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
Fields Modifier and Type Field Description private ChannelBuffer[]
delimiters
private boolean
discardingTooLongFrame
private boolean
failFast
private LineBasedFrameDecoder
lineBasedDecoder
Set only when decoding with "\n" and "\r\n" as the delimiter.private int
maxFrameLength
private boolean
stripDelimiter
private int
tooLongFrameLength
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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 Static Methods Instance Methods Concrete Methods Modifier and Type Method Description protected java.lang.Object
decode(ChannelHandlerContext ctx, Channel channel, ChannelBuffer buffer)
Decodes the received packets so far into a frame.private void
fail(ChannelHandlerContext ctx, long frameLength)
private static int
indexOf(ChannelBuffer haystack, ChannelBuffer needle)
Returns the number of bytes between the readerIndex of the haystack and the first needle found in the haystack.private static boolean
isLineBased(ChannelBuffer[] delimiters)
Returns true if the delimiters are "\n" and "\r\n".private boolean
isSubclass()
Returntrue
if the current instance is a subclass of DelimiterBasedFrameDecoderprivate static void
validateDelimiter(ChannelBuffer delimiter)
private static void
validateMaxFrameLength(int maxFrameLength)
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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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Field Detail
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delimiters
private final ChannelBuffer[] delimiters
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maxFrameLength
private final int maxFrameLength
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stripDelimiter
private final boolean stripDelimiter
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failFast
private final boolean failFast
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discardingTooLongFrame
private boolean discardingTooLongFrame
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tooLongFrameLength
private int tooLongFrameLength
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lineBasedDecoder
private final LineBasedFrameDecoder lineBasedDecoder
Set only when decoding with "\n" and "\r\n" as the delimiter.
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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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isLineBased
private static boolean isLineBased(ChannelBuffer[] delimiters)
Returns true if the delimiters are "\n" and "\r\n".
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isSubclass
private boolean isSubclass()
Returntrue
if the current instance is a subclass of DelimiterBasedFrameDecoder
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decode
protected java.lang.Object decode(ChannelHandlerContext ctx, Channel channel, ChannelBuffer buffer) throws java.lang.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:
java.lang.Exception
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fail
private void fail(ChannelHandlerContext ctx, long frameLength)
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indexOf
private static int indexOf(ChannelBuffer haystack, ChannelBuffer needle)
Returns the number of bytes between the readerIndex of the haystack and the first needle found in the haystack. -1 is returned if no needle is found in the haystack.
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validateDelimiter
private static void validateDelimiter(ChannelBuffer delimiter)
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validateMaxFrameLength
private static void validateMaxFrameLength(int maxFrameLength)
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