```
public interface MqttClient
```
An MQTT client

Method Summary

All Methods Static Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`Future<Void>`	`authenticationExchange(MqttAuthenticationExchangeMessage message)`	It is used for Enhanced Authentication and is able to carry an authentication method and authentication data.
`MqttClient`	`authenticationExchangeHandler(Handler<MqttAuthenticationExchangeMessage> authenticationExchangeHandler)`	Sets handler which will be called after AUTH packet receiving
`String`	`clientId()`
`MqttClient`	`closeHandler(Handler<Void> closeHandler)`	Set a handler that will be called when the connection with server is closed
`Future<MqttConnAckMessage>`	`connect(int port, String host)`	Connects to an MQTT server calling connectHandler after connection
`Future<MqttConnAckMessage>`	`connect(int port, String host, String serverName)`	Connects to an MQTT server calling connectHandler after connection
`static MqttClient`	`create(Vertx vertx)`	Return an MQTT client instance using the default options
`static MqttClient`	`create(Vertx vertx, MqttClientOptions options)`	Return an MQTT client instance
`Future<Void>`	`disconnect()`	Disconnects from the MQTT server
`MqttClient`	`exceptionHandler(Handler<Throwable> handler)`	Set an exception handler for the client, that will be called when an error happens in internal netty structures.
`boolean`	`isConnected()`
`MqttClient`	`ping()`	This method is needed by the client in order to avoid server closes the connection due to the keep alive timeout if client has no messages to send
`MqttClient`	`pingResponseHandler(Handler<Void> pingResponseHandler)`	Sets handler which will be called after PINGRESP packet receiving
`Future<Integer>`	`publish(String topic, Buffer payload, MqttQoS qosLevel, boolean isDup, boolean isRetain)`	Sends the PUBLISH message to the remote MQTT server
`MqttClient`	`publishCompletionExpirationHandler(Handler<Integer> publishCompletionExpirationHandler)`	Sets a handler which will be called when the client does not receive a PUBACK or PUBREC/PUBCOMP for a message published using QoS 1 or 2 respectively.
`MqttClient`	`publishCompletionHandler(Handler<Integer> publishCompletionHandler)`	Sets a handler which will be called each time the publishing of a message has been completed.
`MqttClient`	`publishCompletionUnknownPacketIdHandler(Handler<Integer> publishCompletionPhantomHandler)`	Sets a handler which will be called when the client receives a PUBACK/PUBREC/PUBCOMP with an unknown packet ID.
`MqttClient`	`publishHandler(Handler<MqttPublishMessage> publishHandler)`	Sets handler which will be called each time server publish something to client
`Future<Integer>`	`subscribe(String topic, int qos)`	Subscribes to the topic with a specified QoS level
`Future<Integer>`	`subscribe(Map<String,Integer> topics)`	Subscribes to the topics with related QoS levels
`MqttClient`	`subscribeCompletionHandler(Handler<MqttSubAckMessage> subscribeCompletionHandler)`	Sets handler which will be called after SUBACK packet receiving
`Future<Integer>`	`unsubscribe(String topic)`	Unsubscribe from receiving messages on given topic
`Future<Integer>`	`unsubscribe(List<String> topics)`	Unsubscribe from receiving messages on given list of topic
`MqttClient`	`unsubscribeCompletionHandler(Handler<Integer> unsubscribeCompletionHandler)`	Sets handler which will be called after UNSUBACK packet receiving

- Method Detail
  - create
```
static MqttClient create(Vertx vertx,
                         MqttClientOptions options)
```
    Return an MQTT client instance
    
    Parameters:
    
    vertx - Vert.x instance
    
    options - MQTT client options
    
    Returns:
    
    MQTT client instance
  - create
```
static MqttClient create(Vertx vertx)
```
    Return an MQTT client instance using the default options
    
    Parameters:
    
    vertx - Vert.x instance
    
    Returns:
    
    MQTT client instance
  - connect
```
Future<MqttConnAckMessage> connect(int port,
                                   String host)
```
    Connects to an MQTT server calling connectHandler after connection
    
    Parameters:
    
    port - port of the MQTT server
    
    host - hostname/ip address of the MQTT server
    
    Returns:
    
    a future notified when the connect call ends
  - connect
```
Future<MqttConnAckMessage> connect(int port,
                                   String host,
                                   String serverName)
```
    Connects to an MQTT server calling connectHandler after connection
    
    Parameters:
    
    port - port of the MQTT server
    
    host - hostname/ip address of the MQTT server
    
    serverName - the SNI server name
    
    Returns:
    
    a future notified when the connect call ends
  - disconnect
```
Future<Void> disconnect()
```
    Disconnects from the MQTT server
    
    Returns:
    
    a Future of the asynchronous result
  - publish
```
Future<Integer> publish(String topic,
                        Buffer payload,
                        MqttQoS qosLevel,
                        boolean isDup,
                        boolean isRetain)
```
    Sends the PUBLISH message to the remote MQTT server
    
    Parameters:
    
    topic - topic on which the message is published
    
    payload - message payload
    
    qosLevel - QoS level
    
    isDup - if the message is a duplicate
    
    isRetain - if the message needs to be retained
    
    Returns:
    
    a Future completed after PUBLISH packet sent with packetid (not when QoS 0)
  - publishCompletionHandler
```
MqttClient publishCompletionHandler(Handler<Integer> publishCompletionHandler)
```
    Sets a handler which will be called each time the publishing of a message has been completed.
    For a message that has been published using
    
    QoS 0 this means that the client has successfully sent the corresponding PUBLISH packet,
    
    QoS 1 this means that a corresponding PUBACK has been received from the server,
    
    QoS 2 this means that a corresponding PUBCOMP has been received from the server.
    Parameters:
    
    publishCompletionHandler - handler called with the packetId
    
    Returns:
    
    current MQTT client instance
  - publishCompletionExpirationHandler
```
MqttClient publishCompletionExpirationHandler(Handler<Integer> publishCompletionExpirationHandler)
```
    Sets a handler which will be called when the client does not receive a PUBACK or PUBREC/PUBCOMP for a message published using QoS 1 or 2 respectively.
    The time to wait for an acknowledgement message can be configured using MqttClientOptions.setAckTimeout(int). If the client receives a PUBACK/PUBREC/PUBCOMP for a message after its completion has expired, the handler registered using publishCompletionUnknownPacketIdHandler(Handler) will be invoked.
    Note that this behavior is outside the scope of the MQTT 3.1.1 specification. The client's default behavior is therefore to wait forever for the server's corresponding acknowledgement.
    
    Parameters:
    
    publishCompletionExpirationHandler - the handler to call with the ID of the expired packet
    
    Returns:
    
    current MQTT client instance
  - publishCompletionUnknownPacketIdHandler
```
MqttClient publishCompletionUnknownPacketIdHandler(Handler<Integer> publishCompletionPhantomHandler)
```
    Sets a handler which will be called when the client receives a PUBACK/PUBREC/PUBCOMP with an unknown packet ID.
    
    Parameters:
    
    publishCompletionPhantomHandler - the handler to call with the unknown packet ID
    
    Returns:
    
    current MQTT client instance
  - publishHandler
```
MqttClient publishHandler(Handler<MqttPublishMessage> publishHandler)
```
    Sets handler which will be called each time server publish something to client
    
    Parameters:
    
    publishHandler - handler to call
    
    Returns:
    
    current MQTT client instance
  - subscribeCompletionHandler
```
MqttClient subscribeCompletionHandler(Handler<MqttSubAckMessage> subscribeCompletionHandler)
```
    Sets handler which will be called after SUBACK packet receiving
    
    Parameters:
    
    subscribeCompletionHandler - handler to call. List inside is a granted QoS array
    
    Returns:
    
    current MQTT client instance
  - subscribe
```
Future<Integer> subscribe(String topic,
                          int qos)
```
    Subscribes to the topic with a specified QoS level
    
    Parameters:
    
    topic - topic you subscribe on
    
    qos - QoS level
    
    Returns:
    
    a Future completed after SUBSCRIBE packet sent with packetid
  - subscribe
```
Future<Integer> subscribe(Map<String,Integer> topics)
```
    Subscribes to the topics with related QoS levels
    
    Parameters:
    
    topics - topics and related QoS levels to subscribe to
    
    Returns:
    
    a Future completed after SUBSCRIBE packet sent with packetid
  - unsubscribeCompletionHandler
```
MqttClient unsubscribeCompletionHandler(Handler<Integer> unsubscribeCompletionHandler)
```
    Sets handler which will be called after UNSUBACK packet receiving
    
    Parameters:
    
    unsubscribeCompletionHandler - handler to call with the packetid
    
    Returns:
    
    current MQTT client instance
  - unsubscribe
```
Future<Integer> unsubscribe(String topic)
```
    Unsubscribe from receiving messages on given topic
    
    Parameters:
    
    topic - Topic you want to unsubscribe from
    
    Returns:
    
    a Future completed after UNSUBSCRIBE packet sent with packetid
  - unsubscribe
```
Future<Integer> unsubscribe(List<String> topics)
```
    Unsubscribe from receiving messages on given list of topic
    
    Parameters:
    
    topics - list of topics you want to unsubscribe from
    
    Returns:
    
    a Future completed after UNSUBSCRIBE packet sent with packetid
  - authenticationExchangeHandler
```
MqttClient authenticationExchangeHandler(Handler<MqttAuthenticationExchangeMessage> authenticationExchangeHandler)
```
    Sets handler which will be called after AUTH packet receiving
    
    Parameters:
    
    authenticationExchangeHandler - handler to call
    
    Returns:
    
    current MQTT client instance
  - authenticationExchange
```
Future<Void> authenticationExchange(MqttAuthenticationExchangeMessage message)
```
    It is used for Enhanced Authentication and is able to carry an authentication method and authentication data.
    
    Parameters:
    
    message - authentication exchange message
    
    Returns:
    
    a Future completed after AUTH packet sent
  - pingResponseHandler
```
MqttClient pingResponseHandler(Handler<Void> pingResponseHandler)
```
    Sets handler which will be called after PINGRESP packet receiving
    
    Parameters:
    
    pingResponseHandler - handler to call
    
    Returns:
    
    current MQTT client instance
  - exceptionHandler
```
MqttClient exceptionHandler(Handler<Throwable> handler)
```
    Set an exception handler for the client, that will be called when an error happens in internal netty structures. io.netty.handler.codec.DecoderException can be one of the cause
    
    Parameters:
    
    handler - the exception handler
    
    Returns:
    
    current MQTT client instance
  - closeHandler
```
MqttClient closeHandler(Handler<Void> closeHandler)
```
    Set a handler that will be called when the connection with server is closed
    
    Parameters:
    
    closeHandler - handler to call
    
    Returns:
    
    current MQTT client instance
  - ping
```
MqttClient ping()
```
    This method is needed by the client in order to avoid server closes the connection due to the keep alive timeout if client has no messages to send
    
    Returns:
    
    current MQTT client instance
  - clientId
```
String clientId()
```
    Returns:
    
    the client identifier
  - isConnected
```
boolean isConnected()
```
    Returns:
    
    if the connection between client and remote server is established/open

Interface MqttClient

Method Summary

Method Detail

create

create

connect

connect

disconnect

publish

publishCompletionHandler

publishCompletionExpirationHandler

publishCompletionUnknownPacketIdHandler

publishHandler

subscribeCompletionHandler

subscribe

subscribe

unsubscribeCompletionHandler

unsubscribe

unsubscribe

authenticationExchangeHandler

authenticationExchange

pingResponseHandler

exceptionHandler

closeHandler

ping

clientId

isConnected