Using a Universal Messaging Channel
This JavaScript code snippet demonstrates how to create a channel object, which allows you to publish or subscribe to a Universal Messaging channel:
var myChannel = mySession.getChannel("/fxdemo/prices");
Note that unlike the Enterprise APIs, the JavaScript API does not support programmatic creation of channels; instead, you can use the Enterprise Manager GUI to create a Universal Messaging Channel.
A channel object offers several methods. Three of the more important ones are:
myChannel.subscribe()myChannel.unsubscribe() myChannel.publish(Event event) Please see JavaScript API Documentation for Channels for information on all available methods on a channel.
Each of the above methods can invoke one or more optional user-specified callback functions which you can (and probably should) implement and assign as follows:
var myChannel = mySession.getChannel("/fxdemo/prices");
// Assign a handler function for Universal Messaging Events received on the Channel,
// then subscribe:
function myEventHandler(event) {
var dictionary = event.getDictionary();
console.log(dictionary.get("name") + " " + dictionary.get("bid"));
}
myChannel.on(Nirvana.Observe.DATA, myEventHandler);
myChannel.subscribe();
