org.jboss.netty.handler.codec.frame
Class FixedLengthFrameDecoder

java.lang.Object
  org.jboss.netty.channel.SimpleChannelUpstreamHandler
      org.jboss.netty.handler.codec.frame.FrameDecoder
          org.jboss.netty.handler.codec.frame.FixedLengthFrameDecoder

All Implemented Interfaces:

ChannelHandler, ChannelUpstreamHandler

public class FixedLengthFrameDecoder
extends FrameDecoder

A decoder that splits the received ChannelBuffers 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 |
 +-----+-----+-----+
 

Version:

$Rev:231 $, $Date:2008-06-12 16:44:50 +0900 (목, 12 6월 2008) $

Author:

The Netty Project, Trustin Lee

Nested Class Summary

Nested classes/interfaces inherited from interface org.jboss.netty.channel.ChannelHandler

ChannelHandler.Sharable

Constructor Summary

FixedLengthFrameDecoder(int frameLength)
Creates a new instance.

Method Summary

protected Object

decode(ChannelHandlerContext ctx, Channel channel, ChannelBuffer buffer) Decodes the received packets so far into a frame.

Methods inherited from class org.jboss.netty.handler.codec.frame.FrameDecoder

channelClosed, channelDisconnected, decodeLast, exceptionCaught, messageReceived

Methods inherited from class org.jboss.netty.channel.SimpleChannelUpstreamHandler

channelBound, channelConnected, channelInterestChanged, channelOpen, channelUnbound, childChannelClosed, childChannelOpen, handleUpstream, writeComplete

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FixedLengthFrameDecoder

public FixedLengthFrameDecoder(int frameLength)

Creates a new instance.

Parameters:

frameLength - the length of the frame

Method Detail

decode

protected Object decode(ChannelHandlerContext ctx,
                        Channel channel,
                        ChannelBuffer buffer)
                 throws Exception

Description copied from class: FrameDecoder

Decodes the received packets so far into a frame.

Specified by:

decode in class FrameDecoder

Parameters:

ctx - the context of this handler

channel - the current channel

buffer - the cumulative buffer of received packets so far. Note that the buffer might be empty, which means you should not make an assumption that the buffer contains at least one byte in your decoder implementation.

Returns:

the decoded frame if a full frame was received and decoded. null if there's not enough data in the buffer to decode a frame.

Throws:

Exception