A static reference to the selector this Subscription was created for.
Close the stream. No further events will be emitted.
This does not unsubscribe the topic. Other streams may still receive updates for the same topic selector. To unsubscribe, use Session.unsubscribe
Remove a listener from a specified event.
Example:
// Bind a single listener to the 'foo' event and then deregister it
var listener = function() {};
stream.on('foo', listener);
stream.off('foo', listener);Example:
// Bind a listener to the 'foo' event and deregister all listeners
var listener = function() {};
stream.on('foo', listener);
stream.off('foo');the listener to remove. All listeners for the event are removed if this is not specified. This argument is ignored if the first argument is a CallbackMap.
this stream.
Register listeners against events.
A single listener may be bound to an event by passing the event name and listener function.
Multiple listeners may be bound by passing in a CallbackMap, mapping event names to listener functions.
Example:
// Bind a single listener to the 'foo' event
stream.on('foo', function(arg1, arg2) {
console.log("Called for 'foo' event", arg1, arg2);
});Example:
// Bind multiple listeners
stream.on({
foo : function() { ... },
bar : function() { ... },
baz : function() { ... }
});the event name or CallbackMap mapping event names to listeners
the listener to bind to the event, if passed as string. This argument is ignored if the first argument is a CallbackMap.
this stream.
Provides a stream of topic events, specific to the topic selector that this ValueStream was created for, with topic values provided as instances of the associated DataType.
ValueStream inherits all functions defined on Stream.
Example:
// Create a value stream for topic 'foo' session.addStream('foo', datatype).on('value', function(topic, specification, newValue, oldValue) { // Receive updates for the topic 'foo' }); // Then subscribe to topic 'foo' session.select('foo');Example:
// Attach multiple listeners for events session.addStream('foo', datatype).on({ subscribe : function(topic, specification) { // Subscribed to a particular topic }, unsubscribe : function(topic, specification, reason) { // Unsubscribed from a particular topic }, value : function(topic, specification, newValue, oldValue) { // Value from a topic } });Events
openEmitted when the subscription is initially opened, passing a reference to the subscription itself. This will only be fired once.
subscribeEmitted when a topic that is selected by this ValueStream's topic selector is subscribed to by this session. Once subscribed,
valueupdate events may be received for this topic. The specification is a TopicSpecification instance that contains details about the topic.Parameters:
topic: string - The topic to which the subscription appliesspecification: TopicSpecification - Instance that contains details about the topicunsubscribeEmitted when a topic that was previously subscribed, has been unsubscribed. No further update events will be received from this topic until subscribed again. Unsubscriptions may occur due to the topic being removed, or through calling Session.unsubscribe - an object containing the reason is provided.
Parameters:
topic: string - The topic to which the unsubscription appliesspecification: TopicSpecification - Instance that contains details about the topicreason: UnsubscribeReason - the reason for the unsubscriptionvalueEmitted when an update has been received for a topic's value. Values will be provided as instances appropriate for the associated DataType this subscription was created for. Both the previous value and the new value are provided.
Parameters:
topic: string - The topic to which the update appliesspecification: TopicSpecification - Instance that contains details about the topicnewValue: any - the new value of the topicoldValue: any - the old value of the topiccloseEmitted when the subscription has been closed using ValueStream.close.
errorEmitted when the subscription request fails. No further events will be emitted after this.
Parameters:
error: ErrorReason - the error the subscription request failed with