket;
  import org.eclipse.jetty.websocket.servlet.ServletUpgradeRequest;
  import org.eclipse.jetty.websocket.servlet.ServletUpgradeResponse;
  import org.eclipse.jetty.websocket.servlet.WebSocketCreator;
  import org.eclipse.jetty.websocket.servlet.WebSocketServlet;
  import org.eclipse.jetty.websocket.servlet.WebSocketServletFactory;
  
  @SuppressWarnings("serial")
  public class WebSocketChatServlet extends WebSocketServlet implements WebSocketCreator
  {
      /** Holds active sockets to other members of the chat */
      private final List<ChatWebSocket> members = new CopyOnWriteArrayList<ChatWebSocket>();
  
      @Override
      protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
      {
          getServletContext().getNamedDispatcher("default").forward(request,response);
      }
  
      @Override
      public Object createWebSocket(ServletUpgradeRequest req, ServletUpgradeResponse resp)
      {
          if (req.hasSubProtocol("chat"))
          {
              resp.setAcceptedSubProtocol("chat");
              return new ChatWebSocket();
          }
          return null;
      }
  
      @Override
      public void configure(WebSocketServletFactory factory)
      {
          factory.register(ChatWebSocket.class);
          factory.setCreator(this);
      }
  
      /* ------------------------------------------------------------ */
      /**
       * Create a WebSocket that echo's back the message to all other members of the servlet.
       */
      @WebSocket
      public class ChatWebSocket
      {
          volatile Session session;
          volatile RemoteEndpoint remote;
  
          @OnWebSocketConnect
          public void onOpen(Session sess)
          {
              this.session = sess;
              this.remote = sess.getRemote();
              members.add(this);
          }
  
          @OnWebSocketMessage
          public void onMessage(String data)
          {
              if (data.contains("disconnect"))
              {
                  session.close();
                  return;
              }
  
              ListIterator<ChatWebSocket> iter = members.listIterator();
             while (iter.hasNext())
             {
                 ChatWebSocket member = iter.next();
 
                 // Test if member is now disconnected
                 if (!member.session.isOpen())
                 {
                     iter.remove();
                     continue;
                 }
 
                 // Async write the message back.
                 member.remote.sendString(data,null);
             }
         }
 
         @OnWebSocketClose
         public void onClose(int code, String message)
         {
             members.remove(this);
         }
     }
 }