## org.jboss.netty.handler.codec.frame
Class DelimiterBasedFrameDecoder

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

All Implemented Interfaces:
  ChannelHandler, ChannelUpstreamHandler

    public class DelimiterBasedFrameDecoder

extends FrameDecoder

A decoder that splits the received `ChannelBuffer`s by one or more delimiters. It is particularly useful for decoding the frames which ends with a delimiter such as `NUL` or newline characters.

### Predefined delimiters

`Delimiters` defines frequently used delimiters for convenience' sake.

### Specifying more than one delimiter

`DelimiterBasedFrameDecoder` allows you to specify more than one delimiter. If more than one delimiter is found in the buffer, it chooses the delimiter which produces the shortest frame. For example, if you have the following data in the buffer:

     +--------------+
     | ABC\nDEF\r\n |
     +--------------+

a `DelimiterBasedFrameDecoder` `(` `Delimiters.lineDelimiter()` `)` will choose `'\n'` as the first delimiter and produce two frames:

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

rather than incorrectly choosing `'\r\n'` as the first delimiter:

     +----------+
     | ABC\nDEF |
     +----------+

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
`DelimiterBasedFrameDecoder(int maxFrameLength, boolean stripDelimiter, ChannelBuffer... delimiters)` Creates a new instance.
`DelimiterBasedFrameDecoder(int maxFrameLength, boolean stripDelimiter, ChannelBuffer delimiter)` Creates a new instance.
`DelimiterBasedFrameDecoder(int maxFrameLength, ChannelBuffer... delimiters)` Creates a new instance.
`DelimiterBasedFrameDecoder(int maxFrameLength, ChannelBuffer delimiter)` 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

### DelimiterBasedFrameDecoder

    public DelimiterBasedFrameDecoder(int maxFrameLength,
                                      ChannelBuffer delimiter)

  Creates a new instance.

  Parameters:
    `maxFrameLength` - the maximum length of the decoded frame. A `TooLongFrameException` is thrown if the length of the frame exceeds this value.
    `delimiter` - the delimiter

### DelimiterBasedFrameDecoder

    public DelimiterBasedFrameDecoder(int maxFrameLength,
                                      boolean stripDelimiter,
                                      ChannelBuffer delimiter)

  Creates a new instance.

  Parameters:
    `maxFrameLength` - the maximum length of the decoded frame. A `TooLongFrameException` is thrown if the length of the frame exceeds this value.
    `stripDelimiter` - whether the decoded frame should strip out the delimiter or not
    `delimiter` - the delimiter

### DelimiterBasedFrameDecoder

    public DelimiterBasedFrameDecoder(int maxFrameLength,
                                      ChannelBuffer... delimiters)

  Creates a new instance.

  Parameters:
    `maxFrameLength` - the maximum length of the decoded frame. A `TooLongFrameException` is thrown if the length of the frame exceeds this value.
    `delimiters` - the delimiters

### DelimiterBasedFrameDecoder

    public DelimiterBasedFrameDecoder(int maxFrameLength,
                                      boolean stripDelimiter,
                                      ChannelBuffer... delimiters)

  Creates a new instance.

  Parameters:
    `maxFrameLength` - the maximum length of the decoded frame. A `TooLongFrameException` is thrown if the length of the frame exceeds this value.
    `stripDelimiter` - whether the decoded frame should strip out the delimiter or not
    `delimiters` - the delimiters

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`

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