org.apache.activemq.transport.mqtt.strategy

Class AbstractMQTTSubscriptionStrategy

java.lang.Object

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

All Implemented Interfaces:

BrokerServiceAware, MQTTSubscriptionStrategy

Direct Known Subclasses:

MQTTDefaultSubscriptionStrategy, MQTTVirtualTopicSubscriptionStrategy

public abstract class AbstractMQTTSubscriptionStrategy
extends Object
implements MQTTSubscriptionStrategy, BrokerServiceAware

Abstract implementation of the MQTTSubscriptionStrategy interface providing the base functionality that is common to most implementations.

Field Summary

Fields

Modifier and Type	Field and Description
protected BrokerService	brokerService
protected LongSequenceGenerator	consumerIdGenerator
protected ConcurrentMap<String,MQTTSubscription>	mqttSubscriptionByTopic
protected MQTTProtocolConverter	protocol
protected Set<String>	restoredDurableSubs
protected ConcurrentMap<org.apache.activemq.command.ConsumerId,MQTTSubscription>	subscriptionsByConsumerId

Constructor Summary

Constructors

Constructor and Description
AbstractMQTTSubscriptionStrategy()

Method Summary

Modifier and Type	Method and Description
protected void	deleteDurableSubs(List<org.apache.activemq.command.SubscriptionInfo> subs)
protected byte	doSubscribe(org.apache.activemq.command.ConsumerInfo consumerInfo, String topicName, org.fusesource.mqtt.client.QoS qoS)
void	doUnSubscribe(MQTTSubscription subscription)
protected org.apache.activemq.command.ConsumerId	getNextConsumerId()
MQTTProtocolConverter	getProtocolConverter()
MQTTSubscription	getSubscription(org.apache.activemq.command.ConsumerId consumerId) Lookup an MQTTSubscription instance based on known ConsumerId value.
void	initialize(MQTTProtocolConverter protocol) Initialize the strategy before first use.
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 $).
protected List<org.apache.activemq.command.SubscriptionInfo>	lookupSubscription(String clientId)
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(org.fusesource.mqtt.client.Topic topic) Called for each Topic that a client requests to subscribe to.
protected void	restoreDurableSubs(List<org.apache.activemq.command.SubscriptionInfo> subs)
void	setBrokerService(BrokerService brokerService)
void	setProtocolConverter(MQTTProtocolConverter parent) Sets the MQTTProtocolConverter that is the parent of this strategy object.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.activemq.transport.mqtt.strategy.MQTTSubscriptionStrategy

onConnect, onSubscribe, onUnSubscribe

Field Detail

protocol

protected MQTTProtocolConverter protocol

brokerService

protected BrokerService brokerService

subscriptionsByConsumerId

protected final ConcurrentMap<org.apache.activemq.command.ConsumerId,MQTTSubscription> subscriptionsByConsumerId

mqttSubscriptionByTopic

protected final ConcurrentMap<String,MQTTSubscription> mqttSubscriptionByTopic

restoredDurableSubs

protected final Set<String> restoredDurableSubs

consumerIdGenerator

protected final LongSequenceGenerator consumerIdGenerator

Constructor Detail

AbstractMQTTSubscriptionStrategy

public AbstractMQTTSubscriptionStrategy()

Method Detail

initialize

public void initialize(MQTTProtocolConverter protocol)
                throws MQTTProtocolException

Description copied from interface: MQTTSubscriptionStrategy

Initialize the strategy before first use.

Specified by:

initialize in interface MQTTSubscriptionStrategy

Parameters:

protocol - the MQTTProtocolConverter that is initializing the strategy

Throws:

MQTTProtocolException - if an error occurs during initialization.

setBrokerService

public void setBrokerService(BrokerService brokerService)

Specified by:

setBrokerService in interface BrokerServiceAware

setProtocolConverter

public void setProtocolConverter(MQTTProtocolConverter parent)

Description copied from interface: MQTTSubscriptionStrategy

Sets the MQTTProtocolConverter that is the parent of this strategy object.

Specified by:

setProtocolConverter in interface MQTTSubscriptionStrategy

Parameters:

parent - the MQTTProtocolConverter that owns this strategy.

getProtocolConverter

public MQTTProtocolConverter getProtocolConverter()

Specified by:

getProtocolConverter in interface MQTTSubscriptionStrategy

Returns:

the MQTTProtocolConverter that owns this strategy.

onSubscribe

public byte onSubscribe(org.fusesource.mqtt.client.Topic topic)
                 throws MQTTProtocolException

Description copied from interface: MQTTSubscriptionStrategy

Called for each Topic that a client requests to subscribe to. The strategy needs check each Topic for duplicate subscription requests and change of QoS state.

Specified by:

onSubscribe in interface MQTTSubscriptionStrategy

Parameters:

topic - the MQTT Topic instance being subscribed to.

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

Parameters:

mqttSubscription - the MQTTSubscription that contains the subscription state.

Throws:

MQTTProtocolException

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

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

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

Parameters:

destination - the destination to query.

Returns:

true if the destination is an MQTT control topic.

getSubscription

public MQTTSubscription getSubscription(org.apache.activemq.command.ConsumerId consumerId)

Description copied from interface: MQTTSubscriptionStrategy

Lookup an MQTTSubscription instance based on known ConsumerId value.

Specified by:

getSubscription in interface MQTTSubscriptionStrategy

Parameters:

consumerId - the consumer ID to lookup.

Returns:

the MQTTSubscription for the consumer or null if no subscription exists.

getNextConsumerId

protected org.apache.activemq.command.ConsumerId getNextConsumerId()

doSubscribe

protected byte doSubscribe(org.apache.activemq.command.ConsumerInfo consumerInfo,
                           String topicName,
                           org.fusesource.mqtt.client.QoS qoS)
                    throws MQTTProtocolException

Throws:

MQTTProtocolException

doUnSubscribe

public void doUnSubscribe(MQTTSubscription subscription)

deleteDurableSubs

protected void deleteDurableSubs(List<org.apache.activemq.command.SubscriptionInfo> subs)

restoreDurableSubs

protected void restoreDurableSubs(List<org.apache.activemq.command.SubscriptionInfo> subs)

lookupSubscription

protected List<org.apache.activemq.command.SubscriptionInfo> lookupSubscription(String clientId)
                                                                         throws MQTTProtocolException

Throws:

MQTTProtocolException