/*
* 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.felix.http.samples.cometd;
import java.io.IOException;
import java.io.PrintWriter;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Timer;
import java.util.TimerTask;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.cometd.bayeux.MarkedReference;
import org.cometd.bayeux.server.BayeuxServer;
import org.cometd.bayeux.server.ConfigurableServerChannel;
import org.cometd.bayeux.server.LocalSession;
import org.cometd.bayeux.server.ServerChannel;
import org.cometd.bayeux.server.ServerMessage;
public class TimeServlet
extends HttpServlet
{
private static final long serialVersionUID = 1L;
private enum SystemTopics {
Time
};
private BayeuxServer bayeuxServer;
private LocalSession session;
private List<ServerChannel> channels;
private Timer updateTimer;
private SimpleDateFormat logDateFormat;
private String html =
"<html>\n" +
" <head>\n" +
" <title>System Information</title>\n" +
" <script type='text/javascript' src='/js/dojo/dojo.js'></script>\n" +
" <script type='text/javascript'>\n" +
" dojo.require('dojox.cometd');\n" +
"dojo.addOnLoad(function()\n" +
"{\n" +
" var cometd = dojox.cometd;\n" +
"\n" +
" function _connectionEstablished()\n" +
" {\n" +
" dojo.byId('body').innerHTML += '<div>CometD Connection Established</div>';\n" +
" }\n" +
"\n" +
" function _connectionBroken()\n" +
" {\n" +
" dojo.byId('body').innerHTML += '<div>CometD Connection Broken</div>';\n" +
" }\n" +
"\n" +
" function _connectionClosed()\n" +
" {\n" +
" dojo.byId('body').innerHTML += '<div>CometD Connection Closed</div>';\n" +
" }\n" +
"\n" +
" // Function that manages the connection status with the Bayeux server\n" +
" var _connected = false;\n" +
" function _metaConnect(message)\n" +
" {\n" +
" if (cometd.isDisconnected())\n" +
" {\n" +
" _connected = false;\n" +
" _connectionClosed();\n" +
" return;\n" +
" }\n" +
"\n" +
" var wasConnected = _connected;\n" +
" _connected = message.successful === true;\n" +
" if (!wasConnected && _connected)\n" +
" {\n" +
" _connectionEstablished();\n" +
" }\n" +
" else if (wasConnected && !_connected)\n" +
" {\n" +
" _connectionBroken();\n" +
" }\n" +
" }\n" +
"\n" +
" // Function invoked when first contacting the server and\n" +
" // when the server has lost the state of this client\n" +
" function _metaHandshake(handshake)\n" +
" {\n" +
" if (handshake.successful === true)\n" +
" {\n" +
" cometd.batch(function()\n" +
" {\n" +
" cometd.subscribe('/System/Time', function(message)\n" +
" {\n" +
" dojo.byId('systemTime').innerHTML = '<div>' + message.data + '</div>';\n" +
" });\n" +
" });\n" +
" }\n" +
" }\n" +
"\n" +
" // Disconnect when the page unloads\n" +
" dojo.addOnUnload(function()\n" +
" {\n" +
" cometd.disconnect(true);\n" +
" });\n" +
"\n" +
" var cometURL = \"http://localhost:8080/system/cometd\";\n" +
" cometd.configure({\n" +
" url: cometURL,\n" +
" logLevel: 'debug'\n" +
" });\n" +
"\n" +
" cometd.addListener('/meta/handshake', _metaHandshake);\n" +
" cometd.addListener('/meta/connect', _metaConnect);\n" +
"\n" +
" cometd.handshake();\n" +
"});\n" +
" </script>\n" +
" </head>\n" +
" <body>\n" +
" <h2 id='systemTime'></h2>\n" +
" </body>\n" +
"</html>\n";
public TimeServlet(BayeuxServer bayeuxServer)
{
this.bayeuxServer = bayeuxServer;
this.channels = new ArrayList<ServerChannel>();
for (SystemTopics topic : SystemTopics.values()) {
MarkedReference<ServerChannel> created = bayeuxServer.createChannelIfAbsent("/System/" + topic, new ConfigurableServerChannel.Initializer() {
@Override
public void configureChannel(ConfigurableServerChannel channel) {
channel.setPersistent(true);
}
});
this.channels.add(topic.ordinal(), created.getReference());
}
this.logDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
this.updateTimer = new Timer("System.Time.ClientNotifier");
this.updateTimer.scheduleAtFixedRate(new ClientNotifier(), 1000, 1000);
this.session = bayeuxServer.newLocalSession(TimeServlet.class.getName());
this.session.handshake();
}
@Override
public void init(ServletConfig config)
throws ServletException
{
doLog("Init with config [" + config + "]");
super.init(config);
}
@Override
public void destroy()
{
doLog("Destroyed servlet");
this.updateTimer.cancel();
this.session.disconnect();
super.destroy();
}
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException
{
res.setContentType("text/html");
PrintWriter out = res.getWriter();
out.println(this.html);
}
private void doLog(String message)
{
System.out.println("## TimeServlet: " + message);
}
private class ClientNotifier
extends TimerTask
{
@Override
public void run() {
for (SystemTopics topic : SystemTopics.values()) {
String topicData;
switch (topic) {
case Time:
topicData = logDateFormat.format(new Date());
break;
default:
topicData = "unknown topic: " + topic.toString();
}
ServerMessage.Mutable message = bayeuxServer.newMessage();
message.setChannel(channels.get(topic.ordinal()).getId());
message.setData(topicData);
channels.get(topic.ordinal()).publish(session, message);
}
}
}
}