Class DelimiterBasedFrameDecoder
- java.lang.Object
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- org.jboss.netty.channel.SimpleChannelUpstreamHandler
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- org.jboss.netty.handler.codec.frame.FrameDecoder
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- org.jboss.netty.handler.codec.frame.DelimiterBasedFrameDecoder
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- All Implemented Interfaces:
ChannelHandler
,ChannelUpstreamHandler
,LifeCycleAwareChannelHandler
public class DelimiterBasedFrameDecoder extends FrameDecoder
A decoder that splits the receivedChannelBuffer
s by one or more delimiters. It is particularly useful for decoding the frames which ends with a delimiter such asNUL
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 | +--------------+
aDelimiterBasedFrameDecoder
(
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 | +----------+
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Nested Class Summary
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Nested classes/interfaces inherited from interface org.jboss.netty.channel.ChannelHandler
ChannelHandler.Sharable
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Field Summary
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Fields inherited from class org.jboss.netty.handler.codec.frame.FrameDecoder
cumulation, DEFAULT_MAX_COMPOSITEBUFFER_COMPONENTS
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Constructor Summary
Constructors Constructor Description DelimiterBasedFrameDecoder(int maxFrameLength, boolean stripDelimiter, boolean failFast, ChannelBuffer delimiter)
Creates a new instance.DelimiterBasedFrameDecoder(int maxFrameLength, boolean stripDelimiter, boolean failFast, ChannelBuffer... delimiters)
Creates a new instance.DelimiterBasedFrameDecoder(int maxFrameLength, boolean stripDelimiter, ChannelBuffer delimiter)
Creates a new instance.DelimiterBasedFrameDecoder(int maxFrameLength, boolean stripDelimiter, ChannelBuffer... delimiters)
Creates a new instance.DelimiterBasedFrameDecoder(int maxFrameLength, ChannelBuffer delimiter)
Creates a new instance.DelimiterBasedFrameDecoder(int maxFrameLength, ChannelBuffer... delimiters)
Creates a new instance.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description 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
actualReadableBytes, afterAdd, afterRemove, appendToCumulation, beforeAdd, beforeRemove, channelClosed, channelDisconnected, cleanup, decodeLast, exceptionCaught, extractFrame, getMaxCumulationBufferCapacity, getMaxCumulationBufferComponents, internalBuffer, isUnfold, messageReceived, newCumulationBuffer, replace, setMaxCumulationBufferCapacity, setMaxCumulationBufferComponents, setUnfold, unfoldAndFireMessageReceived, updateCumulation
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Methods inherited from class org.jboss.netty.channel.SimpleChannelUpstreamHandler
channelBound, channelConnected, channelInterestChanged, channelOpen, channelUnbound, childChannelClosed, childChannelOpen, handleUpstream, writeComplete
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Constructor Detail
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DelimiterBasedFrameDecoder
public DelimiterBasedFrameDecoder(int maxFrameLength, ChannelBuffer delimiter)
Creates a new instance.- Parameters:
maxFrameLength
- the maximum length of the decoded frame. ATooLongFrameException
is thrown if the length of the frame exceeds this value.delimiter
- the delimiter
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DelimiterBasedFrameDecoder
public DelimiterBasedFrameDecoder(int maxFrameLength, boolean stripDelimiter, ChannelBuffer delimiter)
Creates a new instance.- Parameters:
maxFrameLength
- the maximum length of the decoded frame. ATooLongFrameException
is thrown if the length of the frame exceeds this value.stripDelimiter
- whether the decoded frame should strip out the delimiter or notdelimiter
- the delimiter
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DelimiterBasedFrameDecoder
public DelimiterBasedFrameDecoder(int maxFrameLength, boolean stripDelimiter, boolean failFast, ChannelBuffer delimiter)
Creates a new instance.- Parameters:
maxFrameLength
- the maximum length of the decoded frame. ATooLongFrameException
is thrown if the length of the frame exceeds this value.stripDelimiter
- whether the decoded frame should strip out the delimiter or notfailFast
- If true, aTooLongFrameException
is thrown as soon as the decoder notices the length of the frame will exceed maxFrameLength regardless of whether the entire frame has been read. If false, aTooLongFrameException
is thrown after the entire frame that exceeds maxFrameLength has been read.delimiter
- the delimiter
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DelimiterBasedFrameDecoder
public DelimiterBasedFrameDecoder(int maxFrameLength, ChannelBuffer... delimiters)
Creates a new instance.- Parameters:
maxFrameLength
- the maximum length of the decoded frame. ATooLongFrameException
is thrown if the length of the frame exceeds this value.delimiters
- the delimiters
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DelimiterBasedFrameDecoder
public DelimiterBasedFrameDecoder(int maxFrameLength, boolean stripDelimiter, ChannelBuffer... delimiters)
Creates a new instance.- Parameters:
maxFrameLength
- the maximum length of the decoded frame. ATooLongFrameException
is thrown if the length of the frame exceeds this value.stripDelimiter
- whether the decoded frame should strip out the delimiter or notdelimiters
- the delimiters
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DelimiterBasedFrameDecoder
public DelimiterBasedFrameDecoder(int maxFrameLength, boolean stripDelimiter, boolean failFast, ChannelBuffer... delimiters)
Creates a new instance.- Parameters:
maxFrameLength
- the maximum length of the decoded frame. ATooLongFrameException
is thrown if the length of the frame exceeds this value.stripDelimiter
- whether the decoded frame should strip out the delimiter or notfailFast
- If true, aTooLongFrameException
is thrown as soon as the decoder notices the length of the frame will exceed maxFrameLength regardless of whether the entire frame has been read. If false, aTooLongFrameException
is thrown after the entire frame that exceeds maxFrameLength has been read.delimiters
- the delimiters
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Method Detail
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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. If an sub-class wants to extract a frame out of the buffer it should use theFrameDecoder.extractFrame(ChannelBuffer, int, int)
method, to make optimizations easier later.- Specified by:
decode
in classFrameDecoder
- Parameters:
ctx
- the context of this handlerchannel
- the current channelbuffer
- 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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