Motivation:
When the MqttDecoder decodes a message larger than the 'maxBytesInMessage' a DecoderException is thrown and a MqttMessage with just the failure cause is returned. Even if I can't handle the message, I might want to send an ACK so that I won't have to worry about it again.
Modification:
The DecoderException is thrown after the variableHeader is decoded. The fixed and variable headers are then added to the MqttMessage along with the failure cause.
Result:
The invalid MqttMessage will have headers if available.
- Use simple string concatenation instead of String.format()
- Rewrite exception messages so that it follows our style
- Merge MqttCommonUtil and MqttValidationUtil into MqttCodecUtil
- Hide MqttCodecUtil from users
- Rename MqttConnectReturnCode.value to byteValue
- Rename MqttMessageFactory.create*() to new*()
- Rename QoS to MqttQoS
- Make MqttSubAckPayload.grantedQoSLevels immutable and add more useful
constructor
MQTT is a open source protocol on top of TCP which is widely used in
mobile communication and also for IoT (Internet of Things) today. This
will add an open source implementation of MQTT so that it becomes easier
for Netty users to implement an MQTT application.
For more information about the MQTT protocol, read this:
http://public.dhe.ibm.com/software/dw/webservices/ws-mqtt/mqtt-v3r1.html
