Class EventHandler - deepstreamHub Java SDK EventHandler

The entry point for events, such as subscribe(eventName, listener), emit(eventName) and provider functionality such as listen(eventName, listener).

Methods

void emit(String eventName)

Sends the event to all subscribed clients without a payload.

Show example...

client.event.emit("notifications");

void emit(String eventName, Object data)

Sends the event to all subscribed clients with the given payload.

Show example...

client.event.emit("notifications", "example payload")

void subscribe(String eventName, EventListener EventListener)

Subscribes to eventName and notifies the listener via EventListener whenever it occurs locally or remotely.

Show example...

client.event.subscribe("notifications", new EventListener() {
    @Override
    public void onEvent(String eventName, Object data) {
        // handle event
    }
});

void unsubscribe(String eventName, EventListener EventListener)

Unsubscribes from an event that was previously registered with subscribe(). This stops a client from receiving the event.

Show example...

client.event.unsubscribe(eventListener);

void listen(String pattern, ListenListener listen)

Registers the client as a listener for event subscriptions made by other clients. This is useful to create active data providers - processes that only send events if clients are actually interested in them. You can find more about listening in the events tutorial.

Show example...

client.event.listen("users/", new ListenListener() {
  @Override
  public boolean onSubscriptionForPatternAdded(String subscription) {
    if (/ can provide */) {
      return true;
    } else {
      return false;
    }
  }



  @Override
  public void onSubscriptionForPatternRemoved(String subscription) {
    // handle unsubscription
  }
});

void unlisten(String pattern)

Remove the listener added via listen(pattern,listener). This will remove the provider as the active provider and allow another provider to take its place.

Show example...

client.event.unlisten("users/*", listener);