gwt-cometd

A GWT module that wraps the CometD JavaScript client library.

Installation

Clone the repository and import the gwt-cometd project into your Eclipse workspace. Then add the gwt-cometd project to the build path of your GWT module.

Add the following entry to the .gwt.xml file of your GWT module:

<inherits name="org.lutzmann.gwt.cometd.gwtcometd"/>

Usage

Configuration & Instantiation

CometDConfiguration config = new CometDConfiguration("http://127.0.0.1:8080/cometd");
config.setLogLevel(LogLevel.debug);
...

CometD cometd = new CometD(config);

Add and remove listeners

Subscription connectSubscription = cometd.addMetaListener(MetaChannel.connect,
			new CometDListener<BayeuxMessage>() {
				@Override
				public void processMessage(BayeuxMessage message) {
					if (message.isSuccessful()) {
						// connected
						...
					} else {
						// disconnected
						...
					}
				}
			});
...
cometd.removeListener(connectSubscription);

Handshake

cometd.handshake();

Subscribe and unsubscribe

Subscription quoteSubscription = cometd.subscribe("/FX/EURCHF",
			new CometDListener<BayeuxMessage>() {
				@Override
				public void processMessage(BayeuxMessage message) {
					JSONObject data = new JSONObject(message.getData());
					
					JSONNumber bid = (JSONNumber) data.get("bid");
					JSONNumber ask = (JSONNumber) data.get("ask");
					
					...
				}
			});

...

cometd.unsubscribe(quoteSubscription);

Publish

JSONObject data = new JSONObject();
data.put("bid", new JSONNumber(1.2011));
data.put("ask", new JSONNumber(1.2014));

cometd.publish("/FX/EURCHF", data.getJavaScriptObject());

Message batching

cometd.startBatch();
...
cometd.endBatch();

NOTE: Do not forget to call endBatch() after a call to startBatch()!

Unregister transport

cometd.unregisterTransport(Transport.websocket);

For details on the described methods here have a look at the excellent CometD Reference Manual.

Contributors

• Bernhard Lutzmann
• Ondrej Galik
• Julien Faucher

Thanks!