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  1. #1
    Power Member
    Join Date
    Nov 2012
    Posts
    182

    My notifyUserMessage method is not getting called

    I have just started evaluating Lightstreamer and worked my way through the "HelloWorld" tutorial successfully. Next I wanted to create a simple "Echo" facility just to ensure I understand what is going on. My understanding (could be wrong) is that if I want to send a message from the client and have it echoed back to me, I need to create a metadata adapter to pass the incoming message to my data adapter, which can then echo it back. However, the "notifiyUserMessage" method in my metadata adapter never gets fired - so either I have misunderstood the way I am to do this, or I just have a plain old bug I don't understand.

    So, firstly, is my understanding correct? If so, can anyone tell me what I am doing wrong because it is a pretty simple thing.

    Here is my metadata code:
    Code:
    public class MetadataAdapter extends LiteralBasedProvider {
       
        private void loadEchoFeed() throws CreditsException {
            if (this.echoFeed == null) {
                try {
                    // Get the IMDataAdapter instance to bind it with this
                    // Metadata Adapter and send instant messages through it
                    this.echoFeed = EchoDataAdapter.feedMap.get(this.adapterSetId);
                } catch (Throwable t) {
                    // It can happen if the Messenger Data Adapter jar was not even
                    // included in the Adapter Set lib directory (the Messenger
                    // Data Adapter could not be included in the Adapter Set as
                    // well)
                    logError("EchoDataAdapter class was not loaded: " + t);
                    throw new CreditsException(0, "No echo feed available",
                            "No echo feed available");
                }
    
                if (this.echoFeed == null) {
                    // The feed is not yet available on the static map, maybe the
                    // Echo Data Adapter was not included in the Adapter Set
                    logError("EchoDataAdapter not found");
                    throw new CreditsException(0, "No echo feed available",
                            "No echo feed available");
                }
            }
        }
    
        private void handleEchoMessage(String message) throws CreditsException {
            this.echoFeed.sendMessage(message);        
        }
    
        //------- Public methods--------
        public MetadataAdapter() {
        }
    
      
        public void init(Map params, File configDir) throws MetadataProviderException  {
            super.init(params, configDir);
    
            String logConfig = (String)params.get("log_config");
            if (logConfig != null) {
                File logConfigFile = new File(configDir, logConfig);
                String logRefresh = (String)params.get("log_config_refresh_seconds");
                if (logRefresh != null)
                    DOMConfigurator.configureAndWatch(logConfigFile.getAbsolutePath(), Integer.parseInt(logRefresh) * 1000);
                else {
                    DOMConfigurator.configure(logConfigFile.getAbsolutePath());
                }
    
            }
    
            this.adapterSetId = ((String)params.get("adapters_conf.id"));
    
        }
        
          
        public void notifyUserMessage(String user, String session, String message) throws NotificationException, CreditsException {
            // Triggered by a client "sendMessage" call.
            // The message encodes an instant message from the client.
            
            if (message == null) {
                logger.warn("Null message received");
                throw new NotificationException("Null message received");
            }             
            
            // Load the echco feeder
            this.loadEchoFeed();
            this.handleEchoMessage(message);
        }    
    
    }
    Here is my data adapter code
    Code:
    public class EchoDataAdapter implements SmartDataProvider {
        
        private ItemEventListener listener;
        private final ExecutorService executor; //Used to enqueue the calls to the listener.
        private Logger logger;
      
        public static final ConcurrentHashMap<String, EchoDataAdapter> feedMap =
            new ConcurrentHashMap<String, EchoDataAdapter>();
        
        //------- Private methods--------
        
    
        //------- Public methods--------
        public EchoDataAdapter() {
            executor = Executors.newSingleThreadExecutor();
        }
        
        public void init(Map params, File configDir) throws DataProviderException   {
            String logConfig = (String) params.get("log_config");
            if (logConfig != null) {
                File logConfigFile = new File(configDir, logConfig);
                String logRefresh = (String) params.get("log_config_refresh_seconds");
                if (logRefresh != null) {
                    DOMConfigurator.configureAndWatch(logConfigFile.getAbsolutePath(), Integer.parseInt(logRefresh) * 1000);
                } else {
                    DOMConfigurator.configure(logConfigFile.getAbsolutePath());
                }
            }
            
            // Read the Adapter Set name, which is supplied by the Server as a parameter
            String adapterSetId = (String) params.get("adapters_conf.id");
    
            // Put a reference to this instance on a static map
            // to be read by the Metadata Adapter
            feedMap.put(adapterSetId, this);
    
           
        }
    
        public boolean isSnapshotAvailable(String itemName) throws SubscriptionException  {
            return false;
        }
    
        public void setListener(ItemEventListener listener) {
            // We will be passed a reference to a listener that we will use to inject the real-time events
            this.listener = listener;
        }
    
        public void subscribe(String itemName, Object itemHandle, boolean needsIterator) throws SubscriptionException, FailureException  {
            // We must be ready to accept subscription requests. If we receive an "echo" item we will start a thread to
            // handle the data.
            // When the “echo” item is subscribed to by the first user, our Adapter receives that method call and starts a thread 
            // that will generate the real-time data. 
            // If more users subscribe to the “echo” item, the subscribe method is not called anymore. 
            // When the last user unsubscribes from this item, our Adapter is notified through the unsubscribe call
            if (itemName.equals("echo")) {
               // Nothing to do        
            }
        }
    
        public void subscribe(String itemName, boolean needsIterator) throws SubscriptionException, FailureException  {
        }
    
        public void unsubscribe(String itemName) throws SubscriptionException, FailureException  {
            // No more users
            if (itemName.equals("echo")) {
              // Nothing to do
            }
        }
        
        public void sendMessage(String message) {
            // Receives a message from the metadata adapter, which we will simply echo back
            this.echoMessage(message);
        }
    
        private void echoMessage(String message) {
            final HashMap<String, String> echo = new HashMap<String, String>();
            echo.put("message", message);
            
            //If we have a listener create a new Runnable to be used as a task to pass the
            //new update to the listener
            Runnable echoMessage = new Runnable() {
                public void run() {
                    // call the update on the listener;
                    // in case the listener has just been detached,
                    // the listener should detect the case
                    listener.smartUpdate(listener, echo, false);
                }
            };
    
            //We add the task on the executor to pass to the listener the actual status
            executor.execute(echoMessage);
    
        }
        
    }
    and my client just does this
    Code:
            function extractFieldData(event,field) {
                    var value;
                    if (event.isValueChanged(field)) {
                            value = event.getValue(field);
                    }
    
                    return value;
            }
    
            function handleEcho(event) {
                    var eventType = event.item; //This provides the update event name
    
                    var echoed=extractFieldData(event,"message");
    
                    alert("Echo: "+echoed);
            }
    
    
            var client = new LightstreamerClient("http://rnsdev:8080","RNS");
            client.connect();
    
            var echoSub = new Subscription("DISTINCT","echo",new Array("message"));
            echoSub.setDataAdapter("ECHO");
            echoSub.addListener({
                    onItemUpdate:handleEcho
            });
    
            client.subscribe(echoSub);
    
            client.sendMessage("Will this message get back to me?");
    Last edited by kpturner; December 3rd, 2012 at 02:47 PM.

  2. #2
    Power Member
    Join Date
    Nov 2012
    Posts
    182
    Ahh, I see I am sending the message too soon. I have to wait until the subscription is complete (onSubscription).

    Still not quite working though so I will debug it some more.

  3. #3
    Power Member
    Join Date
    Nov 2012
    Posts
    182
    My sendMessage method was rubbish. I have "fixed" it so that it works, but now....
    http://forums.lightstreamer.com/show...=5090#post5090

 

 

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