org.apache.activemq.transport.mqtt.strategy

Class MQTTVirtualTopicSubscriptionStrategy

java.lang.Object

org.apache.activemq.transport.mqtt.strategy.AbstractMQTTSubscriptionStrategy

org.apache.activemq.transport.mqtt.strategy.MQTTVirtualTopicSubscriptionStrategy

All Implemented Interfaces:

BrokerServiceAware, MQTTSubscriptionStrategy

public class MQTTVirtualTopicSubscriptionStrategy
extends AbstractMQTTSubscriptionStrategy

Subscription strategy that converts all MQTT subscribes that would be durable to Virtual Topic Queue subscriptions. Also maps all publish requests to be prefixed with the VirtualTopic. prefix unless already present.

Field Summary

Fields inherited from class org.apache.activemq.transport.mqtt.strategy.AbstractMQTTSubscriptionStrategy

brokerService, consumerIdGenerator, mqttSubscriptionByTopic, protocol, restoredDurableSubs, subscriptionsByConsumerId

Constructor Summary

Constructors

Constructor and Description
MQTTVirtualTopicSubscriptionStrategy()

Method Summary

Modifier and Type	Method and Description
boolean	isControlTopic(org.apache.activemq.command.ActiveMQDestination destination) Allows the protocol handler to interrogate an destination name to determine if it is equivalent to the MQTT control topic (starts with $).
void	onConnect(org.fusesource.mqtt.codec.CONNECT connect) Allows the strategy to perform any needed actions on client connect prior to the CONNACK frame being sent back such as recovering old subscriptions and performing any clean session actions.
void	onReSubscribe(MQTTSubscription mqttSubscription) Called when a client sends a duplicate subscribe request which should force any retained messages on that topic to be replayed again as though the client had just subscribed for the first time.
String	onSend(org.apache.activemq.command.ActiveMQDestination destination) Intercepts send operations from the broker and allows the strategy to map the target topic name so that the client sees a valid Topic name.
org.apache.activemq.command.ActiveMQDestination	onSend(String topicName) Intercepts PUBLISH operations from the client and allows the strategy to map the target destination so that the send operation will land in the destinations that this strategy has mapped the incoming subscribe requests to.
byte	onSubscribe(String topicName, org.fusesource.mqtt.client.QoS requestedQoS) Called when a new Subscription is being requested.
void	onUnSubscribe(String topicName) Called when a client requests an un-subscribe a previous subscription.

Methods inherited from class org.apache.activemq.transport.mqtt.strategy.AbstractMQTTSubscriptionStrategy

deleteDurableSubs, doSubscribe, doUnSubscribe, getNextConsumerId, getProtocolConverter, getSubscription, initialize, lookupSubscription, onSubscribe, restoreDurableSubs, setBrokerService, setProtocolConverter

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MQTTVirtualTopicSubscriptionStrategy

public MQTTVirtualTopicSubscriptionStrategy()

Method Detail

onConnect

public void onConnect(org.fusesource.mqtt.codec.CONNECT connect)
               throws MQTTProtocolException

Description copied from interface: MQTTSubscriptionStrategy

Allows the strategy to perform any needed actions on client connect prior to the CONNACK frame being sent back such as recovering old subscriptions and performing any clean session actions.

Throws:

MQTTProtocolException - if an error occurs while processing the connect actions.

onSubscribe

public byte onSubscribe(String topicName,
                        org.fusesource.mqtt.client.QoS requestedQoS)
                 throws MQTTProtocolException

Description copied from interface: MQTTSubscriptionStrategy

Called when a new Subscription is being requested. This method allows the strategy to create a specific type of subscription for the client such as mapping topic subscriptions to Queues etc.

Parameters:

topicName - the requested Topic name to subscribe to.

requestedQoS - the QoS level that the client has requested for this subscription.

Returns:

the assigned QoS value given to the new subscription

Throws:

MQTTProtocolException - if an error occurs while processing the subscribe actions.

onReSubscribe

public void onReSubscribe(MQTTSubscription mqttSubscription)
                   throws MQTTProtocolException

Description copied from interface: MQTTSubscriptionStrategy

Called when a client sends a duplicate subscribe request which should force any retained messages on that topic to be replayed again as though the client had just subscribed for the first time. The method should not unsubscribe the client as it might miss messages sent while the subscription is being recreated.

Specified by:

onReSubscribe in interface MQTTSubscriptionStrategy

Overrides:

onReSubscribe in class AbstractMQTTSubscriptionStrategy

Parameters:

mqttSubscription - the MQTTSubscription that contains the subscription state.

Throws:

MQTTProtocolException

onUnSubscribe

public void onUnSubscribe(String topicName)
                   throws MQTTProtocolException

Description copied from interface: MQTTSubscriptionStrategy

Called when a client requests an un-subscribe a previous subscription.

Parameters:

topicName - the name of the Topic the client wishes to unsubscribe from.

Throws:

MQTTProtocolException - if an error occurs during the un-subscribe processing.

onSend

public org.apache.activemq.command.ActiveMQDestination onSend(String topicName)

Description copied from interface: MQTTSubscriptionStrategy

Intercepts PUBLISH operations from the client and allows the strategy to map the target destination so that the send operation will land in the destinations that this strategy has mapped the incoming subscribe requests to.

Specified by:

onSend in interface MQTTSubscriptionStrategy

Overrides:

onSend in class AbstractMQTTSubscriptionStrategy

Parameters:

topicName - the targeted Topic that the client sent the message to.

Returns:

an ActiveMQ Topic instance that lands the send in the correct destinations.

onSend

public String onSend(org.apache.activemq.command.ActiveMQDestination destination)

Description copied from interface: MQTTSubscriptionStrategy

Intercepts send operations from the broker and allows the strategy to map the target topic name so that the client sees a valid Topic name.

Specified by:

onSend in interface MQTTSubscriptionStrategy

Overrides:

onSend in class AbstractMQTTSubscriptionStrategy

Parameters:

destination - the destination that the message was dispatched from

Returns:

an Topic name that is valid for the receiving client.

isControlTopic

public boolean isControlTopic(org.apache.activemq.command.ActiveMQDestination destination)

Description copied from interface: MQTTSubscriptionStrategy

Allows the protocol handler to interrogate an destination name to determine if it is equivalent to the MQTT control topic (starts with $). Since the mapped destinations that the strategy might alter the naming scheme the strategy must provide a way to reverse map and determine if the destination was originally an MQTT control topic.

Specified by:

isControlTopic in interface MQTTSubscriptionStrategy

Overrides:

isControlTopic in class AbstractMQTTSubscriptionStrategy

Parameters:

destination - the destination to query.

Returns:

true if the destination is an MQTT control topic.