Class ISCMessageDispatcher

Method Details

• instance

  public static ISCMessageDispatcher instance() throws Exception

  Returns a new instance of the configured concrete ISCMessageDispatcher class - scan the client-side documentation for "messaging.dispatcherImplementer" for details of how this is configured. NOTE: This method is a factory, not a singleton accessor: it creates a fresh dispatcher - and, on first use, a new broker connection - on every call.

  For server-side publishing (e.g. from a DMI method), callers must cache and reuse the returned dispatcher across calls rather than invoking instance() on each send. Creating a new dispatcher per send will open a new broker connection each time and never close it, leaking connections and their associated threads until the application is restarted. The recommended pattern is a lazily-initialised static reference:

       private static ISCMessageDispatcher dispatcher;
  
       private static synchronized ISCMessageDispatcher getDispatcher() throws Exception {
           if (dispatcher == null) dispatcher = ISCMessageDispatcher.instance();
           return dispatcher;
       }
   

  To release the dispatcher and its underlying resources (e.g. in a ServletContextListener.contextDestroyed callback), call stop().

  Returns:

  a new concrete ISCMessageDispatcher for sending/receiving Realtime Messages.

  Throws:

  Exception

• instance

  public static ISCMessageDispatcher instance(RequestContext context) throws Exception

  Equivalent to instance(); the context parameter is ignored. This overload exists for backwards compatibility only.

  Parameters:

  context - ignored

  Returns:

  a new concrete ISCMessageDispatcher for sending/receiving Realtime Messages.

  Throws:

  Exception

• register

  public void register(ISubscriber subscriber) throws Exception

  register this subscriber

  Parameters:

  subscriber -

  Throws:

  Exception

• unregister

  public void unregister(ISubscriber subscriber) throws Exception

  unregister this subscriber

  Parameters:

  subscriber -

  Throws:

  Exception

• subscribe

  public void subscribe(ISubscriber subscriber, String channel) throws Exception

  subscribe a given subscriber to a given channel

  Parameters:

  subscriber -

  channel -

  Throws:

  Exception

• subscribe

  public abstract void subscribe(ISubscriber subscriber, String channel, String selector) throws Exception

  subscribe a given subscriber to a given channel

  Parameters:

  subscriber -

  channel -

  selector -

  Throws:

  Exception

• unsubscribe

  public abstract void unsubscribe(ISubscriber subscriber, String channel) throws Exception

  unsubscribe a given subscriber from a given channel

  Parameters:

  subscriber -

  channel -

  Throws:

  Exception

• send

  public void send(ISCMessage msg) throws Exception

  send a message

  Parameters:

  msg -

  Throws:

  Exception

• stop

  public abstract void stop()

  Releases all resources held by this dispatcher. You can call this when the dispatcher is no longer needed — for example in a ServletContextListener.contextDestroyed callback — to ensure that the underlying broker connection and its threads are shut down cleanly.

  You can also use this method to reset the existing connection when the underlying broker throws an Exception or otherwise reports a problem on send(ISCMessage). stop() closes and deletes its connection reference, which causes the next send() on the dispatcher to create a new connection.

• closeConnection

  public abstract void closeConnection()

  Closes the underlying broker connection held by this dispatcher without releasing other resources first. Prefer stop(), which releases all resources in the correct order. This method is provided for advanced use cases such as forcing a reconnect after a configuration change.

• isSubscribed

  public boolean isSubscribed(ISubscriber subscriber, String channel) throws Exception

  Check to see if a given subscriber is subscribed to a given channel. Note: not applicable to JMS (meaningless in a distributed context)

  Parameters:

  subscriber -

  channel -

  Returns:

  true if subscribed, false if not

  Throws:

  Exception