Blog: CDI Event Based Development with WebSockets and JBoss AS7

cdiJavascriptListener.js

window.addEventListener('memberEvent', function(e) {
    alert(e.name + ' just registered!');
}, false);

ChatServerServletContextListener.java

private Server server = null;
    /**
     * Start Embedding Jetty server when WEB Application is started.
     *
     */
    public void contextInitialized(ServletContextEvent event) {
        try {
            // 1) Create a Jetty server with the 8081 port.
            InetAddress addr = InetAddress.getLocalHost();
            this.server = new Server();
            Connector connector = new SelectChannelConnector();
            connector.setPort(8081);
            connector.setHost(addr.getHostAddress());

            server.addConnector(connector);

            // 2) Register ChatWebSocketHandler in the Jetty server instance.
            ChatWebSocketHandler chatWebSocketHandler = new ChatWebSocketHandler();
            chatWebSocketHandler.setHandler(new DefaultHandler());

            server.setHandler(chatWebSocketHandler);

            // 2) Start the Jetty server.
            server.start();
        } catch (Throwable e) {
            e.printStackTrace();
        }
    }

....
}

ChatWebSocketHandler-observer.java

    public void observeItemEvent(@Observes Member member) {
        try {
            for (ChatWebSocket webSocket : websockets) {
                webSocket.connection.sendMessage("{\"cdievent\":{\"fire\":function(){" +
                                                        "eventObj.initEvent(\'memberEvent\', true, true);" +
                                                        "eventObj.name = '" +  member.getName() + "';\n" +
                                                        "document.dispatchEvent(eventObj);" +
                                                        "}}}");
            }
        } catch (IOException x) {
            //todo - do something?
        }
    }

ChatWebSocketHandler.java

public class ChatWebSocketHandler extends WebSocketHandler {

    private static Set<ChatWebSocket> websockets = new ConcurrentHashSet<ChatWebSocket>();

    public WebSocket doWebSocketConnect(HttpServletRequest request,
            String protocol) {
        return new ChatWebSocket();
    }

    public class ChatWebSocket implements WebSocket.OnTextMessage {

        private Connection connection;

        public void onOpen(Connection connection) {
            // Client (Browser) WebSockets has opened a connection.
            // 1) Store the opened connection
            this.connection = connection;
            // 2) Add ChatWebSocket in the global list of ChatWebSocket
            // instances
            // instance.
            getWebsockets().add(this);
        }

        public void onMessage(String data) {
            // Loop for each instance of ChatWebSocket to send message server to
            // each client WebSockets.
            try {
                for (ChatWebSocket webSocket : getWebsockets()) {
                    // send a message to the current client WebSocket.
                    webSocket.connection.sendMessage(data);
                }
            } catch (IOException x) {
                // Error was detected, close the ChatWebSocket client side
                this.connection.disconnect();
            }

        }

        public void onClose(int closeCode, String message) {
            // Remove ChatWebSocket in the global list of ChatWebSocket
            // instance.
            getWebsockets().remove(this);
        }
    }

    public static synchronized Set<ChatWebSocket> getWebsockets() {
        return websockets;
    }

}

haproxy.config

global
    maxconn     4096 # Total Max Connections. This is dependent on ulimit
    nbproc      1

defaults
    mode        http

frontend all 0.0.0.0:8080
    timeout client 86400000
    default_backend www_backend
    acl is_websocket hdr(Upgrade) -i WebSocket
    acl is_websocket hdr_beg(Host) -i ws

    use_backend socket_backend if is_websocket

backend www_backend
    balance roundrobin
    option forwardfor # This sets X-Forwarded-For
    timeout server 30000
    timeout connect 4000
    server apiserver 192.168.1.101:8080 weight 1 maxconn 4096 check

backend socket_backend
    balance roundrobin
    option forwardfor # This sets X-Forwarded-For
    timeout queue 5000
    timeout server 86400000
    timeout connect 86400000
    server apiserver 192.168.1.101:8081 weight 1 maxconn 4096 check

MemberService.java

   @POST
   @Consumes(MediaType.APPLICATION_FORM_URLENCODED)
   @Produces(MediaType.APPLICATION_JSON)
   public Response createMember(@FormParam("name") String name, @FormParam("email") String email, @FormParam("phoneNumber") String phone) {
     ...

      //Create a new member class from fields
      Member member = new Member();
      member.setName(name);
      member.setEmail(email);
      member.setPhoneNumber(phone);

      try {

         //Fire the CDI event
         memberEventSrc.fire(member);

pom.xml

      <jettyVersion>8.1.0.RC2</jettyVersion>

      <dependency>
        <groupId>org.eclipse.jetty</groupId>
        <artifactId>jetty-continuation</artifactId>
        <version>${jettyVersion}</version>
      </dependency>

      <dependency>
        <groupId>org.eclipse.jetty</groupId>
        <artifactId>jetty-http</artifactId>
        <version>${jettyVersion}</version>
      </dependency>

       <dependency>
        <groupId>org.eclipse.jetty</groupId>
        <artifactId>jetty-io</artifactId>
        <version>${jettyVersion}</version>
      </dependency>

      <dependency>
        <groupId>org.eclipse.jetty</groupId>
        <artifactId>jetty-server</artifactId>
        <version>${jettyVersion}</version>
      </dependency>

       <dependency>
        <groupId>org.eclipse.jetty</groupId>
        <artifactId>jetty-util</artifactId>
        <version>${jettyVersion}</version>
      </dependency>

      <dependency>
        <groupId>org.eclipse.jetty</groupId>
        <artifactId>jetty-websocket</artifactId>
        <version>${jettyVersion}</version>
      </dependency>
   </dependencies>

websocketBasic.js

objWebSocket.onopen = function(evt)
{
   alert("WebSocket connection opened successfully");
};
objWebSocket.onmessage = function(evt)
{
   alert("Message : " + evt.data);
};
objWebSocket .onclose = function(evt)
{
   alert("WebSocket connection closed”);
};

websocketclient.js

        ...

        var location = "ws://192.168.1.101:8081/"
        this._ws = new WebSocket(location);  

        ....     

        _onmessage : function(m) {
            if (m.data) {

                //check to see if this message is a CDI event
                if(m.data.indexOf('cdievent') > 0){
                    try{
                        //$('log').innerHTML = m.data;

                        //avoid use of eval...
                        var event = (m.data);
                        event = (new Function("return " + event))();
                        event.cdievent.fire();
                    }catch(e){
                        alert(e);
                    }
                }else{
                    //... append data in the DOM
                }
            }
        },