Package 

Class MqttMessage

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public class MqttMessage

    An MQTT message holds the application payload and options specifying how the message is to be delivered The message includes a "payload" (the body of the message) represented as a byte[].

    • Field Summary

      Fields 
      Modifier and Type Field Description
      private Array<byte> payload
      private int qos
      private boolean retained

    • Constructor Summary

      Constructors 
      Constructor Description
      MqttMessage() Constructs a message with an empty payload, and all other values set to defaults.
      MqttMessage(Array<byte> payload) Constructs a message with the specified byte array as a payload, and all other values set to defaults.

    • Method Summary

      Modifier and Type Method Description
      Array<byte> getPayload() Returns the payload as a byte array.
      void setPayload(Array<byte> payload) Sets the payload of this message to be the specified byte array.
      int getQos() Returns the quality of service for this message.
      void setQos(int qos) Sets the quality of service for this message.
      void setRetained(boolean retained) Whether or not the publish message should be retained by the messaging engine.
      static void validateQos(int qos) Utility method to validate the supplied QoS value.
      void clearPayload() Clears the payload, resetting it to be empty.
      boolean isRetained() Returns whether or not this message should be/was retained by the server.
      String toString() Returns a string representation of this message's payload.
      boolean isDuplicate() Returns whether or not this message might be a duplicate of one which has already been received.
      int uniqueCode()

      • Methods inherited from class java.lang.Object

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

    • Constructor Detail

      • MqttMessage

        MqttMessage()
        Constructs a message with an empty payload, and all other values set to defaults.

      • MqttMessage

        MqttMessage(Array<byte> payload)
        Constructs a message with the specified byte array as a payload, and all other values set to defaults.

    • Method Detail

      • setPayload

         void setPayload(Array<byte> payload)

        Sets the payload of this message to be the specified byte array.

        Parameters:
        payload - the payload for this message.

      • getQos

         int getQos()

        Returns the quality of service for this message.

      • setQos

         void setQos(int qos)

        Sets the quality of service for this message.

        • Quality of Service 0 - indicates that a message should be delivered at most once (zero or one times). The message will not be persisted to disk, and will not be acknowledged across the network. This QoS is the fastest, but should only be used for messages which are not valuable - note that if the server cannot process the message (for example, there is an authorization problem), then an deliveryComplete. Also known as "fire and forget".
        • Quality of Service 1 - indicates that a message should be delivered at least once (one or more times). The message can only be delivered safely if it can be persisted, so the application must supply a means of persistence using MqttConnectOptions. If a persistence mechanism is not specified, the message will not be delivered in the event of a client failure. The message will be acknowledged across the network. This is the default QoS.
        • Quality of Service 2 - indicates that a message should be delivered once. The message will be persisted to disk, and will be subject to a two-phase acknowledgement across the network. The message can only be delivered safely if it can be persisted, so the application must supply a means of persistence using MqttConnectOptions. If a persistence mechanism is not specified, the message will not be delivered in the event of a client failure.
        Parameters:
        qos - the "quality of service" to use.

      • setRetained

         void setRetained(boolean retained)

        Whether or not the publish message should be retained by the messaging engine. Sending a message with the retained set to false will clear the retained message from the server. The default value is false

        Parameters:
        retained - whether or not the messaging engine should retain the message.

      • validateQos

         static void validateQos(int qos)

        Utility method to validate the supplied QoS value.

      • clearPayload

         void clearPayload()

        Clears the payload, resetting it to be empty.

      • isRetained

         boolean isRetained()

        Returns whether or not this message should be/was retained by the server. For messages received from the server, this method returns whether or not the message was from a current publisher, or was "retained" by the server as the last message published on the topic.

      • toString

         String toString()

        Returns a string representation of this message's payload. Makes an attempt to return the payload as a string. As the MQTT client has no control over the content of the payload it may fail.

      • isDuplicate

         boolean isDuplicate()

        Returns whether or not this message might be a duplicate of one which has already been received. This will only be set on messages received from the server.