io.netty.handler.codec

Class FixedLengthFrameDecoder

java.lang.Object

io.netty.channel.ChannelHandlerAdapter

io.netty.channel.ChannelStateHandlerAdapter

io.netty.channel.ChannelInboundByteHandlerAdapter

io.netty.handler.codec.ByteToMessageDecoder

io.netty.handler.codec.FixedLengthFrameDecoder

All Implemented Interfaces:

ChannelHandler, ChannelInboundByteHandler, ChannelStateHandler

public class FixedLengthFrameDecoder
extends ByteToMessageDecoder

A decoder that splits the received ByteBufs by the fixed number of bytes. For example, if you received the following four fragmented packets:

 +---+----+------+----+
 | A | BC | DEFG | HI |
 +---+----+------+----+
 

A FixedLengthFrameDecoder(3) will decode them into the following three packets with the fixed length:

 +-----+-----+-----+
 | ABC | DEF | GHI |
 +-----+-----+-----+
 

Nested Class Summary

Nested classes/interfaces inherited from interface io.netty.channel.ChannelHandler

ChannelHandler.Sharable

Constructor Summary

Constructors

Constructor and Description
FixedLengthFrameDecoder(int frameLength) Calls FixedLengthFrameDecoder(int, boolean) with false
FixedLengthFrameDecoder(int frameLength, boolean allocateFullBuffer) Creates a new instance.

Method Summary

Methods

Modifier and Type	Method and Description
protected Object	decode(ChannelHandlerContext ctx, ByteBuf in) Decode the from one ByteBuf to an other.
ByteBuf	newInboundBuffer(ChannelHandlerContext ctx) Create a new unpooled ByteBuf by default.

Methods inherited from class io.netty.handler.codec.ByteToMessageDecoder

callDecode, channelInactive, channelReadSuspended, decodeLast, inboundBufferUpdated, isSingleDecode, setSingleDecode

Methods inherited from class io.netty.channel.ChannelInboundByteHandlerAdapter

discardInboundReadBytes, freeInboundBuffer, inboundBufferUpdated

Methods inherited from class io.netty.channel.ChannelStateHandlerAdapter

channelActive, channelRegistered, channelUnregistered, userEventTriggered

Methods inherited from class io.netty.channel.ChannelHandlerAdapter

afterAdd, afterRemove, beforeAdd, beforeRemove, exceptionCaught

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.ChannelStateHandler

channelActive, channelRegistered, channelUnregistered, userEventTriggered

Methods inherited from interface io.netty.channel.ChannelHandler

afterAdd, afterRemove, beforeAdd, beforeRemove, exceptionCaught

Constructor Detail

FixedLengthFrameDecoder

public FixedLengthFrameDecoder(int frameLength)

Calls FixedLengthFrameDecoder(int, boolean) with false

FixedLengthFrameDecoder

public FixedLengthFrameDecoder(int frameLength,
                       boolean allocateFullBuffer)

Creates a new instance.

Parameters:

frameLength - the length of the frame

allocateFullBuffer - true if the cumulative ByteBuf should use the frameLength as its initial size

Method Detail

newInboundBuffer

public ByteBuf newInboundBuffer(ChannelHandlerContext ctx)
                         throws Exception

Description copied from class: ChannelInboundByteHandlerAdapter

Create a new unpooled ByteBuf by default. Sub-classes may override this to offer a more optimized implementation.

Specified by:

newInboundBuffer in interface ChannelInboundByteHandler

Overrides:

newInboundBuffer in class ChannelInboundByteHandlerAdapter

Throws:

Exception

decode

protected Object decode(ChannelHandlerContext ctx,
            ByteBuf in)
                 throws 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 anymore, till nothing was read from the input ByteBuf or till this method returns null.

Specified by:

decode in class ByteToMessageDecoder

Parameters:

ctx - the ChannelHandlerContext which this ByteToByteDecoder belongs to

in - the ByteBuf from which to read data

Returns:

message the message to which the content of the ByteBuf was decoded, or null if there was not enough data left in the ByteBuf to decode.

Throws:

Exception - is thrown if an error accour