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package cool.mqtt.hooks;
/**
* An abstraction of the {@code PUBLISH} Control Packet, sent by a client and then passed to the
* Hook, before being encoded and finally delivered to the target MQTT broker.
*/
public interface MqttMessage {
/**
* Gets the name of the topic to which this message is being published.
*
* @return the topic name
*/
String getTopicName();
/**
* Gets the Application Message carried by this message.
*
* The MQTT Protocol Specifications defines the Application Message as the payload of the
* {@code PUBLISH} Control Packet.
*
* @return the byte array containing the Application Message info
*/
byte[] getApplicationMessage();
/**
* Gets the Quality of Service level with which this message has been delivered.
*
* @return the Quality of Service level
*/
QoS getQos();
/**
* Gets the retained flag of this message.
*
*
The retain flag specifies whether the MQTT broker must store this message, in order to be
* immediately delivered to future clients as they subscribe to matching topics.
*
* @return {@code true} if the retained flag is set
*/
boolean isRetained();
/**
* Gets the duplicate flag of this message.
*
*
Only for messages with {@code QoS level > 0}, the duplicate flag indicates that this message
* might have been re-sent because not acknowledged in an earlier attempt.
*
*
In case of {@link QoS#AT_MOST_ONCE} level, this method always returns {@code false}.
*
* @return {@code true} if the duplicate flag is set
*/
boolean isDuplicate();
}