V
- the value classpublic static interface Topics.ValueStream<V> extends Topics.SubscriberStream
A stream implementation can be registered using
addStream
. The
stream will receive events for the topics that are selected by the topic
selector and have a compatible type.
A stream implementation can also be registered as a fallback stream using
addFallbackStream
.
Fallback streams will receive events for all topics that are not selected
by other streams the session has registered using addStream
.
If the stream is removed
,
onClose
will be called.
If the session is closed,
onError
will be called with ErrorReason.SESSION_CLOSED
.
See Topics
class documentation for further details of the use of
value streams.
Modifier and Type | Interface and Description |
---|---|
static class |
Topics.ValueStream.Default<V>
Default
Topics.ValueStream implementation. |
Modifier and Type | Method and Description |
---|---|
void |
onValue(String topicPath,
TopicSpecification specification,
V oldValue,
V newValue)
Notifies an update to a topic value from the server.
|
onSubscription, onUnsubscription
void onValue(String topicPath, TopicSpecification specification, V oldValue, V newValue)
This is also called to provide the current value for any matching topic that the session is already subscribed to when the stream is added.
topicPath
- the topic pathspecification
- the topic specificationoldValue
- the previous value. Will be null for the initial call
to onValue for a topic. It can also be null if the topic's
data type supports null values.newValue
- the new value derived from the last update received
from the server. It can be null if the topic's data type
supports null values.Copyright © 2024 DiffusionData Ltd. All Rights Reserved.