org.onosproject.store.service

Interface Topic<T>

Type Parameters:

T - The type of message to be distributed to subscribers

All Superinterfaces:

DistributedPrimitive

public interface Topic<T>
extends DistributedPrimitive

A distributed publish subscribe primitive.

This primitive provides ordered message delivery guarantee i.e. all messages will be delivered to all active subscribers and messages published from each publisher will be delivered to all active subscribers in the order in which they are published.

Transient disruptions in communication such as occasional message drops are automatically handled and recovered from without loss of delivery guarantees.

However, subscribers need to remain active or alive for these guarantees to apply. A subscriber that is partitioned away for an extended duration (typically 5 seconds or more) will be marked as inactive and during that period of inactivity will be removed from the list of current subscribers.

Nested Class Summary

Nested classes/interfaces inherited from interface org.onosproject.store.service.DistributedPrimitive

DistributedPrimitive.Status, DistributedPrimitive.Type

Field Summary

Fields inherited from interface org.onosproject.store.service.DistributedPrimitive

DEFAULT_OPERATION_TIMEOUT_MILLIS, DEFAULT_OPERTATION_TIMEOUT_MILLIS

Method Summary

Modifier and Type	Method and Description
CompletableFuture<Void>	publish(T message) Publishes a message to all subscribers.
default CompletableFuture<Void>	subscribe(Consumer<T> callback) Subscribes to messages published to this topic.
CompletableFuture<Void>	subscribe(Consumer<T> callback, Executor executor) Subscribes to messages published to this topic.
CompletableFuture<Void>	unsubscribe(Consumer<T> callback) Unsubscribes from this topic.

Methods inherited from interface org.onosproject.store.service.DistributedPrimitive

addStatusChangeListener, applicationId, destroy, name, primitiveType, removeStatusChangeListener, statusChangeListeners

Method Detail

publish

CompletableFuture<Void> publish(T message)

Publishes a message to all subscribers.

The message is delivered in a asynchronous fashion which means subscribers will receive the message eventually but not necessarily before the future returned by this method is completed.

Parameters:

message - The non-null message to send to all current subscribers

Returns:

a future that is completed when the message is logged (not necessarily delivered).

subscribe

CompletableFuture<Void> subscribe(Consumer<T> callback,
                                  Executor executor)

Subscribes to messages published to this topic.

Parameters:

callback - callback that will invoked when a message published to the topic is received.

executor - executor for running the callback

Returns:

a future that is completed when subscription request is completed.

subscribe

default CompletableFuture<Void> subscribe(Consumer<T> callback)

Subscribes to messages published to this topic.

Parameters:

callback - callback that will invoked when a message published to the topic is received.

Returns:

a future that is completed when subscription request is completed.

unsubscribe

CompletableFuture<Void> unsubscribe(Consumer<T> callback)

Unsubscribes from this topic.

Parameters:

callback - previously subscribed callback

Returns:

a future that is completed when unsubscription request is completed.