MqttDecoder (Netty API Reference (4.2.1.Final))

java.lang.Object
- io.netty.channel.ChannelHandlerAdapter
- - io.netty.channel.ChannelInboundHandlerAdapter
  - - io.netty.handler.codec.ByteToMessageDecoder
    - - io.netty.handler.codec.ReplayingDecoder<io.netty.handler.codec.mqtt.MqttDecoder.DecoderState>
      - io.netty.handler.codec.mqtt.MqttDecoder

All Implemented Interfaces:

ChannelHandler, ChannelInboundHandler
```
public final class MqttDecoder
extends ReplayingDecoder<io.netty.handler.codec.mqtt.MqttDecoder.DecoderState>
```
Decodes Mqtt messages from bytes, following the MQTT protocol specification v3.1 or v5.0, depending on the version specified in the CONNECT message that first goes through the channel.

Nested Class Summary
- Nested classes/interfaces inherited from class io.netty.handler.codec.ByteToMessageDecoder
  ByteToMessageDecoder.Cumulator
- Nested classes/interfaces inherited from interface io.netty.channel.ChannelHandler
  ChannelHandler.Sharable

Field Summary
- Fields inherited from class io.netty.handler.codec.ByteToMessageDecoder
  COMPOSITE_CUMULATOR, MERGE_CUMULATOR

Constructor Summary

Constructors
Constructor Description

MqttDecoder()

MqttDecoder(int maxBytesInMessage)

MqttDecoder(int maxBytesInMessage, int maxClientIdLength)

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`protected void`	`decode(ChannelHandlerContext ctx, ByteBuf buffer, java.util.List<java.lang.Object> out)`	Decode the from one `ByteBuf` to an other.

Methods inherited from class io.netty.handler.codec.ReplayingDecoder
callDecode, checkpoint, checkpoint, state, state

Methods inherited from class io.netty.handler.codec.ByteToMessageDecoder
actualReadableBytes, channelInactive, channelRead, channelReadComplete, decodeLast, discardSomeReadBytes, handlerRemoved, handlerRemoved0, internalBuffer, isSingleDecode, setCumulator, setDiscardAfterReads, setSingleDecode, userEventTriggered

Methods inherited from class io.netty.channel.ChannelInboundHandlerAdapter
channelActive, channelRegistered, channelUnregistered, channelWritabilityChanged, exceptionCaught

Methods inherited from class io.netty.channel.ChannelHandlerAdapter
ensureNotSharable, handlerAdded, isSharable

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface io.netty.channel.ChannelHandler
handlerAdded

- Constructor Detail
  - MqttDecoder
```
public MqttDecoder()
```
  - MqttDecoder
```
public MqttDecoder(int maxBytesInMessage)
```
  - MqttDecoder
```
public MqttDecoder(int maxBytesInMessage,
                   int maxClientIdLength)
```
- Method Detail
  - decode
```
protected void decode(ChannelHandlerContext ctx,
                      ByteBuf buffer,
                      java.util.List<java.lang.Object> out)
               throws java.lang.Exception
```
    Description copied from class: ByteToMessageDecoder
    
    Decode the from one ByteBuf to an other. This method will be called till either the input ByteBuf has nothing to read when return from this method or till nothing was read from the input ByteBuf.
    
    Specified by:
    
    decode in class ByteToMessageDecoder
    
    Parameters:
    
    ctx - the ChannelHandlerContext which this ByteToMessageDecoder belongs to
    
    buffer - the ByteBuf from which to read data
    
    out - the List to which decoded messages should be added
    
    Throws:
    
    java.lang.Exception - is thrown if an error occurs