com.hivemq.spi.callback.events

Interface OnTopicSubscriptionCallback

All Superinterfaces:

Callback, SynchronousCallback

public interface OnTopicSubscriptionCallback
extends SynchronousCallback

This callback returns the SubackReturnCode for a Topic and a ClientData.

This callback is called after the OnAuthorizationCallback but before the OnSubscribeCallback. When more OnTopicSubscriptionCallbacks are added the one that fires last (with the least priority) has the final say. It is possible to override the MQTT specification for SUBACK payloads with this callback.

This callback is called once for every topic for every SUBSCRIBE, it is highly recommended to make the implementation as efficient as possible.

Since:

3.2

Author:

Georg Held

Method Summary

Methods

Modifier and Type	Method and Description
SubackReturnCode	getSubackReturnCodeForClient(Topic topic, SubackReturnCode authorizationResult, ClientData clientData) Returns a SubackReturnCode for a Topic, a previous SubackReturnCode and a ClientData.

Methods inherited from interface com.hivemq.spi.callback.SynchronousCallback

priority

Method Detail

getSubackReturnCodeForClient

SubackReturnCode getSubackReturnCodeForClient(Topic topic,
                                            SubackReturnCode authorizationResult,
                                            ClientData clientData)

Returns a SubackReturnCode for a Topic, a previous SubackReturnCode and a ClientData.

Parameters:

topic - the topic to which the client wants to subscribe

authorizationResult - the result of a OnTopicSubscriptionCallback with higher priority if available, or of the OnAuthorizationCallbacks if available, or the QoS the client requested.

clientData - information about the client

Returns:

the SubackReturnCode that corresponds to the topic in the SUBACK to be sent to the client, a good default would be authorizationResult