Package cool.mqtt.hooks

Interface MqttBrokerConfig

public interface MqttBrokerConfig
An encapsulation of the MQTT broker configuration corresponding to the connection alias provided by a client on connection establishment with MQTT.Cool.

The Hook is expected to supply an instance of MqttBrokerConfig (through an invocation of MQTTCoolHook.resolveAlias(String)) if no static entries have been provided in the mqtt_master_connector_conf.xml file for a given connection alias.

The configuration is made up of:

  • Mandatory address of the MQTT broker.
  • Optional connection timeout and keep alive interval values.
  • Optional ClientId prefix.
  • Optional username and password, if the MQTT broker requires an authenticated access.
  • Optional Will Message.
  • Optional set of parameters for encrypted connections.
See Also:
MQTTCoolHook.resolveAlias(String)

  • Method Summary

    Modifier and Type Method Description
    java.lang.String getAddress()
    Gets the address of the MQTT broker to connect to.
    java.lang.String getClientIdPrefix()
    Gets the ClientId prefix to be used for shared connections.
    java.lang.Integer getConnectionTimeout()
    Gets the connection timeout expressed in seconds.
    java.lang.Integer getKeepAlive()
    Gets the keep alive interval expressed in seconds.
    java.lang.String getPassword()
    Gets the password for authenticating with the MQTT broker.
    SecurityParams getSecurityParams()
    Gets the SecureParams instance to be used for supporting the setting up of encrypted connections to the MQTT broker.
    java.lang.String getUsername()
    Gets the username for authenticating with the MQTT broker.
    MqttMessage getWillMessage()
    Gets the Will Message to be stored by the MQTT broker.

  • Method Details

    • getAddress

      java.lang.String getAddress()
      Gets the address of the MQTT broker to connect to.

      The address must be specified in one of the following URI forms:

      • tcp://<host>:<port>
      • mqtt://<host>:<port>
      • mqtts://<host>:<port>
      • ssl://<host>:<port>
      otherwise MQTT.Cool will invalidate it and the client will be notified with an error.

      Note that use of mqtts and ssl triggers encrypted communication with the MQTT broker, therefore further parameters (provided through an instance of SecurityParams) might be required in order to properly support the setting up of secure channels.

      Returns:
      the address of the MQTT broker
      See Also:
      getSecurityParams()

    • getClientIdPrefix

      java.lang.String getClientIdPrefix()
      Gets the ClientId prefix to be used for shared connections.

      If the clients want to share a single connection, MQTT.Cool concatenates the ClientId prefix with a randomly generated suffix in order to make a unique ClientId for opening the physical connection to the MQTT broker. Uniqueness of the ClientId is mandatory as multiple shared connections may exist for the same MQTT broker.

      In case of blank return value (that is, an empty, whitespace or null string), the default ClientId prefix "MQTT_Cool" will be used.

      Returns:
      the ClientId prefix, or a blank value (as defined above) if the default ClientId prefix is accepted

    • getConnectionTimeout

      java.lang.Integer getConnectionTimeout()
      Gets the connection timeout expressed in seconds.

      In case of a null return value, a default value of 5 seconds will be used.

      Returns:
      the connection timeout expressed in seconds, or null if the default value is accepted

    • getKeepAlive

      java.lang.Integer getKeepAlive()
      Gets the keep alive interval expressed in seconds.

      In case of a null return value, a default value of 30 seconds will be used.

      Returns:
      the keep alive interval expressed in seconds, or null if the default value is accepted

    • getUsername

      java.lang.String getUsername()
      Gets the username for authenticating with the MQTT broker.

      If the MQTT broker does not require authentication, this method should return a null value. Empty or blank values will be provided as is in the CONNECT Control Packet built to connect to the broker.

      Note that the username which may be provided by the client will take precedence over the one returned by this method.

      Returns:
      the username, or null if no credential is provided
      See Also:
      MqttConnectOptions.getUsername()

    • getPassword

      java.lang.String getPassword()
      Gets the password for authenticating with the MQTT broker.

      As for getUsername(), this method should returns null value in the case of unauthenticated access. Empty or blank values will be provided as is in the CONNECT Control Packet built to connect to the broker.

      Note that the password which may be provided by the client will take precedence over the one returned by this method.

      Returns:
      the password, or null if no credential is provided
      See Also:
      MqttConnectOptions.getPassword()

    • getWillMessage

      MqttMessage getWillMessage()
      Gets the Will Message to be stored by the MQTT broker.

      Note that the Will Message which may be provided by the client will take precedence over the one returned by this method.

      Returns:
      the Will Message to be stored by the MQTT broker if any, or null
      See Also:
      MqttConnectOptions.getWillMessage()

    • getSecurityParams

      SecurityParams getSecurityParams()
      Gets the SecureParams instance to be used for supporting the setting up of encrypted connections to the MQTT broker.

      Note that this method will be invoked only in the case the address returned by getAddress() specifies a secure schema.

      Furthermore, if null is returned, the MQTT.Cool server will try to establish a secure channel using the following default settings:

      • TLSv1.2 as security protocol.
      • Default truststore and keystore, determined according to the JSSE Reference Guide.
      Returns:
      a SecureParams instance, or null