io.vertx.mqtt

## Interface MqttClient

-     public interface MqttClient

  An MQTT client

- - ### Method Summary

    All Methods Static Methods Instance Methods Abstract Methods Default Methods
    Modifier and Type | Method and Description
    --- | ---
    `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)` Like `connect(int, String, Handler)` but returns a `Future` of the asynchronous result
    `MqttClient` | `connect(int port, String host, Handler<AsyncResult<MqttConnAckMessage>> connectHandler)` Connects to an MQTT server calling connectHandler after connection
    `Future<MqttConnAckMessage>` | `connect(int port, String host, String serverName)` Like `connect(int, String, String, Handler)` but returns a `Future` of the asynchronous result
    `MqttClient` | `connect(int port, String host, String serverName, Handler<AsyncResult<MqttConnAckMessage>> connectHandler)` 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` | `disconnect(Handler<AsyncResult<Void>> disconnectHandler)` Disconnects from the MQTT server calling disconnectHandler after disconnection
    `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` | `publish(String topic, Buffer payload, MqttQoS qosLevel, boolean isDup, boolean isRetain, Handler<AsyncResult<Integer>> publishSentHandler)` 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(Map<String,Integer> topics)` Subscribes to the topics with related QoS levels
    `MqttClient` | `subscribe(Map<String,Integer> topics, Handler<AsyncResult<Integer>> subscribeSentHandler)` Subscribes to the topic and adds a handler which will be called after the request is sent
    `Future<Integer>` | `subscribe(String topic, int qos)` Subscribes to the topic with a specified QoS level
    `MqttClient` | `subscribe(String topic, int qos, Handler<AsyncResult<Integer>> subscribeSentHandler)` Subscribes to the topic with a specified QoS level
    `MqttClient` | `subscribeCompletionHandler(Handler<MqttSubAckMessage> subscribeCompletionHandler)` Sets handler which will be called after SUBACK packet receiving
    `Future<Integer>` | `unsubscribe(List<String> topics)` Unsubscribe from receiving messages on given list of topic
    `MqttClient` | `unsubscribe(List<String> topics, Handler<AsyncResult<Integer>> unsubscribeSentHandler)` Unsubscribe from receiving messages on given topics
    `Future<Integer>` | `unsubscribe(String topic)` Unsubscribe from receiving messages on given topic
    `MqttClient` | `unsubscribe(String topic, Handler<AsyncResult<Integer>> unsubscribeSentHandler)` Unsubscribe from receiving messages on given 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

          MqttClient connect(int port,
                             String host,
                             Handler<AsyncResult<MqttConnAckMessage>> connectHandler)

      Connects to an MQTT server calling connectHandler after connection
      Parameters:
        `port` - port of the MQTT server
        `host` - hostname/ip address of the MQTT server
        `connectHandler` - handler called when the asynchronous connect call ends
      Returns:
        current MQTT client instance

    - #### connect

          Future<MqttConnAckMessage> connect(int port,
                                             String host)

      Like `connect(int, String, Handler)` but returns a `Future` of the asynchronous result

    - #### connect

          MqttClient connect(int port,
                             String host,
                             String serverName,
                             Handler<AsyncResult<MqttConnAckMessage>> connectHandler)

      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
        `connectHandler` - handler called when the asynchronous connect call ends
      Returns:
        current MQTT client instance

    - #### connect

          Future<MqttConnAckMessage> connect(int port,
                                             String host,
                                             String serverName)

      Like `connect(int, String, String, Handler)` but returns a `Future` of the asynchronous result

    - #### disconnect

          Future<Void> disconnect()

      Disconnects from the MQTT server
      Returns:
        a `Future` of the asynchronous result

    - #### disconnect

          MqttClient disconnect(Handler<AsyncResult<Void>> disconnectHandler)

      Disconnects from the MQTT server calling disconnectHandler after disconnection
      Parameters:
        `disconnectHandler` - handler called when asynchronous disconnect call ends
      Returns:
        current MQTT client instance

    - #### 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)

    - #### publish

          MqttClient publish(String topic,
                             Buffer payload,
                             MqttQoS qosLevel,
                             boolean isDup,
                             boolean isRetain,
                             Handler<AsyncResult<Integer>> publishSentHandler)

      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
        `publishSentHandler` - handler called after PUBLISH packet sent with packetid (not when QoS 0)
      Returns:
        current MQTT client instance

    - #### 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

          MqttClient subscribe(String topic,
                               int qos,
                               Handler<AsyncResult<Integer>> subscribeSentHandler)

      Subscribes to the topic with a specified QoS level
      Parameters:
        `topic` - topic you subscribe on
        `qos` - QoS level
        `subscribeSentHandler` - handler called after SUBSCRIBE packet sent with packetid
      Returns:
        current MQTT client instance

    - #### 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

    - #### subscribe

          MqttClient subscribe(Map<String,Integer> topics,
                               Handler<AsyncResult<Integer>> subscribeSentHandler)

      Subscribes to the topic and adds a handler which will be called after the request is sent
      Parameters:
        `topics` - topics you subscribe on
        `subscribeSentHandler` - handler called after SUBSCRIBE packet sent with packetid
      Returns:
        current MQTT client instance

    - #### 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

    - #### unsubscribe

          MqttClient unsubscribe(List<String> topics,
                                 Handler<AsyncResult<Integer>> unsubscribeSentHandler)

      Unsubscribe from receiving messages on given topics
      Parameters:
        `topics` - list of topics you want to unsubscribe from
        `unsubscribeSentHandler` - handler called after UNSUBSCRIBE packet sent
      Returns:
        current MQTT client instance

    - #### unsubscribe

          MqttClient unsubscribe(String topic,
                                 Handler<AsyncResult<Integer>> unsubscribeSentHandler)

      Unsubscribe from receiving messages on given topic
      Parameters:
        `topic` - list of topics you want to unsubscribe from
        `unsubscribeSentHandler` - handler called after UNSUBSCRIBE packet sent
      Returns:
        current MQTT client instance

    - #### 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

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