* Copyright 2011 JBoss, by Red Hat, Inc

*

* Licensed 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.

*/

* The default client <tt>MessageBus</tt> implementation.  This bus runs in the browser and automatically federates

* with the server immediately upon initialization.

*

* @author Mike Brock

*/

  private String clientId;

  private String sessionId;

  /* The encoded URL to be used for the bus */

  String OUT_SERVICE_ENTRY_POINT = "out.erraiBus";

  String IN_SERVICE_ENTRY_POINT = "in.erraiBus";

  /* ArrayList of all subscription listeners */

  private List<SubscribeListener> onSubscribeHooks;

  /* ArrayList of all unsubscription listeners */

  private List<UnsubscribeListener> onUnsubscribeHooks;

  /* Used to build the HTTP POST request */

  private RequestBuilder sendBuilder;

  private volatile boolean cometChannelOpen = true;

  private volatile boolean webSocketOpen = false;

  private String webSocketUrl;

  private String webSocketToken;

  private Object webSocketChannel;

  public final MessageCallback remoteCallback = new RemoteMessageCallback();

  private RequestCallback receiveCommCallback = new NoPollRequestCallback();

  private Map<String, List<MessageCallback>> subscriptions =

          new HashMap<String, List<MessageCallback>>();

  private Map<String, List<MessageCallback>> localSubscriptions =

          new HashMap<String, List<MessageCallback>>();

  private Map<String, MessageCallback> remotes;

  private List<SessionExpirationListener> sessionExpirationListeners

          = new ArrayList<SessionExpirationListener>();

  private List<PreInitializationListener> preInitializationListeners

          = new ArrayList<PreInitializationListener>();

  /* Map of subjects to references registered in this session */

  private Map<String, List<Object>> registeredInThisSession = new HashMap<String, List<Object>>();

  /* A list of {@link Runnable} initialization tasks to be executed after the bus has successfully finished it's

* initialization and is now communicating with the remote bus. */

  private List<Runnable> postInitTasks = new ArrayList<Runnable>();

  private List<Message> deferredMessages = new ArrayList<Message>();

  private Queue<Message> toSendBuffer = new LinkedList<Message>();

  /* True if the client's message bus has been initialized */

  private boolean initialized = false;

  private boolean reinit = false;

  private boolean postInit = false;

  /**

   * The unique ID that will sent with the next request.

   * <p/>

   * IMPORTANT: only access this member via {@link #getNextRequestNumber()}.

   */

  private int txNumber = 0;

  private int rxNumber = 0;

  private long lastTx = System.currentTimeMillis();

  private boolean disconnected = false;

  private BusErrorDialog errorDialog;

  static {

    MarshallerFramework.initializeDefaultSessionProvider();

  }

  private List<MessageInterceptor> interceptorStack = new LinkedList<MessageInterceptor>();

  private LogAdapter logAdapter = new LogAdapter() {

    @Override

    public void warn(String message) {

      GWT.log("WARN: " + message, null);

    }

    @Override

    public void info(String message) {

      GWT.log("INFO: " + message, null);

    }

    @Override

    public void debug(String message) {

      GWT.log("DEBUG: " + message, null);

    }

    @Override

    public void error(String message, Throwable t) {

      showError(message, t);

    }

  };

  public ClientMessageBusImpl() {

    init();

  }

  private void createRequestBuilders() {

    sendBuilder = getSendBuilder();

    logAdapter.debug("Connecting Errai at URL " + sendBuilder.getUrl());

  }

  private RequestBuilder getSendBuilder() {

    String endpoint = OUT_SERVICE_ENTRY_POINT;

    RequestBuilder builder = new RequestBuilder(

            RequestBuilder.POST,

            URL.encode(endpoint) + "?z=" + getNextRequestNumber()

    );

    builder.setHeader("Content-Type", "application/json");

    builder.setHeader(ClientMessageBus.REMOTE_QUEUE_ID_HEADER, clientId);

    return builder;

  }

  private RequestBuilder getRecvBuilder() {

    String endpoint = IN_SERVICE_ENTRY_POINT;

    RequestBuilder builder = new RequestBuilder(

            RequestBuilder.GET,

            URL.encode(endpoint) + "?z=" + getNextRequestNumber()

    );

    builder.setHeader("Content-Type", "application/json");

    builder.setHeader(ClientMessageBus.REMOTE_QUEUE_ID_HEADER, clientId);

    return builder;

  }

  /**

   * Removes all subscriptions attached to the specified subject

   *

   * @param subject - the subject to have all it's subscriptions removed

   */

  @Override

  public void unsubscribeAll(String subject) {

    fireAllUnSubscribeListeners(subject);

    removeSubscriptionTopic(subject);

  }

  /**

   * Add a subscription for the specified subject

   *

   * @param subject  - the subject to add a subscription for

   * @param callback - function called when the message is dispatched

   */

  @Override

  public Subscription subscribe(final String subject, final MessageCallback callback) {

    return _subscribe(subject, callback, false);

  }

  @Override

  public Subscription subscribeLocal(final String subject, final MessageCallback callback) {

    return _subscribe(subject, callback, true);

  }

  private Subscription _subscribe(final String subject, final MessageCallback callback, final boolean local) {

    if (BuiltInServices.ServerBus.name().equals(subject) && subscriptions.containsKey(BuiltInServices.ServerBus.name()))

      return null;

    if (!postInit) {

      final DeferredSubscription deferredSubscription = new DeferredSubscription();

      addPostInitTask(new Runnable() {

        @Override

        public void run() {

          deferredSubscription.attachSubscription(_subscribe(subject, callback, local));

        }

      });

      return deferredSubscription;

    }

    fireAllSubscribeListeners(subject, local, directSubscribe(subject, callback, local));

    return new Subscription() {

      @Override

      public void remove() {

        List<MessageCallback> cbs = local ? localSubscriptions.get(subject) : subscriptions.get(subject);

        if (cbs != null) {

          cbs.remove(callback);

        }

      }

    };

  }

  private boolean directSubscribe(final String subject, final MessageCallback callback, boolean local) {

    boolean isNew = !isSubscribed(subject);

    MessageCallback cb = new MessageCallback() {

      @Override

      public void callback(Message message) {

        try {

          executeInterceptorStack(true, message);

          callback.callback(message);

        }

        catch (Exception e) {

          logError("receiver '" + subject + "' threw an exception", decodeCommandMessage(message), e);

        }

      }

    };

    if (local) {

      addLocalSubscriptionEntry(subject, cb);

    }

    else {

      addSubscriptionEntry(subject, cb);

    }

    return isNew;

  }

  /**

   * Fire listeners to notify that a new subscription has been registered on the bus.

   *

   * @param subject - new subscription registered

   * @param local   -

   * @param isNew   -

   */

  private void fireAllSubscribeListeners(String subject, boolean local, boolean isNew) {

    Iterator<SubscribeListener> iter = onSubscribeHooks.iterator();

    SubscriptionEvent evt = new SubscriptionEvent(false, false, local, isNew, 1, "InBrowser", subject);

    while (iter.hasNext()) {

      iter.next().onSubscribe(evt);

      if (evt.isDisposeListener()) {

        iter.remove();

        evt.setDisposeListener(false);

      }

    }

  }

  /**

   * Fire listeners to notify that a subscription has been unregistered from the bus

   *

   * @param subject - subscription unregistered

   */

  private void fireAllUnSubscribeListeners(String subject) {

    Iterator<UnsubscribeListener> iter = onUnsubscribeHooks.iterator();

    SubscriptionEvent evt = new SubscriptionEvent(false, "InBrowser", 0, false, subject);

    while (iter.hasNext()) {

      iter.next().onUnsubscribe(evt);

      if (evt.isDisposeListener()) {

        iter.remove();

        evt.setDisposeListener(false);

      }

    }

  }

  private static int conversationCounter = 0;

  /**

   * Have a single two-way conversation

   *

   * @param message  - The message to be sent in the conversation

   * @param callback - The function to be called when the message is received

   */

  @Override

  public void conversationWith(final Message message, final MessageCallback callback) {

    final String tempSubject = "temp:Reply:" + (++conversationCounter);

    message.set(ReplyTo, tempSubject);

    subscribe(tempSubject, new MessageCallback() {

      @Override

      public void callback(Message message) {

        unsubscribeAll(tempSubject);

        callback.callback(message);

      }

    });

    send(message);

  }

  /**

   * Globally send message to all receivers.

   *

   * @param message - The message to be sent.

   */

  @Override

  public void sendGlobal(Message message) {

    send(message);

  }

  /**

   * Sends the specified message, and notifies the listeners.

   *

   * @param message       - the message to be sent

   * @param fireListeners - true if the appropriate listeners should be fired

   */

  @Override

  public void send(Message message, boolean fireListeners) {

    // TODO: fire listeners?

    send(message);

  }

  private static final ResourceProvider<RequestDispatcher> dispatcherProvider

          = new ResourceProvider<RequestDispatcher>() {

    @Override

    public RequestDispatcher get() {

      return ErraiBus.getDispatcher();

    }

  };

  /**

   * Sends the message using it's encoded subject. If the bus has not been initialized, it will be added to

   * <tt>postInitTasks</tt>.

   *

   * @param message -

   * @throws RuntimeException - if message does not contain a ToSubject field or if the message's callback throws

   *                          an error.

   */

  @Override

  public void send(final Message message) {

    message.setResource(RequestDispatcher.class.getName(), dispatcherProvider);

    message.setResource("Session", JSONUtilCli.getClientSession());

    executeInterceptorStack(false, message);

    message.commit();

    try {

      if (message.hasPart(MessageParts.ToSubject)) {

        if (!initialized) {

          deferredMessages.add(message);

        }

        else {

          if (!hasListeners(message.getSubject())) {

            throw new NoSubscribersToDeliverTo(message.getSubject());

          }

          directStore(message);

        }

      }

      else {

        throw new RuntimeException("Cannot send message using this method" +

                " if the message does not contain a ToSubject field.");

      }

    }

    catch (RuntimeException e) {

      callErrorHandler(message, e);

      throw e;

    }

  }

  private boolean hasListeners(String subject) {

    return subscriptions.containsKey(subject)

            || remotes.containsKey(subject)

            || localSubscriptions.containsKey(subject);

  }

  private void callErrorHandler(final Message message, final Throwable t) {

    if (message.getErrorCallback() != null) {

      message.getErrorCallback().error(message, t);

    }

    logError(t.getMessage(), "none", t);

  }

  private void directStore(final Message message) {

    String subject = message.getSubject();

    if (remotes.containsKey(subject)) {

      remotes.get(subject).callback(message);

    }

    else if (subscriptions.containsKey(subject)) {

      deliverToSubscriptions(subscriptions, subject, message);

    }

    else if (localSubscriptions.containsKey(subject)) {

      deliverToSubscriptions(localSubscriptions, subject, message);

    }

    else {

      throw new NoSubscribersToDeliverTo(subject);

    }

  }

  boolean txActive = false;

  private boolean throttleOutgoing() {

    return (System.currentTimeMillis() - lastTx) < 150;

  }

  /**

   * Add message to the queue that remotely transmits messages to the server.

   * All messages in the queue are then sent.

   *

   * @param message -

   */

  private void encodeAndTransmit(final Message message) {

    if (initialized && !message.hasPart(MessageParts.PriorityProcessing)

            && (!toSendBuffer.isEmpty() || throttleOutgoing())) {

      toSendBuffer.offer(message);

      if (!txActive && toSendBuffer.size() == 1) {

        new Timer() {

          @Override

          public void run() {

            if (!initialized) return;

            transmitRemote(BusTools.encodeMessages(toSendBuffer), new ArrayList<Message>(toSendBuffer));

          }

        }.schedule(150);

      }

    }

    else {

      transmitRemote(BusTools.encodeMessage(message), Collections.singletonList(message));

    }

  }

  private void addSubscriptionEntry(String subject, MessageCallback reference) {

    _addCallbackEntry(subscriptions, subject, reference);

  }

  private void addLocalSubscriptionEntry(String subject, MessageCallback reference) {

    _addCallbackEntry(localSubscriptions, subject, reference);

  }

  private static void _addCallbackEntry(Map<String, List<MessageCallback>> subscriptions, String subject,

                                        MessageCallback reference) {

    if (!subscriptions.containsKey(subject)) {

      subscriptions.put(subject, new ArrayList<MessageCallback>());

    }

    if (!subscriptions.get(subject).contains(reference)) {

      subscriptions.get(subject).add(reference);

    }

  }

  private void removeSubscriptionTopic(String subject) {

    subscriptions.remove(subject);

  }

  // TODO delete this method

  private void resubscribeShadowSubcriptions() {

    for (Map.Entry<String, List<MessageCallback>> entry : subscriptions.entrySet()) {

      for (MessageCallback callback : entry.getValue()) {

        _subscribe(entry.getKey(), callback, false);

      }

    }

  }

  private static void deliverToSubscriptions(Map<String, List<MessageCallback>> subscriptions,

                                             String subject, Message message) {

    for (MessageCallback cb : subscriptions.get(subject)) {

      cb.callback(message);

    }

  }

  /**

   * Checks if subject is already listed in the subscriptions map

   *

   * @param subject - subject to look for

   * @return true if the subject is already subscribed

   */

  @Override

  public boolean isSubscribed(String subject) {

    return subscriptions.containsKey(subject);

  }

  /**

   * Retrieve all registrations that have occured during the current capture context.

   * <p/>

   * The Map returned has the subject of the registrations as the key, and Sets of registration objects as the

   * value of the Map.

   *

   * @return A map of registrations captured in the current capture context.

   */

  @Override

  public Map<String, List<Object>> getCapturedRegistrations() {

    return registeredInThisSession;

  }

  /**

   * Marks the beginning of a new capture context.<p/>  From this point, the message is called forward, all

   * registration events which occur will be captured.

   */

  @Override

  public void beginCapture() {

    registeredInThisSession = new HashMap<String, List<Object>>();

  }

  /**

   * End the current capturing context.

   */

  @Override

  public void endCapture() {

    registeredInThisSession = null;

  }

  /**

   * Transmits JSON string containing message, using the <tt>sendBuilder</tt>

   *

   * @param message    - JSON string representation of message

   * @param txMessages - Messages reference.

   */

  private void transmitRemote(final String message, final List<Message> txMessages) {

    if (message == null) return;

  //  System.out.println("TX: " + message);

    try {

      txActive = true;

      if (webSocketOpen) {

        if (ClientWebSocketChannel.transmitToSocket(webSocketChannel, message)) {

          return;

        }

        else {

          LogUtil.log("websocket channel is closed. falling back to comet");

          //disconnected.

          webSocketOpen = false;

          webSocketChannel = null;

          cometChannelOpen = true;

          if (receiveCommCallback instanceof LongPollRequestCallback) {

            ((LongPollRequestCallback) receiveCommCallback).schedule();

          }

        }

      }

      try {

        sendBuilder.sendRequest(message, new RequestCallback() {

          @Override

          public void onResponseReceived(Request request, Response response) {

            switch (response.getStatusCode()) {

              case 1:

              case 404:

              case 408:

              case 502:

              case 503:

              case 504: {

                // Sending the message failed.

                // Although the response may still be valid

                // Handle it gracefully

                //noinspection ThrowableInstanceNeverThrown

                TransportIOException tioe = new TransportIOException(response.getText(), response.getStatusCode(),

                        "Failure communicating with server");

                for (Message txM : txMessages) {

                  callErrorHandler(txM, tioe);

                }

                return;

              }

            }

            /**

             * If the server bus returned us some client-destined messages

             * in response to our send, handle them now.

             */

            try {

              procIncomingPayload(response);

            }

            catch (AssertionFailedError e) {

              throw e;

            }

            catch (Throwable e) {

              for (Message txM : txMessages) {

                callErrorHandler(txM, e);

              }

            }

            finally {

              lastTx = System.currentTimeMillis();

            }

          }

          @Override

          public void onError(Request request, Throwable exception) {

            for (Message txM : txMessages) {

              if (txM.getErrorCallback() == null || txM.getErrorCallback().error(txM, exception)) {

                logError("Failed to communicate with remote bus", "", exception);

              }

            }

          }

        });

      }

      catch (Exception e) {

        for (Message txM : txMessages) {

          callErrorHandler(txM, e);

        }

      }

    }

    finally {

      txActive = false;

    }

  }

  boolean rxActive = false;

  private void performPoll() {

    try {

      if (rxActive || !cometChannelOpen) return;

      rxActive = true;

      getRecvBuilder().sendRequest(null, receiveCommCallback);

    }

    catch (RequestTimeoutException e) {

      statusCode = 1;

      receiveCommCallback.onError(null, e);

    }

    catch (Throwable t) {

      DefaultErrorCallback.INSTANCE.error(null, t);

    }

    finally {

      rxActive = false;

    }

  }

  @Override

  public void stop(boolean sendDisconnect) {

    try {

      if (sendDisconnect && isRemoteCommunicationEnabled()) {

        sendBuilder.setHeader("phase", "disconnect");

        Message m = MessageBuilder.createMessage()

                .toSubject(BuiltInServices.ServerBus.name())

                .command(BusCommands.Disconnect).getMessage()

                .set(MessageParts.PriorityProcessing, "1");

        encodeAndTransmit(m);

      }

      unsubscribeAll(BuiltInServices.ClientBus.name());

      subscriptions.clear();

    }

    finally {

      this.lastTx = 0;

      this.toSendBuffer.clear();

      this.txActive = false;

      this.rxActive = false;

      this.remotes.clear();

      this.disconnected = true;

      this.initialized = false;

      this.postInit = false;

      this.sendBuilder = null;

      this.postInitTasks.clear();

      InitVotes.reset();

    }

  }

  public class RemoteMessageCallback implements MessageCallback {

    @Override

    public void callback(Message message) {

      encodeAndTransmit(message);

    }

  }

  private void initFields() {

    initialized = false;

    disconnected = false;

    clientId = String.valueOf(com.google.gwt.user.client.Random.nextInt(99999))

            + "-" + (System.currentTimeMillis() % com.google.gwt.user.client.Random.nextInt(99999));

    IN_SERVICE_ENTRY_POINT = "in." + clientId + ".erraiBus";

    OUT_SERVICE_ENTRY_POINT = "out." + clientId + ".erraiBus";

    onSubscribeHooks = new ArrayList<SubscribeListener>();

    onUnsubscribeHooks = new ArrayList<UnsubscribeListener>();

    remotes = new HashMap<String, MessageCallback>();

  }

  public void setInitialized(boolean initialized) {

    this.initialized = initialized;

  }

  public boolean isReinit() {

    return this.reinit;

  }

  private void setReinit(boolean reinit) {

    this.reinit = reinit;

  }

  private void registerInitVoteCallbacks() {

    InitVotes.waitFor(ClientMessageBusImpl.class);

    InitVotes.waitFor(RpcProxyLoader.class);

    InitVotes.registerOneTimeInitCallback(new Runnable() {

      @Override

      public void run() {

        completeInit();

      }

    });

  }

  /**

   * Initializes the message bus, by subscribing to the ClientBus (to receive subscription messages) and the

   * ClientErrorBus to dispatch errors when called.

   */

  @Override

  public void init() {

    declareDebugFunction();

    if (!reinit) {

      registerInitVoteCallbacks();

    }

    if (sendBuilder == null) {

      if (!GWT.isScript()) {   // Hosted Mode

        initFields();

        createRequestBuilders();

        if (isReinit()) {

          setReinit(true);

          init();

          setReinit(false);

          return;

        }

        else {

          init();

          return;

        }

      }

      else {

        initFields();

        createRequestBuilders();

      }

    }

    if (sendBuilder == null) {

      return;

    }

    if (reinit) {

      resubscribeShadowSubcriptions();

    }

    /**

     * Fire initialization listeners now.

     */

    for (PreInitializationListener listener : preInitializationListeners) {

      listener.beforeInitialization();

    }

    if (isRemoteCommunicationEnabled()) {

      remoteSubscribe(BuiltInServices.ServerEchoService.name());

    }

    directSubscribe(BuiltInServices.ClientBus.name(), new MessageCallback() {

      @Override

      @SuppressWarnings({"unchecked"})

      public void callback(final Message message) {

        switch (BusCommands.valueOf(message.getCommandType())) {

          case RemoteSubscribe:

            if (message.hasPart(MessageParts.SubjectsList)) {

              LogUtil.log("remote services available: " + message.get(List.class, MessageParts.SubjectsList));

              for (String subject : (List<String>) message.get(List.class, MessageParts.SubjectsList)) {

                remoteSubscribe(subject);

              }

            }

            else {

              String subject = message.get(String.class, Subject);

              remoteSubscribe(subject);

            }

            break;

          case RemoteUnsubscribe:

            unsubscribeAll(message.get(String.class, Subject));

            break;

          case CapabilitiesNotice:

            LogUtil.log("received capabilities notice from server. supported capabilities of remote: "

                    + message.get(String.class, MessageParts.CapabilitiesFlags));

            String[] capabilites = message.get(String.class, MessageParts.CapabilitiesFlags).split(",");

            for (String capability : capabilites) {

              switch (Capabilities.valueOf(capability)) {

                case WebSockets:

                  webSocketUrl = message.get(String.class, MessageParts.WebSocketURL);

                  webSocketToken = message.get(String.class, MessageParts.WebSocketToken);

                  LogUtil.log("attempting web sockets connection at URL: " + webSocketUrl);

                  Object o = ClientWebSocketChannel.attemptWebSocketConnect(ClientMessageBusImpl.this, webSocketUrl);

                  if (o instanceof String) {

                    LogUtil.log("could not use web sockets. reason: " + o);

                  }

                  break;

                case LongPollAvailable:

                  LogUtil.log("initializing long poll subsystem");

                  receiveCommCallback = new LongPollRequestCallback();

                  break;

                case NoLongPollAvailable:

                  receiveCommCallback = new ShortPollRequestCallback();

                  if (message.hasPart(MessageParts.PollFrequency)) {

                    POLL_FREQUENCY = message.get(Integer.class, MessageParts.PollFrequency);

                  }

                  else {

                    POLL_FREQUENCY = 500;

                  }

                  break;

              }

            }

            break;

          case RemoteMonitorAttach:

            break;

          case FinishStateSync:

            if (isInitialized()) {

              return;

            }

            new Timer() {

              @Override

              public void run() {

                LogUtil.log("received FinishStateSync message. preparing to bring up the federation");

                List<String> subjects = new ArrayList<String>();

                for (String s : subscriptions.keySet()) {

                  if (s.startsWith("local:")) continue;

                  if (!remotes.containsKey(s)) subjects.add(s);

                }

                sessionId = message.get(String.class, MessageParts.ConnectionSessionKey);

                remoteSubscribe(BuiltInServices.ServerBus.name());

                MessageBuilder.createMessage()

                        .toSubject(BuiltInServices.ServerBus.name())

                        .command(RemoteSubscribe)

                        .with(MessageParts.SubjectsList, subjects)

                        .with(PriorityProcessing, "1")

                        .noErrorHandling()

                        .sendNowWith(ClientMessageBusImpl.this);

                MessageBuilder.createMessage()

                        .toSubject(BuiltInServices.ServerBus.name())

                        .command(BusCommands.FinishStateSync)

                        .with(PriorityProcessing, "1")

                        .noErrorHandling().sendNowWith(ClientMessageBusImpl.this);

                /**

                 * ... also send RemoteUnsubscribe signals.

                 */

                addSubscribeListener(new SubscribeListener() {

                  @Override

                  public void onSubscribe(SubscriptionEvent event) {

                    if (event.isLocalOnly() || event.getSubject().startsWith("local:")

                            || remotes.containsKey(event.getSubject())) {

                      return;

                    }

                    if (event.isNew()) {

                      MessageBuilder.getMessageProvider().get().command(RemoteSubscribe)

                              .toSubject(BuiltInServices.ServerBus.name())

                              .set(Subject, event.getSubject())

                              .set(PriorityProcessing, "1")

                              .sendNowWith(ClientMessageBusImpl.this);

                    }

                  }

                });

                addUnsubscribeListener(new UnsubscribeListener() {

                  @Override

                  public void onUnsubscribe(SubscriptionEvent event) {

                    MessageBuilder.getMessageProvider().get().command(BusCommands.RemoteUnsubscribe)

                            .toSubject(BuiltInServices.ServerBus.name())

                            .set(Subject, event.getSubject())

                            .set(PriorityProcessing, "1")

                            .sendNowWith(ClientMessageBusImpl.this);

                  }

                });

                subscribe(DefaultErrorCallback.CLIENT_ERROR_SUBJECT, new MessageCallback() {

                  @Override

                  public void callback(Message message) {

                    String errorTo = message.get(String.class, MessageParts.ErrorTo);

                    if (errorTo == null) {

                      logError(message.get(String.class, MessageParts.ErrorMessage),

                              message.get(String.class, MessageParts.AdditionalDetails), null);

                    }

                    else {

                      message.toSubject(errorTo);

                      message.sendNowWith(ClientMessageBusImpl.this);

                    }

                  }

                });

                InitVotes.voteFor(ClientMessageBusImpl.class);

                // end of FinishStateSync Timer

              }

            }.schedule(5);

            break;

          case SessionExpired:

            if (isReinit()) {

              showError("Session was terminated and could not be re-established", null);

              return;

            }

            if (!isInitialized()) return;

            for (SessionExpirationListener listener : sessionExpirationListeners) {

              listener.onSessionExpire();

            }

            stop(false);

            setReinit(true);

            init();

            setReinit(false);

            break;

          case WebsocketChannelVerify:

            LogUtil.log("received verification token for websocket connection");

            MessageBuilder.createMessage()

                    .toSubject(BuiltInServices.ServerBus.name())

                    .command(BusCommands.WebsocketChannelVerify)

                    .copy(MessageParts.WebSocketToken, message)

                    .done().sendNowWith(ClientMessageBusImpl.this);

            break;

          case WebsocketChannelOpen:

            cometChannelOpen = false;

            webSocketOpen = true;

            // send final message to open the channel

            ClientWebSocketChannel.transmitToSocket(webSocketChannel, getWebSocketNegotiationString());

            LogUtil.log("web socket channel successfully negotiated. comet channel deactivated.");

            break;

          case WebsocketNegotiationFailed:

            webSocketChannel = null;

            logError("failed to connect to websocket: server rejected request",

                    message.get(String.class, MessageParts.ErrorMessage), null);

            break;

          case Disconnect:

            stop(false);

            if (message.hasPart("Reason")) {

              logError("The bus was disconnected by the server", "Reason: "

                      + message.get(String.class, "Reason"), null);

            }

            break;

        }

      }

    }, false);

    /**

     * Send initial message to connect to the queue, to establish an HTTP session. Otherwise, concurrent

     * requests will result in multiple sessions being created.  Which is bad.  Avoid this at all costs.

     * Please.

     */

    if (!sendInitialMessage()) {

      logError("Could not connect to remote bus", "", null);

    }

  }

  private void completeInit() {

    if (!postInit && !initialized) {

      postInit = true;

      LogUtil.log("received final vote for initialization ...");

      if (!postInitTasks.isEmpty())

        LogUtil.log("executing " + postInitTasks.size() + " post init task(s)");

      do {

        for (Runnable runnable : new ArrayList<Runnable>(postInitTasks)) {

          postInitTasks.remove(runnable);

          runnable.run();

        }

      }

      while (!postInitTasks.isEmpty());

      sendAllDeferred();

      postInitTasks.clear();

      setInitialized(true);

      LogUtil.log("bus federation complete. now operating normally.");

    }

  }

  private void remoteSubscribe(String subject) {

    remotes.put(subject, remoteCallback);

    //  addShadowSubscription(subject, remoteCallback);

  }

  Set<String> getRemoteSubscriptions() {

    if (remotes == null)

      return null;

    return remotes.keySet();

  }

  private void sendAllDeferred() {

    if (!deferredMessages.isEmpty())

      LogUtil.log("transmitting deferred messages now ...");

    for (Iterator<Message> iter = deferredMessages.iterator(); iter.hasNext(); ) {

      Message m = iter.next();

      if (m.hasPart(MessageParts.PriorityProcessing)) {

        directStore(m);

        iter.remove();

      }

    }

    for (Iterator<Message> iter = deferredMessages.iterator(); iter.hasNext(); ) {

      directStore(iter.next());

      iter.remove();

    }

  }

  /**

   * Sends the initial message to connect to the queue, to establish an HTTP session. Otherwise, concurrent

   * requests will result in multiple sessions being created.

   *

   * @return true if initial message was sent successfully.

   */

  private boolean sendInitialMessage() {

    if (!isRemoteCommunicationEnabled()) {

      LogUtil.log("Initializing client bus in offline mode (erraiBusRemoteCommunicationEnabled was set to false)!");

      InitVotes.voteFor(ClientMessageBusImpl.class);

      InitVotes.voteFor(RpcProxyLoader.class);

      return true;

    }

    try {

      LogUtil.log("sending initial handshake to remote bus");

      String initialMessage = "{\"CommandType\":\"ConnectToQueue\",\"ToSubject\":\"ServerBus\"," +

              " \"PriorityProcessing\":\"1\"}";

      RequestBuilder initialRequest = getSendBuilder();

      initialRequest.setHeader("phase", "connection");

      initialRequest.sendRequest(initialMessage, new RequestCallback() {

        @Override

        public void onResponseReceived(Request request, Response response) {

          try {

            LogUtil.log("received response from initial handshake.");

            procIncomingPayload(response);

            initializeMessagingBus();

          }

          catch (Exception e) {

            e.printStackTrace();

            logError("Error attaching to bus", e.getMessage() + "<br/>Message Contents:<br/>"

                    + response.getText(), e);

          }

        }

        @Override

        public void onError(Request request, Throwable exception) {

          logError("Could not connect to remote bus", "", exception);

        }

      });

    }

    catch (RequestException e) {

      e.printStackTrace();

      return false;

    }

    return true;

  }

  /**

   * Returns true if client message bus is initialized.

   *

   * @return true if client message bus is initialized.

   */

  @Override

  public boolean isInitialized() {

    return this.initialized;

  }

  int maxRetries = 5;

  int retries = 0;

  int timeout = 2000;

  int statusCode = 0;

  DialogBox timeoutDB;

  Label timeoutMessage;

  private void createConnectAttemptGUI() {

    timeoutDB = new DialogBox();

    timeoutMessage = new Label();

    timeoutDB.add(timeoutMessage);

    RootPanel.get().add(timeoutDB);

    timeoutDB.show();

    timeoutDB.center();

  }

  private void clearConnectAttemptGUI() {

    timeoutDB.hide();

    RootPanel.get().remove(timeoutDB);

    timeoutDB = null;

    timeoutMessage = null;

    retries = 0;

  }

  protected class LongPollRequestCallback implements RequestCallback {

    @Override

    public void onError(Request request, Throwable throwable) {

      switch (statusCode) {

        case 1:

        case 408:

        case 502:

        case 504:

          if (retries != maxRetries) {

            if (timeoutDB == null) {

              createConnectAttemptGUI();

            }

            logAdapter.warn("Attempting reconnection -- Retries: " + (maxRetries - retries));

            timeoutMessage.setText("Connection Interrupted -- Retries: " + (maxRetries - retries));

            retries++;

            new Timer() {

              @Override

              public void run() {

                performPoll();

              }

            }.schedule(timeout);

            statusCode = 0;

            return;

          }

          else {