Package io.netty.handler.codec
Class DelimiterBasedFrameDecoder
- java.lang.Object
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- io.netty.channel.ChannelHandlerAdapter
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- io.netty.channel.ChannelInboundHandlerAdapter
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- io.netty.handler.codec.ByteToMessageDecoder
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- io.netty.handler.codec.DelimiterBasedFrameDecoder
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- All Implemented Interfaces:
ChannelHandler
,ChannelInboundHandler
public class DelimiterBasedFrameDecoder extends ByteToMessageDecoder
A decoder that splits the receivedByteBuf
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 class io.netty.handler.codec.ByteToMessageDecoder
ByteToMessageDecoder.Cumulator
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Nested classes/interfaces inherited from interface io.netty.channel.ChannelHandler
ChannelHandler.Sharable
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Field Summary
Fields Modifier and Type Field Description private ByteBuf[]
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 io.netty.handler.codec.ByteToMessageDecoder
COMPOSITE_CUMULATOR, cumulation, MERGE_CUMULATOR
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Constructor Summary
Constructors Constructor Description DelimiterBasedFrameDecoder(int maxFrameLength, boolean stripDelimiter, boolean failFast, ByteBuf delimiter)
Creates a new instance.DelimiterBasedFrameDecoder(int maxFrameLength, boolean stripDelimiter, boolean failFast, ByteBuf... delimiters)
Creates a new instance.DelimiterBasedFrameDecoder(int maxFrameLength, boolean stripDelimiter, ByteBuf delimiter)
Creates a new instance.DelimiterBasedFrameDecoder(int maxFrameLength, boolean stripDelimiter, ByteBuf... delimiters)
Creates a new instance.DelimiterBasedFrameDecoder(int maxFrameLength, ByteBuf delimiter)
Creates a new instance.DelimiterBasedFrameDecoder(int maxFrameLength, ByteBuf... 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, ByteBuf buffer)
Create a frame out of theByteBuf
and return it.protected void
decode(ChannelHandlerContext ctx, ByteBuf in, java.util.List<java.lang.Object> out)
Decode the from oneByteBuf
to an other.private void
fail(long frameLength)
private static int
indexOf(ByteBuf haystack, ByteBuf needle)
Returns the number of bytes between the readerIndex of the haystack and the first needle found in the haystack.private static boolean
isLineBased(ByteBuf[] 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(ByteBuf delimiter)
private static void
validateMaxFrameLength(int maxFrameLength)
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Methods inherited from class io.netty.handler.codec.ByteToMessageDecoder
actualReadableBytes, callDecode, channelInactive, channelInputClosed, channelRead, channelReadComplete, decodeLast, decodeRemovalReentryProtection, discardSomeReadBytes, expandCumulation, fireChannelRead, fireChannelRead, handlerRemoved, handlerRemoved0, internalBuffer, isSingleDecode, setCumulator, setDiscardAfterReads, setSingleDecode, userEventTriggered
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Methods inherited from class io.netty.channel.ChannelInboundHandlerAdapter
channelActive, channelRegistered, channelUnregistered, channelWritabilityChanged, exceptionCaught
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Methods inherited from class io.netty.channel.ChannelHandlerAdapter
ensureNotSharable, handlerAdded, isSharable
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Methods inherited from interface io.netty.channel.ChannelHandler
handlerAdded
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Field Detail
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delimiters
private final ByteBuf[] 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, ByteBuf 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, ByteBuf 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, ByteBuf 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, ByteBuf... 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, ByteBuf... 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, ByteBuf... 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(ByteBuf[] 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 final void decode(ChannelHandlerContext ctx, ByteBuf in, java.util.List<java.lang.Object> out) throws java.lang.Exception
Description copied from class:ByteToMessageDecoder
Decode the from oneByteBuf
to an other. This method will be called till either the inputByteBuf
has nothing to read when return from this method or till nothing was read from the inputByteBuf
.- Specified by:
decode
in classByteToMessageDecoder
- Parameters:
ctx
- theChannelHandlerContext
which thisByteToMessageDecoder
belongs toin
- theByteBuf
from which to read dataout
- theList
to which decoded messages should be added- Throws:
java.lang.Exception
- is thrown if an error occurs
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decode
protected java.lang.Object decode(ChannelHandlerContext ctx, ByteBuf buffer) throws java.lang.Exception
Create a frame out of theByteBuf
and return it.- Parameters:
ctx
- theChannelHandlerContext
which thisByteToMessageDecoder
belongs tobuffer
- theByteBuf
from which to read data- Returns:
- frame the
ByteBuf
which represent the frame ornull
if no frame could be created. - Throws:
java.lang.Exception
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fail
private void fail(long frameLength)
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indexOf
private static int indexOf(ByteBuf haystack, ByteBuf 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(ByteBuf delimiter)
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validateMaxFrameLength
private static void validateMaxFrameLength(int maxFrameLength)
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