com.yahoo.bard.webservice.async.broadcastchannels

Interface BroadcastChannel<T>

Type Parameters:

T - The type of message that the BroadcastChannel publishes

All Superinterfaces:

AutoCloseable, Closeable

All Known Implementing Classes:

RedisBroadcastChannel, SimpleBroadcastChannel

public interface BroadcastChannel<T>
extends Closeable

Bard may exist in a system where multiple Bard hosts exist, it is possible that a user may submit a query on one box, and then come back later and perform a long poll on a separate box. Therefore, we need a mechanism to notify all the Bard boxes when a PreResponse is stored in the PreResponseStore by any of the Bard boxes.

BroadcastChannel is the interface that lets you send messages to and receive messages from the other boxes in the cluster.

Field Summary

Fields

Modifier and Type	Field and Description
static String	PUBLISH_ON_CLOSED_ERROR_MESSAGE

Method Summary

Modifier and Type	Method and Description
rx.Observable<T>	getNotifications() This method returns a Hot Observable (Observable which emits events whether someone is listening or not) that emits all the notifications passed to it by Bard instances in the cluster.
void	publish(T message) Publish is used to publish a message from a Bard box.

Methods inherited from interface java.io.Closeable

close

Field Detail

PUBLISH_ON_CLOSED_ERROR_MESSAGE

static final String PUBLISH_ON_CLOSED_ERROR_MESSAGE

See Also:

Constant Field Values

Method Detail

publish

void publish(T message)
      throws UnsupportedOperationException

Publish is used to publish a message from a Bard box.

Parameters:

message - The message to be published

Throws:

UnsupportedOperationException - if someone attempts to publish to the channel after it has been closed

getNotifications

rx.Observable<T> getNotifications()

This method returns a Hot Observable (Observable which emits events whether someone is listening or not) that emits all the notifications passed to it by Bard instances in the cluster.

Returns:

An unbounded stream of notifications from Bard instances